Issue #83, 13 May 2021 Science Illustrated (Australian)

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The Dark Side of PLUTO Hidden oceans & methane cliffs on a dwarf planet 1ST HUMAN IN SPACE

CLIMATE RINGS & BUSHFIRE MANAGEMENT The super-powers of the Australian Synchrotron

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Contents PUBLISHED 13 MAY 2021

ISSUE 83 # AUSTRALIAN SCIENCE ILLUSTRATED

30 ENGINEERING WONDERS

CO STO VER RY

828 metres of steel and glass rise above the former fishing village of Dubai. But the world’s highest building, Burj Khalifa, could never have been built were it not for four brilliant engineers and one disastrous fire.

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THE DARK SIDE OF PLUTO

PAIN – AND WHY WE NEED IT

Astronomers have never thought much of dark, frozen Pluto – until images from the New Horizons probe revealed organic matter and a possible underground ocean.

Without pain, our ancestors wouldn’t have known when to rest an injury. Our genes reveal the history of human pain – and some of us may have inherited Neanderthal sensitivity.

46 DRONE SHIP With no human pilot and no human crew, this AI-captained vessel is planning to voyage across the Atlantic,collecting important scientific information as it goes.

REGULARS AND OTHER FEATURES 6 MEGAPIXELS Fixing an antenna in outer space, and burrowing deep within a Swiss glacier.

10 SCIENCE UPDATE New discoveries and updates from the ever-fascinating world of science.

18 ASK US

50 PARASITE RESCUE

Our experts answer your questions about the world and its ways.

72 SCIENTIFIC ARCHIVES Yuri Gagarin was a hero, but his flight’s brush with disaster was kept quiet.

Now that scientists have identified all visible matter, the race is on to explain the invisible 95% of the universe – dark matter, and dark energy.

80 NAKED APE AUSTRALIAN SYNCHROTRON The resolving power of synchrotron light is contributing to research by young scientists into the history of Southern Hemisphere climate and millennia-old Indigenous bushfire management.

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Parasites tend to invoke disgust, but they are crucial to food chains and some even to human health. Scientists are realising we need to protect them as much as larger creatures.

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EDITORIAL Editor: Jez Ford [email protected]

A sense of fair play seems to be genetic, and we share it with close relatives.

82 TEST YOURSELF! Mind bombs of assorted flavours to test your talents and bend your brain.

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Under license from Bonnier International Magazines. © 2021 Bonnier Corporation and nextmedia Pty Ltd. All Rights Reserved. Reproduction in whole or part without written permission is prohibited. Science Illustrated is a trademark of Bonnier Corporation and is used under limited license. The Australian edition contains material originally published in the Danish edition reprinted with permission of Bonnier Corporation. Articles express the opinions of the authors and are not necessarily those of the Publisher, Editor or nextmedia Pty Ltd. ISSN 1836-5175. Privacy Notice We value the integrity of your personal information. If you provide personal information through your participation in any competitions, surveys or offers featured in this issue of Science Illustrated, this will be used to provide the products or services that you have requested and to improve the content of our magazines. Your details may be provided to third parties who assist us in this purpose. In the event of organisations providing prizes or offers to our readers, we may pass your details on to them. From time to time, we may use the information you provide us to inform you of other products, services and events our company has to offer. We may also give your information to other organisations which may use it to inform you about their products, services and events, unless you tell us not to do so. You are welcome to access the information that we hold about you by getting in touch with our privacy officer, who can be contacted at nextmedia, Locked Bag 5555, St Leonards, NSW 1590 www.scienceillustrated.com.au THE SCIENCE ILLUSTRATED CREDO We share with our readers a fascination with science, technology, nature, culture and archaeology, and believe that through education about our past, present and future, we can make the world a better place.

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MEGAPIXEL

S PA C E WA L K

Reception staff: antenna installed at 400km altitude Astronaut Mike Hopkins needed to take a space walk with a colleague to install the International Space Station’s new antenna. Named ColKa, it is the size of a refrigerator, so the space station’s robotic arm carries it to the required location on the exterior of the Columbus lab module. Then NASA’s mission control in Houston guides the astronauts through the installation – from bolting it in place to connecting the wires. The antenna is providing the space station with its first direct high-speed link to Europe via satellites. Photo // NASA

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MEGAPIXEL

GLACIER EXPEDITION

Tunnel vision: geologists venture into frozen cave The chasm drops vertically into the glacier’s interior, the shaft produced by meltwater flowing down from the surface of a Swiss glacier. By day, water roars through the space within the ice, but at night it freezes, allowing geologists to study the glacier’s formation. The meltwater functions as a lubricant that influences the ice’s motion across the ground below. Many glaciers are retreating due to climate change, and studies of their interiors provide important information about deglaciation. Photo // Robbie Shone

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SCIENCE ILLUSTRATED

S C I E N C E U P D AT E THE LATEST FINDINGS AND DISCOVERIES

Exoplanet improves the chance of an unknown Solar System planet The orbit of an exoplanet 336 light years away from Earth may support the theory that our own Solar System is hiding a yet-undiscovered planet. For decades, astronomers have been searching for an unknown planet in our Solar System: Planet 9. According to the theory, it is located 13-26 times further away from the Sun than the outermost known planet, Neptune. Planet 9 has never been observed, but the orbits of six small worlds on the outskirts of the Solar System indicate that they are influenced by the gravity of an unknown object which is about 10 times heavier than Earth. The weak point of the theory so far is that astronomers consider it unlikely that such a big planet could end up in a stable orbit so far away from the Sun. But now observations of an exoplanet 336 light years away from us show that this is possible. The exoplanet HD 106906 b is orbiting a binary star which is only 15 million years old. Scientists from the US University of California have observed the planet since 2004, and they have ASTRONOMY

concluded that its orbit is elongated and stable, and that it is located at an average distance from the binary star of 25 times the distance between Neptune and the Sun – a position closely corresponding to the predicted one for Planet 9 in our Solar System. HD 106906 b is 11 times larger than Jupiter. Such big planets cannot form so far away from their stars, and scientists have hence devised a scenario that explains how the exoplanet ended up in its present orbit. The binary star’s gravity could have flung it outwards in a spiral motion, while subsequently a passing third star fixed it in a stable orbit. According to the scientists, a similar scenario could have led to the predicted path of Planet 9 in the young Solar System shortly after the formation of the planets.

Newborn planet was flung far The HD 106906 b exoplanet probably formed close to its binary star and was subsequently flung into a much more distant orbit. The same could have happened to an unknown planet in our Solar System. Star

Planet Spiral orbit

Stable orbit

KEN IKEDA MADSEN

Binary star

Unstable orbit Dust disc

The newborn planet migrates towards its binary star

Stars’ gravity flings the planet outwards

The exoplanet HD 106906 b is born in a disc of dust and gas close to a binary star. Friction in the disc makes the planet gradually lose speed, travelling closer to the binary star (green arrow).

The two innermost stars of the binary system rotate around each other, causing a very powerful gravitational pull in their vicinity. When the planet comes close, the forces fling it outwards in a spiral motion (red).

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SCIENCE ILLUSTRATED

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An alien star provides the planet with a stable orbit The spiral motion takes the planet ever

3 further away, but before it leaves the

solar system, it is influenced by a passing star (yellow arrow). The star’s gravity sends the planet into a stable elongated orbit (blue).

Editor: Jens E. Matthiesen

SHUNDONG BI/INDIANA UNIVERSITY OF PENNSYLVANIA & ZHAO CHUANG

The exoplanet HD 106906 b is about 11 times heavier than Jupiter, and takes 15,000 years to complete one orbit around its binary star.

Bones from adult dinosaur

Egg

The bones of a 70-million-year-old oviraptor was located atop 24 eggs with developed embryos. Scientists conclude that the dinosaur must have died as it was hatching the eggs.

Dinosaurs sat and hatched their eggs A unique fossil has finally convinced scientists that at least one group of dinosaurs did not just lay eggs and leave them, but hatched them like birds. Scientists may have answered one of the most debated questions concerning dinosaurs. It has never been clear whether dinosaurs took care of their eggs once they had been laid, or if they just left them. Now it has been definitively proven that at least some species hatched their eggs in a similar manner to modern birds. The evidence comes from a Chinese fossil of a dinosaur which died while lying on 24 eggs which are so well-preserved that they still include the bones of developed embryos. The scientists conclude that the dinosaur could not have died as it was laying the eggs, but must have died as it was hatching them. The scientists behind the discovery are from the US Indiana University of Pennsylvania and the Chinese Academy of Sciences. The fossil, discovered in the PALAEONTOLOGY

Six small worlds reveal Planet 9 The theory of unknown Planet 9 on the outskirts of our Solar System is based on observations of the orbits of six small worlds in the Kuiper Belt. Their orbits can only be explained if they are influenced by the gravity of a big object with a remote and highly elongated orbit around the Sun. Orbits of 6 worlds in the Kuiper Belt Neptune’s orbit Planet 9’s orbit

If Planet 9 exists, it can probably be described as follows:

Test yourself

Chinese province of Jiangxi, is about 70 million years old, and the 2-metrelong dinosaur belongs to the group of oviraptors which walked on two legs. ‘Oviraptor’ means egg thief, because when the first oviraptor was found near eggs, scientists thought that it was stealing them. Later, scientists were unsure if oviraptors hatched their eggs or just guarded them, as do crocodiles. In order to prove their theory about the hatching, the scientists analysed the oxygen content of the embryos’ bones. Oxygen comes in several variants, also known as isotopes, and the relationship between them could reveal the temperature at which the bones formed. The result shows that the embryos developed at a temperature of 36-38°C. In comparison, modern birds have body temperatures of 38-42°C.

Answers to p82. No peeking!

Type: Gas planet.

1: Ignite both ends of one rope (A) and one end of the other rope (B) all at the same time. When the flames of rope A meet, one hour has passed. One hour remains of rope B, so now ignite the other end of rope B. When those flames meet, time is up.

6: C. See page 32. 8: C. See page 70.

4: Move one match from the right number to the left and insert a + sign so it reads: 3: 12: The number in each middle square is the sum of the individual numbers in the left and right squares. 4+4+2+6=16, 5+5+3+1=14, 1+8+1+2=12

Orbit: 10,000-20,000 years.

M. KORNMESSER/HUBBLE/ESA

Distance to the Sun: Earth × 400-800.

5: C. See page 16. 7: A. See page 58.

Mass: Earth × 10 or Neptune × 0.6.

2: 47km: Tommy walks 14km at a speed of 7km/h, so the walk takes two hours. In the first hour, Emerson walks 7km. In the second hour, Emerson runs constantly at a speed of 40km/h, so covers 40km. The total is 47km.

Diameter: Earth × 2-4.

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S C I E N C E U P DAT E

TEAM COSTAR

Intelligent robotic dog to explore Mars’ underground A four-legged robot is learning how it might survey caves under the surface of Mars. The wheeled rovers that have so far roamed Mars have been limited by terrain. Four-legged robots could explore locations on Mars that are impossible for rovers to approach. So in cooperation with the Caltech research institute, NASA has developed a robotic dog, a new version of the four-legged Spot robot developed by Boston Dynamics. Named Au-Spot, its role will be to climb rocky slopes and explore caves and lava tunnels under the surface. The aim is both to search for life on the Red Planet and to find suitable potential locations for a permanent AEROSPACE

Mars base. The robot navigates by means of cameras, but also has LIDAR that uses laser to scan the surroundings. It is equipped with artificial intelligence, so that it learns how best to pass through impassable terrain from its own experience. The robot is training on obstacle courses developed by scientists, and also in more natural environments including abandoned mines and lava tunnels in northern California. Au-Spot is more robust than the Mars rovers and can right if it falls over. It is also much faster. Its top speed is 5km/h, more than 30 times faster than the Curiosity rover that travels at a cautious maximum speed of 0.14km/h.

The Au-Spot robotic dog is training its hole-mapping skills in California. On Mars, the aim will be to find the perfect cave for a permanent base.

18 OCTOBER 2020

Scientists monitoring the ozone layer became concerned late in 2020 when the hole above Antarctica didn’t shrink as normal. In December 2020, meteorologists monitoring the ozone layer became increasingly concerned as a large ozone hole above Antarctica apparently took hold. The hole covered 20+ million square kilometres, a similar size to one that originated in 2018, but it seemed to behave differently. Ozone holes above Antarctica typically emerge in August and September, peak in October, and then start to close again. But in December 2020, the hole was holding its size, still much bigger than any previous holes. Scientists from the European CAMS institute and elsewhere monitor the ozone layer closely, for good reason. Ozone protects against the Sun’s UV radiation, which is harmful to animals and humans. But ozone, located at an altitude of 30-50km, is quite vulnerable. At temperatures below -80°C it is easily broken METEOROLOGY

31 DECEMBER 2020

The ozone hole (blue) was bigger than Antarctica in October 2020, and it remained so until mid-December, when it finally disappeared.

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Size of ozone hole (millions of square km)

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2018 2019 2020

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1/7

1/8

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1/11

1/12

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The ozone hole normally grows in August and shrinks in November, but varies in size from year to year. In 2020 it was large, and late in closing.

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SCIENCE ILLUSTRATED

down by other molecules, and particularly by artificial chlorinecontaining substances. The temperature of the ozone layer above Antarctica is controlled by wind systems, of which the southern polar jet stream is the most important. This rotates Earth in a wave motion, but in some years the fluctuations of the waves are very slight, and the air above Antarctica becomes locked below -80°C for a long period of time. And that’s what happened in 2020. Not until the second half of December did the weather systems unlock, temperatures above Antarctica rose, and the breakdown of the ozone layer subsided. By New Year, the ozone hole had disappeared completely. Although relieved, scientists emphasise that 2020 should remind us to continue reducing emissions of substances that break down the ozone layer.

GSFC/NASA & KEN IKEDA MADSEN

Unusual behaviour of the ozone hole above the South Pole

SHUTTERSTOCK & DAYO O. ADEWOLE ET AL. /BIORXIV

Projections (axons)

Light-sensitive cells

Scientists have designed living electrodes made from light-sensitive nerve cells. When inserted into the brain, they can activate specific areas by means of LED light.

Living nerve cells talk to the brain In the future, electrodes that stimulate the brain with small electric shocks could be replaced by living nerve cells that react to light. Experiments with rats are revealing the possibilities. For the first time, scientists have made electrodes from living nerve cells and implanted them into rat brains. The method represents an entirely new method for stimulating and exploring different areas of the brain. Electrodes in the brain are used for several purposes. Electrical impulses can reduce symptoms in Parkinson’s patients and epileptics, and scientists can use the electrodes to map out different brain functions. The problem with traditional metal electrodes is that they can often be rejected by patients’ immune systems, or MEDICINE

the impulses strike too broadly, affecting cells that are not part of the treatment. The new electrodes can achieve more accurate stimulation. Scientists from the University of Pennsylvania in the US created genetically-manipulated nerve cells that react to light, culturing 10,000 cells at a time at the ends of 0.3mm-wide pipes made of biodegradable gel. The cells projected their axons through the pipes, and when these reached the other end the cells were ready for implantation. The scientists then inserted the pipes into the cerebral cortex of rats and made the

Living electrodes activate the brain

axons form links to the brain cells. When the scientists subsequently illuminated the nerve cells, they activated the brain cells located at the opposite end of the pipes. By varying the length of the pipes, scientists can choose the area deep inside the cerebral cortex they would like to stimulate. The new method could lead to improved communication between brains and computers, as signals can also flow in the other direction, from brain cells to manipulated nerve cells. This could assist patients with paralysis to control computers, artificial limbs and other devices.

GROWING ELECTRODES Scientists create the electrodes from nerve cells 1 that have been genetically manipulated to react to light. The cells are placed at the end of a pipe with a gel in which the cells’ projections – axons – grow.

Scientists can now culture lightsensitive nerve cells and use them to stimulate specific brain regions. Brain cells

KEN IKEDA MADSEN

Light-sensitive nerve cell

Pipe with growth media

Axon Chip with LED

CELLS ARE LINKED The pipe is inserted into the cerebral 2 cortex, and the axons form links to the closest brain cells, those that are located at the opposite end of the pipe.

LIGHT ACTIVATES THE CELLS Scientists can then activate the 3 cells deep inside the cerebral cortex by illuminating the electrode cells using tiny LED lamps on a microchip.

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ASK US SCIENTISTS ANSWER QUESTIONS FROM OUR READERS

How wide is the universe? “I have read that the universe is 13.8 billion years old, but that in size it is much wider than 13.8 billion light years. Is this true – and if so, how can it have got so large when nothing is able to travel faster than the speed of light?” Astronomers’ best theory concerning the width of the universe gives a figure of 93 billion light years. The margin of uncertainty is about 10%, so the safe answer is 84 to 102 billion light years. Yet the universe is 13.8 billion years old, and the speed of light is indeed the absolute speed limit. The explanation is that the universe is constantly expanding. Imagine a galaxy cluster 87 million light years from Earth. Its light begins its journey towards Earth. But the universe is expanding, so the distance that the light must travel is getting longer as it travels, and the light must travel further than just the original 87 million light years. When the light reaches us, the distance between the galaxy cluster and Earth is 173 million light years. So how far did the light travel? Between 87 and 173 million light years. This confusing result has led some scientists to COSMOLOGY

According to astronomers, the entire visible universe is 93 billion light years wide.

suggest that light years should not be used for interstellar distances, and that red shift is a more useful number to use. The same line of thinking is true for the rest of the universe and the light emitted by the first galaxies. The expansion of the universe and the extra distance added en route depends on the distribution of matter and energy. If the universe included only energy in the shape of radiation, light that reached Earth today after 13.8 million years would have been emitted by objects now 27.6 million light years away. If the universe included only matter, the figure would be 41.4 billion light years away. Radiation, matter and dark energy all contribute to the total – currently calculated at 46.5 billion light years from Earth to the the remotest visible objects at the end of the visible universe. So the total width is twice this: 93 billion light years.

Editor: Esben Schouboe

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INSIDE THE BODY

Red light indicates universe width The universe’s width was measured by means of red shift that is due to the universe’s expansion.

The visible universe Galaxy

Light

LIGHT IS EMITTED Light is emitted from a galaxy 1 on the outskirts of the visible universe. The universe is expanding, so the distance that the light needs to travel constantly increases.

SHUTTERSTOCK

Tetanus is caused by a bacterium that enters the body via deep wounds such as those caused by nails.

What is tetanus? Both children and adults are vaccinated against tetanus, which can fracture bones and even prove lethal. But what causes tetanus?

Wavelength

PABLO CARLOS BUDASSI/SHUTTERSTOCK

SHIFT INDICATES WIDTH The longer the wavelength, 3 and the redder the light we observe, the longer the distance covered. So the universe’s width can be calculated based on red shift.

Tetanus is due to infection by a bacterium known as Clostridium tetani. The medical condition has been named tetanus. Clostridium tetani emits a toxin known as tetanospasmin. The toxin disturbs the central nervous system that sends impulses to the muscles, causing cramps. The cramps can be so severe that bones are fractured and breathing stops. Clostridium tetani is particularly common in animal dung, soil, and dirt. The bacterium is up to 2.5 micrometres long and is anaerobic (it lives without oxygen), so infections often take place via deep wounds that offer an oxygenfree environment. Tetanus can not be passed by person-to-person infection. Because of extensive vaccination programmes initiated from the 1940s onwards, tetanus is rare In the developed world. In the developing world the disease still affects hundreds of thousands of people annually, causing deaths in the tens of thousands, and particularly prevalent among infants. INFECTION

LIGHT TURNS RED As the galaxy is moving away 2 from us, the light is stretched on its way towards Earth. When the wavelength of light is extended, the colour becomes more reddish: the red shift.

Tetanus is prevented by vaccination, and in adults it needs to be renewed with a booster dose every 10 years to ensure efficacy. Infants and children must be vaccinated more often, typically three times during their first year of life and subsequently at the age of five. Once contracted, tetanus is combated with antibiotics and normally requires intensive-care hospitalisation. TOXIN AFFECTS NERVOUS SYSTEM WHERE: The tetanospasmin toxin affects the central nervous system in the brain and spinal cord. WHAT: The toxin attacks nerve cells, forcing them into exaggerated activity, causing cramps. HOW: Tetanus is prevented by vaccination. Adults should renew their vaccine every 10 years. scienceillustrated.com.au

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SHUTTERSTOCK

Ions Sodium ion channel

Burnt-out ion channel

SHUTTERSTOCK

USTRATED

SHUTTERSTOCK

If I fire a bazooka, would I fly backwards from the recoil force? On TV you see that even a handgun produces a powerful recoil force. A bazooka launches rockets, so how does the person holding it avoid being blasted backwards? Most ordinary firearms and cannons are essential a closed pipe that uses a small explosion to launch bullets from the front. When the bullet is forced out of a closed pipe, Newton’s third law means that the entire pipe is forced backwards with similar force – the recoil. A bazooka, however, has an open pipe. When a rocket is launched by a bazooka, warm gases are forced out of the rocket’s rear end at high speed. The gases exiting the open rear end provide a balancing force to the forward explosion, so that the firing

A bazooka is known as a ‘recoil-less’ weapon, because the shooter is not pushed backwards as in the case of a gun with a closed pipe.

UNISA

PHYSICS

hardly pushes the pipe backwards at all, as it happens with ordinary firearms. Only the friction between the rocket and the pipe, or between the gases and the pipe, can push the bazooka slightly. Typically the shooter can remain standing or sitting without being overly influenced by the recoil when he fires a missile. A bazooka is often called a ’recoil-less’ weapon for this reason. However, the shooter of a bazooka must not only aim the weapon but check carefully behind. Bazookas need a considerable safety distance at the back, because the gases accelerating from the rear could strike a person – or bounce back on the shooter from a wall. Old bazooka models delivered a flame from their rear ends which sometimes injured those nearby.

Could we use solar power to purify drinking water? Efforts to desalinate or purify water by solar power have proven too inefficient to be practical – until now. There has been significant recent research into the possibility of desalination using photo-thermal evaporators powered only by sunlight. The problem has been achieving an efficiency high enough to make such devices practical. Scientists at the University of South Australia (UniSA) think they have a solution. As in other attempts, they used photothermal materials (PTMs) with excellent solar light absorption, floated on a water surface. Heat from the PTMs is concentrated at the surface causing evaporation and the generation of steam, which is free of salt or other pollutants and can then be harvested as drinking water. One issue is that the water temperature at the point of evaporation increases, then WAT E R

The experimental desalination device used for outdoor sea-water evaporation testing (left) and an envisaged ocean-borne version.

USING THE SUN TO CREATE DRINKING WATER Raising efficiency: The UniSA team improved efficiency of their solar steam generation to a practical level by optimising the energy flows during solar steam generation.

Remote locations: A viable water purifier could provide clean water where existing methods are too expensive, such as in disadvantaged or vulnerable communities and remote locations.

losing energy to both the environment and the water bulk below via radiation and convection respectively. The UniSA team focused on ways to reduce conductive heat loss by adding a cold evaporation surface between the surface being heated and and the bulk of the water. They found that the conductive heat loss could be fully absorbed by the cold evaporation surface and used for cold evaporation before it reached the water bulk. Further, once the area of the cold surface was increased beyond a critical value, energy could be extracted from the bulk water to enhance the overall solar evaporation. The scientists estimate that in this way a 1m2 surface area of salt water or contaminated water could provide enough clean water for a family of four.

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SHUTTERSTOCK

Can you distinguish a dingo from a wild dog by the colour of its coat? Is the colour of a wild dog a reliable indication of how much of their DNA comes from dingoes and how much from feral dogs? Colour is no indication of the breeding of a wild dog or dingo, according to a recent study involving UNSW Sydney. “Dingoes are much more variable than we think,” says Dr Kylie Cairns, conservation biologist from UNSW Sydney and co-author of the study. “We actually found pure dingoes that had brindle, black and tan, patchy or sable coat colour.” It is often believed that dingoes are typically ginger in colour, while unusual coat colours such as brindle (black and brown stripes) or sable (ginger with a black stripe along the spine) are evidence of contemporary domestic dog hybridisation. Such coat variations are even used to justify their culling where wild dogs are a problem. But the study, published in the Journal of Zoology, found that while 53% of dingoes did have a ginger coat colour, 9% were sable, 11% black and tan, 14% brindle, 5% black, 1% white and 6% patchy (white with spots of ginger or black). Other studies are delivering even more remarkable findings. A study published in the CSIRO’s Australian Mammalogy has collated results from more than 5000 DNA samples of wild canines across the country, the largest and most comprehensive such data set to date. Its results revealed that 99% of wild canines tested were pure dingo or dingo-dominant hybrids (a hybrid canine with more than 50% dingo genes). Of the remaining 1%, half were dog-dominant hybrids and the other half feral dogs. ZOOLOGY

ISTOCK

Dingoes are not always ginger-coated like this one pictured on Fraser Island. Pure dingoes can come in a wide variety of colours.

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“There is an urgent need to stop using the term ‘wild dog’ and go back to calling them dingoes,” says Brad Nesbitt at the University of New England, a co-author on the UNSW study. “Only then can we have open public discussion.” “We don’t have a feral dog problem in Australia,” emphasises Dr Cairns. “They just aren’t established in the wild. A dog might go bush, but it isn’t contributing significantly to the dingo population.” Not only can labelling dingoes as wild dogs legitimise eradication programmes, other studies are revealing that dingo impacts can be positive as well as negative. Another UNSW study has examined the environmental impacts of removing dingoes from the landscape using fences. Satellite imagery spanning 32 years was combined with field research either side of fencing in the Strzelecki Desert at the junction between South Australia, New South Wales, and Queensland. Dingoes can attack livestock, usually sheep. But researchers found that without the dingoes, vegetation had poorer longterm growth. Removing an apex predator can trigger a process called trophic cascade. “When dingoes are removed, kangaroo numbers increase, which can lead to overgrazing. This has follow-on effects to the entire ecosystem,” says Professor Mike Letnic. As well as reducing available grazing, lower vegetation can affect smaller animals, like the endangered Plains Wanderer bird.

Hand sanitiser does not ruin disposable gloves, but their tendency to fold make them difficult to clean.

Is hand sanitiser only for skin? Can I use hand sanitiser if I wear disposable gloves, or will I ruin them? Hand sanitiser is primarily meant for skin, but it can also be used for disposable gloves. The most ordinary disposable gloves are made of latex or nitrile, these two materials being a natural and an artificial rubber blend. Neither is harmed by ordinary hand sanitiser to the extent that the gloves could be penetrated by a virus or bacteria, according to a Korean survey headed by physician Jiyoung Chang in 2017. All tested gloves in the study were intact after having been disinfected by ordinary hand sanitiser 30 times. But the same research project indicates that after about 10 rounds of sanitiser, the gloves become increasingly difficult to cleanse thoroughly. Disposable gloves can also be more difficult to disinfect thoroughly than bare hands because they are rarely a perfect fit. If folds appear, they require extra care. The active ingredient of hand sanitiser is often ethanol, a non-toxic type of alcohol. Isopropyl alcohol is also used to disinfect surfaces. Isopropyl alcohol is more harmful than ethanol if the liquid is absorbed by accident, but it will not ruin disposable gloves which are recommended for contact with isopropyl alcohol. HYGIENE

SPECIAL EFFECTS · Poisoning The toxin thallium can cause hair loss, nerve damage, and fatal heart failure.

Thallium breaks down body cells The toxin thallium affects nerves and organs in the body, slowly killing the victim. Thallium

THALLIUM IS ABSORBED INTO THE BODY Thallium is a water-soluble metal 1 and can hence easily be absorbed into the body – not only through food, but also if it ends up on the skin, or if thallium vapours are breathed in.

Can thallium kill? In the Bond film Spectre, the bad guy Mr. White is poisoned with thallium, which makes him so sick that he ends up killing himself. Is the substance really that harmful? that the victim suffers pain, cramps, numbness, psychosis and memory loss. Victims have spoken of a sensation of walking on hot coals. Two to three weeks later the hair falls out, and one week after that the heart may fail. A lethal dose of thallium is about 1gram. Thallium’s slow effect makes it relatively easy for a killer to camouflage their actions, so the substance has been used as a subtle murder weapon. In 1960, a person connected with the French intelligence service murdered FélixRoland Moumié, a well-known anticolonialist from the newly independent former French colony of Cameroon. An antidote against thallium can be given in the form of the ferrous pigment Prussian blue. Substantial daily doses of this can absorb thallium and effectively rinse it out of the body.

Cell

CELLS ARE FOOLED Thallium spreads in the body in the 2 shape of ions with sizes that are very much like the mineral potassium. The cells absorb the thallium ions, believing it is useful potassium.

Cell with thallium

THALLIUM DESTROYS CELLS Thallium destroys vital processes in 3 the cells, so that nerves, muscles, hair roots and organs begin to be broken down, typically over a few weeks. The heart can eventually fail, causing death.

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SCANPIX, CHOIJ OG CLAUS LUNAU

Thallium is a metallic grey and soft element. It is absorbed through the skin, breathed via the air, or eaten with food. If it is not discovered in time, so that an antidote can be taken to eliminate its effect, the toxin is fatal. Thallium ’sneaks’ into the body because its make-up is similar to that of potassium, and the cells of the body cannot always differentiate between the two. They absorb the toxin in the belief that it is the useful mineral potassium, which is good for blood pressure and fluid balance. Once inside the cells, thallium interferes with proteins, important biochemical reactions and more. The first symptoms are relatively mild, showing after two days as nausea and diarrhoea. After a few days, however, thallium begins to harm the nervous system, so POISON

Thallium

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ASK US

How do rocks move on their own? Rocks can rise from the ground in fields, and in various places around the world there are examples of rocks as heavy as 200kg apparently moving independently, even leaving tracks behind them. How can such heavy objects move unaided? Rocks do not move unaided, of course, but are shifted by forces that have required investigation to identify. The founding father of evolutionary theory, Charles Darwin, studied fieldstones in the 1870s. He concluded that when major rocks appear in fields, it is because of farmers, though not because they carry them there. Darwin proved that rocks normally move downwards because of the activity of worms and other digging creatures in the soil below. But when ploughing loosens the soil, subsequently rain causes the soil around a rock to collapse, carrying them higher through the soil layers. However, farmers are not responsible for sailing stones. These exist in several places, but the most famously in the 9km2 seasonally-dry lake of Racetrack Playa in California, USA, where PHYSICS

rocks leave tracks on the dry lake bed when they move. The rocks typically weigh around 3kg, but some are over 200kg. Scientists have tried to solve the mystery of sailing stones since the mid20th century, and they long suspected that wind must play a decisive role. In 2013, three American scientists finally solved the mystery by means of video recordings, weather observations, and sophisticated GPS equipment drilled into the stones. They found that when special conditions exist – perhaps only once a decade – the wind moves the stones aided by huge but shortlived sheets of ice. The movement will only happen on a sunny windy day following a cold night when, for a few days or weeks, the lake becomes covered in 5-10cm of meltwater from heavy snowfall in the mountains surrounding Racetrack Playa.

The sailing stones plough tracks on the bed of the seasonally dry lake of Racetrack Playa. The tracks become visible when the lake dries out.

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Editor: Esben Schouboe

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INSIDE THE BODY · What causes hiccups?

Water, frost, sunlight, and wind move sailing stones Normally the wind isn’t powerful enough to push the large rocks on the bed of Racetrack Playa, a seasonally dry US lake. But temporary ice sheets allow movement across the lake bed. LUNGS

DIAPHRAGM

SHUTTERSTOCK

COLD WEATHER FILLS LAKE Racetrack Playa is dry for most 1 of the year, but occasional rain or meltwater during winter can cover the lake bed in 5-10cm of water.

Diaphragm moves in involuntary rhythm Hiccups are an involuntary rhythmic contraction of the diaphragm and the vocal chord. We get hiccups after eating too fast, drinking something cold, absorbing alcohol, or laughing. Persistent hiccups can be a sign of infection or even nerve damage.

Ice layer

WATER BECOMES ICE SHEETS Heat radiation from the lake on 2 a clear winter night cools the water so much that a thin cover of ice develops on the surface of the lake.

WHERE: Hiccups interrupt breathing, as the epiglottis closes the windpipe. WHAT: A study from 2013 found no medical cure for hiccups. HOW: One piece of good advice to stop hiccups is to drink water as you lean forward.

Where does the water go at low tide? Tides are a wave which flows around the world in 24 hours and 50 minutes. When the water ‘disappears’ at low tide in one place, the water level rises in another place. Tides are caused by the mass attraction of the Moon and the centrifugal force from the rotation of the Earth and the Moon. The Sun also makes a minor contribution. Earth has one tidal wave facing the Moon and another that faces away. In open sea, the waves are about 50cm high, but when the tide is trapped in a dead end such as an inlet, the difference between high and low tides can be more than 10 metres. The record is held by the Bay of Fundy in Canada, with a tide of up to 16.3 metres. ASTRONOMY

SHUTTERSTOCK

SHUTTERSTOCK & LOTTE FREDSLUND

WIND PUSHES ROCKS The next day the sunlight melts 3 the ice, breaking it down into ice sheets. The wind pushes the sheets around, in turn making the rocks “sail”.

At low tide, the fishing boats rest on the dry floor of the Bay of Fundy in Canada. scienceillustrated.com.au

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TORN FA R S ID E I N D I C AT

N ES OCEA

HE ICE UNDER T ORGANIC M AT T E R

COULD

DIN THE BUIL E D U L C IN BLOCKS

OF LIFE

STRIKE A COMET ER G E C R AT U H E H T FORMED ITIA NIK PLAN T U P S F O

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By Rolf Haugaard Nielsen

KILOMET

RE-

SPIKES HIGH ICE E ARE MAD AN OF METH

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An interplanetary probe’s images have turned our impressions of this frozen dwarf planet upside down:

NEW VIEWS OF PLUTO Dark, frozen solid, lifeless – astronomers have never thought much of Pluto. But pictures from the New Horizons probe have shown us otherwise. Deposits of organic matter and cracks in the ice indicate a possible ocean under the crust. Perhaps life is thriving on the freezing outskirts of our Solar System. TENIMAGES

New pictures of Pluto’s far side allow us to see the entire dwarf planet, which seems much more lively than previously believed.

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LOTTE FREDSLUND & SWRI/JHUAPL /NASA

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Collision formed Pluto and its moons More than four billion years ago, two ice worlds collided to form Pluto and its large moon of Charon. The cloud of rock, ice and gas turned into four small moons, while the heat from the collision melted Pluto’s ice sheet and formed a huge ocean.

Hydra Ice world

Collision

Charon

Nix

Charon Styx Pluto

Comets were the building blocks of Pluto and Charon

The small moons formed after the collision

Two ice worlds collided and formed Pluto and its large moon of Charon as we know them today. Those two worlds probably formed through collisions between more than a billion comets. Pluto’s atmosphere and the Sputnik Planitia plain are full of nitrogen, a key ingredient of comets.

The collision between the ice worlds emitted a cloud of rock, ice and gas that also formed Pluto’s four smaller moons: Styx, Nix, Kerberos and Hydra. Kerberos is surprisingly dark and could be the remains of the original ice world that collided with Pluto.

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he excitement was palpable. It was nine in the morning on 14 July 2015, and the leader of the New Horizons mission, Alan Stern, was waiting in the control room of the Johns Hopkins University in Maryland, USA, together with 2000 invited guests. After nine years of space travel, the New Horizons probe was about to make a precision manouevre and fly closely by Pluto, five billion kilometres from Earth. And given the probe’s then speed of 52,000km/h, any collision with even a grain of space dust could spoil two decades of work in a moment. Suddenly, the first signals from the satellite arrived. A few seconds later, giant computers began decoding the signals. One by one, the controllers behind their screens reported that all seven scientific instruments had worked perfectly. Everyone started cheering. But nobody expected the wealth of information that New Horizons would eventually manage to collect and transmit from its 24 hour fly-by. Though gathered in one Earth |

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day, the 50 gigabits of data arrived only slowly to the control centre, at a mere kilobit per second, due to the distance and the probe’s limited energy supply. The full download took 16 months to arrive.

The far side of Pluto

24 hours was the duration of New Horizons’ fly-by of Pluto at a distance of 12,500km. NASA

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Kerberos

Even the very first close-ups, showing Pluto’s illuminated side facing the approaching New Horizons probe, revolutionised scientists’ knowledge of the remote dwarf planet. The high-resolution image was able to resolve detail down to 75 metres. Before the probe’s visit, astronomers knew only that Pluto had a partly red surface, and ice sheets at the poles. The new images revealed mountain ranges, ice volcanoes, and the huge comet crater of Sputnik Planitia with glaciers of nitrogen ice. Scientists have now finally processed the images of Pluto’s far side, which were taken from a greater distance in the days prior to the fly-by. Their resolution is lower, but the images still show details down to two kilometres, which is 250 times more detailed

PLUTO

The comet crater of Sputnik Planitia

All of Pluto’s surface was covered by an ocean The collision heated Pluto to such an extent that the ice melted and covered the dwarf planet in a deep ocean. When the ocean surface froze, cracks opened in the crust (arrows) as the ice expanded. The vast dark crater, Sputnik Planitia, formed in a subsequent comet strike.

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than previous photos from the Hubble space telescope. For the first time ever, we can see all of Pluto, and it turns our expectations of Pluto on their head. The dwarf planet is not the dead lump of ice that astronomers used to think, but rather a geologically active world. And under the thick crust of ice, there is an interior ocean that might harbour life.

Smaller than the Moon While most planets in our Solar System were identified in antiquity, nobody knew about Pluto until around 1900, when American astronomer Percival Lowell concluded that an unknown remote planet must be disturbing the orbits of Uranus and Neptune. Three decades later, in 1930, a young astronomer Clyde Tombaugh noticed a small dot that moved closer to the constellation of Gemini over a few days. He had discovered Lowell’s predicted planet, which was named Pluto, after the Roman god of the underworld. At first, astronomers believed that Pluto had a similar mass to that of Earth. But it

only became possible to calculate its true mass in 1978, when American astronomer James Christy discovered the big moon of Charon. Disappointingly, Pluto had only 0.2% of Earth’s mass. The exact diameter of 2376 kilometres was determined using New Horizon’s data. So Pluto is smaller than the Moon, officially downgraded from ‘planet’ to ‘dwarf planet’ in 2006, the same year that New Horizons was launched as the first reconnaissance of the now dwarf planet Pluto, then to venture deeper into the distant, mysterious Kuiper Belt – a relic of solar system formation.

Mountains of ice 6km high Given its distance and downgraded status, Pluto attracted little further attention until

New Horizons made its 2015 fly-by at a distance of 12,500km. Even then, scientists expected the first close-ups of Pluto to show a dead rock with intact impact craters from the young Solar System. Instead the images have revealed a world where geological activity changes the surface constantly, producing mountain ranges of ice rocks and razor-sharp kilometre-high spikes made of methane ice. The surface temperature on Pluto is -233°C, which changes geology as we understand it here on Earth. Water ice as hard as granite makes up the bedrock and forms mountains as high as Africa’s Mount Kilimanjaro. Elsewhere the surface is covered in softer ice made of nitrogen, which is dominant in the atmosphere. scienceillustrated.com.au

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Comet strike reveals an ocean under the surface Less than 10 million years ago, a comet collided with Pluto, forming a huge impact crater. New pictures from the New Horizons probe demonstrate a torn landscape on the far side of Pluto, revealing that the pressure waves passed through an ocean. New Horizons

Collision sent pressure waves through Pluto A comet of 400-metre diameter struck Pluto to form a 4km-deep impact crater, Sputnik Planitia. The crater covers an area of 797,000km2, and the bedrock is frozen water ice as hard as granite. The impact sent seismic waves through Pluto.

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200KM-THICK ICE CRUST

Seismic wave

150KM-DEEP OCEAN

Torn far side

Shock tore up Pluto’s far side The new images of Pluto’s far side show chaotic terrain diametrically opposite the crater. The surface seems to have been torn up by pressure waves from the impact, and that is only possible if the waves travelled through an ocean situated between the rocky core and the ice crust.

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SERPENTINITE CORE

Pressure waves allow us to peek under the ice Based on New Horizons’ observations, astronomers have calculated the composition of Pluto’s interior: a 200+km-thick ice crust over a 150km-deep ocean of liquid water that could include life. The core consists of silicates, primarily serpentinite.

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Organic matter makes water red The images of Pluto’s front side show clear evidence of reddish water that probably gushed from an ocean under the ice and subsequently froze into ice on the surface. The red colour indicates that the water included considerable quantities of organic matter. And we know from lab experiments that charged particles emitted from the Sun’s atmosphere – the solar wind – and cosmic radiation from the outside universe could have been enough to convert simple matter into complex organic molecules. Now astronomer Dale Cruikshank from NASA’s Ames Research Center in California has proved the existence of ammonia in the reddish ice, meaning that the genetic building blocks of RNA and DNA could have formed in the ocean’s red soup. This discovery does not necessarily mean that life originated in Pluto’s ancient ocean, emphasises Cruikshank. But if the

BILL INGALLS/NASA

Cheering in the control centre of Johns Hopkins University as New Horizons sent the first signals from Pluto in 2015. But only now have scientists processed all the pictures, and analysis may reveal still more insights. miracle did happen, then microorganisms could have taken hold and survived. The theory is supported by the fact that a red belt of organic matter has also been found on the dwarf planet’s far side. The belt spans the equator, which receives the most sunlight, and where higher temperatures are experienced than on the rest of Pluto.

NASA

Pluto has canyons deeper than the Grand Canyon, mountains higher than Everest, and ice volcanoes that may have erupted and emitted liquid water during the most recent millions of years. The New Horizons images also included clear evidence of two powerful collisions that created and shaped the dwarf planet. The first of these happened more than four billion years ago, when Pluto and its big moon of Charon formed in a collision between two ice worlds. According to existing theories, the dwarf planet was initially covered in ice, but heat from radioactive decay in its rocky core melted the ice from within, forming an interior ocean under the ice cover. If that was what happened, the ice cover on the surface would contract, causing wrinkles, like on the skin of an old apple. Over time the heat from the core would ease with ever reducing radioactive decay. The ice crust would once again become thicker, and in its expansion would produce large cracks. So scientists expected that Pluto’s surface would be covered in old wrinkles and more recent cracks. But New Horizons’ cameras spotted only cracks, so a new theory has emerged. When the initial versions of Pluto and Charon collided, so much heat was emitted that the dwarf planet became covered by a deep ocean. The surface then quickly froze into ice, which expanded and cracked. The theory is supported especially by a huge crack running all the way from pole to pole on both sides of Pluto. The crack is so ancient that it now seems clear that Pluto was formed with a liquid ocean that almost immediately began to freeze. If correct, then the ancient ocean may have included life.

ALAN STERN, HEAD OF THE NEW HORIZONS MISSION

“Three conditions must be met for life to originate. We have now ticked off the first two for Pluto.”

”Three conditions must be met for life to originate: liquid water, organic matter, and an energy source. We have now ticked off the first two for Pluto,” notes Alan Stern, head of the New Horizons mission. The initial collision between proto-Pluto and Charon pumped in thermal energy, but that was more than four billion years ago. If life originated in that ancient ocean, it’s not clear whether ongoing heat from radioactive decay in Pluto’s rocky core would generate sufficient energy to maintain it. The chances of finding living micro-organisms are likely higher in the interior oceans of Jupiter’s moon Europa or Saturn’s Enceladus, where tidal powers from the huge gas planets are constantly pumping energy into the moons.

A punch in the heart changed Pluto The other major collision that shaped Pluto occurred less than 10 million years ago, when a 400km-wide comet collided with the dwarf planet at a speed over 7000km/h. The impact caused the crater of Sputnik Planitia, which is 4km deep and covers an area comparable to all of New South Wales. The crater forms part of the vast heart-shaped ice plain north of the equator, as revealed in New Horizons’ first images. The new photos of the far side of Pluto show a chaotic landscape torn by seismic waves from the comet strike. Similar phenomena are known from Mars and from Europa, and especially from Mercury, where similarly chaotic terrain exists on the far side of the huge Caloris Basin impact crater. According to researchers, this damage on Pluto’s far side would be possible only if there is a deep ocean of liquid water under the ice crust. Seismic waves have different properties depending on the material through which they propagate. Pressure waves move more slowly through water than through a rocky core, but their destructive force is larger if they are able to travel at a constant speed across the whole world. Simulations carried out by astronomer Adene Denton from Purdue University in the US indicate that Pluto’s core consists primarily of the rock serpentinite, through which seismic waves travel more slowly than through other types of rock. The combination of this special rock and water in Pluto’s interior would allow the pressure waves to send enough energy through the dwarf planet to rip up the surface on the far side. Based on New Horizon’s measurements of the dwarf planet’s diameter and mass, scientists have simulated Pluto’s interior scienceillustrated.com.au

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structure and calculated its mass. The rocky core makes up 70% of the mass, while the rest largely consists of water. The core is surrounded by a 150km-deep ocean, which is covered by a crust of bedrock water ice more than another 200km thick. After the comet strike, the impact crater filled with soft, heavy nitrogen ice from the atmosphere, and from glaciers that flow into the hole from the surrounding mountain ranges. This heavy ice lump would have changed Pluto’s mass distribution. It is thought that the weight from the nitrogen ice in the crater gradually made the dwarf planet tilt, so the tidal axis, where Pluto and its big moon of Charon are pulling most strongly at each other, now passes through the heavy ice in the Sputnik Planitia crater.

Enigmatic ice spikes New Horizons’ photos have revolutionised our knowledge of Pluto, but they have also raised new questions. When the first images

of the dwarf planet were analysed, scientists discovered ’reefs’ on the eastern part of the planet’s front, with sharply pointed spikes a kilometre high. From those early images the spikes were just an oddity on the edge of the map. But now the scientists can see Pluto’s far side, they realise that the huge spikes form a belt through the elevated areas of the equator all the way back round to the western part of the front of Pluto. This discovery has led to mission leader Alan Stern characterising the sharp spikes, which are three times taller than the Empire State Building, as Pluto’s biggest mystery. And if rovers or humans were ever to land on the remote dwarf planet, it would be a nightmare trying to cross such a landscape of huge pointed reef spikes. New Horizons’ data shows that the spikes consist of methane ice, which is also connected with Pluto’s atmosphere. While the lower part of the atmosphere consists primarily of the nitrogen which filled the deep impact crater of Sputnik Planitia with

nitrogen ice, there are major quantities of methane higher up, which probably contributed to the huge spikes in the highlands. But how they formed remains a mystery. Perhaps the spikes are the remains of a thick layer of methane ice that once covered the high plateaus but which has slowly been eroded by the sunlight. Or perhaps the methane was frozen out of the atmosphere in the same way that water vapour in the air can freeze to ice on Earth’s surface. Only one thing is for sure: the spikes took millions of years to form, and climate change might have played a role.

More Plutonic revelations to come In spite of the new revelations, the exploration of this remote dwarf planet has only just begun. Scientists will undoubtedly continue to make new discoveries based on the data that New Horizons has already sent back to Earth. And later this year, NASA’s new large James Webb space telescope will be launched, and will closely study Pluto. Although

Pluto is full of evidence of life In spite of Pluto’s location on the outskirts of the Solar System, the New Horizons images reveal a geologically vibrant world: an ice volcano that is evidence of recent geological activity, an extensive atmosphere, and organic matter that could be the building blocks of life.

SWRI/JHUAPL/NASA

SWRI/JHUAPL/NASA

Foggy atmosphere rises above Pluto Pluto’s atmosphere rises 200km above the surface, which is 10 times higher than expected before New Horizons’ images were received. The atmosphere consists primarily of nitrogen that produces several layers of fog, but no clouds have yet been discovered.

SWRI/JHUAPL/NASA

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Young ice volcano indicates heat in Pluto’s interior

Deposits could include the building blocks of life

The 3.5-metre-high ice volcano of Wright Mons is made of water that has melted its way to the surface. The volcano is no more than one billion years old, so that it is possible Pluto’s core is still emitting sufficient heat to provide energy to maintain life in the ocean.

A dark belt by the equator on the far side of Pluto includes organic matter probably ejected from a freezing ocean. The deposits include ammonia, which can be converted into the building blocks of DNA.

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the James Webb telescope will have a lower resolution than the close fly-by of New Horizons, it will allow direct comparisons with observations of other dwarf planets in the Kuiper Belt such as Ceres, Eris, Haumea and Makemake. And planet researchers would like to know still more. Some scientists are hoping for a NASA-supported satellite that could orbit Pluto and produce even higher-resolution images of the entire planet, in combination with more accurate measurements of the substances on the surface and in the atmosphere. And by making observations over several years, such a satellite would be able to identify changes, if any, in Pluto’s atmosphere and weather over time. If the satellite is approved and built, it would launched in the 2030s at the earliest. Subsequently, there would be a 15-year space mission to this surprisingly active dwarf planet on the freezing outskirts of the Solar System, where life might just exist – against all previous expectations.

The James Webb space telescope that is planned for launch in October this year. Among many tasks it will study Pluto over longer periods of time than ever before. The next step would be to launch a satellite into orbit around the dwarf planet. NASA

SWRI/JHUAPL/NASA

RAZOR-S

HARP

ES ICE SPIK IGH TOWER H LUTO P E V O B A

Kilometre-high ice spikes are made of methane Pluto’s far side reveals kilometre-high, razorsharp ice spikes by the equator. The spikes are made up of frozen methane. Sunlight may have melted these from a thick layer of methane, or they may have formed from frozen atmospheric methane.

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7 ENGINEERING WONDERS

B U R J K H A L I FA

NEW SERIES 7 ENGINEERING WONDERS Our modern world of skyscrapers, bridges, and powerful machines is built on the brilliant ideas of engineers, who often suffered tragedies of trial and error.

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SKYSCRAPER Burj Khalifa

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SPACE ROCKET Saturn V

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SUSPENSION BRIDGE Akashi

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POWERFUL ENGINE Wärtsilä RT-flex96C

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POWER STATION Three Gorges Dam

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TUNNEL Gotthart Base Tunnel

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HIGH-SPEED TRAIN Shanghai Maglev

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By Antje Gerd Poulsen

Burj Khalifa’s glass facade is covered in a layer of metal that reflects UV radiation, keeping the skyscraper cool. ALI HAIDER/EPA/RITZAU SCANPIX

Fire and steel allow buildings to grow sky-high 828 metres of steel and glass facade rise above the former fishing village of Dubai. But the world’s highest building, Burj Khalifa, would never have been built had it not been for four bright people – and one disastrous fire.

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erhaps the cow had pushed the lantern, or maybe it was one of the men playing cards. Nobody knows exactly what happened in 1871 to ignite an inferno of fire which developed in O’Leary’s barn and quickly spread between Chicago’s bone-dry wooden buildings. “Pieces of burning roof-plates, planks, roofing felt and other objects fell through the air like snow,” wrote one eyewitness. “The wind was blowing like a hurricane,

THANKS TO WILLIAM LEBARON JENNEY

howling like myriads of evil spirits,” wrote another, “drove the flames before it with a force and fierceness which could never be described or imagined.” Three hundred lives were lost; 18,000 houses collapsed. But new types of buildings rose from the ash – higher than ever before. Today’s soaring skyscrapers, including the current record-holding 828-metre-high Burj Khalifa in Dubai, are all rooted in 18th century Chicago – where they sprang from the unremitting efforts of four men.

Four engineers behind the skyscraper HENRY BESSEMER

E L I S H A G R AV E S O T I S

Jenney gave up load-bearing walls American constructional engineer William Le baron Jenney (1832-1907) thought of building around an interior, load-bearing metal skeleton. The construction replaced thicker heavier brick walls and allowed higher structures. CHICAGO HISTORY MUSEUM/GETTY IMAGES

FAZLUR RAHMAN KHAN

Bessemer made steel cheap Otis ensured lift safety No lifts, no skyscrapers. Thanks to a safety device invented by American mechanic Elisha Graves Otis (1811-1861), the lift became fit for carrying people, so buildings could have more floors. SPL/RITZAU SCANPIX

British engineer Henry Bessemer (1813-1898) developed a quick and cheap steelmaking method which boosted the steel industry, paving the way for ever higher skyscrapers. UNIVERSAL HISTORY ARCHIVES/GETTY IMAGES

Khan eased construction Constructional engineer Fazlur Rahman Khan (1929-1982) catapulted the development of skyscrapers when he invented an interior tube structure that saved building materials and made better use of the building’s space. FAZLURRKHAN.COM

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Inspired by a bird cage When the ‘Great Chicago Fire’ ended on 9 October 1871, Chicago’s city government approved an emergency law: new structures were to be made of fireproof materials such as brick, marble, and limestone. But these were expensive, so that only a few private individuals could afford to comply, and the empty lots in downtown Chicago were soon taken over by banks and big businesses. One of these was the New York Home Insurance Company, which aimed to build a new headquarters. The company challenged local architects to invent designs by which all floors of the building were showered in natural light. The challenge fit perfectly into the vision of William Le Baron Jenney, a 39-year-old architect who wanted to use some of the period’s newest technologies to erect a supporting metal skeleton, instead of having bricks carry the structure. According to popular tradition, Jenney was inspired when he noticed a bird cage in his home had not collapsed when his wife placed a heavy book on top of it. But whatever the inspiration, Jenney realised that a similar steel structure could be light and flexible but yet strong enough that he could construct up to 10 storeys in height. The building would be strong enough for large windows to be added on all sides, meeting the insurance company’s requirement of

B U R J K H A L I FA

natural light. Jenney won the tender, and the world’s first skyscraper, the Home Insurance Building, was completed in 1885. Builders in New York City quickly noted this sensationally high light-filled building. The number of citizens in New York had tripled between 184 and 1870, and one way of accommodating more people was to build higher buildings. By 1889, the New York City building authorities had approved Jenney’s metal frame, and shortly afterwards the 11-floor Tower Building was inaugurated. From there, the only way was up. The two cities began competing to have the highest buildings, so that by 1900, the first structures of 25-30 storeys had been completed.

Strong yet flexible steel Before industrialisation, steel-making was a tricky time-consuming and manual business. Hence the first rail tracks and bridges were all made of cast iron. However, the iron often included too much carbon, so that it cracked, potentially causing accidents. In order to gain more control over the quantity of carbon in iron, British engineer and inventor Henry Bessemer in 1855 tried to patent a new steel-making method. The Bessemer process took place in a huge furnace known as a converter, in which the pig iron was subjected to a powerful air current. Under the influence of intense heat,

the oxygen of the air reacted with the pig iron’s content of silicon, manganese, and carbon, while flames of carbon monoxide 5 to 10 metres high rose from the furnace’s top. Once the iron had been completely cleared of impurities, the right quantities of carbon were added afresh, depending on the required strength of the steel. When pig iron was mixed with just the right quantity of carbon, the result was an alloy that was unprecedentedly strong and flexible. With the Bessemer process, 15 tonnes of steel that would previously have taken two weeks to make could now be made in an hour, and rails, steel plates, beams and other building materials were being rolled out en masse. In 1860, global steel production had been 50,000 tonnes. In 1870 it had increased to 500,000 tonnes, and by 1899 it was up to 28 million tonnes. And cheaper stronger steel was the very basis of the ongoing successful rise of skyscrapers.

The stairs limitation In the mid-1850s, the number of flights of stairs people were prepared to climb had set a natural limit on how high buildings could rise, and structures were no higher than seven floors. So apart from steel, William Le Baron Jenney also took advantage of another new invention, a lift powered by compressed air, which he installed in the Home 800 700

History’s highest structures

600

The first high buildings were made of bricks, but then steel and concrete came along. Now engineers can build ever taller structures thanks to composites with special strength and durability.

500 400 300 200 100

G R E AT P Y R A M I D O F G I Z A

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COLOGNE CATHEDRAL

EIFFEL TOWER

CHRYSLER BUILDING

BURJ KHALIFA

ANTIQUITY: Pyramids were mountains

MIDDLE AGES: Churches rise high

1800s: The age of steel begins

1900s: The era of skyscrapers

NOW: Towards the magic kilometre

The Great Pyramid of Giza measured 147 metres high when it was completed, and for millennia was the world’s highest structure. With wide foundations and thick rock walls, the pyramids rose like mountains above the surroundings.

From the Middle Ages up until the 1800s, cathedrals were built ever higher. External pillars distributed the weight, allowing the Cologne Cathedral to be equipped with large windows and rise 157 metres above the ground.

With the iron and steel industries, engineers set new records. When the Eiffel Tower in Paris was completed in 1889, it was the first structure to reach 300 metres, ushering in a new era of ever higher stuctures.

Steel skeletons let high-rises grow taller. In 1930, the Chrysler Building in New York City of 319 metres took over the height record from the Eiffel Tower, and new records were set regularly. The 1900s became the century of skyscrapers.

Today, builders want “megahigh structures” of 600 metres and more. Pure steel structures are replaced by buildings made of composites such as carbon-fibre and fibre-glass, in which several types of materials merge.

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BREAKTHROUGH

3 inventions contributed to the first skyscraper In the 1800s, industrialisation boosted mass production of steel. As stairs were made redundant and a flexible steel skeleton was invented, the upwards path was cleared for new height records. CHICAGO HISTORY MUSEUM/GETTY IMAGES

Intense heat mass-produced steel Steel production gathered speed in 1855, when the converter was invented. Intense heat first removed impurities from the pig iron, and carbon was added to make steel. The most powerful types of steel include 0.99% carbon.

AKG/RITZAU SCANPIX

1

Steel skeleton distributed weight High structures were heavy, as they required large foundations and ever thicker walls. With a lighter interior skeleton, the load was distributed onto many beams and posts, so buildings could become 10+ floors high.

CHICAGO ARCHIVE

3

Lifts carried people up and down Lifts were lethal and considered safe only for carrying goods until a safety device was invented, by which a metal rod grabbed teeth on each side of the lift if the cable collapsed. It was then considered safe for people.

ARCHIVE PHOTOS/GETTY IMAGES

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7 ENGINEERING WONDERS

B U R J K H A L I FA

like the one used in medieval cathedrals, where exterior structures contribute to the support of interior vaults and windows.

SOM.COM

Heat and wind challenge height

Willis Tower, also known as Sears Tower, was inspired by bundled bamboo and made of nine posts that distribute the load between them. The building was the world’s highest for 25 years.

Insurance Building. While service lifts were already familiar, they were deemed too dangerous to carry passengers, lest the cable collapsed. That changed in 1853 when mechanic Elisha Graves Otis from Vermont invented an automatic emergency brake. Otis’ lift was mounted in a metal frame with interior teeth like those of a toothed wheel. On top of the elevator there was a metal rod, and if the cable collapsed this rod was triggered and stuck to the frame. He founded the Otis Elevator Company, which went on to supply lifts for the Eiffel Tower, the Empire State Building, and other great buildings around the world – indeed the Otis name is on the 57 lifts that travel silently up and down Burj Khalifa’s 19 lift wells at a speed of 36km/h.

Young man delivers interior space By the 1960s, skyscrapers based on William Le Baron Jenney’s interior metal skeleton were rising to touch skies around the world. But the steel skeletons, with their interior tubes and beams, took up a lot of internal space, and the higher they went the larger the skeletons, making each square metre of office or living space increasingly expensive, so that it was not considered worthwhile to build structures higher than 300 metres. A young man from Bangladesh changed that. When engineer Fazlur Rahman Khan arrived in Chicago aged 21 to study building construction, he had never seen a skyscraper 34

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before. But Khan completed his education in record time, and soon became famous for his creativity. Khan turned Jenney’s steel construction inside out and invented the tube construction method, by which the massive, interior steel skeleton was replaced by an external structure that supported the building, combined with transverse steel beams which distributed the weight. The John Hancock Center in Chicago was the first skyscraper built using the new method. When the structure was completed in 1969, it was 344 metres high, with 100 floors. Fazlur Rahman Khan continued developing several variants of his tube design. The most famous is the bundledtube construction method he used in the 447-metre-high Willis Tower of 1973, also known as the Sears Tower. Inspired by a bundle of bamboo canes, Khan merged several partial structures to distribute wind and weight loads across several constituent parts. Willis Tower consists of nine square posts of different lengths that share the different loads between them.

Dubai’s record holder The world’s highest building, Burj Khalifa, is based on Khan’s ideas, with several tubeshaped parts that are linked. But it also represents a new development. The engineers behind Burj Khalifa developed a hexagonal core structure supported by the building’s special Y shape. The principle is

Conditions in Dubai also presented a particular challenge during the construction of Burj Khalifa – particularly as it grew higher. It took 40 minutes and a pressure of 206 kg/cm2 to pump concrete to a height of 600 metres, and engineers had to mix the concrete with ice to prevent chemical reactions that would make it brittle in the desert heat of the United Arab Emirates. Apart from heat, the wind is a challenge for Burj Khalifa. The very first skyscrapers demonstrated how important it was to allow for wind when constructing high buildings. When wind encounters large and straight expanses of building, it speeds up, moving both upwards and downwards along the building. Around sharp corners, powerful whirls of wind can develop, like miniature tornadoes. This happens both at height and on the ground. In cities with high structures, narrow streets and a square town plan, wind tunnels can form with speeds that knock people over, as has happened in both London and New York. Higher up, wind can make a building sway, and although they can be designed to withstand this without any danger of collapse, people inside the structure can feel sick. So engineers try to limit such skyscraper motions through wind by breaking up the straight lines in building designs. Burj Khalifa has an asymmetrical shape, using rounded corners and different heights for different elements to break up the wind paths and slow them down. The design means that the building’s maximum sway is 1.5 metres at the tip of the spire; it feels slow and does not cause motion sickness.

Next to take the record? Burj Khalifa has held the height record since 2010, but Saudi Arabia is already building the next record holder, the Kingdom Tower, that is to rise close to the landmark level of 1000 metres, a full kilometre high. But then Dubai plans to construct an even higher skyscraper than that, with the 1400-metrehigh Dubai Creek Tower. So the 1800s’ race between Chicago and New York City has now moved to the Arabian Peninsula. According to some scientists, it is in principle possible to build as high as Mount Everest, if the foundations are strong enough. So what began by rising from the smouldering ruins of Chicago might one day end up rising 9km into the air.

WONDER Ornate design confuses the wind

The world’s highest structure is partly inspired by historical construction methods, and partly based on new inventions and sophisticated wind design. SHUTTERSTOCK

DAVID HOBCOTE/SHUTTERSTOCK/RITZAU SCANPIX

Burj Khalifa is a mixture of old and new ideas

Dubai is often struck by sandstorms with wind gusts of up to 100km/h. So Burj Khalifa consists of 27 towers of different levels with rounded corners that interrupt the wind, preventing it from making the structure sway.

Tubes reinforce tower

SHUTTERSTOCK

In 1963, engineer Fazhur Rahman Khan designed a building structure inspired by bundled bamboo. The principle of constructing a building from different, tube-shaped segments improves the structure’s carrying capacity and wind resistance.

CLAUS LUNAU

Y shape supports the core Inspired by medieval cathedral pillars which kept vaults and windows in place, Burj Khalifa’s ground plan is shaped like a Y. The lower levels support the hexagonal core, stabilising the entire structure.

Concrete pillars secure foundations The foundations are shaped like a huge concrete snowshoe on top of the sand, anchored by 192 concrete pillars. The friction between the 50-metre-long concrete pillars and the deep sand keeps the structure safely in place.

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(˿RUWOHVV/DZQ&DUH Packed with premium features, the award-winning battery-driven SILENO Robotic Lawnmower mows the lawn without human intervention, reliably, evenly and quietly. It knows where to mow and when to return to its charging station. Rain or shine. Simple or tricky. Steep or narrow. A GARDENA Robotic Lawnmower can handle complex lawns with ease.

Now with bluetooth® connectivity, you can set and adjust mowing programs directly from your smart phone or device. The future is here. Enjoy it!

By Ulla Edelbo Raaschou

NT SCIE

ISTS

YOUR D A E R CAN PA I N

FROM

GENE YOUR

S.

OUCH! WHY PAIN IS CRUCIAL

Your genes reveal the vital importance of pain – and that you might have inherited your pain thresholds from a Neanderthal. New knowledge about pain could help prevent excessive suffering. SHUTTERSTOCK

scienceillustrated.com.au CLAUS LUNAU & SHUTTERSTOCK

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T

he year is 35,000 BC. A young man – half Neanderthal, half Homo sapiens – stands behind a rock, silently poised. A few metres away is a mammoth, towering above him. On his leader’s signal, the young man raises his spear and runs towards the animal, which turns its huge body suddenly. The man leaps aside, but tumbles down a slope. And as he falls he hears an ominous crack from his left foot. Then he feels the pain – like thousands of small stabs perforating his foot. His face contorts in agony, and he sees flashes of light behind his closed eyelids. His body feels both warm and cold as he rolls around on the bumpy rock. He wants the sensation to stop. But it continues, mercilessly. Tens of thousands of years later – in 2014 – the remains of this hunter’s fractured foot is found in a cave in modern Israel. The severe injury may not have occurred exactly as we have guessed in our story, but the experience of pain is in no doubt. It is confirmed in the genes that scientists have extracted from ancient bone – and the same genes have also been found in highly pain-sensitive modern people. The ancient, fractured foot also hides another truth: the pain is for your own good.

Knife gives you three sensations You know it only too well. At some point pain affects all of us – except for a very few – and more than half of us have experienced it within the last three months. The familiar sensation seems to have a simple enough

phenomenon. Inflammation or tissue damage activates a nerve cell, which sends a message to the brain, which translates the signal into a sensation of discomfort. But this relatively simple series of events can result in many different types of pain. If you cut yourself with a knife, you will experience first an acute piercing pain, then prolonged burning pain, and finally diffuse throbbing pain. The different sensations are because your body has many types of nerve cells that send messages to the brain. Some react to pressure from the knife, some to substances from damaged cells, and others to inflammatory substances in the wound. Your brain’s handling of the signals also influences what you feel. One brain centre can intensify the pain, another can try to reduce it. The interaction between these brain centres depends on whether the injury is unexpected or not, and how much you fear the pain.

Mutations intensify the pain So a simple injury can cause different pain sensations in the same person. But the differences can be even more significant from person to person. That difference lies in our genes, and one gene in particular has proved to be very important. The gene is known as SCN9A, and it codes for an ion channel on the surface of nerve cells sending pain signals to the brain. Ion channels are proteins that allow electrically-charged ions to flow in or out of cells, and they play an important role in the formation of electrical signals in nerve

AF ARCHIVE/ALAMY/IMAGESELECT

Fossils reveal that our ancestors often fractured bones, most likely when they fought or hunted.

The first pain signals reach your brain around 0.1 second after the harm is done. SHUTTERSTOCK

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The brain converts electricity into pain A nail pushes through the sole of your shoe and into your foot. A few milliseconds later your brain is bombarded with electrical impulses – and you cry out in pain. SHUTTERSTOCK & MALENE VINTHER

Lactic acid

Sodium ions

Nail initiates a surge of ions You step on a nail, and receptors on the foot’s nerve cells are quickly activated – by the pressure from the nail, lactic acid from destroyed cells, or substances from the immune system. The receptors open up ion channels that allow positively-charged potassium ions to flow in – all along the long body of the nerve cell.

1

Receptor

Signal

Signal towards the brain

The signal is passed on in the spinal cord The flow of ions reaches the end of the nerve cell, located in the spinal cord. There the ions make the cell release neurotransmitters stored in small containers. The neurotransmitters activate receptors on another nerve cell, which then uses its own ion channels to pass on the signal.

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Neurochemicals

Motor cortex

The limbic system

Brain centres allow you to feel the pain The signal flows to the thalamus brain centre, which distributes it to several other brain centres. The insula contributes to creating the sensation of pain. The motor cortex makes sure that your body reacts quickly – such as by lifting the foot. And the limbic system decides whether to flee the situation or not.

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Insula

Thalamus

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HUMANS

PA I N

cells. Any mutation of the SCN9A gene can thereby alter the nature of your body’s pain signals. Whether this increases or decreases your sensitivity to pain, it can greatly affect your wellbeing throughout life. One American boy with an SCN9A mutation felt no pain at all. As a baby, he smiled even during his circumcision, as if he was being tickled. At the age of nine months, he chewed on his toe until the bone was visible. Other mutations of the gene result in sudden outbreaks of extreme burning pain, often caused by factors that are usually harmless – the heat from a pair of socks, or even a big yawn.

Neanderthals were sensitive These SCN9A mutations, and pain itself, have been parts of our lives for millions of years. Like modern people, our ancestors were frequently tormented by pain, and there is no shortage of bones discovered which reveal signs of bone fractures. The injuries are most frequent in men, and so

scientists think that they were often caused during activities that are believed to have been primarily carried out by males. such as hunting or violent confrontation. One of the ancient injuries is that bone fracture discovered in the Manot Cave in Israel in 2014. It is from a young individual of the Early Upper Paleolithic period which began about 40,000 years ago, and CT scans show that the fracture was so severe that the bone was pushed away from its normal position and detached. The accident was undoubtedly very painful. New research demonstrates that the pain was probably even worse than most modern people would experience after a similar accident. The Israeli bone belonged to a person who was at least part Neander-

thal – and according to a study from 2020, the Neanderthals had SCN9A gene mutations that made their pain nerves more sensitive. Only a few individuals among modern Homo sapiens share this gene mutation, and they suffer around 7% higher risk of being tormented by pain than the average person. They probably inherited this problem directly from Neanderthals. The bone from Israel includes direct evidence of how it happened. It has both Neanderthal characteristics and features that are normally observed only in Homo sapiens. Hence the bone’s owner was very probably a hybrid from interbreeding: other similar finds and DNA analyses confirm that our species must have exchanged genes with the Neanderthals. The fact that the Neanderthal pain threshold survived in some modern humans may partly explain why some people have a lower pain threshold than others. But the Israeli bone also helps scientists understand why a high sensitivity to pain can be a major advantage.

?

Pain can also arrive out of the blue

?

?

NOCIPLASTIC PAIN?

SHUTTERSTOCK & MALENE VINTHER & CLAUS LUNAU

There are three basic categories of pain that doctors use to keep track of the countless different pain disorders from which their patients suffer. The three types differ from each other in one fundamental way: the origin of the pain. One type begins with tissue damage, one is incited by an irritated nerve, and the third originates out of the blue, inside your head.

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NOCICEPTIVE PAIN?

NEUROPATHIC PAIN?

Suffering saves lives

ROYAL BELGIAN INSTITUTE OF NATURE SCIENCE & EYE OF SCIENCE/SCIENCE PHOTO LIBRARY

The young Neanderthal who fractured his foot thousands of years ago would have been in tremendous pain not only immediately after the accident, but for a long time after. Such a fracture typically takes about three months to heal, and the Neanderthal was probably in pain during the entire period. It would have made him unable to walk – and that was a good thing. If a bone fracture of this kind is not rested, the healing process will fail, causing long-term walking difficulties for which the body will try to compensate – with excessive straining and perhaps even stress fractures as a result. In an era when physical condition was vital for their survival, this type of defect could have been a death sentence. However, scientists can tell from the Israeli bone that the fracture did not kill the Neanderthal. The bone healed well, and he survived for several years after the injury. Had the young man not felt intense ongoing pain in his foot, nothing would have moti-

Scientists have found remains of pain-relieving and antibiotic herbal medicine in Neanderthal teeth.

Receptors

Lactic acid

Injury causes pain Direct tissue damage

When you fall over and hurt yourself, cut yourself on a knife, or have an infected wound, you feel nociceptive pain. It originates when pain-sensitive nerve cells are activated by lactic acid and other substances from damaged cells. This type of pain is often beneficial, because it persuades you to keep your body at rest following an injury. But it can also result in chronic pain in arthritic joints or in a strained back in which muscles and tendons are influenced by long-term infection.

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Nerve signal Nerve ending

Pain nerve is under pressure Nerve ending

Neuropathic pain, also known as nerve pain, originates when the pain-sensitive nerve cell is damaged or irritated. The cell starts to send signals even though the receptors on its nerve endings are not activated. This type of pain is observed in connection with slipped discs and carpal tunnel syndrome, where the nerve cells are pinched, or in connection with diabetes, where elevated blood sugar levels will poison nerve cells and causes neuritis.

2

Nerve damage

Neuron

Nerve signal

The brain hurts you

Brain

Many specialists used to think that pain which had no apparent specific physical cause could be considered purely imaginary. But now, they take a more multifaceted approach. The pain is referred to as nociplastic pain and may originate because the nervous system develops hypersensitivity to pain. The problem can be located in the brain centres that handle pain, such as the insula. The condition of fibromyalgia and some types of head and back ache belong to this type of pain.

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Insula

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EMNE

HVILKET

Women feel more pain than men

During childbirth, both contractions and the baby’s passage through the birth canal cause extreme pain. MORAG HASTINGS WWW.APPLEBLOSSOMFAMILIES.COM

Pain-killing sex hormones and poor memory can reduce men’s sensitivity to pain. And men can be thankful that a testicular blow is a fairly short pain event compared with childbirth.

EXPERIMENTS REVEAL GENDER DIFFERENCE A series of experiments show that women are more sensitive to pain than men, and have a lower pain threshold than men.

0.5 0.4 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5

Pain threshold compared with the average

Pain threshold for heat

Pain threshold for cold

Pain threshold for pressure onback muscle

Pain threshold for pressure on face muscle

TESTOSTERONE

Days with menstruation

OESTROGEN

Female rats' pain nerves are less sensitive.

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Experiments on animals indicate that the nerve endings of females are less sensitive to pain than males’. Yet females – including humans – feel more pain than males. So scientists believe that women’s brains intensify pain signals so that they end up having a greater intensity than for men.

SCIENCE ILLUSTRATED

Testosterone helps relieve pain

Better memory intensifies the pain

The brain’s pain centres include receptors to which sex hormones can bind. So the hormones can affect our sensation of pain. The female sex hormones oestrogen and progesterone can both relieve and intensify pain, whereas the male sex hormone of testosterone will almost always relieve pain.

According to scientists, the menstrual cycle makes women focus more on what is going on in their bodies – and so they become more aware of unpleasant influences. Women are also better at remembering previous painful experiences than men, and hence react more strongly to pain.

R A L U C I T S E T BLOW SHUTTERSTOCK

SHUTTERSTOCK

The brain intensifies weak signals

H T R BI

Childbirth or a testicular blow – which hurts more? Testicles are covered in many pain-sensitive nerve cells of a type otherwise only observed on internal organs. These nerve cells are very sensitive and are linked with the brain’s vomiting centre. A kick in the testicles can hence cause nausea, elevated blood pressure, higher pulse rate, and sweating. Similar pain-sensitive cells are numerous in a woman’s birth canal. During natural childbirth the canal is tremendously expanded, and the woman experiences

pain of the same type that men do when they are kicked in the testicles. But whereas a kick is brief, childbirth lasts an average of eight hours. Moreover, childbirth includes tension and stretching of muscles that cause other acute local pain. Childbirth does at least have the benefit of delivering new life, whereas a kick in the nuts might ruin the chances of the very same thing.

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vated him to remain at rest long enough for the bone to heal – and he might have lost his life as a result.

The disadvantage of pain Millions of years of evolution have provided us with this important ability to feel pain. But evolution has also given us another type of pain that just makes life harder for us. When our ancestors descended from trees and began to walk on two legs, our spines were forced to change. They developed a new shape – like an S when viewed from the side. This was better at supporting our new way of life, but it was far from an optimal solution. In the long term our backs have difficulty tolerating the pressure to which they are subjected, so approximately 20% of people aged between 20 and 60 years of age suffer chronic back pain. This back pain – and some other types of chronic pain – does not appear to benefit us in the same way as the pain of a fractured foot. Instead, it prevents us from carrying out daily routines. It keeps us away from social activities and often causes depression. So it seems to be a design flaw brought on by our change in lifestyle. Chronic pain leads to more years of lost capacity for work worldwide than any other condition, and it’s a huge challenge for modern medicine. In spite of tremendous improvements in our understanding of the human body and brain, chronic pain

The Neanderthals had three mutations of the SCN9A gene. These all seem to intensify the sensation of pain. ELISABETH DAYNES/SCIENCE PHOTO LIBRARY

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remains an almost unbeatable opponent, although in recent years scientists have made several ground-breaking discoveries. In 2019, Danish and Canadian scientists managed to uncover one of the basic mechanisms behind chronic pain. They identified a protein known as sortilin that intensifies pain signals following back injury. So by blocking sortilin with antibodies, the scientists were able to soothe pain, in mice at least. Now they hope that their method might help millions of people. Another new discovery could prove to be important in the struggle against unnecessary pain. English scientists have revealed that our lifestyle can deactivate the TRPA1 gene, which helps in keeping pain under control. This can contribute to chronic pain. But the effect is not necessarily permanent, and changes of lifestyle or new types of drugs might reactivate the gene, so that chronic pain could be relieved. It is clear that scientists must better understand the DNA of pain before they can get it properly under control – the DNA that we inherited from our die-hard but sensitive ancestors, and which governs the pain that both torments us and saves our lives.

How drugs relieve the pain Your cells make you suffer, but you can do something about it. Ordinary non-prescription painkilling drugs such as ibuprofen can enter deep into the cells and stop the painful activity. The drug functions like a plug which halts the flow of pain-causing substances and makes sensitive nerves relax.

Ibroprofen is absorbed from the intestines into the blood, which carries it to the source of the pain. SHUTTERSTOCK

Inflammation

Prostaglandin

Arachidonic acid SHUTTERSTOCK & MALENE VINTHER

COX

Prostaglandin

Nerve cell

Ibuprofen

COX

Cell nucleus

Pain nerve

Cell nucleus

Inflammation makes enzyme set to work

Pain substances make nerves sensitive

Ibuprofen blocks painful enzyme

Inflammation or tissue damage make the cell membranes of nearby cells release the unsaturated fatty acid arachidonic acid to cell interiors. The cyclooxygenase (COX) enzyme converts the fatty acid into prostaglandins, which the cell subsequently releases to its surroundings.

The prostaglandins reach the tissue’s pain-sensitive nerve cells and bind to receptors on their surfaces. The receptors subsequently make sure that the nerve cells become more sensitive to external influence. The sensitive cells start to send more signals, and you feel more pain.

The drug ibuprofen works at the site of the damage by entering into the cells and blocking the COX enzyme. The enzyme can no longer produce prostaglandins, which subsequently slowly disappear from the tissue. Without prostaglandins, the pain-sensitive nerve cells return to their normal activity, and the pain is relieved.

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TECHNOLOGY

DRONE SHIP

Sunlight and wind power the 15-metre-long trimaran that will take two weeks to cross the Atlantic. UNIVERSITY OF BIRMINGHAM’S HUMAN INTERFACE TECHNOLOGIES TEAM/IBM

FACTS LENGTH: 15 metres WEIGHT: 5 tonnes SPEED: Up to 10 knots (18.5km/h) POWERED BY: Wind and sunlight (diesel engine backup)

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By Ebbe Rasch

Autonomous drone ship to cross the Atlantic unmanned The Mayflower research ship is launched and preparing for an Atlantic crossing – captained only by AI. The voyage of the world’s most sophisticated drone ship may mark the beginning of an era of cheaper and safer shipping.

H

undreds of people will line the pier to wave bon voyage w hen the Mayflower Autonomous Ship (MAS) leaves on its maiden ocean voyage across the Atlantic. But nobody will wave back. No sailors will be on deck, nobody will take the helm. Not even a captain will be aboard to chart the course. The Mayflower is the world’s most sophisticated autonomous ship, and it is currently completing trials before travelling 5800km from England’s Plymouth across the challenging waters of the North Atlantic to Plymouth, Massachusetts in the US, on the way providing scientists with new knowledge about the ocean, and perhaps how shipping could become safer and cheaper.

Pilgrimage route The Mayflower name may seem an odd choice for one of the world’s most sophis-

ticated vessels, but the drone ship is named after the wooden Mayflower that carried 102 Christian separatists on exactly the same route in 1620. They landed 401 years ago to establish the first permanent English colony in North America – the very beginning of the modern USA. The route between the two Plymouths is not the easiest one for a drone ship on its maiden ocean voyage. The North Atlantic can be rough all year: meteorological buoys have recorded waves 30 metres high. The waters are busy with freighters travelling between Europe and North America, making navigation difficult. And an almost endless series of unpredictable problems could arise in the open sea, creating problems that even experienced sailors would find challenging. The RMS Titanic followed almost the same route in 1912, carrying well-trained sailors and 1317 passengers... and as we all know, that didn’t end well. The drone ship will

carry out its mission in the same dangerous waters, assisted only by sensors and computers aboard the vessel.

The captain’s name is AI Apart from their names and routes, the two Mayflower ships are very different. The ship from the 1600s was a carrack – a 30-metre-long merchant ship with three masts and a high cargo-carrying capacity. The drone ship, on the other hand, is a slim 15-metre-long trimaran with three parallel hulls made of aluminium and plastic. It has only one small mast, and a solid sail. The vessel is powered by the small sail and by electric motors which are powered from solar panels incorporated into the deck of the modern Mayflower. Only in emergencies will its diesel generator take over. In 1620, the captain was a middle-aged Brit by the name of Christopher Jones, who was highly experienced when it came to

Mayflower ‘drone’ ship will journey 5800km across the Atlantic without a crew

Cape Cod

The Titanic wrecked here Isles of Scilly

LOTTE FREDSLUND/ILLUSTRERET VIDENSKAB

The drone ship will pass through challenging waters in the North Atlantic. From Plymouth, UK, the Mayflower will sail south-west to the Isles of Scilly – the last landfall before the open sea. From there, the ship will pass across the Mid-Atlantic Ridge and past the place at which the Titanic struck an iceberg and sank in 1912. The last few thousand kilometres will be due west, until the ship arrives safely in Plymouth, Massachusetts, USA. En route, the Mayflower’s artificial intelligence will independently adjust course if the ship encounters obstacles such as other ships, wreckage, or bad weather.

Plymouth, UK

Mid-Atlantic Ridge Plymouth, USA

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TECHNOLOGY

The Mayflower was launched in Plymouth, UK, on 15 September 2020. The ship is preparing to cross the Atlantic as we go to press.

European waters. Today’s Mayflower has a captain called ‘AI’ – artificial intelligence. And from its first day on the job, this captain was already as experienced as was Jones. Technology company IBM is responsible for the ‘captain’, which includes the IBM Power System AC922, a powerful computer developed especially for artificial intelligence training – and the device has been receiving special sailing tuition over the past two years. The computer has been fed millions of at-sea situations that have been recorded during commercial vessel navigation – encounters with other ships, special weather conditions and so on. Based on the information and images, Captain AI has learned what real captains do when they encounter another ship, big waves, buoys and other situations in the open sea. After this theoretical training on dry land, technicians installed the semi-experienced AI technology onto the Plymouth Quest supply vessel, which functioned as a training ship. There the computer was asked

Ship powered by sun and wind The Mayflower research ship has three hulls to make it stable and reduce wind resistance. The trimaran concept provides it with a large surface covered in solar panels that generate energy for the vessel’s computers and motors.

UNIVERSITY OF BIRMINGHAM’S HUMAN INTERFACE TECHNOLOGIES TEAM/IBM

Outrigger hull

6.2 metres

Solar panels

Mast with sail

15 metres

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to take over the navigation of the vessel while a real captain was ready to intervene at any time, in a similar way to how self-driving cars are still in most places required to have the driver on alert for situations where the AI can’t cope. Every time the human captain intervened on the training ship, the IBM computer would analyse the situation, improving all the time when it came to making the right decisions – just as when a human learns new things from a more experienced tutor.

Explain your decision With the AI computer now moved to the Mayflower, test voyages are underway to ensure that the artificial captain is ready to take the ship safely across the Atlantic. Navigation will be undertaken according to three levels of data. The first data level is onboard from the beginning, with the computers having been fed all relevant nautical charts and data about weather, currents, and more. The next data level is collected

Solar panels power the ship The solar cells on the deck generate electricity that powers the ship’s computers and electric motor. Any surplus power from daylight is stored in batteries in the two outriggers. The diesel generator can be used in emergencies.

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2 years of one-to-one tuition have prepared the Mayflower’s AI computer.

en route while the Mayflower is on the open sea, with the ship downloading information about local shipping traffic and the meteorological conditions. If a storm is approaching, the Mayflower may correct its course in time to steer free of problems. Of course, all this can be done by most modern shipping, the point being that the Mayflower will not require any special treatment. The ship is to obey international

shipping rules like any other vessel – and must be able to prove that it has done so. In the same way that a human captain must give a statement and account for their actions if a ship is been involved in an incident at sea, the Mayflower must also be able to explain why the ship chose to alter its course at any critical moment. That means all important decisions must be traceable, and for this the programmers have borrowed software from the world of finance. When millions of shares are transferred in milliseconds via artificial intelligence, bank software must be able to explain subsequently those automated decisions – just like Captain AI.

The future is autonomous During test voyages off the coast of England, the IT systems aboard the Mayflower have worked perfectly. But the upcoming maiden voyage is not just to show off the new technology. The project has been developed in cooperation with the

ProMare marine research organisation, and the real purpose is a scientific one. En route the Mayflower is to collect water samples to track down microplastic, count animals in the ocean, and map out the ocean floor. And that is only the beginning. A fully autonomous ship is the perfect platform for maritime research. Without the need for crew, cabins, galley, bridge, supplies and fresh water aboard, designers have much freer rein over the shape of the ship and room for scientific equipment. And with self-powered technology on the ship, missions could last for months or years. With no wages bill for scientists and sailors, maritime research would be cheap once the drone ship has been paid for. Interest in a crew-less autonomous ship is also high in fields other than science. With 90% of all goods in the world carried by ship, and many sailors trapped aboard for months during the pandemic, commercial shipping is on the lookout for any solution that can make business more profitable.

Mast with light and sail

Antennas send data back

The small mast with a sail made of a composite material serves two purposes: a lantern at the top of the mast makes the Mayflower visible to conventional ships, and the sail contributes to making the vessel move forwards. The ship can travel at a top speed of 10 knots.

On the stern are the ship’s radars, wind gauges, and satellite antennas. The Mayflower can send data back to scientists and receive instructions from landbased technicians, but she is designed to handle situations without human interference.

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Hull includes a laboratory The central hull includes the ship’s computers, measuring equipment, and motor. As neither standing height nor cabins and food are required, the hull includes lots of space for equipment and for samples collected en route.

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The Mayflower has three hulls to make the vessel stable and reduce wind resistance.

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Parasites are nature’s most unexpected heroes, so let’s

SAVE THE PARASITES! Parasites are nature’s most hated creatures – they eat their victims from within, even drive them to suicide. But they are indispensable in the food chain. A large-scale research project will try to save these tiny terrors from extinction. SHUTTERSTOCK

Large-scale project to save parasites Scientists know only 10% of all parasite species, but a major preservation project is to change that. Apart from identifying the endangered parasites, the project will establish their importance. Collect information Counting parasites in different ecosystems, mapping DNA and behaviour. Describe species Describing half of all parasite species. Identify risks Mapping out the most endangered species and key negative factors in their potential survival.

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Prepare a ‘red’ list Listing the most endangered parasite species. Offer legal protection Lawmakers must introduce laws that protect parasites. Educate Students and scientists should learn more about parasites. Inform The general population needs to be informed of parasites' roles.

By Jonas Grosen Meldal

USE THE LO TONGUE E H T S E AT H, THEN S I F A OF PLACE. S T I S E TA K

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eep in a southern Californian coastal swamp, tiny sperm-like cercariae are swimming about in search of a host. As a killifish passes by, the cercariae dart directly towards it, penetrating the fish at full speed. Once inside the fish, they travel via blood vessels and nerves to the brain, which they cover in thousands of cysts. This makes the fish swim towards the surface and wriggle, where it is more likely to end up in the stomach of a predatory bird – in which the parasite would like to lay its eggs. The parasite’s capture of the fish brain is just one example of one parasite’s morbid yet complex behaviour. So why would a large international team of scientists headed by American researchers prepare a rescue plan that aims to protect this brain parasite – and thousands of other parasites?

75% of all links in nature’s food chains involve parasites.

Put simply, it is because many parasites risk extinction. And although to many of us a world without parasites might not sound too bad, their disappearance could have severe consequences for the world’s ecosystems. Yet support for the ambitious project is somewhat limited. With so many issues in the world, so many more endearing animal species facing extinction, parasites face not only the challenges of climate change and declining biodiversity, but also a lack of enthusiasm for a salvage operation to assist the tiny creatures with their manipulative life-cycles. However, the scientists behind the rescue plan are convinced that parasites are indispensable partners in more visible struggles nature is facing. They play a key role when it comes to balancing ecosystems.

All organisms have parasites Parasites are organisms that live in or on another organism, dependent on the host to survive. The organisms vary from protozoa, bacteria and viruses to larger creatures such as worms, lice and ticks. They also include plants, such as the mistletoe that grows on trees, drilling its roots into them to absorb 52

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nutritious sap. They all have one thing in common: they take advantage of their hosts and use a wealth of inventive strategies to infect them and feed on their resources. Some castrate the host. Others make the host raise their offspring. And a great many manipulate the host’s behaviour in some way, to the benefit of the parasite. A parasite’s existence depends on the host, but usually the host does not benefit from the parasite at all. On the contrary, parasitic infections often result in a sick and weakened host. If the host is infected with many of them, and especially if it is only an intermediate link to another host, the coexistence can end with death, even though parasites rarely benefit from killing their host. Parasitic behaviour provokes little sympathy (more often disgust) but such tactics can be very successful. Parasites are probably the most species-rich of all animal groups. All of Earth’s ecosystems include parasites, and all the world’s other animals are infected at some point in their lives. Scientists estimate that parasitic species make up 30-50% of all species on Earth. Indeed an accurate impression of the distribution of parasites is difficult to get, as the creatures exist inside other organisms. Probably only around 10% of parasitic species have been identified at this point in time.

Parasites are food-chain heroes Traditionally, scientists have been eager to combat these apparently unpleasant creatures, seeing them take advantage of their hosts and causing diseases in animals and humans. But they are important factors in ecosystems. First and foremost parasites have a major influence on food chains, regulating the populations of their host species and causing a domino effect of influence on species that are the host’s natural predators or prey. Studies have demonstrated that about 75% of all links in nature’s food chains involve parasites. And although many individual parasites are tiny, their total biomass is huge. A study of the biomass of individual species’ in ecosystems along the coasts of California revealed that the biomass of parasites outcompeted that of top predators.

ROUNDWORMS CAN GROW ALMOST 1 METRE LONG.

GILLES SAN MARTIN & EYE OF SCIENCE/SPL & AMI IMAGES/SPL & DR. RICHARD KESSEL & DR. GENE SHIH/VISUALS UNLIMITED/SPL & JUAN GAERTNER/SPL & SHUTTERSTOCK

Climate change threatens parasites

DEGREE OF DANGER:

Parasites exist throughout nature, and the major groups include lice, worms and ticks. A large number of these parasites are endangered by climate change and declining biodiversity.

C R I T I C A L LY ENDANGERED

ENDANGERED

VULNERABLE

LEAST WORRYING

Acanthocephalans drill with proboscis

Mites feed on blood, skin, hair follicles

Tapeworms eat without a mouth

Ticks swell from blood

These parasitic worms are characterised by a spiked proboscis that they use to pierce host organisms. Their life-cycles involve at least two hosts. Around 1400 species have been identified.

Many mites are parasitic. They live on their hosts (often insects, mammals and birds), getting nutrition from blood, skin, auditory canals, hair follicles, feathers, and airways. Around 4500 species have been described.

Tapeworms are long, band-like flatworms. They have no mouth, but absorb nutrition from the host’s intestines. Humans are typically infected via poorly-cooked meat. 6000+ species have been described.

Ticks are related to spiders, and they can grow to two or three times their original size when they suck their host’s blood. Ticks transmit borreliosis. Approximately 900 species exist.

Roundworm sizes vary greatly

Lice feed on blood and waste products

Trematodes pass through two hosts

Fleas bite holes in the skin

Roundworms vary in size up to lengths of around one metre. It is estimated that about one million species exist, distributed between 2250+ groups, onethird of which are parasitic.

Lice are insects that live in the host’s hair, feathers or skin. Some eat waste products from the skin, others bite a hole in the skin to drink blood. Scientists know 5000 different species.

The tiny fat worms live inside their hosts. The main host is typically a big animal in which the trematode lays eggs, whereas the intermediate host is a small animal such as a snail. Some 24,000 species have been identified.

The tiny insects that live on birds and mammals do not grow any bigger than 3mm. They use their sharp claws and mouthpieces to bite a hole in the skin and suck blood. About 2500 flea species exist.

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Brain parasite manipulates fish Some parasites have a complex life-cycle requiring them to pass though several hosts. This is true for the trematode Euhaplorchis californiensis, which is remarkably adept at forcing cooperation between coastal birds, snails, and killifish. When the parasite infects a fish, the fish is more likely to be consumed by birds, and so the parasite plays a key role in keeping the fish population balanced.

In many ecosystems, parasites are important food sources for other species. On the islands in the Gulf of California, small predators such as lizards, spiders and scorpions are around twice as numerous in places with many coastal birds. That’s because the predators eat parasites on the birds, particularly lice and fleas. The same principle is followed in the ocean, where shrimps and lipfish feast on trout parasites. When parasites end up on the menu, it is not always a random coincidence. In many cases, the parasites very much want their host to be eaten, or to be eaten themselves, so they can reach another host and begin the next stage of their life-cycle. And to that end many of them have developed alarming abilities to manipulate the host, changing its behaviour so it is in greater risk of being consumed by a predator. On the ocean floor, shrimps are infected by a tapeworm parasite that makes them move more, increasing their risk of being eaten by rays. Some worms drive insects to 54

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drown themselves so the worms can lay eggs in the water. Trematodes go so far as to make infected frogs develop an extra pair of hind legs that make them clumsy, less able to escape from predators. The manipulations have one thing in common: they regulate the population of host organisms and so also the hosts’ natural predators and prey. Without parasites to keep populations at bay, the numbers of

30-50% of all species in the world may be parasites, according to scientists.

When the heron catches an infected killifish, the parasite can lay its eggs in the bird’s intestines.

some species would grow radpidly at the expense of other organisms. The killifish is one of the most common fish species along the Californian coast. The trematode Euhaplorchis californiensis attacks the fish’s brain, making it head towards the surface and into the mouths of coastal birds. This prevents fish populations from growing disproportionately – which would have disastrous consequences for the entire ecosystem. So the parasite balances the food chain to the benefit of both the birds and the prey of the fish – small shrimps. Other parasites influence populations in another way. Instead of changing the host’s behaviour, they somehow prevent it from breeding, using its resources for themselves, while deleting future generations.

Pandas steal the attention Scientists and activists sound the alarm to save endangered animals such as bees, tigers, elephants, and pandas, but parasitic species don’t get a lot of attention. Hence

Bold fish ends up as bird food VISUALS UNLIMITED/NATUREPL & SHUTTERSTOCK & H. ZELL & KELLY WEINERSMITH & KELLY WEINERSMITH

The parasite changes the fish’s behaviour, making it swim to the surface and twitch. This catches the attention of predatory birds, so that infected fish are 30 times more likely to be captured.

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Bird pass the parasite eggs In the bird’s intestines, the parasite develops into an adult trematode and lays eggs. The eggs are included in the bird’s droppings that end up in ponds and coastal swamps.

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H E A LT H Y BRAIN

SICK BRAIN

Parasites capture fish brain

Snail hatches cercariae

The cercariae penetrate a killifish’s skin, finding their way to the brain via blood vessels and nerves. In the brain they produce a layer of cysts that disturb the neurotransmitters of serotonin and dopamine.

Mudsnails eat the bird droppings. Inside the snails, the eggs hatch into tiny, sperm-like creatures known as cercariae. Thousands of cercariae can exit an infected snail in one day.

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DAVID HERASIMTSCHUK

some scientists fear that although parasites are the most species-rich creatures on Earth, they are also the most endangered. Thousands, perhaps millions of parasitic creatures are probably being negatively affected by climate change and declining biodiversity. The problem is that scientists know so little about the parasites’ lives, how the changes are influencing most of them, or how their loss would affect the wider ecosystems. Even specialist parasite researchers disagree on how the parasites are likely to react to the upheaval. Some believe that they, just like many other species on Earth, risk extinction as their host species disappear. Others think that ailing ecosystems will weaken host species, making them more vulnerable to parasitic infection. A group of American scientists, also involved in the new rescue plan, initiated a major experiment around 16 ponds in the San Francisco Bay area to learn more about how biodiversity changes affect parasite diversity. At half of these ponds the

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Parasites are manipulation experts. One trematode causes frogs to develop extra limbs, whereupon they become clumsy and less mobile – easier prey for the birds which are the next step in the parasite’s life-cycle. scienceillustrated.com.au

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Parasites are inventive survivors

Parasite turns the snail’s antennae into bait

They hatch their offspring in the host, change its behaviour, even make it commit suicide. Parasites have developed nature’s cleverest and most macabre methods for taking maximum advantage of other creatures.

When the flatworm’s eggs hatch inside an infected snail, the tiny worms enter the snail's antennae, making them look like larvae. Plus the snail is manipulated to move into the light, where it is consumed by birds.

PAUL COOPER

In Amazon rainforest rivers, the eel-like vampire fish is swimming in search of a host. In the muddy darkness, a parasite tracks down its victim by sensing the nitrogenous ammonia secreted from fish gills. When the ammonia has directed the vampire to its victim, it holds on to the gills to suck blood.

ARDEA PICTURE LIBRARY/RITZAU SCANPIX

Nitrogen leads vampire to the prey

Worm manipulates the host to commit suicide Horsehair worms hatch and grow inside large predatory insects such as crickets or locusts. However, the parasite must lay its eggs in water, so it drives its host to throw itself into water – where it drowns.

When a crab is infected by the Sacculina carcini crab hacker barnacle larvae, it will no longer have its own offspring. Instead, the parasite grows inside the crab and lays its own eggs in a bag under the crab’s stomach.

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NATURE PHOTOGRAPHERS LTD/ALAMY/IMAGESELECT

Crab hacker barnacle uses crab as surrogate mum

PAULO OLIVEIRA/ALAMY/IMAGESELECT

Louse replaces fish tongue An extra set of eyes stare out of this fish’s mouth. The eyes belong to a parasite with a macabre behaviour. The tongue-eating louse grows up to 3cm, then consumes the fish’s tongue and takes over its position, feeding on blood and slime.

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KENNETH R. WEISS

N AT U R E

Biologist Kevin Lafferty is one of the scientists behind the parasite conservation project. He has studied the trematode Euhaplorchis californiensis, which attacks the brain of its host killifish to change the fish’s behaviour so that it it far more likely to be eaten by a bird. scientists installed bird houses, decoys, and floating roosts to attract more birds. In this way, the ecosystem was changed and biodiversity boosted. After a few years, the scientists analysed parasite diversity in all ponds. The result was ambiguous. Some species had been reduced as a result of improved bird diversity; others had grown. The scientists concluded that when biodiversity changes due to climate change or other factors, it will affect parasites differently – even among species of the same ecosystem. So there is evidence for both theories held by parasite scientists: the parasites could either thrive or weaken as a result of ecosystem biodiversity changes. The next step, then, is to find out which factors determine what happens to individual species.

it will simply require a higher priority in the world of science, which is now better equipped for the task than ever. Many biologists are exploring biodiversity in areas spanning the globe, but currently they rarely include parasites in their counts. The team of scientists wants to change that, and

10% of parasites have been identified so far. Scientists are now aiming for 50% within 10 years.

Mapping out the parasites The scientists’ overall rescue plan consists of 12 objectives, distributed between four main categories: data collection, risk evaluation, conservation and information, and education. One of the most important objectives is to learn more about parasitic species. One of the most ambitious items on the agenda is that the scientists are going to identify and describe half of the world’s parasitic species over the next 10 years. Considering that scientists have probably identified only 10% of all species up to now, that’s a huge task, but not impossible. According to the scientists, 58

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then organise huge quantities of collected data in digital libraries where they can more easily be compared. Knowledge of more species forms the basis of the rescue plan. For scientists to estimate how endangered individual species are and to initiate the right conservation initiatives, it is necessary to identify and describe life-cycles and roles in the ecosystem. One of the methods that the scientists will use is DNA barcoding, which involves the use of a species’ unique DNA signature to identify or monitor it in any given envi-

ronment. In this way, scientists can learn about the parasite’s role and life-cycle by analysing soil, air or water samples; they do not need to capture them. Knowledge of the genetics is key to an understanding of the organisms. All the collected data is to be used to find out which parasites are the most endangered and what the consequences of their extinction might be. The scientists will also become better at estimating whether the parasites are as endangered as their hosts. More immediately, some initiatives that protect the hosts can also help the parasites. One obvious conservation initiative for the trematode Protofasciola robusta, which thrives in elephant intestines, would be to ensure elephant survival. But scientists also intend to introduce initiatives specifically aimed at the parasites. To provide a general idea of the species’ risk of going extinct, the parasites will have their own ‘red’ list that evaluates the risk level of individual species. But before conservation efforts can really progress, the reputation of parasites must be improved. That is to happen via improved education and training of students and researchers concerning ecology and nature conservation. And beyond students and university graduates, the scientists behind the conservation project also want to provide the general public with a more multifaceted impression of parasites, via the media. A broad understanding of parasites’ key role in food chains will be central to ensuring widespread support for conservation efforts.

Parasites make people healthier To assist public acceptance, the scientists have decided to exclude parasites that infect humans. But there is every indication that the disappearance of some parasitic species could be costly for humans. Studies have demonstrated that parasitic infection at an early age reduces the risk of developing autoimmune diseases later in life. This explains why the western world, where infectious diseases have been dramatically reduced, is increasingly affected by autoimmune diseases. In recent decades, scientists have found out that parasites actively relieve diseases such as allergies, asthma, inflammatory bowel diseases, and sclerosis. All these diseases have one thing in common: they are caused by a hyperactive immune system. Parasites have developed methods to curb immune system activity by producing substances that soothe immune cells and limit secretions that cause inflammation. In doing this they’re trying to help their own survival – but in the process, they help ours too.

Parasites can help humans To the host, parasites are often unwelcome guests. Some parasites attack humans, their activity causing agony while also transmitting contagious diseases such as Lyme’s disease. But according to new research, parasites can also cure diseases such as chronic inflammatory bowel disease and asthma. HOOKWORM

FRIEND

NEMATODE INFECTED AREAS NORMAL A I RWAY

ASTHMA

Nematodes prevent inflammatory bowel disease

Hookworms help asthmatics breathe

In regions of the world where bowel parasites are common, inflammatory bowel diseases such as Crohn’s disease are rare. Scientists have found out why. One of the causes of Crohn’s and similar diseases is harmful bowel bacteria. Mouse experiments show that nematodes in the bowels make beneficial bowel bacteria outcompete harmful ones. In this way, parasites indirectly combat infection.

Parasites can be a cure against asthma. Scientists have identified a promising protein secreted by hookworms, AIP-2, which has proved both to reduce inflammation in the airways of mice and to curb the level of immune cells in the blood of people with allergies. Asthma is caused by a hyperactive immune system that results in a high inflammation level, forcing the airways to narrow.

ENEMY

eye Worms in the rrifying

SHUTTERSTOCK & CNRI/SPL & DAVID SCHARF/SPL

te One of the more is the African s te si ra human pa the a, which enters eye worm Loa lo n travel s. The worms ca body via fly bite ly r years, eventual under the skin fo the as ch su places to ay w r ei th ng findi heart, sticles, kidneys, penis, nipples, te the eyes. lungs, and even

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Scientists have found all visible matter, but...

WHERE IS THE REST OF THE UNIVERSE? Astronomers have been looking for 20 years and have now found all the visible matter in the universe. But they are still searching for the remaining 95%, which is invisible. A new telescope is to focus on the biggest mystery: dark energy.

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By Rolf Haugaard Nielsen

After 20 years of searching, scientists have mapped out all visible matter in the universe. Almost half of it is in ultra-thin hydrogen gas clouds. KEN IKEDA MADSEN & SHUTTERSTOCK

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Telescopes find missing matter in cosmic cobwebs Radio waves from fast radio bursts in remote galaxies reveal that about half of all visible matter in the universe exists in the form of ultra-thin hydrogen gases in the vast spaces between galaxy clusters.

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n the darkness between the galaxies of the universe, there are vast spaces of almost nothing. But thin clouds of hydrogen gases drift there – impossible to see, even for our most powerful telescopes. The clouds are so thin that only a few atoms exist in a volume of several cubic metres. Yet the clouds stretch billions and billions of kilometres. And if the mass of all the clouds is combined, you get a very special number: a number that fits perfectly into a 24-year-old calculation. Around half of all ordinary visible matter – stars, planets, dust, gases – has escaped the lenses of scientists’ telescopes since 1993, when scientists calculated how much we should be able to observe. And it turns out that the mass of the hydrogen clouds corresponds exactly to the missing matter. Now astronomers are turning their attention to the universe’s dark energy, which makes up a remarkable 68% of everything. By means of 5000 customised optical fibres for a telescope in the US, the collection of light from 35

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5% of the matter in the universe is visible to telescopes.

million galaxies has begun. The result could solve the biggest mystery in cosmology.

Radio bursts reveal hidden gases Everything that we can see, touch, and smell consists of atomic matter – the atoms and molecules formed from what we know as the elements. The same is true in the rest of the universe, but out there it is more difficult to find solid proof that the elements

Mysterious bursts come from remote galaxy Astronomers have observed fast radio bursts, typically from remote galaxies. They are thought to be triggered by neutron stars with powerful magnetic fields, known as magnetars. The bursts last only a few milliseconds, but they emit more energy than the Sun does over several decades.

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exist. For decades, scientists have tried to map out all atomic matter in the universe. There are some 200 billion known galaxies that include 14% of the visible matter that, according to astronomical calculation models, should exist out there. And astronomers have found gas clouds between the galaxies within galaxy clusters, and more gas clouds between the clusters. But still around 50% of the expected visible matter has been hiding from telescopes since 1997. Astronomers have long suspected that the matter was to be found in extremely thin yet millions-of-degrees-hot clouds of hydrogen gases that exist in pockets of empty space between the galaxy clusters. But their telescopes could not identify the gases. Due to the heat, the hydrogen atoms have been split: the proton in the atomic nucleus and the solitary electron have been separated as plasma, making the hydrogen atoms effectively invisible, as a split atom can no longer absorb or emit any light. However, the free-flying electrons can still

KEN IKEDA MADSEN & SHUTTERSTOCK

Distance

Hydrogen

ASKAP telescope

Ultrathin hydrogen clouds delay long waves

Radio telescope records wave delay

Telescope measures distance and hydrogen is weighed

If the universe was entirely empty, then short and long radio waves would travel at the same speed. But the radio waves pass by thin, millions-of-degrees-hot hydrogen clouds, and are refracted a little, like light through a prism. This delays long radio waves more than short ones.

The ASKAP telescope array in Australia observes fast radio bursts from remote galaxies and the time lag between short and long wavelengths in the bursts. The more delay experienced by long waves compared with short ones, the more hydrogen gas a burst has passed on its way to Earth.

The Very Large Telescope in Chile finds the distance to the galaxies from where the fast radio bursts come, by measuring how much the galaxies’ light is stretched on its way towards Earth. Based on the quantity of hydrogen and the distance to the bursts, astronomers can calculate the mass of the hydrogen clouds.

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influence light passing through these thin hydrogen clouds. When light waves travel through hydrogen plasma, the waves are spread by the free electrons in the same way that light is refracted by a prism. With this knowledge in mind, scientists from the US and Australia analysed fast radio bursts. Astronomers are not sure of the origin of all these bursts, but according to the prevailing theory they come from magnetars – neutron stars with particularly powerful magnetic fields – and this was recently confirmed for one particular burst (see news last issue). The bursts last only a few millionths of a second, but can emit as much energy as the Sun does in 80 years. Scientists have observed the high-energy bursts that reach Earth in the shape of radio waves using 36 coordinated radio telescopes here in Australia: the Australian Square Kilometer Array Pathfinder (ASKAP). Radio waves with long wavelengths are refracted more by the free electrons than radio waves with short wavelengths, and so are

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Up to 203 million light years

The visible universe is a cosmic cobweb. The bright dots represent galaxy clusters. But between the clusters there are less bright threads of ultra-thin gas clouds. scienceillustrated.com.au

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delayed more. The ASKAP telescope has recorded the difference. The time lag between the wavelengths of the bursts and the distance to their sources can be used to calculate the mass of the red-hot hydrogen clouds that the radio waves passed through. And the result of that calculation was a eureka moment for the team of scientists led by Associate Professor Jean-Pierre Macquart from the Curtin University node of the International Centre for Radio Astronomy Research. When they completed their calculations, the result perfectly matched the visible matter missing since 1997.

200 billion galaxies exist in the universe.

Fly’s eye in search of dark energy With all the missing visible matter ticked off, scientists now hope to map out the rest of the universe. Some 26.8% of the universe’s matter is dark matter, never directly observed. Astronomers know it exists because galaxy motions can only be explained if the invisible matter is affecting the galaxies with its gravity. Ordinary matter and dark matter attract each other via gravity and have paired up since the young universe, when lumps of dark matter attracted the hydrogen gases that gave birth to the first galaxies. Without dark matter, the galaxies would not exist today. Of the combined matter in galaxies and galaxy clusters, dark matter makes up 85%. The stuff that we can see comprises only 15% of what is there. However, the largest puzzle piece of the universe is dark energy. For a long time, astronomers thought that the expansion of the universe would begin to slow down, because gravity would stop the universe’s expansion over time and ‘pull’ everything back again. But in 1998, two teams of scientists, which were awarded the Nobel Prize in physics for their work, made a revolutionary discovery. If the expansion of the universe was slowly being halted by gravity, the most remote supernovas would be travelling ever more slowly away from us. But observations showed that this isn’t the case – the remote supernovas travelled faster. So the expan64

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sion of the universe was accelerating. Scientists named the force that accelerates the expansion ‘dark energy’. Even more amazingly, the same scientists concluded that this energy makes up 68.3% of the universe. It may seem odd to correlate energy with mass, but Einstein’s relativity theory confirmed that mass can be converted into energy and vice versa. When wood burns, much of its mass is converted into energy. And when scientists convert two photons (which do not have any mass) into an electron and a positron, the photons’ energy is converted into mass. So when astrophysicists talk about dark ‘energy’, the force corresponds to 68.3% of the universe’s mass. But this doesn’t help explain what the repellent force is, or how it works. Now a new instrument is ready to explore dark energy: the Dark Energy Spectroscopic Instrument (DESI). Over the next five years, DESI will construct a 3D map spanning the nearby universe to 11 billion light years distance. DESI uses an ‘eye’ like that of a fly, with 5000 separate optical fibres pointed at the sky and creating separate images. The telescope is aimed at a region 38 times bigger than a full moon, with scientists choosing regions which they know from earlier observations contain multiple galaxies. Then the 5000 fibres are individually adjusted so that each can observe one galaxy. In this way, DESI can detect light from some 5000 galaxies every 20 minutes. The light data is sent from the fly eye to a series of spectrographs that measure the different wavelengths of the light. The redder the light, the more stretched it has become on its way from remote galaxies. The extent of the stretching demonstrates both how far away the galaxies are, and how fast the galaxies are travelling away from us. In this way scientists hope to take the first step in revealing dark energy, which is to find out whether it is constant or varying. Existing studies indicate that it is constant, so a space of any given volume should always include the same quantity of dark energy. When dark energy sped up the expansion of the universe 56 billion years ago, it was because space itself grows all the time through the universe’s expansion. But in recent years, cosmologists have made a few debated observations that could indicate that dark energy varies, and increased when the expansion of the universe began to accelerate. If dark energy is constant, it is generated by virtual particles that form and disappear again almost immediately. But if it varies, it might consist of unknown force particles. And if scientists can solve that mystery, it would be the biggest revolution in cosmology for more than 20 years.

The Dark Energy Spectroscopic Instrument (DESI) is to measure the light from 35 million galaxies. NOIRLAB/KPNO/NSF/AURA/P. MARENFELD

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Field of vision corresponds to 38 times a full moon The light captured by the telescope’s 4-metre primary mirror is focused at the DESI instrument at the top of the telescope. DESI spots the light from 5000 galaxies at different distances in time and space within a region corresponding to 38 times the area of a full moon in the sky.

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Telescope to find dark energy in galaxy motions 5000 optical fibres collect light from 35 million galaxies to figure out their speeds over 11 billion years. This will indicate whether dark energy is constant or varies, the first step to identifying the nature of this energy.

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DESI COLLABORATION

Galaxy light is captured by 5000 optical fibres

Cables direct light from fibres to spectrometers

Wavelengths show the universe’s expansion

The light from the galaxies strikes a ‘fly eye’ with 5000 optical fibres individually aimed at each galaxy. The optical fibres can be twisted and turned by means of robotic motors, so that DESI can be prepared to observe a new region of the sky in only 20 minutes.

50-metre cables direct the light to 10 spectrometers that measure light intensity and wavelengths. The further away the galaxy, the weaker its light and the more the wavelengths are stretched due to the expansion of the universe. So the light from more remote galaxies is redder.

The analysis of wavelengths also shows the speed of the expansion. The more the wavelengths have been stretched since the light was emitted, the faster space has expanded. This could determined if the strength of the dark energy has always been constant, or if it has varied.

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Ready for your close-up? For maximum resolution, you’ll need:

AUSTRALIA’S GREAT RING OF LIGHT

ANSTO

Young scientists are using the resolving power of the Australian Synchrotron to shed new light on lost millennia of climate data and Indigenous bushfire management.

The Australian Synchrotron is on ANSTO’s Clayton campus located some 22km south-east of Melbourne CBD. 66

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reg Le Blanc and his team are some 22km south-east of the CBD in Melbourne, working underground in the middle of the night. In an enclosed room they huddle over monitor screens, while around them stretches a shiny new facility filling an area the size of a football field, encompassing a vast circular vacuum chamber surrounded on all sides by machinery designed to accelerate and then maintain a beam of electrons travelling at almost the speed of light. If all goes according to plan, those electrons will be deflected through powerful magnetic fields to create a ‘light’ source a million times brighter than the sun. But if the beam strays by so much a micron from its path as it traverses the circular chamber 1.4 million times a second, it will fail. To keep going, it must be perfectly synchronised with bursts of a powerful electric field, meeting them at exactly the right moment – a time window of less than a billionth of a second. This need for precise synchronisation is how the whole facility gets its name – the Australian Synchrotron. It is 14 July 2006. Le Blanc and his team of scientists and engineers have already spent

six weeks checking and rechecking the many systems, crunching the numbers and tweaking the energies, trying to maintain the beam. They have got close, achieving first one complete revolution of the outer storage ring, then 20, then 80. Nearing the end of another long night, at 3.15 AM one scientist suddenly points to a spot on a screen at the end of a row of monitors. “Look!” he calls to the others, and immediately the team erupts into cheers. This is the moment they have been waiting for. The Synchrotron has achieved ‘first light’. First light is the moment when the beam is kept in constant motion, generating highenergy X-rays and infrared light that can be used for scientific research. For the physicists and engineers on the project, first light confirms that the entire chain of precision instruments is perfectly lined up, allowing the beam to shine through. And it is no simple process to raise and maintain electrons to a speed at which they could travel around the Earth seven times in one second.

Keeping the beam alive The acceleration process starts with a giant electron gun which works not unlike the old

3GeV is the final energy of the Synchrotron’s electrons, a speed close to that of light.

cathode-ray-tube TV sets, using thermionic emission to extract electrons and aim them — at an energy of some 90,000 electron volts (90keV) — into a linear accelerator. Within just a few metres this uses electromagnetic radiation in the form of radio frequencies to accelerate the electrons to an energy of 100MeV, already very close to the speed of light. They are then focused, to prevent the beam expanding outward, and pass into a booster ring 130 metres in circumference, where 60 steering and focusing electromagnets keep the electrons inside the stainless steel vacuum chamber while a 5-cell

D D D

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Australia’s circuit of light From the electron gun A , the electrons are accelerated into the booster ring B where they complete around a million laps in half a second before passing into the storage ring C . There they release intense radiation which is channelled by the Synchrotron’s 10 beamlines D to the ‘hutches’ where experiments are performed.

radio-frequency cavity — metallic chambers containing an electromagnetic field — provide an electrical impulse that accelerates them further. An electron spends only around half a second in the booster ring, completing over one million laps to achieve a final energy of 3GeV. Once at their top speed the electrons pass into a storage ring 216 metres in circumference, where they can typically be maintained for up to 20 hours if everything is kept in perfect alignment. When high-energy electrons are forced to travel in a circular orbit in this way, they release extremely intense radiation. From the storage ring, various ‘beamlines’ are used to channel this radiation and convert it into the type of synchrotron light required for practical experimental use. Synchrotron light scores over conventional techniques in terms of accuracy, quality, robustness and the level of detail that can be seen and collected; it can also be much faster than traditional methods. Often described as being like an enormously powerful microscope, the synchrotron light reveals the innermost, sub-macroscopic secrets of materials from human tissue to plants to metals and more.

Today, nearly 15 years after first light, Australia’s synchrotron hosts 10 separate beamlines for a broad range of applications: health and biological sciences, earth and environmental sciences, advanced materials, engineering and manufacturing, energy and sustainability science, cultural heritage and archaeology, as well as fundamental physics, chemistry and accelerator science. Each beamline has an initial photon delivery system (the ‘beamline optics’) to focus and select appropriate wavelengths for the particular research. The experiments then take place in ‘hutches’ that are within radiation-shielding enclosures, to protect staff and visitors. Scientists can’t enter these hutches during data collection, so they use motors and robotic devices to make any adjustments required.

synchrotron – the Linac Coherent Light Source in the US and SPring-8 in Japan can both achieve energies of 8GeV, while the biggest colliders use synchrotron-like acceleration to still greater energies. But it is nevertheless one of Australia’s most significant pieces of scientific infrastructure. Yet remarkably, while commercial research requires payment, the Australian Synchrotron is free of charge to researchers who are publishing results in open literature. Its use is allocated through a peerreview application process, including work by students who have received scholarships from AINSE, the Australian Institute of Nuclear Science and Engineering, under the umbrella network of the Graduate Institute in the ANSTO Innovation Precinct where the Synchrotron is situated.

Who gets to use it?

Rings of time and climate

Most of the initial funding for the Australian Synchrotron came from the Victorian Government, but it has always operated for all Australians under ANSTO (Australia’s Nuclear Science and Technology Organisation), open also to international scientists. It is far from being the world’s only or largest

One of those scholarships was awarded to Priyadarshini Parsons O’Brien at the University of New South Wales. Her plan was to use the synchrotron’s powers of analysis to unearth Australia’s ancient climate history by radiocarbon-dating partially-fossilised samples of Tasmania’s famous Huon pine

ANSTO

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trees. The Huon pine is the oldest living tree species in Australia, and is considered the second oldest in the world, with only the North American bristle cone living longer. The oldest Huon trees alive today are between 1500 and 2000 years old, but there’s a twist — individual groups of trees are all genetically identical, with the above-ground trees sharing a common root stock. Those common roots survive far longer than the individual ‘trees’, and represent a single genetic individual: one stand of Huon pines is in the Guinness Book of Records as the world’s oldest colony, believed to be over 10,500 years old. Huon pine is considered “the prince of Tasmanian timbers”, desirable for furniture, boat-building and veneering due to the richness of its colour plus natural oils which provide an insect-repelling fragrance. But the species is protected, and old trees are very rarely cut down. Only a limited amount is released for sale each year by sawmillers who salvage rejected offcuts from the forest floor and logs from river beds, where it survives because Huon pine is rot-proof.

VERSUS

10,500 years is the time one Huon pine stand has maintained one genetic individual.

One set of partially-fossilised Huon pines was excavated more than 20 years ago from flood plains in western Tasmania, and these were found to date back over 10,000 years. This offers the possibility of establishing the longest naturally-preserved climate record in the Southern Hemisphere from the information preserved within their growth patterns. Some 250 samples have been taken from the partially-fossilised pines, but there is a gap in the timeline. The current record extends back 3500 years, then contains

a short gap before another 1500-year continuous stretch. Priya’s research would attempt to fill in that gap, with field work in Tasmania to find priority pine samples and then prepare them for radiocarbon analysis using the Synchrotron. Once complete, this could establish the longest naturally-preserved climate record in the Southern Hemisphere. But things did not go according to plan. “I started my project in February 2020,” says Priya, “and of course it was heavily affected by COVID restrictions. We had to pivot my project and focus instead on a treering dataset of New Zealand kauri, along with samples that could be more easily accessed for chipping.” The kauri is another ancient conifer, and another species which provided a target for the early woodcutting industry since it grows broad and straight, as high as 50 metres. The kauri is also long-lived and sensitive to climate conditions, and a series of previous research projects has already created a network of 17 chronologies, from both modern kauri sites and ancient kauri wood recovered from bog sites.

· Huon Pine vs New Zealand Kauri ISTOCK

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NEW ZEALAND KAURI

Lagarostrobos franklinii Tasmania Near Threatened

10-20m up to 30 metres

Agathis australis

Location Conservation status

Conservation Dependent

Usual height

20m up to 50 metres

Origins

Jurassic period

Cretaceous period ~100 million years ago

Oldest known: At Lake Johnston Nature Reserve in Tasmania, a Huon stand has individuals 1500-2000 years old, with the stand itself perhaps 10,500 years old.

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North Island of New Zealand

~190-135 million years ago

Oldest known: Tãne Mahuta, also called God of the Forest, in the Waipoua Forest of Northland Region has an estimated age between 1250 and 2500 years.

Another AINSE Honours Scholarship went to Nikola Ristovski, Honours student from the University of Western Australia, who is working alongside researchers from ANSTO and UWA to uncover details about the deep history of Indigenous culture in Australia over the past tens of thousands of years. Nikola’s team is focusing research on how Indigenous Australians used and controlled fire in their daily lives. “Evidence of fire is frequent in the archaeological record, but the further back you look, the more ambiguous its nature becomes,” says Nikola. “My thesis considers the potential of micro-archaeological techniques like infrared spectroscopy and scanning electron microscopy to determine the heating temperature of archaeological bone and charcoal.” The Australian Synchrotron’s infrared spectroscopy beamline delivers polarised infrared beams up to 100 times more intense than conventional sources. By using Fourier Transform Infrared Spectroscopy (FTIR) to microanalyse charred sediment and bone fragments from archaeological sites in north-western Australia and then comparing them to a reference collection he has built up himself, Nikola aims to accurately estimate the temperature at which

NIKOLA RISTOVSKI

Fighting fire with FTIR

PRIYADARSHINI PARSONS O’BRIEN

“The research goal was to synthesise over 20 years of collection and archiving of ancient material to understand climate trends in the Northland region beyond the limits of radiocarbon dating,” Priya tells us. “As the material had never been comprehensively analysed it was unknown exactly what kind of information was available in the data set, as well as by applying novel methods to analyse the material remotely and computationally.” Her work included carbon-dating of kauri samples in the Chronos lab at the UNSW Mark Wainwright Analytical Centre, but she notes that the oldest samples are at the 50-55,000-year limit of radiocarbon dating. The Australian Synchrotron’s deeper analysis would allow a further source of dating to confirm and potentially extend her findings, which are already intriguing. “For the kauri we were able to identify wavelet periodicities at the boundary of radiocarbon dating which indicated climate trends influencing the tree-ring growth over multiple decades at that time, and between multiple kauri sites,” Priya tells us. “Particularly the analysis indicated limited influence of the El Niño-Southern Oscillation on the growth of the kauri.”

Scholarship recipient Priyadarshini Parsons O’Brien is studing ancient climate patterns via tree samples.

Nikola Ristoviski shown sampling kangaroo bones from recent fires as part of his reference collection.

these human-controlled fires burned, and the extent of the fires. This knowledge could provide important clues about how fire was used by Indigenous Australians tens of thousands of years ago, where evidence is scarce or complex. “FTIR and X-ray diffraction work great alongside the microscopic study of undisturbed sediments,” says Nikola, “and can sometimes be applied directly to these microscopic slides to better understand spatial relationships between differentially heated artefacts and how they change through time.” Nikola has already analysed his first set of samples under the light of the Synchrotron’s FTIR beamline. “We managed to sample and estimate the temperatures of about 80 bone fragments in thin sections, which showed that FTIR could be a viable method for predicting temperatures of cultural fire activities”, he tells us. “We realised that better sample preparation would help, and accuracy may depend on the condition of bone. We’ve applied for another go at the FTIR beamline later this year where we’ll analyse bone and charcoal from another site called Riwi Cave. We predict it’ll give us better results as the site contains distinct fire features, with less altered organics which seem to be burned at higher temperatures.”

and land management. Ellie-Rose Rogers from the University of Melbourne has been conducting radiometric dating on sediment cores collected from under the rainforest of Surrey Hills in northern Tasmania. By combining this data with tree-ring analysis, Ellie-Rose and a team of researchers from ANSTO and the University of Melbourne aim to build a timeline of exactly how this area of land changed from the open forest and treeless plains described by British surveyors in 1828, into the rainforest which covers most of the area today. “These techniques allow us to test the notion that the western Tasmanian landscape was constructed by Aboriginal people and that contemporary rainforest in this region overtook open fire-maintained vegetation following the British invasion,” she says. This window into the past will allow an accurate assessment of how the fuel load has changed over the centuries – and how far the fuel load might be decreased through a return to traditional techniques.

Core expertise Nikola’s is not the only Synchrotron research targeting the vital issue of bushfire

BRIGHT future Fifteen years after Greg Le Blanc and his team achieved ‘first light’ at the Australian Synchrotron, then, the ANSTO facility continues to shine its powerful light into new areas of research. With plans for eight further beamlines to be constructed under the ongoing ‘Project BRIGHT’, the capacity and output of research will be limited only by the imagination of the scientists who seek to use its extraordinary powers. scienceillustrated.com.au

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h t 0 6

RY A S R E ANNIV T S R I F E OF TH N HUMA CE A P S N I

GAGARIN OUT OF CONTROL In 1961, Yuri Gagarin was the first human in history to escape Earth’s atmosphere and travel through space. The 27-year-old cosmonaut was orbiting our world at a speed above 27,000km/h as the Soviet Union published the news. But moments later, Gagarin’s space capsule went out of control. Wearing an orange spacesuit, Gagarin left on a mission that involved unknowable risks. DETLEV VAN RAVENSWAAY/SPL & SOVFOTO/ UIG/GETTY IMAGES

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tion at a technical college. He wasn’t any closer to his dream of flying: he was to learn how to build the indispensable work-horses of the collective farms: tractors. But a few hours after Gagarin got off the train in Saratov, he noticed a sign on a door, marked ‘AeroClub’. Almost without thinking he entered the room, managed to join the club, and after his first long day of tractor lectures, he hurried to the airfield. In awe, he watched a canvas-clad Jak-18 training plane taxi along the runway, and he was so entralled that he did not notice the flying club instructor Dmitry Martjanov approaching him. “Would you like a short flight?” the instructor asked. In an event that he never forgot, Gagarin took off for the first time. The plane climbed to 1500 metres at a speed of 100km/h, before landing again. “You did well,” said instructor Martjanov. ”One would think you had done it before,” . “Ah well,” replied the young Gagarin, ”in my dreams I have flown all my life.”

Rocket prophet inspired Gagarin One of Gagarin’s favourite subjects at school was physics. And when his teacher asked the students each to give a short lecture, this son of a peasant chose to talk about the Russian scientist Konstantin Tsiolkovsky and his research into thundering rocket engines and space missions. Konstantin Tsiolkovsky (1857-1935) was Gagarin’s role model, and he devoured all the rocket prophet’s scientific writings. Like his hero, Gagarin was confident that man’s dream of conquering space would one day come true. Gagarin ended his school lecture by saying: “Man cannot remain on Earth forever. In his search for light and space, he will first escape the atmosphere and then conquer all of space surrounding the Sun”. By the spring of 1955, when he received his college diploma at the age of 21, Gagarin was already following his dream of being a pilot. He had passed his instructor’s theory tests, and one night in July he was working on the Jak-18 plane in which he had taken SHUTTERSTOCK/RITZAU SCANPIX

nsistent ringing of the phone wakes up General Andrey Stuchenko in the middle of the night. Drowsily he lifts the receiver, then fully wakes when he hears an official voice on the line. The unexpected call is from his superior at the Kremlin, and Stuchenko immediately senses something out of the ordinary about this call. The voice on the phone continues: “Very soon, a man will be launched into space. Our glorious cosmonaut will be landing in your district. Make sure to organise a safe rescue and suitable reception. You will answer for the task with your life!” It is April 1961, and the general is in the barracks on the outskirts of Saratov, a city in in southern Russia. Stumbling out of bed, he fetches his map of the region and uses a pencil and ruler to divide the area into squares. Then he assembles his troops and despatches groups to each separate square. “Look towards the sky and watch for something out of the ordinary,” General Stuchenko orders them, quietly adding: “A man will fall out of the sky.” What neither the general nor his troops know is that the man they are waiting for, cosmonaut Yuri Gagarin, is struggling with problems that threaten to turn the Soviet Union’s triumph into a humiliating fiasco.

Peasant’s son wanted to fly Yuri Gagarin’s parents were peasants in a Soviet agricultural production cooperative, and the boy grew up during World War II. As a child, he had been fascinated by planes, but when 16-year-old Yuri left home in 1950, he began with machinery that was more down to Earth: the teenage Gagarin became a steel works apprentice in Moscow. He performed exceptionally well, and in 1951 he was allowed to continue his educa-

The Soviet Union led the space race US scientists were anxious spectators of the Soviet Union’s early space triumphs.

In 1957, 23-year-old Gagarin married Valentina Goryacheva. Together they had two daughters.

PROPHET In 1903, Russian scientist Konstantin Tsiolkovsky wrote “Exploration of the World Space with Reaction Machines” – which contained an accurate description of weightlessness and equations predicting how rockets would travel in the vacuum of space. PUBLIC DOMAIN

FIRST SATELLITE

SPUTNIK 1

With the launch of the Sputnik satellite on 4 October 1957, the Soviet Union became the first nation in space. Sputnik broadcast beeping sounds that receivers throughout the world could ‘hear’. SOVFOTO/UIG/GETTY IMAGES

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LIVING PROOF On 3 November 1957, the dog Laika became the first living creature to orbit Earth. Aboard Sputnik 2, the four-legged pioneer proved that it is possible to survive outside Earth’s atmosphere – although the dog died of stress and overheating after 3-5 hours. UPPA/PHOTOSHOT/RITZAU SCANPIX

2 SPUTNIK

Man cannot remain on Earth forever...”

quite a few lessons. Martjanov approached him and suggested he take a solo flight. A few minutes later, Gagarin took off. Alone in the plane for the first time he felt an overwhelming sense of joy as he circled the airfield once and came down for his landing. Beaming with joy, the young pilot reported back: “Mission completed.”

Star City ordeals Gagarin completed his studies at the technical college, but left the tractors to others and enrolled in the Soviet air force. After completing his training, he was sent to an air base near the Norwegian border. And while there in October 1959, a mysterious recruiting team arrived at the base. Nobody knew what they wanted, or even which government organisation they represented. But the mysterious delegates were keen to talk with a selected number of pilots, which included Gagarin. The recruiting team went through the papers of all the fighter pilots, and summoned them for informal talks in groups of 20. The questions concerned matters both minor and major. Do you like to fly? What books do you read? What do you do in your spare time? As the days passed, the groups shrank. Gagarin remained among the chosen who

ESCAPING EARTH

HARD LUNAR LANDING

At a speed of 40,000km/h, Luna 1 was the first probe to escape Earth’s field of gravity. According to the plan, the probe was to crash on the Moon, but due to a control error, it managed only a fly-by in January 1959.

On 14 September 1959, Luna 2 hit the Moon. For the Soviet Union, the feat was not merely a propaganda success. Much to the annoyance of the US, the mission also demonstrated that the Russians had technology that could be used to make intercontinental nuclear missiles hit targets in America.

SOVFOTO/UIG/GETTY IMAGES

SOVFOTO/UIG/GETTY IMAGES

LUNA 2

LUNA 1

SHUTTERSTOCK

GARGARIN DURING A SCHOOL LECTURE IN THE 1950s.

were told to attend a thorough physical examination in a Moscow military hospital. After the examination, the interview questions changed. The pilots were now asked how they felt about flying more modern aircraft – were they interested in trying something completely different? Confused, Gagarin answered the many questions without being able to find what they were talking about. Was it a helicopter? A new secret type of fighter plane? Finally the committee revealed their hand. “We are talking about long-distance rocket flights,” they told Gagarin. “Rockets flying around the entire world.” From a group of 2200 fighter pilots taken from the entire Soviet Union, 26-year-old Gagarin ended up in a squad of 20 cosmonaut trainees. In June 1960, they moved to the training centre of Svyozdny Gorodok, 40km east of Moscow. The place would later become known in the West under the name ‘Star City’. In these new facilities, trainees were instructed by a team headed by General Kamanin, whose programme consisted of hard physical exercise, long lectures, and practical drills in a replica spacecraft. The trainees had to prove themselves. In a pressure chamber, Gagarin and the others were subjected to extremely low air pressure to test how they reacted to high altitudes. They learned how to handle the extreme conditions in a centrifuge – the faster the centrifuge rotated, the more intense the force of gravity that the trainees experienced. The powers of acceleration to which the cosmonauts would be subjected during the ascent might shift their blood away from their brains and knock them unconscious. In the centrifuge, Gagarin could not close his eyes, he had difficulties breathing, and his face seemed distorted. But even this was

Gagarin originated space superstitions Before his space mission, Gagarin carried out a series of more or less conscious actions. They set a fashion which, ever since, Russian cosmonauts have superstitiously imitated before they are launched into space.

Two days before launch, the cosmonauts visit a hairdresser.

The night before launch, the cosmonauts watch a film.

A few hours before launch, they write their names on the door to the room in which they spent the night.

On their way to the launch pad, male cosmonauts briefly leave the bus to take a leak at the left rear wheel of the bus.

THE MOON’S FAR SIDE

Luna 3 was the first spacecraft to pass by the far side of the Moon on 7 October 1959. With an electronic camera system, it took the first images of the Moon’s unseen side. The images were sent back to Earth via radio signals. NASA

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soon surpassed as he moved on to the space centre’s other training tools: the vibration device and the heat chamber. The vibration device imitated the vibrations of a spacecraft, shaking Gagarin thoroughly for more than an hour. In the heat chamber he was subjected to extreme fluctuations in temperature. When he returned to his wife and their daughter following day after day of training, he was often so exhausted that he could hardly feel his legs.

programme’s tough elimination race. The men’s physical health, abilities and training results played the main role in the selection, but their size was also a factor. Space in the capsule was limited, so the cosmonaut could not be too tall. At 157 cm, Gagarin was a perfect fit. His friend and rival Gherman Titov was also popular with Korolev, but Gagarin’s humble background gave him a small

Critical boots-off training After a year of intensive training, the launch of Earth’s first manned spacecraft was drawing nearer. Yet still nobody knew who would be selected to make the attempt at being the first man in space. It turned out that the first encounter with the spacecraft itself played a decisive role. Chief designer Sergei Korolev, the brains behind the Soviet space programme, introduced the cosmonaut trainees to the Vostok space capsule. The sight of it struck awe in the men, and one after another they were allowed to step into the narrow capsule. Korolev noticed that Gagarin was the only one to take off his boots, and he smiled appreciatively at the charming young man with the boyish smile. Korolev had already heard good things about Gagarin from a military doctor, who worked in Star City: “Gagarin is eager to learn, robust, intelligent, and focused,” the doctor had reported. “During training he has demonstrated that he is able to strike a fine balance between blind obedience and independence. I have not noticed one single inappropriate detail about his behaviour.” Korolev named his favourite, “My little eagle,” and by April 1961 Gagarin was one of only six remaining trainees in the Vostok

advantage. Titov was middle class, but Gagarin’s peasant origins would give the Soviet Communist Party something it could use in its propaganda. In the Soviet Union, they could say, even peasants stood a chance of achieving their dreams. The final decision was made in a closed meeting of a special government committee on 8 April 1961 – only four days before the planned launch. The committee’s most important votes were those of Chief Designer Korolev and of General Nikolai Kamanin, the head of cosmonaut training. After the meeting they summoned the trainees to inform them of the result – the air thick with a mix of excitement and anxiety.

On the morning of 12 April 1961, Gagarin was on the bus to the launch pad of the space centre in the Soviet republic of Kazakhstan. He could see first the rocket’s base, then its tall, silvery body. As he approached, the rocket grew and grew, until finally it seemed like a huge lighthouse. An elevator was to lift Gagarin the last 50 metres up to the hatch of the space capsule. Before entering the elevator, the cosmonaut turned and gave a speech. “Dear friends, both known and unknown to me, fellow Russians, and people of all countries and continents, in a few minutes a mighty spaceship will carry me into the far-away expanses of space,” he said and made a brief pause to collect his thoughts. “Am I happy as I set off on this space flight? Of course I’m happy,” he stated, looking directly at his audience. “To be the first to enter the cosmos, to engage single-handed in an unprecedented duel with nature – could anyone dream of anything greater than that? In all times and epochs, the greatest happiness for man has been to take part in new discoveries.” Gagarin noticed that Chief Designer Korolev was looking impatiently at his watch, and he realised he should hurry aboard. A few minutes later, Gagarin was sitting in the space capsule. With the hatch closed and sealed, it was his turn to look at the watch – it said 9.07 AM Moscow time.

THE FIRST MAN IN SPACE

After orbiting Earth for one day, two dogs returned to the surface on 19 August 1960. The females Strelka and Belka are officially the first living creatures to survive a space mission, though the two dogs were accompanied by a rabbit, two rats and 42 mice, which also survived.

After several successful dog experiments, the Soviet Union in 1961 launched Gagarin into an orbit around Earth. The feat created a stir throughout the world, humiliating the US in the space race. Until the US lunar landing in 1969, the Russians ruled space:

Strelka and Belka became extremely popular and participated on Russian TV shows. TEKNORAVER

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To be the first to enter the cosmos, to engage single-handed in an unprecedented duel with nature – could anyone dream of anything greater?”

Rocket looked like a lighthouse

SPACE MISSION SURVIVORS

STRELKA

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YURI GAGARIN MINUTES BEFORE SPACE MISSION:

“Yuri Gagarin has been selected to be the first cosmonaut, and Gherman Titov is his substitute,” Kamanin announced, without any further explanation. Gagarin stepped forwards, trying to mask a wide smile. “I promise to carry out my duties very diligently,” he replied.

SCIENCE ILLUSTRATED

VOSTOK 1

In August 1961, Gagarin’s friend Gherman Titov spends a full day in space. Alexei Leonov makes the first space walk in 1965.

BELKA

An unmanned Soviet spacecraft makes the first soft lunar landing in 1966.

Gagarin’s scorched capsule after the landing. AFP/RITZAU SCANPIX

DORLING KINDERSLEY/GETTY IMAGES

Vostok was on autopilot From launch to landing 108 minutes later, Gagarin’s spacecraft was locked on autopilot. The first man in space was really playing the role of passenger during this historical mission.

Gagarin did not control anything

Gagarin’s emergency handle

Nobody knew how a human being would behave in space, so Gagarin was not allowed to control anything. Vostok’s route was preprogrammed into the space capsule’s primitive computers, with course adjustments sent as radio signals from mission control to the craft’s antennas.

If the remote control failed, Gagarin could access manual control by means of a handle and control the capsule himself. The procedure involved entering a three-digit code.

Tanks included oxygen and nitrogen Space includes no oxygen, and so Gagarin had to bring the air he needed to breathe. Nitrogen from circular tanks was mixed with 20.1% pure oxygen to imitate Earth’s atmosphere.

Catapult seat was to save the cosmonaut Russian calculations had shown that the landing would be so hard that humans would barely be able to survive inside the capsule. So Gagarin catapulted and parachuted.

Service module became space junk The space capsule rested on a conical service module that functioned as Vostok’s engine room. Prior to landing, the service module was to be disengaged and remain in orbit around Earth, but a thick bundle of cables got stuck and prevented the disengagement.

Vostok space capsule Crew

SOVFOTO/UIG/GETTY IMAGES

HUGE ROCKET LIFTED GAGARIN A 30-metre-high rocket made sure that the space capsule and Gagarin entered space. Vostok-K weighed 267 tonnes and included fuel for three stages that combined to push the cosmonaut upwards for 13 minutes. When the last rocket stage was disengaged, Gagarin was in space. Vostok-K rockets were used for all of the Soviet Union’s manned space missions up until 1964.

1

Length

4.4 metres

Diameter

2.3 metres

Weight

4725kg

Launched from

Baikonur, Kazakhstan

Distance covered

40,868.6km

Mission duration

108 minutes

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S PA C E

GAGARIN

At that very moment he heard a whine, then an increasing howl. Finally Gagarin felt the huge spacecraft slowly lift off from the launch pad and begin to accelerate. An irresistible force pushed him ever deeper into his seat. “Poyekhali! [‘Off we go!’],” he cheered. “Seventy seconds have passed since launch,” his mission control said. “Roger. 70 seconds. I am fine. I continue the flight – the G force is intensifying. Everything is fine,” Gagarin said. “How are you?”, mission control asked him a few seconds later. “I am fine. How about you?” the rocket man answered. A few minutes into the mission, Gagarin was experiencing serious G forces, tearing at his face muscles. It was difficult for him to speak, but he quickly got used to it – the centrifuge training had not been in vain. When the last rocket stage had lifted Yuri Gagarin into orbit around Earth after nine minutes, he reported: “Weightlessness has set in. It does not feel unpleasant in any way; I am fine.” As the cosmonaut unbuckled his seat

belt, he quietly floated out of his seat. He was hovering between the cabin floor and ceiling, as if his arms and legs no longer belonged to him. His pencil sailed slowly past him. Through one of the space capsule’s portholes, Gagarin noticed below the jagged

YURI GAGARIN FROM SPACE:

Weightlessness has set in. It does not feel unpleasant in any way.

mountains, river courses, vast forests, and the gleaming ocean surface. The sky behind the bluish-green Earth was inky black, and the stars shone so brightly that he had to screw up his eyes. Mission control communicated with him constantly over the radio: “How are you now?”

Over and over again, Gagarin replied, as he travelled at a speed of 27,400km/h: “The flight is still fine. The machinery is functioning normally. Excellent visibility. I can see everything. It is beautiful.”

Vostok in crisis About half an hour after launch, Vostok had travelled from Siberia into the night above the Pacific. From there, it sped south to pass by the southernmost point of South America. For a few minutes Gagarin was out of radio contact, and that was when Radio Moscow and the Soviet news agency TASS sent a triumphant message to the world. “The Soviet Union has successfully launched a manned satellite into orbit around Earth. Aboard the spacecraft is cosmonaut Yuri Gagarin, a 27-year-old airforce pilot.” In fact, the authories had prepared three separate bulletins: the one released, announcing a successful flight, another in case of problems, and a third one should the mission end in disaster. And for a while, it looked as if TASS might need all three. At 9.52 AM, Gagarin passed above South America’s Cape Horn and on across the

Gagarin’s triumph took him across the world London, Copenhagen and Paris were just some of the capital cities to which the first man in space was sent – on a charm campaign for Communism. In a single day, the formerly-unknown pilot Gagarin became the superhero of the entire world. The Soviet Union’s Communist government was quick to leverage the success. In July 1961 Gagarin was sent on an international charm campaign, where he was applauded in grand parades throughout the world. During a visit to Denmark in September 1962, Copenhagen’s mayor Urban Hansen asked about a distinct scar that Gagarin had above his eyebrow. The cosmonaut said that during a holiday, he had stumbled while carrying his daughter on his shoulders. To spare the little girl, he

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had fallen on his head. The truth, however, was not quite so innocent. In September 1961, Gagarin had been on holiday in a sanatorium on the Crimean peninsula with his family and other cosmonauts. The men had been drinking, and on the last night Gagarin had approached a young nurse who worked at the sanatorium. Rather drunk, he sneaked into the woman’s room on the first floor and was about to kiss her, when his wife suddenly appeared. Panicking, Gagarin fled via the room’s balcony, hitting his forehead when he landed. He had to live with the scar, and the embarassment.

Two weeks after his space mission, Gagarin drove through Prague, the capital of Czechoslovakia. KEYSTONE/HULTON ARCHIVE/GETTY IMAGES

was intensifying. In a nightmarish position, Gagarin could see the Earth and Sun whizzing by outside the portholes. “One moment I see Africa – it happened over Africa – another the horizon, another the sky,” he wrote in his post-flight report, which remained secret for decades. “I barely had time to shade myself from the sun, so the light did not blind my eyes.” And there was absolutely nothing he could do, because Vostok had no mechanisms available to cut the cables. Gagarin feared that the capsule and service module would approach each other and finally collide. He had no idea what would happen if they did. But then, after 10 long minutes of chaos, the capsule suddenly righted itself. The flames had burned through the cables of the service module, and Gagarin was safe. “Everything is OK!” a relieved Gagarin reported to mission control. The cosmonaut was still shaken as he sped down through Soviet airspace, but he pulled himself together. There was one final test, as in a roar of noise the capsule blew its hatch at an altitude of seven kilometres, and the next second Gagarin and his seat were catapulted out like a living cannon ball. When he reached an altitude of four kilometres, the catapult seat was released, and Gagarin gently approached the ground in his parachute. Below him the Volga River gleamed, and the first man in space enjoyed the sight of Russian fields in spring, forests, and the city of Saratov, where the houses rose slowly towards him. He knew it well, as this was where, only 10 years previously, he had taken his first flight.

Received by peasants

In Communist Cuba, Gagarin was embraced by the nation’s charismatic leader, Fidel Castro. JOSEPH SCHERSCHEL/LIFE/GETTY IMAGES

Exactly 108 minutes after his launch from Baikonur, Gagarin was back on Earth. The first people he met were a peasant woman and a little girl, scared to see the big orange spacesuit. Gagarin called to them: “I am a friend, comrades, a friend. I have just returned from space!” General Stuchenko’s soldiers soon arrived. “Yuri Gagarin, Yuri Gagarin,” they cheered and surrounded the cosmonaut. The soldiers hugged Gagarin and shook his hand. The Soviet Union’s new

The new Soviet leader, Leonid Brezhnev (front right), was one of the men who carried Gagarin’s coffin.

Moonshot demotion led to his death Gagarin had the dream of also becoming the first man to set foot on the Moon. But then in April 1967 cosmonaut Vladimir Komarov crashed and died when the landing parachute of his Sojuz capsule failed. Communist Party leaders feared that another aerospace accident could kill famous Gagarin, their international hero, so they forbade him to work as a cosmonaut. Heartbroken and angry, he wrote asking them to relent, but they refused. Instead, he was moved to a job as an airforce pilot – a change of career that had fatal consequences. During a training session with a MiG-15 fighting plane, he and flight instructor Vladimir Seregin crashed and died on 27 March 1968.

superhero was flown by helicopter to the closest military base, where President Nikita Khrushchev was waiting on the phone: “I am happy to hear your voice, Gagarin. I congratulate you on the successful completion of the first cosmic flight.” “Thank you for the confidence you have shown me,” answered the new hero. “I assure you that I am ready to carry out any new mission in service of our nation.” scienceillustrated.com.au

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TASS/AFP/RITZAU SCANPIX

Atlantic, back towards the Soviet Union and daylight. Over Africa, the lonely cosmonaut continued to send radio updates. At last the spacecraft activated its rocket engines to slow down as Vostok prepared to approach southern Russia, where the landing was supposed to take place. The craft slowed, passing back from empty space into Earth’s dense atmosphere. Gagarin noticed a red-yellow glow from flames caused by friction around the space capsule. The temperature inside the space capsule increased tremendously – just as Gagarin’s training had prepared him for. The weightlessness was gone, and the G forces once again pushed him into his seat – now with even more force than during the launch. Then suddenly, Vostok began to spin out of control, and Gagarin was facing a problem for which he was not prepared. According to the plan, the space capsule should have disengaged the service module – but a bundle of cables still held the two modules together. The dangling service module pulled Gagarin’s capsule into a spin. Sometimes he felt he was about to pass out, and he reported to mission control that the spin

PSYCHOLOGY

MEET YOUR APE BRAIN

SHUTTERSTOCK

OUR Y T MEE BRAIN so APE ating

he ? take c us angry e w o s e d y k l y l a h a m W ic sly it e bas s seriouause we ar g in group s t n s i a v Bec e i ild b pes, l still a aring the w o many of S and fe savanna. iours are er v e a h oth h t of sic be e from our baent in thos mily tree. r fa vid also e nches of ou bra

SCA LINDA KASTRUP/RITZAU

NPIX

HAVING YOUR CAKE... BUT NOT EATING IT WHO’S WHO HOR ARTICLE AUT

Jill Byrnit TITLE

bachelor Authorised psychologist, PhD degree in biology and a s of degree in the social skill ates. humans and other prim RESEARCH

ia’s She is one of Scandinav ate leading experts on prim s behaviour, which she ha primate observed in the wild, in stations, and in zoos. 80

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SCIENCE ILLUSTRATED

Why we share and share alike People would rather say no to cake than yes to a piece that is unfairly small. The reason for this can be found in evolution, and in our close relationship with apes and monkeys.

I

f you have ever watched a group of baboons being fed, you may have seen how higher-ranking group members always end up with the most attractive food. The same is true for a long list of other animals, such as lions, macaques, and mandrills. It is not just coincidence. Clearly the most powerful individuals within a group of these animal

species have the right to take whatever they want. Power gives them the right. Yet this is not true among humans. A few individuals do not play by the same rules as everybody else and might threaten their way to advantages to which they would otherwise have no right. But generally, humans have sophisticated rules governing what is fair, though we rarely articulate or discuss them.

By Jill Byrnit

These sophisticated rules are implicit preconditions of just about all forms of human interaction, and often it is only when somebody breaks the rules that we realise these standards of justice. Scientists have studied such standards via games that were originally experimental economics games, but now are also much used in psychology and biology, when scientists want to understand human distribution mechanisms.

relatives. In a thought-provoking American experiment, scientists aimed to study how South-American capuchin monkeys react to injustice. The monkeys were placed in separate cages, from where they could see their peers. All the monkeys had previously learned that they could swap a stone for a piece of cucumber – something which capuchins will eat, but do not find particularly delicious. The experiment began, and the monkeys happily swapped their stones for cucumber. But then the procedure was changed, with one monkey receiving a nice juicy grape. The lead researcher returned to to the previous cage, where the monkey was awarded not with another nice grape, but with the usual cucumber piece. How did the monkey react? Not very well. It didn’t eat the cucumber. Indeed subsequently the monkey threw both the cucumber and stones out of the cage at the lead researcher, to make sure their displeasure at such unfairness was understood. Since then, this same experiment has been carried out with our closest relative, the chimp, and the results were the same. Capuchins, chimps and humans simply do not put up with being treated unjustly; individuals from these species get so angry that they would rather not have anything than get an unjust share. Back in 1872, Charles Darwin introduced the idea that it makes sense for the development of morals to have been a biological one. If gregarious animals are to coexist, some basic principles of sharing must be held in common; not every action can benefit only oneself. Otherwise, the price of being in a group would simply be too high. So evolutionary selection pressure produced the building blocks of what is now recognised as a sense of justice.

SEVERAL ANIMALS U N D E R S TA N D FA I R N E S S

Game punishes tyrants One of the experiments is known as the ultimatum game, in which a test subject such as yourself is placed in a waiting room. At some point, a lead researcher enters the room, gives you $100, and tells you that another test subject is sitting in the next room.

The sense of justice could be a natural instinct in humans.

Generous bats get more blood

Vampire bats feed only on blood, and they die if they don’t get any for two days. But the bats happily share the blood, and studies have revealed that generous bats receive more blood when they need it than non-generous individuals.

JILL BYRNIT

The lead researcher explains that you must share the money, and you can decide the distribution. You are also told that you will not meet the other test subject. Then here’s the catch. If the other test subject accepts the amount you suggest, you share the money according to your wishes. But if the test subject says no to the amount, neither of you gets any money. So how much money will you offer the other test subject? If you do as most people do, you will offer the other test subject around half of the amount, understanding that those on the receiving end will refuse a low offer (less than 20% is nearly always refused) even though neither of you then gets anything. Where does this focus on fair treatment come from? The ultimatum game has been carried out in developed nations, agricultural communities, even among hunter-gatherers, and the results are very much alike.

Others have the same principles

The blue jay has also participated in scientific gameplay. Birds play either against pretend opponents that always give their fair share, or against opponents that never do. The birds cooperate stably only with fair opponents.

WATCH WHAT HAPPENS WHEN MONKEYS RECEIVE UNEQUAL PAY This YouTube video shows what happens when one monkey is rewarded with tasty grapes, while another gets only cucumber...

Chimps allow finders keepers

Among macaques and mandrills, higher-ranking individuals can always take food from lower group members. But among chimps and bonobos, the individual that gets the food first becomes its owner. If higher-ranking group members want something, they must beg.

tinyurl.com/science83

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Apparently, this sense of justice is so deeply rooted in humans that it does not require any cultural influence or training to be expressed. Scientific evidence indicates that the inherent sense of justice could be a natural instinct in humans. Scientists have found clear indications that the sense of justice also exists in some of our primate

Jay chooses fair partners

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Editor: David Dragsted

TEST YOURSELF

Solve problems designed for different types of intelligence, and find out in which you excel!

ANSWERS ON PAGE 11

Text & Art: Anker Tiedemann & Erik Wied

LOGIC 1

You have a lighter and two burnable ropes. It takes exactly two hours for one rope to burn up. The ropes cannot be bent to measure lengths. How will you time 1.5 hours with those tools?

2

Tommy walks 14km a day with his labrador retriever, Emerson. As the dog prefers to run faster than Tommy walks, Tommy keeps Emerson on a leash for the first 7km, both walking at the same speed of 7km/h. Then Emerson is allowed off-leash, running first back to the house, then back to Tommy, then back home, then back to Tommy, etc., until they are both home. Emerson runs at an average speed of 40km/h, whereas Tommy continues home at a speed of 7km/h. Emerson is constantly in motion, and he does not zigzag. How many kilometres does Emerson cover in total?

NUMERACY 3

What number should replace the question mark?

44 16 26 18

?

MEMORY

12 c Scieuniz Q

55 14 31 4

Move one match and insert either to replace the question mark.

?

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+, −, × or /

e

FROM THIS ISSUE

Answers on p11: no peeking!

This Au-Spot robotic dog is being trained for a particular task. What is it?

5

William Le Baron Jenney’s metal skeleton for tall buildings was reportedly inspired by what?

A) Mining in California B) Entering a volcano C) Surveying Martian caves D) Walking other dogs

A) His wife’s slender frame B) His dog’s metal muzzle C) His bird’s metal cage D) His daughter’s braces

7

8

Of all parasite species thought to exist in the world, how many have scientists identified? A) 10% B) 30% C) 50% D) 70%

6

A stand of Huon pines in Tasmania has maintained one genetic individual for how long? A) 150 years B) 1500 years C) 10,500 years D) 105,000 years

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