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6 6 ' 2 March 2019 | NewScientist | 29

large group of women and men. They reported running of predetermined internal software, stronger connections within each brain but also external inputs. One famous example hemisphere in men and stronger connections was reported in working London taxi drivers between hemispheres in women. This, they who have done The Knowledge, which claimed, showed that “male brains are requires memorising different routes through structured to facilitate connectivity between the 25,000 or so London streets within a perception and coordinated action, whereas 6-mile radius of Charing Cross. Their brains female brains are designed to facilitate communication between analytical and “Playing computer games is intuitive processing modes”. a better predictor of spatial But the study didn’t measure whether its skills than biological sex is” subjects actually showed these supposedly typical male and female traits. Measurements of brain connectivity were being filtered are different from those of trainee taxi drivers, through preconceived, stereotypical beliefs. retired taxi drivers and even bus drivers, who What’s more, many of the reported differences navigate fixed routes. were quite small, and there were many more Crucially, brain-changing experiences may possible pathway comparisons that didn’t differ for men and women. Perhaps it was this show any differences. The study only reported effect that early researchers, focusing solely on those that did. Yet the results were eagerly dividing their groups of participants into men reported in the popular press, with headlines and women, were actually tapping into. such as “The hardwired difference between Take one of the allegedly most robust male and female brains could explain why brain differences: in spatial thinking, the men are ‘better at map reading’ ”. skill underpinning navigational abilities or There are good reasons to think that such map-reading. In 2005, psychologists Melissa studies are chasing shadows. For a start, Terlecki of Cabrini College and Nora correcting the data for brain size can cause Newcombe of Temple University, both in the apparent differences in brain structures between women and men to disappear. The claimed difference in the size of the corpus callosum is one casualty of this rethink.

The fact is, bigger people have bigger brains, regardless of their gender. Bigger brains are different from smaller brains, in both their core structures and the connecting pathways between them. But there is no evidence to suggest that bigger brains are better brains. After all, humans are (on average) cognitively superior to species with far larger brains, including the sperm whale and the African elephant, to name just two. More crucially, the idea of distinct female and male brains depends on the adult endpoint of brain development being a fixed, predetermined destination. Scientists used to think that beyond the changes that occur during the highly plastic early years of the brain, and barring deviations caused by damage, disease or deprivation, you generally end up with the brain you were born with, only bigger and better connected. We now know that isn’t the case. Our brains are very much a product of the lives we have lived, the experiences we have had, and our education, occupations, sports and hobbies. The way we perform tasks reflects not just the 30 | NewScientist | 2 March 2019

DAN KITWOOD/GETTY IMAGES

Not born this way

Pennsylvania, showed that playing computer and video games is a better predictor of spatial skills than biological sex is. There were higher levels of such experience among male participants, but women with the same level of experience had equally good spatial skills. Any regular activity, be it playing Tetris or Super Mario, or learning juggling or origami, can change our brains. So if one group is more likely to engage in an activity than another, this will determine their ability, rather than any other characteristic. In addition, stereotypes about any group’s innate abilities can become self-fulfilling prophecies. If someone is made aware of a negative stereotype about the group to which they belong, this can impair their performance in a related task. For example, if a woman is told that women are poor at a particular mathematical skill, there is a consequent drop in performance in tests of that skill. Studies of this so-called stereotype threat have shown that if a task is presented in a positive context, then both the associated brain processes and how well someone performs the task will be different from when it is presented in a negative context. It isn’t

By learning routes, taxi drivers physically alter their brains

@JAMES WALLER

just experiences that can change our brains: attitudes, especially powerful social stereotypes, can too. And it may be that we need to challenge the assumptions behind the hunt for differences between male and female brains. Its origin is in the assumption that men and women are profoundly different in their abilities, behaviours and preferences. But what if these “well-known” differences aren’t as marked as has been claimed, and have changed over time or in different contexts or cultures? This would certainly challenge the notion that they are inevitable or based on fixed brain characteristics. Revisiting the evidence suggests that women and men are more similar than they are different. In 2015, a review of more than 20,000 studies into behavioural differences, comprising data from over 12 million people, found that, overall, the differences between men and women on a wide range of characteristics such as impulsivity, cooperativeness and emotionality were vanishingly small. Perhaps the final nail in the coffin of female and male brains as a scientific concept can

PROFILE Gina Rippon is a cognitive neuroscientist at the University of Aston in Birmingham, UK, where she uses brain-imaging techniques to study conditions such as autism and dyslexia. She is the author of The Gendered Brain (Bodley Head)

be found in a 2015 study by Daphna Joel at of a brain-based condition as belonging solely Tel Aviv University in Israel and her to women or men may miss the clues offered colleagues. They examined the characteristics by, for example, brain size or body weight, of more than 100 brain structures in over 1400 or brain-changing life experiences. brain scans and found that it was impossible In some of my own team’s research on to divide these neatly into two sets of “female- autism, we are starting to realise that holding typical” or “male-typical” brains. Each brain to the belief that this is a “male” condition had a mosaic of different characteristics, means we are missing the many girls and some considered “female”, some “male”. women who clearly fit the diagnosis. Only around one in 20 of the brains even had Diagnostic tools are masculinised, with sets of characteristics that could be described examples of children’s unusual interests as predominantly one or the other. and obsessions slanted towards those more Applying similar analyses to data sets of commonly associated with boys. Not only psychological variables such as engagement does this mean that the undiagnosed girls in sports, impulsivity or scores on tests of aren’t getting the help they might need, but masculinity-femininity revealed the same research is losing a rich source of additional lack of binary grouping: no individual had evidence: many brain-imaging studies of all-female or all-male tendencies. More recently, using machine-learning techniques “It’s not just experiences on data from more than 2000 brains that change our brains – showed that none fitted into one of two neat, social stereotypes can too” non-overlapping sets that could be labelled “brains from women” or “brains from men”. Where does all this leave us? We find autism have only male participants. ourselves talking about average differences This isn’t just a question of importance between men and women that, in general, to individuals, however. Believing that only reflect a tiny difference between two closely one type of brain is capable of certain core overlapping sets of data. Not only that, but the skills may lead to an immense loss of human variability and range within each supposedly capital, to the detriment of wider society. Who homogenous set is usually far greater than knows how many more software engineers the differences between the sexes. You might global tech firms might find if we accepted start to wonder why we are still talking about that there is little reason to believe that this these differences at all. is a pursuit to which only men are suited. For sure, biological sex must be considered It is finally time to discard this old chestnut. as one of the variables in investigations into The concept of the female brain or the male brain differences, so we can understand brain is outdated and inaccurate. Every things such as responsiveness to different person’s brain is unique. The value comes medications, or susceptibilities to mental from knowing where these individual health problems such as depression, physical differences come from and what they might problems such as Alzheimer’s disease or mean for the brain’s owners. ■ immune disorders. This might also give Hear Gina Rippon and other neuroscientists at insights into the true reasons for women’s our Mysteries of the Mind event in London on 11 May under-representation in fields of science and newscientist.com/science-events technology. But a focus on biological sex as For links to the studies quoted, see the online version the sole source of such differences is at best incomplete and could be misleading. Thinking of this article 2 March 2019 | NewScientist | 31

2 8 . 0 8 6

THE PATTERN OF REALITY

Silicon 2 8 . 0 8 6

O

Krypton

ne hundred and fifty years ago this Friday, a Siberian chemist named Dmitri Mendeleev sent a manuscript to his publishers. It contained an outline of the periodic table, descendants of which would go on to grace the walls of schools the world over. It depicts the chemical elements that make up everything around us and, at a glance, conveys a sense of order to the building blocks of everything. But don’t be fooled. The periodic table didn’t appear complete and out of nowhere – it had a troubled birth (page 34). Neither is it as solid as it may appear. There’s still plenty of disagreement about exactly how the table is best set out (page 36). What is certain is that it remains unfinished, and that researchers are on the cusp of producing elements that exist beyond its bounds in quantities that we can actually study for the first time (page 39).

Neon Argon Lithium

MY FAVOURITE ELEMENT

Boron Yttrium Caesium

Si

Zinc Xenon

Silicon

Lead Fluorine

Frances Arnold is a chemist at the California Institute of Technology. She won the 2018 Nobel prize in chemistry for her work on evolved enzymes

Lutetium

~

Rubidium

Silicon is readily available on Earth in the form of sand. In the periodic table, it sits just below carbon, the element that nature uses to build DNA, proteins and other molecules of life. Why wasn’t silicon chosen? Can life build organosilicon compounds? We wanted to know, and discovered that enzymes that forge carbon-silicon bonds could be evolved in a test tube. We are just beginning to explore the possibilities that exist for life.

Copper

Flerovium Radon

1 0 . 8 1 1

Boron

2 March 2019 | NewScientist | 33

BRINGING ORDER TO CHAOS Mendeleev’s periodic table broke through the chemical haze. But it wasn’t a dream discovery, says Philip Ball

D

MITRI Mendeleev had a problem. As a professor at the University of St Petersburg in Russia, he was supposed to teach chemistry to students, and to guide him in that task he had arranged a contract with a Russian publisher to write a twovolume textbook. By January 1869, he had completed the first volume, but it covered only eight of the 63 chemical elements then known. How was he going to cram the remaining 55 into volume two? Clearly he couldn’t afford to take the same rambling stroll through the properties of the elements as he had in the first volume. He needed some system to organise the material. But was there any order to the building blocks of the physical world? When we retell stories of scientists pondering great questions like this, they are often made to seem romantic. There is the period of struggle and confusion that ends when a lone genius sees the light, perhaps in a reverie or dream. Then everything falls into place, the paradigm shifts, and nothing is ever the same. How much more noble this sounds than a desperate attempt to meet a publisher’s deadline. Some accounts of how Mendeleev devised the periodic table try to make it fit that romantic template. They allege that the Russian, originally from the remote town of Tobolsk in Siberia, was obsessed with finding structure among the elements and laid them out written on cards, like a game of solitaire. He tried all sorts of arrangements without

34 | NewScientist | 2 March 2019

MY FAVOURITE ELEMENT

Tc

Technetium

Lee Cronin is a chemist at the University of Glasgow, UK

~ Technetium is the lightest radioactive element and all of its isotopes are radioactive. It can be produced in any reasonable amount only in a nuclear reactor. That appeals to me because it means that if you found this element elsewhere in the cosmos it would be good evidence that intelligent alien life exists. Plus, it can be made from radioactive molybdenum, which is my next favourite element because I’m trying to make nanomachines using it.

success, the story goes, until he fell asleep, exhausted, in his study in February 1869. “I saw in a dream a table where all the elements fell into place as required,” he was later reported to have said. On waking, he hastily wrote down his vision, and two weeks later published his “Suggested System of the Elements”. At last, the steadily growing

list of elemental substances from hydrogen to lead had a logic to it. That logic, said Mendeleev, is essentially this: if you order the elements according to their atomic weight – how much a constant quantity of each element weighs relative to the lightest, hydrogen – their properties seem to repeat at regular intervals. You can therefore write the list of elements as a table, with columns of elements that share similar attributes. This pattern is still the basis of modern periodic tables, but the tale of how Mendeleev discovered it crumbles under examination. Take the dream. “I don’t believe it,” says historian of science Michael Gordin at Princeton University, an expert on Mendeleev’s life and work. “The sources are too iffy.” Mendeleev never made the dream claim himself; it came from a colleague 40 years later. Even then, he could easily have meant something like a daydream, says Gordin. Mendeleev himself emphasised that his discovery “was the product of insight and chemical knowledge”, he adds. But Gordin admits that “people seem to love this story, so I don’t think my historian’s fussiness is going to squelch it anytime soon”. At any rate, there was never a perfect arrangement of the table that made sense of all the available knowledge. For one thing, Mendeleev’s ranking of the elements by atomic weight isn’t what we use today. Atomic weights were deduced by experiment: by breaking chemical compounds into

Be2O3, to get beryllium into the same column as magnesium, with which it seemed to have similarities. Mendeleev would later be proved right about the formula. In this and other small ways, his table is an example of an idea asserting precedence over the available data, challenging the common view in science that if your hypothesis disagrees with the data then you must discard it, no matter how elegant it is. And even if Mendeleev’s table was a master stroke, it wasn’t a total revelation. The German chemist Johann Wolfgang Döbereiner had done something similar, by grouping chemically alike elements into groups of three, which he called “triads”, in the 1820s. Others, including William Odling and John Newlands in the UK, Alexandre-Émile Béguyer de Chancourtois in France, and Julius Lothar Meyer in Germany, sketched out

PICTORIAL PRESS LTD/ALAMY STOCK PHOTO

“The steadily growing list of elemental substances finally had a logic to it”

their constituent elements and weighing how much of each they contained. But the more fundamental ranking comes from the atomic number of each element, the number of protons in nuclei of their atoms. In the middle of the 19th century, no one was sure if atoms were even real, and Mendeleev himself was sceptical. Even the atomic weights were disputed. For example, oxygen and hydrogen combined to make water in a ratio of eight parts to one, but did this mean water molecules contained equal numbers of hydrogen and

oxygen atoms, with the latter eight times heavier, or twice as many hydrogen atoms as oxygens, with the latter 16 times heavier? (It is actually the second of these, the molecular formula being H2O.) It was, in fact, growing support for the H2O formula of water that helped Mendeleev order the elements properly. But he needed to take some liberties to ensure that elements with similar chemical behaviour fell into the same group. For example, he decided to give beryllium oxide the formula BeO, rather than (as most people thought)

Mendeleev’s table of elements wasn’t the first, but it was the best

arrangements of the elements gathered into families in the 1850s and early 1860s. Meyer virtually had the periodic table sorted by 1868, but he didn’t publish it until a year after Mendeleev. This work was no secret, although Mendeleev insisted later that he had been unaware of it. “This seems a little odd,” says chemist Eric Scerri at the University of California, Los Angeles, a leading expert on the periodic table. Disputes about who got there first ensued, making you wonder if the dream was just a convenient device. Finally, the notion that, thanks to Mendeleev’s periodic table, the scales fell from the eyes of his peers doesn’t stack up. A few scientists, such as Russian chemist Julia Lermontova, did take note and tried to clarify the ordering of elements by improving methods of separation and characterisation. But there was no abrupt paradigm shift in chemistry. “At first, there wasn’t too much of a reaction to it,” says Gordin. Curiosity about Mendeleev’s table only began to grow six or seven years > 2 March 2019 | NewScientist | 35

F

18.998 Fluorine

after it was published, when the element gallium was discovered by French chemist Paul-Émile Lecoq. It fitted the prediction made by Mendeleev of a heavier element below aluminium with atomic weight 68, for which he had left a space in his table, giving it the provisional name eka-aluminium. Ostensibly, Lecoq named it patriotically after the old Latin form of his country, Gallia. But it is widely suspected that the name was also a bit of sly self-advertising, as the Latin word gallus means cockerel – le coq in French. Another of Mendeleev’s predicted elements, labelled eka-silicon, was discovered in 1886 and christened

“Curiosity about the table grew as some of the gaps were filled” germanium. This capacity to make predictions was what distinguished Mendeleev’s table from earlier ones. Still, recognition was a long time coming. That may have been partly due to Mendeleev’s eccentric demeanour: his long hair, unruly beard and allegedly bad temper. The British chemist William Ramsay, having met him in London in 1884, described him as peculiar, “every hair of whose head acted in independence of every other”. But having conversed with him in broken German, Ramsay – who augmented the periodic table with a whole column of noble gases at the end of the century – found Mendeleev “a nice sort of fellow”. Although the tales of Mendeleev’s invention of the periodic table can be more fiction than fact, that doesn’t detract from its significance. It was the most comprehensive ordering of the building blocks of matter and, unwittingly, it pointed the way to the underlying quantum rules that govern the composition and properties of atoms. It helped unite chemistry and physics, and revealed a deep aspect of nature’s design. Just don’t try to pretend that it arrived in a dream. Q Philip Ball is a science writer based in London

36 | NewScientist | 2 March 2019

RESETTING THE TABLE It is the iconic picture of nature’s basic substances, but are they arranged correctly, asks Joshua Howgego

R

UN your fingers over the white keys of a piano. The notes get higher and higher as your hand moves to the right. On the eighth key, something beautiful happens: a note hangs in the air that embodies something of the first, only with a different pitch. We began to twig that something

MY FAVOURITE ELEMENT

Mt

Meitnerium Helen Arney is a comedian who spent nine months learning a song that lists all 118 elements

~ On top of battling prejudice about her gender and Jewish background, physicist Lise Meitner was passed over for a share of the 1944 Nobel chemistry prize. She had worked with her friend Otto Hahn to discover nuclear fission in heavy elements – but Hahn alone got the prize. I like the fact that the periodic table recognises Meitner: there is no hahnium, but there is a meitnerium. And while there is a copy of the iconic element chart on my daughter’s bedroom wall, there isn’t a list of Nobel prizewinners.

similar was going on with the chemical elements more than 150 years ago. Scientists even called it the law of octaves. And it is this repetition in the properties of the elements that the periodic table captures so beautifully. Similar elements end up stacked in columns or groups. One group comprises noble gases like argon and neon that barely react with anything, another contains reactive metals, some of which, like francium, explode on contact with water. But there are doubts over whether the periodic table is in the best possible configuration. Just as notes can be arranged in various ways to produce music, so the essence of the relationships between the elements could be depicted differently. There is no easy way to judge which is better, or more “true”. So arguments over perceived flaws in the current arrangement rumble on, with some chemists arguing that certain elements should be relocated – and others working on more radical ways to recompose the table. At first, the elements were organised by atomic weight (see “Bringing order to chaos”, page 34). Now we order them by the number of protons in their nucleus. We also know that their properties are largely determined by the arrangement of the negatively charged electrons that orbit in successive shells around the nucleus. The lightest elements have just one shell, which can hold two of these particles. Heavier elements have more shells that can hold larger numbers of

18

Group 1

2

1

H

WHERE DOES HYDROGEN GO?

13

14

15

16

17

Atomic number

5

6

7

8

9

10

Symbol

B

C

N

O

F

Ne

Name

Boron

Carbon

Nitrogen

Oxygen

Fluorine

Neon

13

14

15

16

17

18

12

Al

Si

P

S

Cl

Ar

Aluminium

Silicon

Phosphorus

Sulphur

Chlorine

Argon

29

30

31

32

33

34

35

36

Ni

Cu

Zn

Ga

Ge

As

Se

Br

Kr

Cobalt

Nickel

Copper

Zinc

Gallium

Germanium

Arsenic

Selenium

Bromine

Krypton

45

46

47

48

49

50

51

52

53

54

Ru

Rh

Pd

Ag

Cd

In

Sn

Sb

Te

I

Xe

Technetium

Ruthenium

Rhodium

Palladium

Silver

Cadmium

Indium

Tin

Antimony

Tellurium

Iodine

Xenon

75

76

77

78

79

80

81

82

83

84

85

86

W

Re

Os

Ir

Pt

Au

Hg

Tl

Pb

Bi

Po

At

Rn

Tantalum

Tungsten

Rhenium

Osmium

Iridium

Platinum

Gold

Mercury

Thallium

Lead

Bismuth

Polonium

Astatine

Radon

105

106

107

108

109

110

111

112

113

114

115

116

117

118

Rf

Db

Sg

Bh

Hs

Mt

Ds

Rg

Cn

Nh

Fl

Mc

Lv

Ts

Og

Rutherfordium

Dubnium

Seaborgium

Bohrium

Hassium

Meitnerium

Copernicium

Nihonium

Flerovium

Moscovium

Livermorium

Tennessine

Oganesson

Hydrogen

2

3

4

Li

Be

Lithium

Beryllium

11

12

Na

Mg

Sodium

Magnesium

3

4

5

6

7

8

9

10

11

19

20

21

22

23

24

25

26

27

28

K

Ca

Sc

Ti

V

Cr

Mn

Fe

Co

Potassium

Calcium

Scandium

Titanium

Vanadium

Chromium

Manganese

Iron

37

38

39

40

41

42

43

44

Rb

Sr

Y

Zr

Nb

Mo

Tc

Rubidium

Strontium

Yttrium

Zirconium

Niobium

Molybdenum

55

56

57-71

72

73

74

Cs

Ba

Lanthanides

Hf

Ta

Caesium

Barium

Hafnium

87

88

89-103

104

Fr

Ra

Actinides

Francium

Radium

Key

Darmstadtium Roentgenium

THE F-BLOCK CONUNDRUM

57

He

58

La

Ce

Lanthanum

Cerium

89

90

59

60

Pr

Nd

Praseodymium Neodymium

91

92

61

62

WHY ARE MERCURY AND GOLD SO WEIRD?

63

64

65

66

67

68

69

70

71

Pm

Sm

Eu

Gd

Tb

Dy

Ho

Er

Tm

Yb

Lu

Promethium

Samarium

Europium

Gadolinium

Terbium

Dysprosium

Holmium

Erbium

Thulium

Ytterbium

Lutetium

93

94

95

96

97

98

99

100

101

102

103

Ac

Th

Pa

U

Np

Pu

Am

Cm

Bk

Cf

Es

Fm

Md

No

Lr

Actinium

Thorium

Protactinium

Uranium

Neptunium

Plutonium

Americium

Curium

Berkelium

Californium

Einsteinium

Fermium

Mendelevium

Nobelium

Lawrencium

electrons. What really matters for each element’s behaviour, however, is how many electrons it has in its outer shell. That number tends to fit nicely with the way the table is arranged, namely to place elements with similar properties in the same group. For instance, group 1 elements have one electron in their outer shell and those in group 2 have two. But it doesn’t always fit together quite as neatly as all that.

WHERE DOES HYDROGEN GO? Take the first element. Hydrogen has one electron in its outermost shell so you might assume it belongs exactly where it is, in group 1 above lithium and sodium, which also have one electron in their outermost shell. Yet hydrogen is a gas, not a metal, so its properties don’t fit. The complication arises because, with an outer shell that can only hold two electrons, hydrogen is one electron away from being full. Given that elements yearn for full outer shells, that makes it very reactive. In this sense, hydrogen resembles the

Helium

elements in group 17, namely the halogens like chlorine. Their outer shells need only gain one electron to achieve a full shell of eight, which makes them similarly reactive. In terms of its properties, then, hydrogen is closer to chlorine than lithium.

WHY ARE MERCURY AND GOLD SO WEIRD? Lower down the table there are no available spaces for misplaced elements. Even so, a couple of the incumbents look like outliers. Take mercury, also known as quicksilver because it is a liquid at room temperature. In that sense, it is quite different to the other members of group 12, including zinc and cadmium, which are all solid metals. What gives? The further down the table you go, the more of the positively charged protons an element’s nucleus contains. This creates a stronger pull on

23

V 5 0 . 9 4 2

Vanadium

the orbiting electrons, meaning they must travel faster and faster. By the time you reach mercury, the electrons are travelling at 58 per cent of the speed of light. According to Einstein’s special theory of relativity, this means their effective mass is significantly higher than an electron’s normal mass, which exacerbates the inward pull they feel. The upshot is that mercury’s electrons orbit so tightly that they can’t be shared to form bonds with other atoms, as is required to make a solid. The same thing explains why gold is gold, a unique colour among metals: relativistic effects change the way electrons absorb light.

THE F-BLOCK CONUNDRUM Group 3 holds two elements that might belong elsewhere. As we move across the upper rows of the table, electrons fill up shells in a sequence of so-called orbitals, waiting until the innermost shell is full before entering the next. By element 57, lanthanum, the electrons begin to enter a new type of orbital, an f-orbital. To account for > 2 March 2019 | NewScientist | 37

GOING LONG 1

2

H

He

3

4

5

6

7

8

9

10

Li

Be

B

C

N

O

F

Ne

13

14

15

16

17

18

Al

Si

P

S

Cl

Ar

11

12

Na

Mg

Atomic number

Key

Symbol

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

K

Ca

Sc

Ti

V

Cr

Mn

Fe

Co

Ni

Cu

Zn

Ga

Ge

As

Se

Br

Kr

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

Rb

Sr

Y

Zr

Nb

Mo

Tc

Ru

Rh

Pd

Ag

Cd

In

Sn

Sb

Te

I

Xe

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

Cs

Ba

La

Ce

Pr

Nd

Pm

Sm

Eu

Gd

Tb

Dy

Ho

Er

Tm

Yb

Lu

Hf

Ta

W

Re

Os

Ir

Pt

Au

Hg

Tl

Pb

Bi

Po

At

Rn

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

Fr

Ra

Ac

Th

Pa

U

Np

Pu

Am

Cm

Bk

Cf

Es

Fm

Md

No

Lr

Rf

Db

Sg

Bh

Hs

Mt

Ds

Rg

Cn

Nh

Fl

Mc

Lv

Ts

Og

STARTING OVER All these niggles have persuaded some chemists that we need to redraw the periodic table – and there is no shortage of ideas. Mark Leach at Manchester Metropolitan University, UK, keeps the internet database of periodic tables, which contains hundreds of versions. In an attempt to better represent the continuity where one row currently ends, retired Canadian chemist Fernando Dufour developed a 3D periodic system that looks like a Christmas tree, with the elements radiating from a trunk in circles that get larger closer to the bottom. An alternative is the spiral developed by Theodor Benfey, which allows the f-block to bulge outwards (see “Elemental cycle”, right). Eric Scerri at the University of

“One proposed redesign looks like a Christmas tree”

But Guillermo Restrepo at the Max Planck Institute for Mathematics in the Sciences, Germany, favours an alternative. He has explored whether chemical similarity of elements in the same columns still holds as well as it did 150 years ago, given our increased knowledge of chemical reactivity. His conclusion is that lanthanum belongs in group 3 – that is, out of sequence. Redesigning the periodic table might seem a quixotic quest, but it could soon take on a new urgency (see “The element factory”, right). We are already on the trail of element 119. Where it will go, and how the table will morph to make space for it, remains to be seen. ■

California, Los Angeles, is among those who has argued for more fundamental changes. He previously proposed that the table could be arranged to maximise the number of “triads”, sets of three elements that share similar properties and are related by their atomic weights. These days, he is backing an even more drastic approach: make the table not 18 but 32 columns by slotting all 30 f-block elements between the current groups 2 and 3 (see “Going long”, above). This allows the atomic number to run in an uninterrupted sequence.

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Joshua Howgego is a features editor at New Scientist

Su pe ra ct in id es

this, most periodic tables hive off the elements making up this f-block, putting it below the table, leaving a gap in group 3. Fair enough. But there is debate over which of the elements in the f-block should come first. Some chemists maintain that the decision should come down to electron configuration, which would leave the table as it is, with lanthanum and actinium at the lefthand end of the f-block. Others point out that chemical properties such as atomic radius and melting point make lutetium and lawrencium, currently at the right end, a better bet. In 2016, the International Union of Pure and Applied Chemistry assembled a task group to settle the argument. But no one expects a decision soon.

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109

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38 | NewScientist | 2 March 2019

SOURCE: doi.org/c2w9

Some chemists think the periodic table should be extended to 32 columns to allow the atomic numbers, or the number of protons in the nucleus, to run in an uninterrupted sequence

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THE ELEMENT FACTORY A machine in Russia’s frozen north is about to begin pumping out the heaviest atoms in the universe. Kit Chapman pays a visit

MAX AGUILERA HELLWEG

Cyclotrons like this now retired one in Dubna, Russia, have been creating new elements for decades

N

ESTLED in thick pine forests north of Moscow, close to the Volga river, lies the town of Dubna. Not far from the centre is a leafy avenue of Soviet-era buildings. It is obvious when I visit that they have seen better days. The railway crossing on the approach is broken, its flashing lights constantly proclaiming the coming of a train that never passes. A few of the buildings have broken windows. In the street, there are liquid nitrogen containers with old baked bean cans acting as lids.

But there is one place within 1 9 6 . 9 6 7 this complex where something groundbreaking is happening. In a vast concrete hangar, workers in hard hats are busy assembling one of the most powerful research machines in the world. Next to me as I look on is the only living person to have an element named after him. Yuri Oganessian, Mr Element 118, is gazing almost lovingly at the 4-metre-wide metal disc in 79 the centre of the hangar. This is one of the first components

Gold

Au

of a machine that will soon begin churning out chemical elements – but not ordinary ones. These elements will be superheavy, with atoms so huge that they stick around barely long enough to be sure they exist. By forging these exotic atoms in quantities sufficient to study properly for the first time, Oganessian and his machine should be able to answer some big questions about how our universe formed, and possibly give us a staggeringly powerful source of energy. He might even disprove some of the rules underpinning the periodic table itself. The birth of the modern table traces back to another Russian city, St Petersburg. It was there that a scientific consultant named Dmitri Mendeleev helped cut through the chaos that was chemical science 150 years ago (see “Bringing order to chaos”, page 34). With Mendeleev’s table, the patterns of chemistry began to make more sense. The Russian organised the 63 known elements by atomic weight, which we now know is determined by the number of protons and neutrons in an atom’s nucleus. As he did this, he found that certain chemical properties were periodic, repeating every eight or so elements. Mendeleev arranged the table’s columns so that each contained elements with similar traits. The first group, for example, holds soft, fiercely reactive metals like lithium, sodium and potassium. The last group contains the noble gases, so called because they are almost completely inert. We now know that these patterns in the way elements react are governed by the electrons that orbit their nuclei. Every time we move one place along the table, an element gains a positively charged proton compared with its > 2 March 2019 | NewScientist | 39

“Elements on the ‘island of stability’ could be amazing fuels for nuclear power plants”

MY FAVOURITE ELEMENT

Na Sodium

Martyn Poliakoff is a chemist at the University of Nottingham, UK. He starred in a series of videos about the elements

~ My mother’s first name was Ina. As a little girl, she abbreviated it to ’Na, and when she became a grandmother she asked my children to call her that. So now, 27 years after her death, I still get a warm motherly feeling whenever I see Na in a chemical formula. I am also fond of hassium, element 108, because in our first video about it, I was recorded saying “I know nothing about hassium. Should we make something up?”. What’s your favourite element? Tell us at newscientist.com/my-favourite-element

predecessor, as well as a negatively charged electron to balance the charge. The electrons sit in a series of concentric shells, which are most stable when completely filled. The extent to which the different elements have their shells filled is what drives their reactivity – and all chemistry on Earth, from the signals of neurotransmitters to the synthesis of antibiotics. As time went on, chemists discovered more elements, filling some of the gaps Mendeleev had astutely left in the table. By the 1940s, we had created the first synthetic elements, such as technetium, which are too unstable to exist in any significant quantity on Earth. The reason for this instability boils down to an eternal rivalry between two of nature’s fundamental forces. The strong force holds protons and neutrons together in the atomic nucleus, but the electromagnetic force makes protons repel each other because they have the same charge. So 40 | NewScientist | 2 March 2019

the more protons an element has, the more likely it is that electromagnetism will win out and make it unstable. The heaviest elements we have made only last a fraction of a second. Nevertheless, we keep trying to create new elements by cramming more protons and neutrons into the atomic nucleus. For that, you need a particle accelerator. Work of this kind has been going on for years at that complex in Dubna, the Joint Institute for Nuclear Research (JINR), which was set up to rival the CERN particle physics laboratory near Geneva, Switzerland, during the cold war. The jewel in the JINR’s crown is the Flerov laboratory, where an accelerator called a cyclotron flings positively charged ions – atoms with slightly too few electrons – around a spiral track using magnets. Once up to speed, the ions are fired down a track to collide with a target nucleus. Most collisions simply break the components to pieces, but on rare occasions they fuse to form a superheavy atom. In the past few years, accelerators in Japan, Germany and Russia have made a spate of new superheavy elements in this way, all the way up to number 118. But we know almost nothing about them. The most advanced experiment so far involves shooting the newly

EXTREME MATTER Superheavy elements might break the rules of the periodic table Rule takers For most elements, it is the arrangement of electrons that largely determines their properties. Those with a vacancy in their outer shell tend to be reactive. Elements in the same column of the periodic table have similar arrangements and therefore similar properties

Rule breakers Superheavy elements may buck these trends. Their electrons move so fast that they gain mass and so orbit more tightly, squeezing the atom’s size. This may change their properties, so they align with those above them in the column

Chlorine Nucleus

Vacant electron site

Flerovium

formed atoms across an array of gold pins with a temperature gradient, looking at how hot the gold must be for them to stick. For anything more involved, you would need a larger sample of atoms. Yet there are hints that superheavy elements don’t play by the same rules as the others. “We assume that the chemical properties in a group change systematically in some way,” says RolfDietmar Herzberg at the University of Liverpool, UK. But calculations suggest that several of the superheavy elements we have already created would behave like a noble gas, even though they don’t sit in that group. If so, he says, “you have to ask yourself if the periodic table as we know it is still valid”.

MAGNETS AND GUNSHOTS The calculations are rooted in Albert Einstein’s theory of special relativity. One of its implications is that objects get heavier the faster they are travelling. This matters in the case of larger elements because their nuclei hold greater positive charge, meaning the electrons are whizzing around faster and so appear a little more massive. In turn, that extra mass means they orbit closer in than we would expect, altering the chemical properties of the atom. That’s the theory. And the new machine being built in that concrete hangar at JINR is where we should soon find out whether it is right. “Is 118 a noble gas or not? If not, it means that this is the end of periodicity,” says Oganessian. When I visited in 2016, the Flerov lab was still building its new cyclotron, known as the Superheavy Elements Factory or SHEF. It wasn’t easy, because this machine relies on a more intense ion beam, and that meant installing a much bigger magnet. There are only so many places that can make a 2000-tonne electromagnet. The Russian scientists chose a factory in eastern Ukraine. But just as the magnet was due to ship in 2014, war broke out. Staff from the JINR say that when they called the factory to check in, they could hear gunshots in the background. Fortunately, the magnet was winched safely onto a train – no

The periodic table looms over old parts and tools in a quiet corner at the Flerov laboratory in Dubna

MAX AGUILERA HELLWEG

road truck would be sturdy enough to carry it – and some days later it arrived, passing the same broken railway crossing I had seen on my way in. Now the SHEF is undergoing final tests, ready to begin running at full capacity this spring. The next best cyclotrons can produce one superheavy atom a week. The element factory should be 100 times more productive, so soon we should have enough superheavy atoms to start trying new experiments. “You can consider things like putting them in a trap, measuring their mass. You can do chemistry experiments,” says Mark Stoyer at Lawrence Livermore National Laboratory in California, who contributed to the discovery of several superheavy elements. The atoms could, for example, be sent into a chamber containing a reactive element such as chlorine to see if they bond with it. If not, that is a hint that the atoms are unreactive like a noble gas. There may also be new hidden gems to discover among the superheavies. This is because elements come in different forms called isotopes, each with a different number of neutrons. Elements are defined by the number of protons in their nucleus: if there is one, it is hydrogen, if there are two, that is helium, and so on. But isotopes of a helium nucleus can contain either one, two or zero neutrons. It is a similar deal at the heavy end of the periodic table. Take element 114, flerovium, which, you guessed it, was first made at the Flerov lab. It has a variety of isotopes, but this time there is a chance that some of them may be stable for long periods of time. It turns out that particles in the nucleus come in shells just like electrons do. In 1963, physicists Maria Goeppert Mayer, Hans Jensen and Eugene Wigner won the Nobel prize in physics for suggesting that protons and neutrons in a nucleus can add up to “magic numbers”. These correspond to when the shells are full, whereupon the nucleus would be highly stable. According to this theory, there should be pockets of superheavy elements that are incredibly stable. Finding this long-fabled “island of stability” could be incredibly useful.

Any superheavies in it could last for thousands of years and would hold incredible amounts of energy because of their huge size. They would be an amazing fuel for nuclear power plants. The SHEF is our best shot at getting to the edge of island of stability. This is where flerovium comes in. It has 114 protons, which is a magic number. And one of its possible isotopes has 184 neutrons, which is also a magic number. If we could make this doubly magic isotope, it could be stable for days – nothing compared with the heart of the island, but still impressive. When researchers make flerovium in a cyclotron, each of the fusing nuclei typically ends up losing three or four neutrons as part of the way the impact energy is dissipated. That leaves an atom with up to eight fewer neutrons than the doubly magic isotope. At the SHEF, researchers can afford to set up collisions at lower energies that would lose fewer neutrons. With lower energies there will also be less chance of the nuclei merging, but there will be plenty of collisions to generate enough atoms to study. “If you have 100 times more production, you can put that into sensitivity, so making something that is 100 times

1 2 7 . 6

Te l l u r i u m

harder to produce,” says Herzberg. If only one or two neutrons were lost in the collisions, we would produce a flerovium isotope that would hang around for perhaps a few hours. We would be on the shores of the island. Even if the SHEF doesn’t pull that off, it offers plenty of interest, says physicist Jon Billowes at the University of Manchester, UK. “It’s going to give us understanding of other areas of physics, such as supernovae,” he says. We know that the superheavy elements are created in supernovae and in neutron star collisions, which are complex cosmic events that even our best computers cannot model. But with more information about what these elements look like, we can build a better picture of how they might act. Supernovae may be light years away from the buildings nestled among the birch trees of Dubna. But this sleepy town might soon get us closer to them than ever before. Q Kit Chapman’s book Superheavy: Making and breaking the periodic table will be published by Bloomsbury Sigma in June Turn to page 55 for the Elements crossword, to celebrate 150 years of the periodic table 2 March 2019 | NewScientist | 41

INTERVIEW

Why I’m on a mission to save humanity’s ancient microbiome Eric Alm is racing to preserve the microbial heritage of our guts before it is too late. Elie Dolgin gets the scoop

HE bacteria in our gut are vital to our health, but urbanisation and antibiotics mean that the rich diversity of the traditional human microbiome is being lost. Eric Alm wants to change this. A biologist at the Massachusetts Institute of Technology, he has set up the non-profit Global Microbiome Conservancy. The aim is to collect stool samples from indigenous and isolated peoples and build a repository of their intestinal inhabitants before they disappear.

T

Why create a library of gut bacteria?

A lot of the biodiversity that is being lost today is housed within humans – in our gut 42 | NewScientist | 2 March 2019

microbiomes – and it could disappear altogether as more people living traditional lifestyles adopt industrialised ways of life. The time to act is now. What we are doing is taking a snapshot of the biodiversity of human gut microbes on Earth today, and then preserving that for future generations so that we always have the biodiversity that co-evolved with us stored somewhere. How much does the gut microbiome differ from one person to the next?

It depends where you look. Across industrialised nations, there are some regional differences but they are relatively small

compared with the differences between an urban North American, say, and someone living a non-industrialised lifestyle elsewhere in the world. When we look at some nonindustrialised populations, many organisms we find don’t exist in urban North Americans. Why do these differences matter?

We already know that there are many diseases of the modern world – inflammatory bowel disease, asthma, allergies, autoimmunity – that are linked to the loss of our microbial heritage. Considering that these conditions are now rising in the developing world, the health crisis has already begun.

Photographed for New Scientist by Ken Richardson

Collecting faeces is no laughing matter for Eric Alm

Just so we are clear: you are talking about collecting stool samples, right?

That is the first step. It isn’t the only step, though. We can’t just take poop, stick it in a freezer, and hope to get back the full picture of biodiversity if we thaw that out. We need to isolate the bacterial strains that are present, grow them up and then create master cell banks, for long-term storage, and working cell banks, for active research.

fact. This seemed like a really good idea to her, and she joked to us, “Hey, can you sign up my neighbour? He comes over every morning, walks across an entire field, and then he poops in front of my house.” This is in a village where people commonly poop outdoors, but usually in a secluded spot. So she asked, “Can you get him into your study, so he stops pooping in front of my house?” And did you?

How many bacterial strains are you looking to collect?

Ideally, we want the whole spectrum of human-associated microbial diversity, but we don’t know what that is yet. We have set an initial target of 100,000 strains for the first few years, representing a few thousand strains each from 34 different countries – but we would like to get a lot more. How is the collection going?

So far, we have collected samples from 19 distinct populations, including many indigenous populations living more traditional lifestyles, in Cameroon, Tanzania, Ghana, Rwanda, Arctic Canada, northern Finland and on a Northern Cheyenne reservation in Montana. We have isolated more than 4000 strains from those expeditions, and we anticipate getting many more. In addition, we have more than 7600 gut bacterial strains from people living in the Boston area whose stool we used to hone our methods of strain isolation. Are people generally willing to participate?

What will you do with the library once it has been built?

One of our foundational assumptions is that this biodiversity is quite valuable. The library is going to be valuable for indigenous peoples, who might want a reserve of their gut microbes that they can tap into and bring back if they need to, either for health reasons or for their traditional diets and lifestyles. It is also going to be valuable for medicine, because these organisms co-evolved with humans over very long periods of time and may have metabolic functions that can be transformed into new therapies.

We learned a lot on our very first trip, which was to the Northern Cheyenne reservation. We didn’t get as much enrolment as we had hoped. Then we went to the rainforests of south-eastern Cameroon, where we changed things logistically, spending time with the people while we were waiting for our supplies to arrive. Not in a structured way, we just hung out with them, chit-chatting, interacting. We realised this was key to gaining people’s trust. You talk about poop, and everyone thinks it is funny, but you also get to explain what you are doing. Only towards the end of the visit do we now ask people to sign up – and they generally do so, eagerly. They don’t find it strange that you want their faeces?

Well, they are almost always shocked that you want the entire stool sample! But there was this one woman, from the Baka people of Cameroon, who was very interested in that

No, unfortunately. We couldn’t sign him up because he wasn’t part of the Baka community that we were sampling at the time. Where are you off to next?

We’re going to Malaysia later this month to meet with different populations, including the Jahai people. They practice a huntergatherer lifestyle, which is pretty exciting

“People are almost always shocked that you want the entire stool sample!” because there aren’t that many isolated people that live this lifestyle anymore – and it may be that the hunter-gatherer lifestyle produces a microbiome that’s more closely adapted to the natural environment. Have you analysed the samples that have been collected so far?

We are starting to perform tests on some of the bacterial strains that have been isolated from the samples, and we do see that they have some metabolic functions that are really rare or entirely absent from the organisms that we have cultured from North America. Not only are we seeing new functional genes, but we are finding that the rate at which genes can jump from one bacterial species to another is very different in industrialised and non-industrialised populations. Who owns this collection of bacterial strains?

Every strain we isolate is owned by the people who contributed the stool samples. And although we don’t restrict who can work on those strains, we do have a clause that the material can’t be made into a commercial product. It is specifically disallowed. If a company takes a strain and wants to use that organism as a therapeutic agent, they need to go back to the owners of that organism and obtain a licence from the community. ■ Elie Dolgin is a science writer in Massachusetts 2 March 2019 | NewScientist | 43

CULTURE

Can artificial intelligence ever make music as wonderful as that of our greatest human composers? Simon Ings talks to the creative minds behind an experiment to find out

The Eternal Golden Braid: Gödel, Escher, Bach, with Marcus du Sautoy, Mahan Esfahani and Robert Thomas, Barbican, London, 9 March

CAN you tell when a piece of music has been written by a machine? Back in 1979, cognitive scientist Douglas Hofstadter was the first to ask that question in his classic book Gödel, Escher, Bach: An eternal golden braid. Forty years on, I thought it was a rather tired question. Of course we cannot tell. Of course we can be fooled. Why worry? After all, no one stopped playing chess or Go when computers proved they could trounce the best players. If anything, the machines inspired people to play more, and better. Pitting yourself against a human adversary is the whole point of these games. And if the point of music is that it conveys emotion, it is only interesting if there is a human doing the conveying. A concert on 9 March should shake up my assumptions. London’s Barbican is bringing together harpsichordist Mahan Esfahani, mathematician Marcus du Sautoy and composer Robert Thomas for a performance lecture – called The Eternal Golden Braid: Gödel, Escher, Bach – that uses an algorithm trained on the music of J. S. Bach. Bach’s compositions have been fed through a machine-learning process created by computational artist Parag K. Mital. It will use what it has learned to create its pieces. Harpsichordist Mahan Esfahani will play music created by an AI 44 | NewScientist | 2 March 2019

The audience will listen to Contemporary Orchestra will also Esfahani playing a piece that work with the audience. But you interlaces real Bach with Bach will need to be there to find out generated by AI – and be asked to how it will work. look for the joins. When people “My feeling is that people find think they have spotted one, they themselves stuck in a particular can flip a card that is a different way of doing things, and that’s colour on each side. They will also “As we search for new listen to new pieces by Thomas musical territories, must and another AI-savvy composer we confront ever stranger Robert Laidlow. sound worlds?” The point isn’t to fool anyone into misattributing music created by AI to a composer regarded by when we start behaving like many as the greatest who ever machines,” says du Sautoy. “My lived. Instead, audience responses hope is that artificial intelligence will be used to create new music may free us from behaving that explores Bach’s sound world mechanically, by showing us and vocabulary. that there are new places to go.” Musicians from the London He cites the work of computer

MARK ALLAN/BARBICAN

AI takes on Bach

scientist François Pachet, director of the Spotify Creator Technology Research Lab. His Flow Machine program jams with jazz musicians in real time, leading them into improvisations that feel natural – and rightly so, since they are derived from a deep learning of the musicians’ output. How does Esfahani feel about such technology? I expected him to be either enthused or threatened. I didn’t think he would regard it as business as usual. “Every innovation has unintended consequences,” he says. “But these include positive consequences.” For Esfahani, the world of classical and contemporary music is anything but a stable environment – it has been in a state of reinvention for centuries. “From Mozart’s birth in 1756 to Schubert’s death in 1828 is no more than a single lifespan,” he says. “Yet in that one generation, the instruments of the orchestra became unrecognisable – sometimes literally so.” It is true that AI threatens to decentre much of human life,

For more books and arts coverage, visit newscientist.com/culture

Dieter Helm’s Green and Prosperous Land: A blueprint for rescuing the British countryside (William Collins) delivers handsomely on the promise in its title.

Visit Craft & Graft: Making science happen, an exhibition (pictured) at the Francis Crick Institute in London, will take visitors behind the scenes to see what is needed to support the research carried out there, including the thousands of flasks and test tubes that need cleaning. From 1 March.

Watch H is for Harry is in some UK cinemas for World Book Day on 7 March. It is a powerful coming-of-age film about the state of education in the UK. A key claim is that one in five English 11-year-olds can’t read well.

Play Vectronom, a hypnotic video game about music, geometry and being in the moment, lands on Steam this month and seals the reputation of developers Ludopium for combining edgy music, art and experimentation.

Listen Particle physicists John Womersley and Harry Cliff will talk about The Next Mega-Collider at London’s Royal Institution at 7pm GMT on 7 March. The Future Circular Collider would be many times more powerful than CERN’s current collider, the LHC.

THE FRANCIS CRICK INSTITUTE

Dangerous light

Read

GETTY

but this continuing reinvention of music means it is relatively safe. Feelings will run high, though. In the 19th century, for example, the German composer Richard Wagner caused great outrage with his radical style. Philosopher Friedrich Nietzsche went as far as to say: “He contaminates everything he touches – he has made music sick.” In fact, Wagner exploited and exhausted contemporary harmonic and chromatic possibilities to the point where, at the turn of the 20th century, younger composers had no choice but to abandon tonal music in a search for a Physicist Jim Al-Khalili reveals why he wanted sound of their own. Will the algorithm used during his first novel to be true to science the upcoming concert reveal compositions that are easier to NEAR-future, science-fiction been weakening for decades. swallow? Or, as we search for new It is also long overdue a flip: territories, must we confront ever thrillers are what Hollywood does best, but the science can when magnetic north and south stranger sound worlds? poles switch. And it is possible, As a mathematician, du Sautoy often be flaky. I have never got angry about that: the key though unlikely, that Earth’s thinks he has an answer. “When word is “fiction”, after all. magnetic field will die one day – I make the mathematics-music My enjoyment of the latest as Mars’s did billions of years ago. connection, people worry that Marvel movies isn’t spoiled The 2041 tech is what I’m taking the emotion out of when physics laws get broken. New Scientist readers might music and making it very cold, My preference, however, is expect: quantum computing, clinical and logical,” he says. for sci-fi to paint a picture of AI, minds controlling cities, “What they don’t realise is that perovskite-crystal technology mathematics is highly emotional. what really could be. So I set my first book, Sunfall, in 2041, far for solar power, and so on. It’s a response to the play of enough from today that tech As for the science of dark extraordinary, surprising based on current developments matter, it is possible that it is patterns. I get the same buzz will have been realised, but not made up of as-yet-undiscovered reading mathematics as I do elementary particles called when I’m listening to Bach.” neutralinos. And while I Music isn’t an arbitrary jumble “Sunfall is meant to be overstress the importance of notes. It is iterative, generative, a page-turner: a fastpaced, race-against-time of dark matter self-interacting algorithmic. Music can be easy techno-thriller” in the book, the physics on and banal, just as mathematics neutralino decay and the role can be, and for the same reason: so far that my predictions of the bending magnets in structurally, easy music isn’t lose reliability. Over the past sending dark matter beams particularly interesting. seven years, I have interviewed to Earth’s core is possible. For both mathematics and 200 of the most brilliant But in the end, Sunfall is music, the point isn’t to hunt scientific minds in their field, meant to be a page-turner: a fastfor novelty for novelty’s sake, which has imbued me with paced, race-against-time technobut to look for results that are a broad understanding of thriller. I have enjoyed building interesting and surprising, and where the world is heading. a “could be” world and found it that lead to further discoveries. The book’s premise is that tremendously satisfying that the Such results are always rare, science is correct. I hope people and the limits of human cognition Earth’s magnetic field is dying, leaving us vulnerable to the sun’s find it a great story too. ■ set a hard barrier beyond which radiation. It isn’t an original idea, the search becomes pointless. By Jim Al-Khalili presents The Life applying AI and machine learning but it is something that could Scientific on BBC Radio 4. Sunfall happen. We know, for instance, to the problem, beautiful (Bantam Press) is out on 18 April that the magnetic field has surprises may await us. ■

DON’T MISS

2 March 2019 | NewScientist | 45

CULTURE

Trapped in the multiverse How do you stop dying over and over at your own party? Chelsea Whyte binges on new drama

THE latest hit on Netflix turns out to be a magic trick in eight parts. As Russian Doll begins, everything looks fairly ordinary for a TV drama – a party, a woman floundering in her mid-30s, death – then, with a single twist, it becomes extraordinary. This dark comedy stars Natasha Lyonne as Nadia, a foul-mouthed New Yorker who we soon learn is stuck in a time loop, repeatedly living through the night of her 36th birthday. She dies, only to be resurrected in the bathroom at her party, but in a new branch of the multiverse. This plays on the “many worlds” concept in physics, the idea the cosmos is constantly splitting into alternate universes. Some of Nadia’s deaths are played for laughs, some are so graphic they are upsetting and some leave her so alone and frantic that it is heartbreaking. But Russian Doll isn’t painful to watch. Each episode is 30 minutes, a welcome change from the trend for prestige television shows to have much longer instalments. Best of all, Lyonne infuses Nadia with almost inexplicable charm. The character is a fabulous dirtbag with the personality of a pit bull. Her unkempt hair has a bottle top stuck in it for most of one episode. Waking up, her first move is to light a cigarette. She did ketamine at a christening. Seemingly self-centred, in real life she would be horrible to know. But Lyonne’s sardonic humour makes Nadia likeable. When the show starts, Nadia has isolated herself from friends, Caught in a loop: Nadia (Natasha Lyonne) is reliving the same night 46 | NewScientist | 2 March 2019

her sad-sack ex and even her that. Nadia tells her drug dealer mother figure, a therapist named that every time she dies it hurts. Ruth, who took care of her during She has been hit by a cab, fallen and after the breakdowns and down the stairs, drowned, been death of Nadia’s actual mother. blown up, plummeted down an Which takes us to the heart of elevator shaft – and more. the series and, be warned, some Around her 14th death, Nadia unavoidable spoilers. To get out of finally realises that her friends her self-centred time loop, Nadia and her beloved Ruth grieve for has to convince someone that she her when she dies. This motivates is reliving the same night, and her to look for a way out, and so come to terms with intimacy and “There is a nod to Einstein abandonment issues. The first that reminds us of his key part is hard to do without getting tenet: there is no such sent to a psychiatric hospital – a fate she avoids only by dying once thing as absolute time” more in the ambulance ride there. Initially, Nadia thinks it may all she notices that after each death, be a drug-induced turn or some things around her die off. Fresh mystical retribution for having flowers wilt, and fruit in bowls a party in what was once a Jewish looks rotten. Nadia tells Alan. school. Then, she meets Alan, She cuts open an orange, and a perfectionist and her opposite though the outside is mouldy, in all ways but one: he too keeps inside it is still edible – just as dying and reliving the same day. their inner lives continue as one Alan sees their experience as a linear experience while their video game, but their trip through bodies keep dying. “Time is the multiverse isn’t as clear cut as relative to your experience.

We’ve been experiencing time differently in these loops, but this tells us that somewhere, linear time as we used to understand it still exists,” she says. This nod to Einstein’s theory of relativity may be a bit simplistic, but it does remind us of his key tenet: there is no such thing as absolute time. Our experience of time is dependent on our point of view. In the final moments of the series, we see two timelines side by side – two branches of the multiverse in which Nadia and Alan change their behaviour and save the other from their first death. The split-screen effect is almost gut-wrenching, as you don’t know whether these two people who have come to care about each other will ever reunite in the same timeline. It isn’t a great magic trick if you just saw the woman in half – you have to put her back together again. Fortunately, Russian Doll delivers on that. ■

RUSSIAN DOLL/COURTESY OF NETFLIX

Russian Doll, streaming on Netflix

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LETTERS the Americas, maintained by mega-herds of herbivores, used to be a great carbon sink. It is naive to think that a landscape of vegetable and fruit monocultures will maintain any ecological diversity. Switching government subsidies from supporting unsustainable, high-carbon emitting, intensive livestock production to no-input, natural grazing techniques can make livestock an agent of biological and ecological creation.

Technologies will drive climate change solutions From Anthony Richardson, Ironbridge, Shropshire, UK Jane Rawson takes a generalised shot at economic growth as a barrier to climate action (Letters, 12 January). Maybe the two aren’t so incompatible. While the notion of infinite economic growth is illogical, developing technologies, soft and hard, will be the major instrument of climate change moderation. And Robert Solow won the 1987 Nobel prize in economics for

showing how technical advances drive economic growth. Yes, politicians need to avoid simplistic populist appeals, such as “Trump digs coal “ or “freeing” the UK from EU standards. But they will always try to be popular to survive. They should note Greta Thunberg’s speech at the climate change conference at Katowice in Poland last December.

This smells like a solution to a statistical puzzle From Geoff Convery, Kirton in Lindsey, Lincolnshire, UK Richard Harris is surprised that, while one in 20 participants in a study carried the gene for either cystic fibrosis or spinal muscular atrophy, only one in 40 has a partner who also carries one (Letters, 2 February). You note that there were just 15 such couples. If an explanation is needed, it may lie in a study involving student volunteers smelling T-shirts previously worn by other students and rating the odours for sexual attraction (24 August 2002, p 20). The personal scents of people with similar genetic

profiles were much less attractive than those of others. If the numbers of carriers of the two disordered genes in the study were similar, if the percentages give a fair representation of the population and if the personal scent effect had protected some participants from forming attachments to people with the same disordered gene, then the one in 40 figure is what random distribution would predict.

No open-plan office can be the right temperature From Scott McNeil, Banstead, Surrey, UK Yvaine Ye discussed pitfalls of open-plan offices (12 January, p 33) and readers expanded on them (Letters, 2 February). Another is the issue of temperature. I am surprised how many buildings have air-conditioning systems that can’t cope with open-plan spaces behind expanses of glass, so occupants of the south side are baking hot while those on the north freeze. I recently worked with people from East Africa who wanted 25°C,

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western Europeans who wanted 20°C and northern Europeans and Canadians who complained of heatstroke at 16°C. The result is open offices cooled, at great expense, to a temperature at which many feel too cold and have to wear additional clothing.

A key question with a mixed readership From David Hoskin, Driffield, East Yorkshire, UK Readers gave several excellent answers to a question about how many rotors on a key safe one should move to lock it (The Last Word, 26 January). These will doubtless find applications in others’ everyday lives. A problem is that, sadly, not all honest householders read New Scientist and, presumably, a number of intelligent rogues do.

Even my kitchen can’t agree on serving sizes From Tony Green, Ipswich, Suffolk, UK With Kayt Sukel’s guide to keeping your mind sharp, you present food recommendations measured in “servings”, defined as roughly half a cup (26 January, p 30). Who measures vegetables in “cups”? According to my kettle, the cup I use for coffee holds two cups; my coffee maker thinks it’s three. The editor writes: Q Researchers tend to discuss servings, meaning the amount of a food you would normally eat as part of a meal. The UK’s National Health Service defines an adult portion of fruit or vegetables as 80 grams (bit.ly/NS-servings). Letters should be sent to: Letters to the Editor, New Scientist, 25 Bedford Street, London, WC2E 9ES Email: [email protected] Include your full postal address and telephone number, and a reference (issue, page number, title) to articles. We reserve the right to edit letters. New Scientist Ltd reserves the right to use any submissions sent to the letters column of New Scientist magazine, in any other format.

54 | NewScientist | 2 March 2019

THE ELEMENTS CROSSWORD Set by Sparticle

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To celebrate 150 years of the periodic table, all the words in this grid are made from chemical element symbols. Fill each white square with one element. Take care! Some squares contain more than one letter, and some words can be made in more than one way: a clue asking for a seven-letter element could yield SiLiCON or SILiCoN, for example. The chemical formula below indicates how many of each element is needed to complete the entire grid. Tell us how you fared at [email protected]

www.galaxyonglass.com +44 (0) 7814 181647 [email protected]

AcAl2AmAr3At2BiC7CaCo3CrEr5Es4Fe2GeH3He I15InKLa2LiN8O8Os2 P6Ra Re3S12Ti4Ts2U4V3W2

ACROSS

1 4 9 10 11 12 13

Summaries (8) Trust fund (6) Unknown (7) Egg production (9) Febrile (8) Device for measuring thickness (7) They come with rights (16)

17 Observer (7) 19 Those who prioritise professional advancement (10) 22 Dish of thinly sliced meat (9) 23 Emblematic (6) 24 Compacted fodder (6) 25 One who tells all (9)

DOWN

1 Elements (6) 2 Notting Hill and Rio, for example (9) 3 Japanese warrior (7) 5 Italian bread-based appetisers (8) 6 Those who nictitate (7) 7 Sit on pistachio (anag) (14)

8 14 15 16 18 20 21

Female demons (7) Span (8) Inebriation (9) Fabric samples (8) Dome (6) Wearing away (7) More aloof (5)

Answers to Cryptic crossword No3 ACROSS: 7 GENERA, 8 ENIGMA, 9 TWIN, 10 INFRARED, 11 EXOSKELETON, 14 POLYNOMIALS, 18 HARMONIC, 19 AXON, 20 JOUNCE, 21 ISOMER. DOWN: 1 BETWIXT, 2 NEON, 3 SALINE, 4 SELFIE, 5 RIGATONI, 6 AMBER, 12 STORMING, 13 FLOODED, 15 YANKEE, 16 ORCHID, 17 TABOO, 19 ATOM

Answers and the next Quick crossword on 16 March

2 March 2019 | NewScientist | 55

For more feedback, visit newscientist.com/feedback

PAUL MCDEVITT

FEEDBACK

AN ELEGANT weapon for a more civilised age? The French Fencing Federation has recognised lightsaber duelling as a sport. The authorities accepted the Star Wars energy swords as a way to encourage more young people to take up the sport. Traditional fencing relies on three blades: the foil, sabre and épée, none of which glows in the dark or makes

the ground, probably feeling rather embarrassed. Animal control workers tranquilised the cat before firefighters slipped it into a harness and lowered it to the ground. It will be released back into the wild once veterinarians give the all-clear, where it will no doubt rush to adapt its story into a heart-warming screenplay.

cattle station, the ground itself has caught fire. Footage from the Mt Denison Station in Northern Territory shows ground resembling a cast-iron pan – not only black and smoking, but with an egg cooking away, as prepared by rancher Terry Martin. ABC News reports that Martin attempted to measure the temperature of the smoking char, but it melted his thermometer. Efforts to quench the fire with water have had limited success, with new fires soon appearing. A “professor of pyrogeography” noted that well-trodden manure in the pens may have contributed to a naturally combustible layer of organic matter. He says similar fires have erupted in dried lake beds and drained swamps during the heatwave. For residents, there is little to be done except allow these fires to burn themselves out – and maybe cook a little breakfast on them while they wait.

Kiselyovsk shared apocalyptic scenes online of homes, cars and fields buried

THERE may be an app for everything,

in the sooty mantle. Blame for the odd precipitation has

generation of wannabe Jedis (or Sith Lords) to put away the games console

but new rules proposed by a province in Eastern China would see homework

fallen on nearby open-cast coal mines, which residents say are responsible

and take up the sport. But with the trend among young Jedi of turning on

apps erased from the curriculum. Zhejiang province is pushing for

for widespread ill-health. One environmentalist told The Guardian:

their mentors, would anyone be brave enough to train these youngsters?

the move to combat high rates of nearsightedness in children. As well as requiring homework to be paper-based, the rules would increase outdoor activities and limit screen time in classrooms. Good news for pupils everywhere.

“There is a lot of coal dust in the air all the time. When snow falls, it just becomes visible. You can’t see it the rest of the year, but it is still there.”

AUSTRALIA is sweltering in a record-breaking heatwave, with temperatures so high that in one

Visitors to the Grand Canyon museum may have felt all aglow after three buckets of uranium ore were discovered in the taxidermy exhibit. The radioactive rubble was rapidly disposed of 56 | NewScientist | 2 March 2019

FROM the ever-productive laboratory of media measurements, Mark Vandersluis finds The Guardian grappling with the size of the database fed to an AI to teach it to write. There was no way to relate this to blue whales, but the cetacean theme endured: the paper reports that the training set contained 40 gigabytes of data, or “enough to store about 35,000 copies of Moby Dick”. This measure will be handy for anyone with a library filled with nothing but Herman Melville novels. “By my reckoning,” says Mark, “that makes a white whale just over 1 Mb in size, with a MegaMoby coming in at around 1.143 Gb.”

MORE blackened earth: people in central Russia awoke recently to discover that their town had been covered in black snow. Residents of

dramatic droning noises. Those qualities are key to inspiring a new

RESCUING cats from trees is all in a day’s work for firefighters, although a team in California deserve a special mention after a wild mountain lion got stuck in a pine tree. A resident of San Bernardino county spotted the big cat trapped 15 metres off

Meanwhile, Bill Barksfield points us to The Daily Telegraph, which features an interview with sheep farmer Sally Shepherd.

WE HAVE only ourselves to blame. We breached our self-imposed ban and now new examples of nominative determinism slip unbidden into our inbox. “I know, I know, how fed up you must be of these,” says Adam Robinson insightfully. “But I love Feedback, and when I saw this I couldn’t help but think of you.” He forwards a newly published paper on tectonic faults co-authored by one Filipe Terra-Nova.

PREVIOUSLY, Feedback reported on a Devon driver investigated for driving under the influence after claiming he swerved to avoid an octopus (16 February). “Perhaps he is telling the truth,” says Peter Slessenger. “There are quite a few seafood restaurants in that part of the world, and octopuses are noted for their escape abilities.” Peter recommends that Feedback takes an investigative trip to the west coast to find out whether restaurateur Rick Stein is missing a starter or two.

You can send stories to Feedback by email at [email protected]. Please include your home address. This week’s and past Feedbacks can be seen on our website.

Last words past and present at newscientist.com/lastword

THE LAST WORD Hot topic I work in catering and often get burned on the hand. Most of these are relatively minor, but painful. The National Health Service advice is to hold the burn under a running tap of cool water for 20 minutes and not to cover it in anything greasy. As burning is caused by a transfer of energy from one substance to another, even a hot oil burn doesn’t need that long to cool down. What is the basis for these measures?

Q The length of time cool water has to be applied to a burn depends on the severity of the burn and how soon the water is applied. If a splash of hot water on the skin is put under a cold tap within seconds its heat will barely have penetrated. It may only need half a minute under the water before it is entirely neutralised. But if a large quantity of boiling jam spills down your leg, it will take time to remove it. The heat will have penetrated some way into your leg before you begin to cool the skin, and will continue to go deeper into your tissues while you cool the surface layers. For minimum damage, cool water must be applied for the 20 minutes cited to ensure that it has reached all the heat. Jane Lilley Dorking, Surrey, UK

For this reason it is better to apply cool water for longer rather than very cold water for a short time. If water is too cold it can lead to reduced sensitivity, making you believe the burn is no longer hot. It can also reduce blood flow, by constricting blood vessels, which slows down damage repair and can even trigger frostbite. Ice can also do this and shouldn’t be put on burns. Vittoria Dessi London, UK

same size as those of a mature oak. In animals, a stricter law of proportion seems to apply: babies have tiny hands and kittens tiny claws. Why this difference?

Q Infant paws and kitten claws are mechanical tools and must be of a size, and leverage, appropriate to the power provided by the limbs. Rather than hands, perhaps it would be more appropriate to compare leaf size with the diameter of the hair on a child’s head or the fur on a kitten, which doesn’t greatly change as the animals mature.

Q Although it cannot be observed, thermal damage beneath the skin can continue once the source of the burn is removed and the burn feels cool.

Q A 2008 study by Leila Cuttle at the University of Queensland in Australia on the treatment of “The amount of light does burns with cool water found have some effect on leaf recommendations ranging from size, and this is used in the 5 minutes to 3 hours. Testing on Japanese art of bonsai” pigs showed treating burns with 20 minutes of cool water resulted Or you could compare leaves in less damage after nine days with mitochondria. Both provide compared with 5 or 10 minutes, power, and neither changes in size and longer durations offered no as the organism grows, they just additional benefit. increase in number. Interestingly, the study also Peter Urben says that while immediate Kenilworth, Warwickshire, UK treatment is best, a delay of 1 to 3 hours is acceptable. This Q The function of leaves is suggests there may be more to different to that of hands or claws. the mechanism than simply Trees use leaves to gain nutrients removing residual heat, such by photosynthesis and energy as minimising inflammation. from respiration. Anthony Roberts As a tree grows, it needs an everRushden, Northamptonshire, UK increasing surface area to perform these functions. But the leaves don’t have to get bigger, the tree Life size just makes more of them. A study I have an oak tree in a pot grown in 2012 calculated that a mature from a seedling. After three years oak has around 230,000 leaves. it is healthy but barely a metre tall. Anne Campbell However, its leaves are much the Cardiff, UK

We pay £25 for every answer published in New Scientist. To answer a question or ask a new one please email [email protected]. Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address. You can also send questions and

answers to The Last Word, New Scientist, 25 Bedford Street, London, WC2E 9ES. New Scientist Ltd retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format and at any time in the future. All unanswered questions and previous questions and answers are at newscientist.com/lastword/

Watch 100 fascinating science talks! Watch mind-expanding talks IURPbHannah Fry, Carlo Rovelli, Tim Peake, Megan Rossi, and PDQ\bRWKHULQVSLULQJVFLHQWLVWV Visit newscientist.com/nsltalks

Q Since a tree leaf has a low weight compared with the rest of the plant, it isn’t a problem for a sapling to grow full-size leaves, unlike hands on a baby. And the law of proportion in animals isn’t so strict: a baby’s head is proportionately bigger than an adult’s. This is mainly so that the brain can be bigger than would otherwise be the case, enabling the baby to learn more quickly. The amount of light does have some effect on leaf size, and this is used in the Japanese art of bonsai. Here, suitable tree varieties (often those with naturally smaller leaves) are kept miniaturised. Leaf size is kept small by a combination of bright light and removing any new leaves that grow in the spring; the tree then grows another set of smaller leaves. This unnatural process puts a large strain on the plant, so needs much skill by its owner to produce the desired appearance without killing it. Richard Swifte Darmstadt, Germany

This week’s question BRING ME SUNSHINE

Can a blind person still benefit from the effect of natural light on circadian rhythms and mental well-being? I lost my remaining light perception 10 years ago and since that time I’ve had insomnia. This would suggest that the answer to my question is no, but maybe I just need to get out more. Allan Tweddle Orpington, Kent, UK