New Scientist May 16_ 2020

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OUR NEAREST BLACK HOLE
ALIGNING THE PYRAMIDS

NEANDERTHAL JEWELRY
THE MYSTERY OF

HIGH BLOOD PRESSURE
AN AUDIENCE WITH
PHILIP PULLMAN
HOW KELP COULD
SAVE THE PLANET

WEEKLY May 16–22, 2020

A FIFTH
FORCE
OF NATURE

Momentous hints emerge of
a whole new world of physics

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This week’s issue

On the 14 Our nearest black hole 40 Features
cover 16 Aligning the pyramids
14 Neanderthal jewellery “Worldwide,
30 A fifth force of nature 40 The mystery of high around
Momentous hints emerge of blood pressure a billion
a whole new world of physics 26 An audience with people have
Philip Pullman high blood
9 Focus on coronavirus 36 How kelp could save pressure”
Covid-19 news and expert the planet

analysis, from risks in
pregnancy to lockdown

exit strategies

Vol 246 No 3282
Cover image: Owen Gent

News News M AFOTO/ALAMY Features

14 Ancient crafts 19 Too damn hot The places already reaching unliveable temperatures 30 A fifth force of nature
Did we teach Neanderthals An unexplained influence
how to make jewellery? is reshaping the cosmos

16 Slow burn 36 How kelp could save
Plans for greener heating the planet
could take 1500 years Seaweed’s potential to clean up
the oceans and the atmosphere
17 Hide and seek
Meet the AI that can see 40 The mystery of high
through camouflage blood pressure
to find hidden objects If we don’t know what its causes
are, should we be medicating it?
Views
The back pages
23 The columnist
James Wong on how increased 53 Puzzles
levels of atmospheric carbon Cryptic crossword and the quiz
will affect food quality
54 More puzzles
24 Letters Can you find the right numbers
Readers’ views on living in to fill in the diagram?
the age of the face mask
and life after lockdown 54 Cartoons
The lighter side of life with
26 Culture Tom Gauld and Twisteddoodles
Philip Pullman talks to us
about science, daemons 55 Feedback
and dust Eels forget what humans
look like: the week in weird
28 Aperture
A gleaming, glorious vista of 56 The last word
solar power’s foothold in the Why do cats pull fewer faces
Mojave desert than dogs? Readers respond

16 May 2020 | New Scientist | 3

Elsewhere A note from
on New Scientist the editor

Virtual events Virtual event FPM/ISTOCKPHOTO Dear reader,
I hope this finds you well. These
Coronavirus: Can we Coronavirus: Can we trust the science? 18 May FERNANDO TRABANCO FOTOGRAFÍA/GETTY IMAGES are difficult times – for individuals,
trust the science? companies and nations. These
Podcast GARY DOAK/ALAMY/PICTURED AT THE EDINBURGH INTERNATIONAL are also terrible times for many
See an unmissable panel BOOK FESTIVAL charities, whose donations may
discussion on 18 May at 6pm BST New Scientist Weekly The truth about murder hornets have dried up, and who may no
on how the outbreak is testing the longer be able to operate as they
limits of the scientific process. Video once did. For the people or the
wildlife depending on those
Decoding Reality Interview with Philip Pullman The renowned author of His Dark charities, locally and across the
Materials shares his scientific influences globe, things may be worse still.
Join physicist Vlatko Vedral at 6pm
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the quantum nature of reality. a project called Signal Boost.
newscientist.com/events
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Novelist Philip Pullman on deprived children and their families
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neuroscience and poetry which promotes social mobility
have had on his writing. and diversity in STEM in the UK.
youtube.com/newscientist
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Online
Emily Wilson
Covid-19 daily update
New Scientist editor
The day’s coronavirus coverage
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newscientist.com/
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4 | New Scientist | 16 May 2020

We’re looking for the best
ideas in the world.

The Ryman Prize is an international award sight for millions of older people in the
aimed at encouraging the best and brightest developing world.
thinkers in the world to focus on ways to
improve the health of older people. World-leading researchers Professor Henry
Brodaty and Professor Peter St George-Hyslop
The world’s ageing population means that in won the prize in 2016 and 2017 respectively for
some parts of the globe – including much of their pioneering work into Alzheimer’s Disease.
the Western world – the population aged 75+
is set to almost triple in the next 30 years. The 2018 Ryman Prize went to inventor
Professor Takanori Shibata for his 25 years of
The burden of chronic diseases including research into robotics and artificial intelligence.
Alzheimers and diabetes is set to grow at the
same time. The 2019 prize winner was Dr Michael Fehlings,
a Canadian neurosurgeon who has dedicated
In order to stimulate fresh efforts to tackle a long career to helping older people suffering
the problems of old age, we’re offering from debilitating spinal problems.
a $250,000 annual prize for the world’s
best discovery, development, advance or If you have a great idea or have achieved
achievement that enhances quality of life for something remarkable like Gabi, Henry, Peter,
older people. Takanori or Michael we would love to hear
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The Ryman Prize was first awarded in 2015
to Gabi Hollows, co-founder of the Hollows Entries for the 2020 Ryman Prize close at 5pm
Foundation, for her tireless work to restore on Friday, June 26, 2020 (New Zealand time).

Go to www.rymanprize.com for more information

Prime Minister Jacinda Ardern with 2019 Ryman Prize winner Dr Michael Fehlings.

www.rymanprize.com



The leader

The other crisis

Focusing on coronavirus is completely justified, but it isn’t the only danger we face

THE coronavirus pandemic might feel pandemic, annual average carbon the human body can’t survive. These
conditions occur for only a few hours
like the biggest crisis most of us have dioxide concentrations will still increase at a time, but the longer we delay action,
the longer that period will grow.
ever faced, but you have already been this year, contributing to a rise in global
Governments around the world
living with a bigger one: climate change. temperatures. The increase will be are rightly focused on tackling the
immediate threat of the coronavirus, but
There has been a lot of excitement smaller than it would have been without this will occupy them for months, if not
years. We can’t afford to tackle our crises
about the falling levels of air pollution the pandemic, but only by 11 per cent. one at a time, and we can’t let politicians
off the hook on climate change.
being seen in many countries because The problem is that by warming Earth,
That means the UK government’s
of lockdowns to tackle the virus. we have reduced the ability of tropical plan for green heating, which will
take 1500 years to hit official targets
Already, people are talking about using (see page 16) isn’t good enough. It also
means the ongoing weakening of the
the pandemic as an opportunity to “We can’t afford to tackle US Environmental Protection Agency
is a huge mistake. And most of all, it
redesign city streets, providing more our crises one at a time, means that we must never forget that
the planet is warming, and will keep
space for cyclists and pedestrians while and we can’t let politicians off warming, until we actually take action. ❚

reducing the emphasis on cars. Could the hook on climate change”

this be the start of a green revolution?

Maybe. It would be fantastic to make ecosystems to absorb carbon. So even

climate lemonade from virus lemons, when our emissions go down, more CO2
but we need to go much further than a remains in the atmosphere than would

few cycle lanes. An analysis published have happened without that warming.

by the Carbon Brief website last week It is now getting more serious. As

found that, while there has been a drop we report on page 19, some parts of the

in carbon emissions as a result of the planet are reaching temperatures that

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News Coronavirus

Self-swabbing Police surveillance Pregnancy data Vulnerable countries Easing lockdown
Are home testing kits Countries turn to A clearer picture of It’s not too late for Some African
accurate enough to be drones to monitor covid-19 in pregnancy rich nations to help countries begin to
trusted? p10 social distancing p10 is emerging p11 the poorest p12 lift restrictions p13

Jacinda Ardern, New
Zealand’s prime minister,
on 11 May

MARK MITCHELL/GETTY IMAGES the virus – of no new cases against
a backdrop of continued testing.
New Zealand’s success
Even if this goal is attained,
The country is tantalisingly close to wiping out covid-19. Does that the country will still need to be
mean life there can go back to normal? Alice Klein reports hypervigilant about not letting
the virus re-enter, for example,
WITH fewer than 100 active or accessing medical care, and and public venues will be able to via airline and shipping crews
confirmed coronavirus cases, New the nation’s borders were closed reopen. Schools are scheduled to delivering goods from overseas,
Zealand has almost eliminated the to travellers. open on 18 May, followed by bars he says.
virus. As a result, restrictions were on 21 May.
eased further this week, but the These measures have been New Zealand may escape a
country will still be feeling the highly effective, with only But Michael Baker at the health disaster, but the economic
effects of the covid-19 pandemic 1497 covid-19 cases and 21 deaths University of Otago in New impact will still make it difficult
for some time yet. recorded in New Zealand to date. Zealand says he is nervous about for life to return to normal, even
Most people infected with the the easing of restrictions because when restrictions are lifted, says
New Zealand was swift to coronavirus have now recovered, there may be undetected covid-19 Martin Berka at Massey University
respond to the pandemic, leaving just 76 active cases. cases in the community that in New Zealand.
introducing some of the Zero new cases were reported could start to spread as people are
strictest measures in the world on 12 May. allowed to mix more freely again. The government has already
on 25 March – a time when the spent more than NZ$10 billion
country had recorded only The lockdown was eased For the nation to feel confident on a wage subsidy scheme to
205 cases and no deaths. slightly on 27 April and will be that it has eliminated covid-19 keep people in their jobs during
lifted further on 14 May to allow altogether, says Baker, it will need the lockdown, and two of the
Under the nation’s lockdown gatherings of up to 10 people. to have 28 days – equivalent to country’s biggest industries –
measures, schools, universities Workplaces, shops, restaurants roughly two incubation cycles of tourism and the education of
and almost all businesses were foreign students – have been
shut. People could only leave Daily coronavirus news round-up shut down. “It’s going to hurt
their homes for essential reasons a lot,” says Berka.
like buying food, exercising Online every weekday at 6pm BST
newscientist.com/coronavirus-latest Another adjustment will be
to not travelling overseas, which
may be off limits until a vaccine
becomes available, says Siouxsie
Wiles at the University of
Auckland in New Zealand.
Australia and New Zealand
have proposed allowing tourism
between the two countries, as
Australia also has low covid-19
numbers, but officials say any
such measure is a while off yet.

On the other hand, there may
be some positive ways in which
life will permanently change, says
Wiles. “Before this whole thing,
a lot of people were told they
couldn’t work from home or
online teaching couldn’t be done,
but we’ve found out very quickly
that they can,” she says. “If things
like work and education become
more flexible and equitable
because of this, then not going
back to normal might actually
be for the best.” ❚

16 May 2020 | New Scientist | 9

News Coronavirus

Analysis Testing

How accurate is self-testing? The UK has embarked on
a programme of self-testing for coronavirus, but can swabs
taken at home be trusted? Michael Brooks reports

IN THE UK, essential workers are AGVI FIRDAU/INA PHOTO AGENCY/SIPA USA/PA IMAGES 500 clinic patients with flu-like
now among those being sent home symptoms to self-swab their nostrils
testing kits for coronavirus. This for coronavirus but is showing the A woman’s throat is and their tongues. The results were
involves swabbing the inside of symptoms, doctors will weigh up swabbed for coronavirus compared with swabs taken by
your own nose and the back of your whether they think the person should in Bandung, Indonesia healthcare professionals from where
throat, but how useful are the results? still be placed in a covid-19 ward. the back of the nose meets the throat.
“If you’re confident someone’s got Yi-Wei Tang at Cepheid, a diagnostics
Studies from early in the outbreak covid, you would still ignore a company in California, says the false The professionals detected more
in China have suggested that swabs negative,” says Cooke. negative rate of around 30 per cent positive results, but the self-swabbers
taken by healthcare professionals recorded early in China’s outbreak were within 10 per cent of the
may give a 30 per cent “false However, false negatives in may have been higher than it is now. professional positives (medRxiv, doi.
negative” rate, where infected people infected but symptomless people For instance, he says, throat swabs org/ggr7f6). Other types of testing
are told they don’t have the virus are more of an issue, as they may were initially recommended. We now may be a better option. A study that
(NEJM, doi.org/ggmzsp; medRxiv, encourage changes in behaviour that know these aren’t as effective as asked participants to drip saliva into
doi.org/dvfr). This has prompted spread the virus. If trained healthcare nasal swabs. collection tubes found that this was
claims that self-testing will give workers get a 30 per cent false a better source of viral material than
even more false negatives and negative rate when administering A more recent study in the US samples from where the nose meets
could raise the risk of infected tests, how bad might self-testing be? suggests self-swabbing is relatively the throat (medRxiv, doi.org/ggssqf).
people spreading the virus. effective. Researchers asked about The false negative rate appears to
There is reason for optimism. be lower too – only 12 per cent,
No test is perfect – swabbing compared with 24 per cent for
technique and analysis errors can traditional swabbing, says Anne
lead to inaccurate results. There is Wyllie at the Yale School of Public
no defined false negative level at Health, who led the study.
which covid-19 tests become
worthless. “It depends what question Last week, the US Food and Drug
you’re asking,” says Graham Cooke Administration authorised testing of
at Imperial College London. home-collected saliva, but studies of
saliva testing have yet to appear in
On a national level, false negatives peer-reviewed academic journals.
matter less, as testing can still give
a useful indication of the rates and The UK isn’t yet turning to saliva
levels of infection, providing the false testing. “We are aware of these tests
negative rate isn’t too high. False and are awaiting peer-reviewed
negatives are more of a concern evidence,” a UK Department of Health
at the individual level. In a hospital and Social Care spokesperson told
setting, if someone tests negative New Scientist. ❚

Surveillance

Drones keep an eye range of between 150 metres loudspeakers to play messages in February, when the covid-19
on people failing outbreak spread domestically there.
to social distance and 1 kilometre. If it spots people urging social distancing. In the UK,
“Police departments around
AS NATIONS gradually reopen after breaking curfew it alerts the police. Derbyshire Police were criticised the world have been looking for a
lockdowns, authorities are using good excuse to begin to acquire and
uncrewed aerial vehicles to enforce The system can also calculate the for posting drone footage on social use drones more regularly,” says
social distancing rules. Matthew Guariglia at the Electronic
physical distance between two or media in March that appeared to Frontier Foundation, a civil liberties
In India, police have turned to group based in San Francisco.
drones to monitor curfews and the more individuals and let the police shame people exercising in the Peak
distance between people outside Although people might not
during the day. Each is fitted with a know if people get too close to one District, even though they were mind drones being used for
camera and an artificial intelligence public health purposes, the EFF
that can detect humans within a another. “Previously, the police adhering to distancing guidelines. is concerned that their use may
continue long afterwards, he says. ❚
had no idea of where people were Drones were also used by Chinese Donna Lu

gathering, so now they are able to authorities at highway checkpoints

view larger areas,” says Amarjot

Singh at Skylark Labs, the firm that “Police departments have

developed the drones in use in India. been looking for a good

In the US, authorities in several excuse to begin to use

states have used drones fitted with drones more regularly”

10 | New Scientist | 16 May 2020

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A monthly dose of health news and analysis
newscientist.com/healthcheck

Pregnancy

Coronavirus may cross placenta

Four months into the crisis, many questions remain over covid-19 in pregnancy

Jessica Hamzelou

A GROWING number of case her colleagues have collected In some cases, the illness may positive for the coronavirus
studies suggest that, while data from 427 pregnant women have triggered an early labour, shortly after birth, and a woman
pregnant people don’t seem to be admitted to UK hospitals with says Edward Mullins at Imperial who lost her pregnancy at
at greater risk of the coronavirus, covid-19. Of these, three have College London. Yet it is also 22 weeks was found to have
covid-19 is linked to a higher rate died with the virus, while another possible that many babies were the coronavirus in her placenta.
of caesareans and preterm births, nine remain in critical care. delivered early as a precaution, to
and the virus may be able to cross protect the mother’s health. “I can However, most studies
the placenta to a fetus. We won’t know how the risk only speculate they wanted to do have found no evidence of such
to pregnant women compares it in a controlled environment transmission, so if it is crossing
In March, the UK government with the general population until with protective equipment in the placenta, this is likely to be
classed pregnant people as we have been able to compare place,” says Zaigham. rare, says Shennan.
“vulnerable” as a precaution.
Back then, much of what we 25.5% One in 20 of the babies born Avoiding the virus
knew about covid-19 in pregnancy to the mothers in Knight’s study
came from data from only around of births to women with tested positive for the coronavirus, We don’t yet know how the virus
20 pregnancies, but it didn’t look covid-19 were preterm and five of the babies died. Three might affect a developing fetus.
like the virus could pass from a of the deaths appear to have been Some other viruses, such as Zika
woman to a fetus. As more cases pregnant and non-pregnant people unrelated to the coronavirus, but and the virus behind chicken pox,
are collected, the picture is of similar ages and backgrounds, two of them might have been, can harm the development of a
beginning to change. says Sonja Rasmussen at the say Knight and her colleagues. fetus’s brain and visual system,
University of Florida. for example. The risks are thought
So far, several hundred births There have been reports to be especially high in early
affected by covid-19 have been The virus may have an effect of miscarriage and stillbirth in pregnancy, when organs are first
reported. Based on these, many on births. In Knight’s study, 63 out women infected with the virus, developing. But when it comes to
doctors and researchers say of 247 deliveries were preterm. In but it is unclear yet whether these the new coronavirus, we simply
they are relieved to see that a review of 108 women who gave were as a result of the coronavirus. don’t have any information,
covid-19 doesn’t appear to be birth with covid-19, Mehreen “It’s difficult to get a clear picture especially when it comes to
as deadly in pregnancy as SARS, Zaigham at Skåne University of the situation,” says Andrew the first and second trimester,
which killed a quarter of the Hospital in Malmö and Ola Shennan at King’s College London. says Rasmussen.
pregnant women who had it. Andersson at Lund University,
Sweden, found that around But there is “fairly convincing” The good news is that
In fact, the virus doesn’t seem 91 per cent of the babies were evidence that the virus can be most newborn babies with the
to produce any symptoms at all delivered by caesarean section passed from a person to their fetus virus have recovered well so far.
in most pregnant women. When a (Acta Obstetricia et Gynecologica via the placenta, says Mullins. Mullins and his colleagues have
team at a New York medical centre Scandinavica, doi.org/ggr2rd). A small number of babies born to launched an international project
administered a test to 215 women people with covid-19 have tested to collect data on the outcomes
who gave birth over a two-week of pregnant people who have
period, it found that four women ANGELO CARCONI/EPA-EFE/SHUTTERSTOCK covid-19 and their babies. The
with a fever or other symptoms project will specifically look at
tested positive for the coronavirus, miscarriage, fetal growth, still
but so did 29 women who had birth, premature birth and
no symptoms whatsoever transmission from mothers
(NEJM, doi.org/ggr28f). to babies. Zaigham and her
colleagues are launching a
Research seems to suggest that similar study in Sweden.
pregnant people are at no greater
risk than the general population Until we have clear answers
when it comes to catching the to the questions surrounding
virus or developing a severe illness. covid-19 in pregnancy, people
But some pregnant women have who are pregnant should do their
become very sick, and some best to adhere to social distancing
have died. Marian Knight at and handwashing advice, says
the University of Oxford and Rasmussen. “Right now, the
important thing is that pregnant
A pregnant woman women do whatever they can to
walking in Rome during avoid getting covid-19,” she says.  ❚
Italy’s lockdown

16 May 2020 | New Scientist | 11

News Coronavirus

Interview

‘On a ledge with no safety net’

There is still time to protect the world’s most fragile countries, David Miliband,
the head of the International Rescue Committee, tells Adam Vaughan

THE world’s richest countries are David Miliband (right) visits
Yemen, one of the world’s
guilty of a myopic international most at-risk countries

response to the coronavirus crisis but also to the overall fight
against the disease.”
that will hurt the world’s poorest
Citizens should urge leaders
people and the global fight against to heed the dangers of the inward-
looking, nationalistic period after
the disease, warns David Miliband, the first world war and take
inspiration from the outward-
CEO of the US-based International looking, multilateral time after the
second world war, says Miliband.
Rescue Committee (IRC).
“There are plenty of
Miliband, a former UK politician ‘nationalists’ willing to say the
lesson of this disease is there’s too
and foreign secretary, says much global connection and we
should crack down on refugees
there is still time to stop human and immigrants. But actually
that’s not the lesson,” he says.
suffering in the world’s most
The IRC is about halfway to
fragile countries, by increasing its goal of raising $30 million to
help fragile countries during the
handwashing, fever testing and pandemic. The group has had to
adapt many of the other services it
building isolation centres. provides to people to avoid risk of
covid-19 transmission. Education
A report by the IRC estimates programmes, which are normally
based on bringing children
that in a worst-case scenario, together, are using radio to reach
people instead, for example.
more than 3 million people
Although the WHO’s actions
will die from covid-19 and a haven’t been perfect, says
Miliband, US president Donald
billion would be infected across Trump’s decision to halt US
funding to the WHO while
34 crisis-affected countries. reviewing its handling of the
coronavirus crisis was unhealthy
The estimates, based on and misguided. The danger
is that there is a cost to the
modelling done by Imperial president’s review of the WHO,
and “that price is paid by the most
College London, are likely to vulnerable people in the world”.

be conservative because they KELLIE RYAN/IRC Miliband says he is “obviously
very worried” that more than
assume levels of healthcare 30,000 people have died in the
UK, the highest level in Europe.
that match those in China,
“‘If everything is going so well,
which many of the countries why are so many people dying?’,
is the question in my mind. There
don’t have, says Miliband. are obviously very hard questions
to ask about how we’ve ended up
Three of the countries most at Nigeria confirmed its highest has to go from a World Health in this situation,” he says. ❚
Organization (WHO) ambition to
risk are Yemen, which already has daily number of covid-19 cases something governments around
the world really commit to.”
the world’s worst humanitarian on the day it began to phase out
Tackling the virus in the world’s
crisis, Nigeria, because it has the lockdown measures. most vulnerable countries isn’t
just a moral argument, but a
largest population in Africa, and “Obviously, it’s very worrying practical one of self-interest for
high-income countries too, he
Bangladesh, which is home to the if countries like Nigeria start argues: “There will be no return
to anything like economic
biggest refugee camp, he says. relaxing their lockdowns at or social normality until the
disease is beaten everywhere.”
Sub-Saharan Africa is puzzling, precisely the time when the
However, richer governments
Miliband says, because although have failed to support poorer
ones with international aid
little covid-19 testing has taken “There will be no return on covid-19, he says.

place in the region, health facilities to economic or social “Up to now, governments are
being understandably focused
run by the IRC there haven’t been normality until the disease on the home front, but myopic
and neglecting the international
overrun. That could be due to a is beaten everywhere” front. That myopia is damaging.
Damaging to the lives of people
younger population in the region. in the countries where we work,

“Demography might be playing a disease might be spreading

part, but it might not. More likely most strongly,” says Miliband.

is that the spread of the disease In many places in the world, he

has not yet hit the full ramp-up, says, people are on an economic

partly because many of the ledge without a safety net. “The

places we work are not as danger is if the health emergency

integrated into the global doesn’t get you, the economic

economy as New York or London.” and social emergency does. The

The coming weeks will be lesson of this crisis is we have to

critical, he says. On 4 May, fill the hole. Universal healthcare

12 | New Scientist | 16 May 2020

National restrictions

Some African countries begin
to ease coronavirus lockdowns

Adam Vaughan

COVID-19 cases across Africa enabled a “sizeable number” of and mask wearing are encouraged. could gain nations an extra three
have continued to be reported at people carrying the virus to leave Koram said that economic months to prepare and mobilise
much lower levels than on other for other parts of the country, Kojo resources (medRxiv, doi.org/dt95).
continents. After many African Ansah Koram, former director of voices had won out over scientific
countries took quick action to stop the Noguchi Memorial Institute advice. While many expected a South Africa seems better
the virus spreading, several have for Medical Research in Ghana, further three weeks of lockdown, placed to capitalise on this. The
begun easing restrictions. told the meeting. the government had to take into country had its first covid-19 case
account the large number of on 5 March and has tested more
South Africa has some of With the lockdown now lifted, people who need to work each than 200,000 people. Although
the continent’s most stringent Ghana is doing as much testing day to earn a living. 1.5 million people in certain
coronavirus measures, including a and tracing as possible – more sectors were allowed back to work
ban on cigarette and alcohol sales than 100,000 people have been Modelling by Francesco Checchi on 1 May, the initial three-week
and a lockdown that allows people tested so far. Physical distancing at the London School of Hygiene lockdown has been extended.
out only to get food or medicine. and Tropical Medicine and his
Its government is relaxing Workers make protective colleagues suggests that short The plan now is for testing and
restrictions only very gradually. equipment during lockdowns in African countries tracing, and for lockdown to be
lockdown in Accra, Ghana can have only “marginal effects”, relaxed in phases at a regional
In contrast, Ghana lifted the whereas two-month lockdowns level. “South Africa has a much
lockdown in its capital, Accra, more advanced health system
after only three weeks. REUTERS/FRANCIS KOKOROKO and could potentially rely on
an exit strategy that mixes
“In balancing lives and distancing with extensive
livelihoods, [African] countries are testing and contact tracing plus
now looking at easing restrictions. scaling up of hospitalisation
In doing so, we are encouraging capacity,” says Checchi.
countries to adjust measures
slowly and in line with the Lockdowns are tough for
evidence,” Matshidiso Moeti at vulnerable people, says Wafaa
the World Health Organization El-Sadr at Columbia University in
told a World Economic Forum New York, and governments must
virtual meeting on 30 April. look to provide food and income
support. “If this does not happen,
Ghana’s first covid-19 cases many will suffer and it will
were reported on 12 March. Before compel people to break lockdown
lockdown was imposed on Accra measures in order to survive.” ❚
at the end of March, a grace period

Testing

Senegal to trial pregnancy kit and can be used chain reaction, or PCR, to detect decentralised and not required
$1 speedy test to turn a profit are essential to
for covid-19 either to detect current infections sequences of viral RNA. Each test addressing covid-19 and future
pandemics, he says.
TRIALS to develop a $1 covid-19 through saliva antigens or previous costs hundreds of dollars and takes
testing kit that produces results in Justine Davies, a global health
less than 10 minutes are under way infections by blood antibodies. several hours to process using researcher at the University of
in Senegal. If it works, the test could Birmingham, UK, says the tests
be a vital tool in sub-Saharan Africa. The institute says it could be rolled sophisticated equipment. The could allow some economic activity
to continue in the region while
Researchers at DiaTropix, an out next month if the trials show team behind the new pocket-sized reducing the burden on Africa’s
infectious disease testing facility limited health services. “If it is
run by the Pasteur Institute in Dakar, it works well enough. test say it would be much cheaper properly validated and found to be
are working alongside UK-based reliable, then it could have major
company Mologic to manufacture Amadou Sall, director of the and easier to distribute across positive impacts, allowing contact
the diagnostic kits. tracing and limiting the spread of
Pasteur Institute in Dakar, said that sub-Saharan Africa. the virus,” she says. ❚
The prototype is similar to a home Peter Yeung
500 to 1000 tests a day could be “Existing systems are not fit

analysed at the facility and that up for purpose,” says Joe Fitchett at

to 4 million could be made annually. Mologic. Testing regimes that are

“There is no need for a highly

equipped lab,” he says. “It is a simple “There is no need for

test that can be done anywhere.” a highly equipped lab.

Most coronavirus tests use This simple test can

a technique called polymerase be done anywhere”

16 May 2020 | New Scientist | 13

News

Human origins

An ancient cultural exchange

Bear teeth pendants suggest a meeting of modern human and Neanderthal minds

Michael Marshall

WHEN modern humans first DIYANA GEORGIEVA/GETTY IMAGES Before humans arrived,
settled in Europe, they met Neanderthals lived in Europe
Neanderthals – and possibly The oldest human bones were Human remains found in for hundreds of thousands of
passed on jewellery-making tips. between 43,700 and 45,800 years Bacho Kiro cave, Bulgaria, years. When the two met, they
old. A deeper layer that is 46,900 date back 45,000 years interbred. Neanderthals died
Jean-Jacques Hublin at the Max years old hasn’t yet yielded human out a few thousand years later:
Planck Institute for Evolutionary remains, but it contained marked Italy, but these bones were only the last well-dated evidence of
Anthropology in Leipzig, Germany, animal bones, suggesting humans indirectly dated to about 45,000 their presence is 40,000 years old.
and his colleagues have confirmed were present. years ago.
for the first time that modern Neanderthals got more creative
humans were in Europe at least The dating “reinforces what It makes sense that the with their tools in their final
45,000 years ago. They also we thought we knew with some Bacho Kiro people were there millennia. The Grotte du Renne
suggest that modern humans stronger evidence”, says Emma earlier than those in Italy or in Arcy-sur-Cure, France, contains
taught Neanderthals to make Pomeroy at the University of Britain, says Katerina Harvati pendants made of bear teeth,
necklaces out of bear teeth. Cambridge. Previous signs of at the University of Tübingen in which Hublin argues were made
modern humans in Europe came Germany, as humans were coming by Neanderthals. All are younger
The researchers re-excavated from sites like Kents Cavern in the from the east, so would have than 45,000 years old.
Bacho Kiro cave in Bulgaria, which UK and the Grotta del Cavallo in reached eastern Europe first.
has been studied since the 1930s. The Bacho Kiro re-excavation
Human remains were found there found 11 pendants made of cave
in the 1970s, but these were lost. bear teeth that predate the
Attempts to date those remains supposedly Neanderthal ones.
gave contradictory results. “It did Hublin says this means modern
imply that potentially this was a humans brought the idea with
really old assemblage,” says team them, and Neanderthals copied it
member Helen Fewlass. (Nature, DOI: 10.1038/s41586-020-
2259-z). The only alternative, he
Using new decontamination says, is that Neanderthals also
methods, the researchers dated invented the pendants just after
95 pieces of bone, identified by humans arrived, but he calls this
analysing their DNA and protein scenario “ridiculous”.
content. Six came from modern
humans, and the remainder were The problem with the idea
animal bones with cut marks or is that we can’t be sure the
other signs of human activity later pendants were made by
(Nature Ecology & Evolution, Neanderthals, as humans were
DOI: 10.1038/s41559-020-1136-3). in Europe by then, says Pomeroy.  ❚

Space

Nearest black hole is team was looking for pairs of stars closer by that we haven’t found yet, practically invisible like this one, so
close enough to ‘see’ finding more like this could help us
without a telescope in which one was a type that rotates but this is the closest that we know,” get a handle on exactly how many
black holes there are in our galaxy.
ASTRONOMERS have found the so quickly it flings off material from says Heida. It is thought that there
closest black hole yet. Just 1000 Luckily, this black hole is far
light years away, you can see the its equator, creating a kind of ring are about 100 million small black enough away that we don’t need to
stars that orbit it without a telescope. worry about it. “Earth is not in any
from its own plasma. holes in the Milky Way, but we have danger,” says Heida. “Given that
Marianne Heida at the European there are two stars that are much
Southern Observatory in Garching, HR 6819 has one of those plus found fewer than 100. If black closer than we are, and they are
Germany, and her colleagues not falling in, we won’t fall in.”
spotted this black hole by accident. a normal star, but the normal one holes were spread evenly in the
It is part of a system called HR 6819 The system can be seen in the
that also contains two stars. The appeared to be orbiting an empty galaxy, the closest should be just sky in the southern hemisphere,
in the constellation Telescopium.  ❚
spot of space once every 40 days. 30 to 40 light years away, she says. Leah Crane

This turned out to be a black hole Most black holes are probably

at least four times as massive as the

sun, invisible because it isn’t actively “If black holes were spread

devouring any material (Astronomy evenly in the galaxy, the

& Astrophysics, doi.org/dt2w). closest should be just 30

“There must be a bunch of them to 40 light years away”

14 | New Scientist | 16 May 2020

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News Climate change

Archaeology UK green heating plan
will take 1500 years
Egyptian pyramids
really were aligned Michael Le Page
to compass points
THE UK won’t be able to meet more energy efficient grid than having heat pumps
Michael Marshall its 2050 climate change targets and switch to renewables. installed, says Lowes, meaning
unless much more is done the UK is going backwards when
SOME ancient Egyptian temples to cut emissions from heating The best way to do this is to it comes to the decarbonisation
and tombs were indeed oriented buildings. The government’s electrify heating by installing of home heating.
towards certain regions of the latest proposals for doing so heat pumps. “Everybody who
sky, according to a new analysis. have been deemed inadequate. looks at this comes to the same A consultation document
conclusion,” says Rosenow. dated 28 April has now set out
Most studies of this phenomenon “They are staggeringly proposals for what happens
map multiple structures made by unambitious,” says Jan Rosenow Heat pumps transfer existing after 2021. There are some
a culture, then look for clusters at the Regulatory Assistance heat energy in the air or ground positive aspects to it, says
that may relate to star or planet Project, an organisation to water for heating radiators, Rosenow. For instance, people
positions. A 2009 study of 330 dedicated to speeding up the  or for baths and showers. who install heat pumps can
ancient Egyptian temples identified transition to clean energy. apply for an upfront grant of
seven groups, each supposedly 19m £4000, rather than only getting
with a different alignment. Unless more is done, it will a payment after the installation,
take about 1500 years to meet Recommended number of heat as is currently the case. Upfront
Yet the clusters could just be a heating target for 2050 pumps in the UK by 2050 costs deter people, he says.
coincidences, says Fabio Silva at recommended by the UK’s
Bournemouth University in the UK. official advisers on cutting Essentially, they work like However, under the new
He devised a method that assumes emissions, Rosenow calculates. a refrigerator in reverse. proposals, which cover the
the original ground-level data has period 2022 to 2024, funding
uncertainties, and introduces more “If this is all there is, then The UK’s official adviser would be capped at £50 million
uncertainty when measurements it would be disastrous,” says on meeting its climate targets, a year. This level of funding
are extrapolated to the sky. Richard Lowes at the University the Committee on Climate would support 12,500
of Exeter, UK. Change (CCC), has said the installations per year. At this
“I certainly appreciate the aim should be to install up to rate, it would take 1520 years
attempt to bring a quantitative Last year, the UK government 19 million heat pumps by 2050. to get to 19 million pumps.
analysis into a field which seems set a legally binding target However, not nearly enough
to me to be somewhat qualitative,” of meeting net-zero emissions is being done to achieve this. “The current proposed
says astronomer Michelle Lochner by 2050, meaning that the funding is clearly insufficient,”
at the University of the Western country needs to drastically So far, only around 60,000 says Jenny Hill at the CCC.
Cape in South Africa. cut its emissions and offset heat pumps have been installed “There is a great opportunity
any that remain, leaving a under the current government here to boost it, particularly as
Silva applied this method to the net total of zero emissions. scheme, the Renewable Heat many of the other proposals
Egyptian temple data. He found that Incentive (RHI), says Lowes. The under the scheme look sensible.”
four of those seven purported groups The UK still relies heavily on total will probably be just 75,000
of sky-oriented structures weren’t fossil fuels, mainly natural gas, when the RHI ends in 2021. There have been reports of
statistically significant (Journal of for heating its poorly insulated teething problems with heat
Archaeological Science, doi.org/ homes. To meet its target, the In fact, more new homes pumps, such as some people
ggts9v). A fifth looked “iffy”, he UK needs to make buildings are being connected to the gas getting higher bills. That can
says. Only two groups held up: happen if heat pumps are
certain temples in the Old Kingdom installed in poorly insulated
(2686-2160 BC) and in the Middle homes, says Rosenow, which
Kingdom (2055-1650 BC). is yet another reason why
improving insulation is
During the Old Kingdom, important. He says he has
some pyramids were built with halved his own heating costs
entrances facing north. Ancient since installing a heat pump.
Egyptians believed that “the north
is the place of the ascent the soul of The UK Department
the pharaoh makes to the northern for Business, Energy and
imperishable stars”, says Bernadette Industrial Strategy didn’t
Brady at the University of Wales respond to questions. ❚
Trinity Saint David in Lampeter, UK.
STEVE BALL/ALAMY UK homes are often
In the Middle Kingdom, the sun poorly insulated, upping
god Ra became prominent, so some carbon emissions
temples faced east towards sunrise.
Other structures like the Karnak
temple near Luxor were aligned to
sunrise on the December solstice.  ❚

16 | New Scientist | 16 May 2020

Biology STANFORD UNIVERSITY

Brain cells have a long reach

Mouse neurons can grow out of cages to contact others

Clare Wilson

THESE microscopic cages, based
on the shape of “buckyball” carbon
molecules, are trapping neurons
taken from the brains of mice. The
cells have grown long branch-like
appendages through the bars
of their cages, allowing them to
make connections with each other
(Biofabrication, doi.org/dt3k).

Trapping brain cells and growing
them in this way allows them to be
manipulated more precisely, says
Aleksandr Ovsianikov at the Vienna
University of Technology in Austria.

The buckyball-shaped cages,
which are 100 micrometres
wide, are made by 3D-printing
a plastic-like material.

The immature brain cells,
obtained from mouse embryos,
are forced into their prisons by
placing a suspension of the cells
over a layer of cages. Ovsianikov
and his colleagues bombarded
the suspension with sound waves
to jostle the cells into place. ❚

Technology

AI can spot objects even if they are hidden

CAMOUFLAGED objects are To improve on this, Jianbing The team manually labelled did better than the other 12 at
difficult to detect, for both isolating camouflaged objects and
humans and artificial Shen at the Inception Institute of each image of a camouflaged identifying their correct shape
intelligence. But now an AI has and nature in both the existing
been trained to parse objects Artificial Intelligence in Abu Dhabi object to highlight characteristics and the training data sets.
from their backgrounds.
in the United Arab Emirates and such as its shape or whether it “Without any bells and whistles,
This could have a variety SINet outperforms various state-
of applications, such as being his colleagues collated a data set was partially obstructed by its of-the-art object detection
used for search-and-rescue baselines on all datasets tested,
work, detecting agricultural of 10,000 photographs to train surrounding environment. making it a robust, general
pests, medical imaging or in framework that can help facilitate
military settings. an AI. The data set includes 5066 They then developed an AI future research,” the researchers
write. They are due to present the
Detecting camouflaged objects images of camouflaged objects, called SINet and trained it on work at the CVPR 2020 conference
requires visual perception and in Seattle, Washington, in June.
knowledge. Until now, many which they have divided into 78 images from the data set.
AIs have struggled with this task The researchers hope the data
because their algorithms rely on categories, such as “amphibian”, The researchers compared set and algorithm can improve AI’s
visual cues, such as differences ability to recognise camouflaged
in colour or easily recognisable “aquatic” and “flying”. SINet to 12 existing algorithms objects, says Shen. ❚
shapes, to identify objects. Donna Lu
The photographs included built to detect generic objects.

both naturally camouflaged They tested all 13 algorithms

animals such as fish and insects using three existing data sets

and examples of artificial of camouflaged objects. SINet

camouflage, such as soldiers

in uniform. Although databases “Many AIs struggle to detect

of camouflaged objects already camouflaged objects

exist, this data set is the largest, because their algorithms

says Shen. rely on visual cues”

16 May 2020 | New Scientist | 17

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News

Climate change Animal behaviour

Some places are already Orangutans catch
too hot for humans to live scratching like we
catch yawns
Adam Vaughan
Michael Marshall
GLOBAL warming has already ASAD/XINHUA/ALAMY
made parts of the world hotter AMONG orangutans, scratching is
than the human body can this magic threshold of 35°C,” he Kuwait saw extreme contagious – just as yawning is in
withstand, decades earlier says. “It looks like, in some cases temperatures in humans. When an orangutan sees
than climate models expected. for a brief period of the day, we June 2019 another scratch, it often starts
have exceeded this value.” scratching, too.
Measurements at Jacobabad capacity to adapt. Even if they
in Pakistan and Ras al Khaimah His team corroborated the could, it would require huge But the behaviour differs from
in the United Arab Emirates breach by looking at a separate, amounts of energy for cooling, contagious yawning in one crucial
have both repeatedly spent at widely used, historical weather possibly further exacerbating respect. Humans catch yawns more
least 1 or 2 hours over a deadly data set, which also showed climate change. readily from family and friends, but
threshold, an analysis of evidence for it occurring. orangutans are more likely to catch
weather station data has found. Steven Sherwood at the scratching if they don’t know the
An analysis of that data set University of New South Wales other orangutan well.
Wet bulb temperature (TW) is suggested several wider areas of in Australia says the study
a measure of heat and humidity, the Gulf, not just a few hotspots, makes a convincing case that Daan Laméris at the University
taken from a thermometer will see the possibility of a TW the measurements are accurate, of Antwerp in Belgium and his
covered in a water-soaked cloth. of 35°C happening once every though it isn’t guaranteed. “The team studied nine adult Bornean
Beyond a TW threshold of 35°C, 30 years at around 2.3°C implications of this study are orangutans living in captivity in
the body is unable to cool itself of global warming. The world that such extreme conditions the Netherlands. The researchers
by sweating. Lower levels can has already warmed about 1°C. which push the tolerance of the recorded yawning and scratching,
also be deadly, as was seen in the human body are not as far off as well as whether the apes seemed
2003 European heatwave, which 35°C into the future as we thought, to be relaxed or stressed. They
killed thousands of people at least in a few locations on also monitored the quality of the
without passing a TW of 28°C. This deadly wet bulb Earth,” he says. orangutans’ relationships by noting
temperature has been passed friendly behaviours like grooming.
Tom Matthews at Clare Heaviside at University
Loughborough University, UK, Such intense humid College London says the The orangutans rarely yawned,
and his colleagues analysed temperatures have so far largely work is  broadly in line with so the team didn’t see contagious
weather station data from affected affluent Gulf states, existing research, but cautioned yawning, but contagious scratching
around the world, and found where air conditioning is against the focus on the TW was evident. An orangutan would
that the frequency of wet bulb widely available to the rich. threshold of 35°C. typically scratch itself within 90
temperatures exceeding a But Matthews warns that with seconds of seeing another scratch
series of temperature intervals continued climate change, the “It is difficult to link a wet (American Journal of Primatology,
between 27°C and 35°C had all extremes will affect more areas bulb temperature threshold doi.org/dt3c). They became three
doubled since 1979. in Pakistan, as well as India, to specific health outcomes, times as likely to scratch if another
which may not have the and for different population orangutan scratched first.
Most frequency increases groups,” she says. ❚
were in the Gulf, India, Pakistan, Scratching was more likely to be
the US and Mexico. But at contagious if the initial scratch took
Jacobabad and Ras al Khaimah, place in a tense context, and if the
a TW of 35°C appears to have two animals had a relatively poor
been passed, the first time relationship. This makes sense if
the breach has been reported you consider when orangutans
in scientific literature (Science and other primates tend to scratch,
Advances, doi.org/ggvfk3). says Laméris. “Scratch rates
increase during arousing events,”
There is a degree of he says, such as when an animal is
uncertainty, because there aggressive, or if a predator attacks.
could be flaws with individual
weather stations, such as how Laméris points out that aroused
they are calibrated or where or stressed individuals often behave
they are sited, but Matthews unpredictably, stressing other
says the overall picture is clear. members of the group – especially
if they aren’t close friends or family.
“The crossings of all of these “If it’s a complete stranger you’re
thresholds imply greater risk to maybe a bit suspicious. Why is this
human health – we can say we individual so stressed? It becomes
are universally creeping close to a bit scary,” he says. ❚

16 May 2020 | New Scientist | 19

News In brief

Solar system Really brief

Carbon on the moon GEORGETTE DOUWMA/NATURE PL Long-lived river
leaves origin puzzle FACULTY OF GEOSCIENCES, UTRECHT UNIVERSITY on ancient Mars

THE moon has its own carbon A 200-metre rocky cliff in
emissions, which may change our Mars’s Hellas basin found in
understanding of its formation. images from NASA’s Mars
Reconnaissance Orbiter
Using data from Japan’s Kaguya seems to have been slowly
lunar orbiter, Shoichiro Yokota at formed by an ancient
Osaka University in Japan and his river over 100,000 years
colleagues found that the moon (Nature Communications,
emits carbon ions across almost doi.org/dtxk).
its entire surface.
BCG vaccine gives
As the total emissions are larger immune boost
than the estimates of the carbon
supplied by the solar wind and The BCG tuberculosis
micrometeoroids, the researchers vaccine increases immune
believe the moon has its own cell production, which may
carbon supply (Science Advances, explain why it can protect
doi.org/dt2v). newborn babies from
sepsis. Researchers looked
The finding suggests the moon at blood samples from
contains volatile carbon. But 85 newborns, half of whom
this undermines the widely held had been vaccinated.
hypothesis that the moon formed Three days on, this group
as a result of an impact between had about twice as many
a young Earth and a Mars-sized immune cells in their blood
body that would have boiled the (Science Translational
volatiles away. Donna Lu Medicine, doi.org/dt2s).

Health Zoology Our brains replay
life while we sleep
Herpes virus causes Nuclear power including tropical ones such as the
signs of Alzheimer’s plant added blue damselfish (pictured) and the Brain implants have given
tropical colour cutribbon wrasse. us the first direct evidence
MINI-BRAINS grown in a dish to Japan’s seas that human brains replay
develop signs of Alzheimer’s These tropical species weren’t waking experiences while
disease when infected with the TROPICAL fish have colonised seen at the other two sites, even we sleep, which may help
common herpes virus that causes a small coastal area in the Sea though their winter temperatures consolidate memories. This
cold sores. This adds to growing of Japan as a result of warm water were only slightly lower, at 12.3°C was seen in neuron activity
evidence that some cases of being discharged from a nearby and 11.7°C. while people slept, which
Alzheimer’s are triggered by nuclear power plant. This suggests matched the activity as
viruses and might be treatable that global warming will drastically In February 2012, operations at they memorised a pattern
with antiviral drugs. alter marine ecosystems around the nuclear plant were suspended of movement on a screen
the temperate areas of Japan over because of the Fukushima disaster. (Cell Reports, doi.org/dtxt).
One hallmark of Alzheimer’s the next few decades. Winter water temperatures at the
is the build-up of protein plaques, nearby dive site fell by 3°C, and the
which might defend against Since 2004, Reiji Masuda at tropical species all disappeared.
viruses and bacteria that can reach Kyoto University and his colleagues
the brain. Herpes simplex virus 1 have been doing underwater In 2017, two of the four units
is one virus linked to the condition. surveys every winter at three coastal at the nuclear plant restarted,
sites near Kyoto. One is warmed by and tropical species are gradually
Dana Cairns at Tufts University the water used to cool the Takahama returning (PLoS One, doi.org/dt2r).
in Massachusetts and her nuclear power plant, keeping winter
colleagues added HSV-1 to clumps water temperatures around 13.6°C. Masuda thinks the findings show
of brain tissue grown in dishes. that winter water temperatures in
Within three days of infection, There, the divers saw more fish the region are just below the critical
the mini-brains formed protein overall than at the two other sites level tropical species require to
plaques reminiscent of those and a greater diversity of species, survive. With water temperatures
in the brains of people with around the temperate parts of Japan
Alzheimer’s (Science Advances, rising fast due to global warming,
doi.org/dt2z). Alice Klein that means tropical species will
soon be able to colonise vast areas
of the coast, reshaping coastal
ecosystems. Michael Le Page

20 | New Scientist | 16 May 2020

18 May 2020 6pm BST/1pm EDT

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CAN WE TRUST
THE SCIENCE?

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Views Columnist

Letters Culture Don’t miss Aperture
Readers views on living in Philip Pullman talks to us The Age of Islands, a book A gleaming, glorious vista
the age of the face mask and about science, daemons charting the rise of artificial of solar power’s foothold
life after lockdown p24 and dust p26 landmasses at sea p27 in the Mojave desert p28

Columnist

A greener planet

More carbon dioxide in the atmosphere may be boosting plants,
but that doesn’t mean it is good news, says James Wong

James Wong is a botanist and IN A world of increasing it isn’t necessarily a very accurate how much we curb emissions,
science writer, with a particular uncertainty, good news one. Much of this carbon is stored the average global temperature
interest in food crops, has a particular allure. So by plants underground, which is is projected to increase to between
conservation and the 1.5°C and 4.5°C above pre-
environment. Trained at the it is unsurprising that studies invisible to orbiting satellites. industrial levels this century.
Royal Botanic Gardens, Kew, he Models predict that this could
shares his tiny London flat with finding that rising carbon dioxide What such studies also can’t do result in as much as 67 per cent of
more than 500 houseplants. plants losing the range in which
You can follow him on Twitter emissions are boosting plant life is distinguish between different they can grow well, which would
and Instagram @botanygeek have such a catastrophic effect on
have attracted a lot of attention in types of plant communities, global agriculture as to make any
James’s week net gain from CO2 fertilisation
recent years. Some people even go which is a major issue. We know, seem insignificant.
What I’m reading
I may be biased, as it is as far as to use this so-called CO2 for example, that old growth In these scenarios, the harvest
written by some of my of the three major crops that
old colleagues, but Just fertilisation effect as evidence forests can store far more carbon provide us with the bulk of our
The Tonic is a fascinating calories could decline by 7.4 per
explanation of how a that an uptick in plants could than quick-growing commercial cent in maize, 6 per cent in wheat
quinine-containing bark and 3.2 per cent in rice, all in a
changed the world. mitigate the effects of climate plantations. Not all green is period while global population
is predicted to increase by over
What I’m watching change. Is there any truth to it? created equal. 3 billion. In some locations, the
It is probably uncool, but effect of temperature in tandem
I’m revisiting the original Firstly, the studies these claims with lower rainfall, such as south-
Jurassic Park trilogy. eastern Australia, is expected to
are based on are far from “fake “Increased levels of show far worse effects on crops,
What I’m working on with decreases of 70 per cent.
A brand new plant news”. They are well-designed and atmospheric carbon
science podcast. often reflect a long-established won’t just impact However, more atmospheric
Watch this space! scientific consensus. As CO2 is the amount of food carbon doesn’t just affect the yield,
one of the essential inputs of we can grow, but but also the quality of crops. It has
This column appears photosynthesis, the process by also the quality of it” also been shown that the nutrient
monthly. Up next week: which plants harness solar energy density falls.
Chanda Prescod-Weinstein
to grow, increasing its availability So, yes, an increase in CO2 levels
may well have direct benefits on
can indeed boost the process. The same studies that show an plant growth for a while, but it is
crucial that these are seen in the
We also know from satellite increased rate of photosynthesis context of the downsides of its
indirect effects – not just for plants,
images that Earth’s surface is with higher CO2 levels also tend but for food crops we all rely on.
These downsides are so large, it is
measurably greener than in to show that these benefits – tricky to describe rising levels of
CO2 as a “benefit” to plants at all.
decades gone by, and this is although significant – are by and So much for a good news story. ❚

extremely likely to be due in large short-lived. This is because

significant part to increases in once CO2 is no longer a limiting

CO2 levels. In fact, some studies factor, plants eventually reach the

suggest that this increased growth next biggest limiting factor, such

can remove as much as 25 per cent as the availability of nitrogen – a

of the emissions we generate, mineral essential for plant growth

equivalent to the total carbon that they usually get from the soil.

footprint of China, the planet’s Ever-increasing CO2 simply doesn’t

largest emitter. But now here mean ever increasing vegetation,

come the caveats, and there as there is an array of other factors

are many of them. that constrain plant growth.

Collating images of the extent One of the outcomes we can

of plants and trees on Earth’s predict with some reliability

surface is a beautifully simple is the effect of extra CO2 in

way to estimate the level of carbon the atmosphere on global

they suck out the atmosphere, but temperatures. Depending on

16 May 2020 | New Scientist | 23

Views Your letters

Editor’s pick Move to reopen Another take on ice cream seem. I suggested this approach
gyms made me gasp and shark attacks in 1971 in two letters to Nature
Beneath the mask (vol 229, p 435 and vol 231, p 201).
lies a complex story 25 April, p 10 25 April, p 32 The idea was, of course, quashed
From Dave Smith, Alnwick, From Brian Horton, West as impractical by a biologist.
18 April, p 11 Northumberland, UK Launceston, Tasmania, Australia
From Lloyd Timberlake, You looked at various claims that As reported, correlation and I also pointed out the
Ridge, Maryland, US breathing exercises may protect causation are very different beasts. possibilities of culturing meat
Jessica Hamzelou’s excellent piece people from covid-19, including An example was given, that ice that we don’t eat today, perhaps
on the science of the protective the view that getting air into cream sales are correlated with because the animals are too
effects of face masks against the the depths of the lungs may be a shark attacks rather than there small to bother with, or for other
coronavirus inevitably didn’t touch strategy to minimise respiratory being any causal link, such as ice reasons. Who knows, mouse
on unscientific, but important, infection more generally. That cream attracting sharks. Having might be delicious.
aspects of masks, which the US brings to mind aerobic exercise. seen this correlation claimed
Centers for Disease Control and many times, I suspect it is faulty. Yet more hints that none
Prevention now recommends we There may be places where of this is actually real
wear in settings like grocery stores. breathing deeply in this way isn’t Sharks most commonly attack
such a great idea. In the US state of surfers, who like beaches with big Letters, 28 March
Masks are a form of theatre, Georgia, gyms have been allowed waves, often in remote locations. From David Norman,
saying: “I am playing the role of to reopen. My fear is that the air Ice cream sellers prefer family- Ipsach, Switzerland
a responsible citizen.” They are in such places will be filled with a friendly beaches that shelve gently Ed Subitzky says that if we live
a uniform expressing serious long-lived aerosol that, nowadays, and have small waves. I suspect in a simulated cosmos, then
solidarity in the war against the is potentially contaminated. It that a critical examination of the major anomalies in physics
pandemic. They are also a polite follows that other people taking data would show that ice cream could actually be bugs in the
way to say: “Stay away from me. strenuous aerobic exercise in the sales near a beach are negatively programming.
You don’t know whether I am same space will be taking virus- correlated with shark attacks.
wearing this mask to protect laden air deep into their lungs, In the same issue, your
me from you or you from me.” their most vulnerable organs. Time to let fever run columnist Chanda Prescod-
its course more often Weinstein (p 24) explains how
Perhaps most importantly, What will we be like when different measurement methods
President Trump won’t wear one. we finally emerge again? 11 April, p 39 return differing values for the
So they must be an excellent idea. From Heinz-Uwe Hobohm, Hubble constant, which describes
11 April, p 10 Giessen, Germany the expansion of space-time.
Also worried about an From Roger Taylor, Linda Geddes’s article on fever Of course, there is absolutely
epidemic of loneliness Meols, Wirral, UK expresses surprise at some of no connection here.
Here’s hoping that when we work its benefits.
25 April, p 40 out how to end the coronavirus From Tim Jackson,
From Anne Brien, restrictions, we will all be wiser: What is surprising to me Rossendale, Lancashire, UK
Sheffield, South Yorkshire, UK more cooperative, less selfish is that medical schools teach In his 1964 science fiction novel
With Moya Sarner’s article on and aware of the balance between doctors to kill the messenger Counterfeit World (which was also
the challenges to mental health rights and responsibilities. rather than focus on the message. published as Simulacron-3), Daniel
during lockdown, one further Fever is a symptom of a disease, Galouye, who probably originated
group of particular concern From Andy Smith, York, UK not a disease itself. In the clinic, the concept that we may be living
is people who live alone. It is After the lockdown ends, it will be the presumption that fever should in a simulation, was clear about
estimated that 15 per cent of interesting to see what impact it be treated ought to be questioned the purpose of the simulated
the adult population of the has had on the health-promoting more, given its benefits. world: it was for market research
UK, or 8.2 million people, are behaviours of the population. and to investigate the likely public
in one-person households. Perhaps we should create more Cultured mouse might response to political policies in
opportunities for exercise to help be a gourmet delight the real world.
Like everyone, they are being combat obesity, heart disease and
asked to stay indoors or, when other conditions that remain a 22 February, p 39 As I receive yet another request
outside, to keep 2 metres from challenge for the UK’s National From Dieter Britz, for feedback on a minor purchase,
others, going without human Health Service, and that seem Aarhus, Denmark I have no doubt that he was right. ❚
touch for months. Chances for to be risk factors for covid-19. Might I point out that the idea of
interaction are inevitably limited. cultured meat is older than it may For the record

In the discussions of how Want to get in touch? ❚  Work showing that “phi” doesn’t
long lockdown may last, there fall for sleep and general anaesthesia
is a worrying silence about the Send letters to [email protected]; was published by Pedro Mediano
potential effects on the mental see terms at newscientist.com/letters (and others) before he joined Daniel
health of this group, and there Letters sent to New Scientist, 25 Bedford Street, Bor’s lab, and the Inland Norway
appears to be little consideration London WC2E 9ES will be delayed University of Applied Sciences is
being given to ways of mitigating in Lillehammer (2 May, p 40).
their isolation.

24 | New Scientist | 16 May 2020

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As Covid-19 hits the science, technology, to unlocking the UK’s potential to remain at CHANGING THE FACE OF STEM
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an overlooked generation that may hold the key

Views Culture

Science, daemons and Dust

Philip Pullman’s stories delve into difficult questions about our existence.
He believes that fiction can fill in the gaps left by science, finds Rowan Hooper

IN WHAT now feels like a distant It is. But what I struggle with is that
time, when we could still travel the hard problem of consciousness,
and meet people, I went to what it is and how it works, doesn't
Oxford,to the home of author really give us anything concrete to
Philip Pullman. He made a pot get to grips with. It doesn't give us
of tea with his favoured blend anything experimental to work on.
of two spoons of Assam, one of No, it doesn’t. Since Galileo, the
lapsang souchong (“for the approach of science has been a
smokiness”), and we sat mathematical one, where you
surrounded by books and pens measure things, you’ve got a
and pads and knick-knacks, and quantity that’s measurable, you
spoke of science, daemons and measure it, and that’s part of
Dust – Pullman’s particle for what you do. But science can’t deal
consciousness. with qualities. It can’t deal with
experiences. It’s just not set up
Pullman had been writing for to do so. You need to accept that
years before he became a global there are things that are important
sensation with the His Dark to us all, which science can’t yet
Materials trilogy. The story of get a grip on. How do you explain
two children crossing into nostalgia for example? How
parallel worlds in a quest to would you build nostalgia into
understand the nature of reality an artificial intelligence?
and humanity draws on fantasy
as well as theology, physics and You could assign different values TOM NICHOLSON/PINPEP
neuroscience, with strong
influences from poets William to its memories and experiences
Blake and John Milton.
in its algorithm. That would be a
Perhaps his most celebrated
creation is the daemon, a physical sort of artificial nostalgia.
manifestation, in the form of an
animal, that represents a person’s Would that be like Proust
consciousness, spirit or soul.
Pullman is following up the [famously reminded of his
trilogy with another, The Book
of Dust. The second part of this, childhood by the taste of a “The things that science day.” I’d say, “Well, you won’t
The Secret Commonwealth, was madeleine cake dunked in tea]? is sceptical about are because it’s just not measurable.”
out last year. I think a lot of the things that these qualities that are
science is either dubious about so well expressed in I feel that’s a pessimistic outlook
Rowan Hooper: Consciousness is or sceptical about, or refuses to literature or music” on what we will be able to explain
explored in various ways in your have anything to do with, are about consciousness. Perhaps I
work, what can science say about it? am being a gung-ho scientist, but
Philip Pullman: Consciousness is these qualities that are so well I feel that we will be able to get
extraordinarily interesting and there eventually.
important, and we still haven’t expressed in terms of literature I’d point out we’ve got there
cracked the hard problem [how it already. You read it in Shelley and
emerges from matter]. Scientists or music, poetry or the visual arts. Keats and Shakespeare, you hear it
can show consciousness in Debussy and Stravinsky. We’ve
happening in the brain, they Those are the tools with which we got there. We’ve done it. But we
can find the bit that lights up don’t do it with science.
when you feel hungry or you’re examine this kind of stuff. That
frightened. But that isn’t the same At the beginning of The Secret
as being hungry or frightened. doesn’t mean I’m a dualist [the Commonwealth there’s a quote
This is the hard problem and it’s a from William Blake: “Everything
very intriguing one. idea mind and body are distinct]. possible to be believed is an image
of the truth.” Tell me about that.
I think dualism is wrong. There are I came across William Blake at that
important stage in adolescence
not two kinds of stuff. There’s one when the wind that blows on you

kind of stuff, but it’s conscious.

How do we move towards a
scientific theory of consciousness
without going down the
dualist road?
Gung-ho triumphalist proponents
of science would say, “We haven’t
got there yet. We’ll measure it one

26 | New Scientist | 16 May 2020

Podcasts | New Scientist Don’t miss

Listen to the full conversation with Philip Pullman
on the Big Interview at newscientist.com/podcasts/

Philip Pullman believe there’s not that much At the end of The Amber Spyglass, Visit
(left) dreamed difference between them, that the main character Lyra and her FACT, a centre for art,
up daemons - there is an imagination going on. daemon Pan say they need to build film and new technology
animal Science is clearly a field where the "the republic of heaven”. Do we in Liverpool, UK, is putting
manifestations imagination can be triumphant. need to build it? Or has it built itself? together a year-long
of the soul. Einstein wasn’t terribly at home William Blake again: “I must create online programme of
Lyra and her with mathematics. But he was a system or be enslaved by another podcasts, live streams,
daemon Pan good at visualising the physical man’s.” That raises questions too. videos, challenges and
from the BBC properties of things and seeing Do we need a system to live by? activities exploring our
version of His deeply into the nature of them. I Can we build our own? What relationship with the
Dark Materials suppose a biologist would have the would it be like to try and live natural environment.
are below same affinity to think themselves without one? Well, in fact, I don’t
into the being of whatever it is, think you can, because whether Read
there sets your course for the rest squirrels, beetles, fish. you consciously built it or not, The Age of Islands is
of your life. I was about 16. I’m your mind, everybody’s mind was a work of non-fiction
very attracted by what he says, for What was your intention with formed not only by evolution, but about people who have
example, about consciousness: the message about religion in also by experiences, by genetic built their own islands for
“How do you know but every His Dark Materials? factors that might predispose fun and profit while rising
bird that cuts the airy way is an I don’t believe in a god. But the one to depression or its opposite. sea levels cause natural
immense world of delight closed questions that religion poses and ones to disappear.
by your senses five?” Or, “Man tries to answer are the important So we have a system, most of Explorer Alastair Bonnett
has no body distinct from his questions about human life. us, but it’s a ragbag of memories, boards a boat to explore
soul, for body that portion of soul Where do we come from? Is there a superstitions, inclinations, things this strange new world.
discerned by the five senses.” purpose in our living? How can we we worked out for ourselves,
be good? Do we have to be good? things we bought wholesale from Watch
I like that way of thinking. What happens if we’re evil? Those the nearest church. We all do have The Art Newspaper
I like that inclusiveness. I like the are big, important questions. And a sort of system, a thing that helps on YouTube ponders
emotional power he gets from it. the Christian religion did give us to live in a meaningful way. And whether art and culture
“Let me show you a world where answers, which worked for most I think what Lyra and Pan were can thrive on the internet.
every particle of dust is alive with of 2000 years and still do work for agreeing at the end of The Amber Covid-19 has forced
joy.” That seems to me highly people. But then other religions Spyglass is that we need to do that museums and galleries
joyful, highly encouraging and have answers which aren’t so for ourselves. And poor Lyra is to reinvent themselves,
healthy, an all round good way different. All that demonstrates discovering in The Book of Dust but will it be enough?
to look at the world. is that people need stories. A that it’s not as easy as she thought.
story will help us make sense of 16 May 2020| New Scientist | 27
Going back to the things that anything. But a story is a story. You Were the daemons in your fictional
Debussy and Keats do, and the don’t have to believe everything worlds created or did they evolve?
things that scientists do, I want to in the story to find it satisfying. The question I’ve had more
often than any other is, how do
BBC/© BAD WOLF/HBO daemons get born? And I will
T&B PAUL CALBAR/GETTY IMAGES; KONSTANTIN SHAKLEIN/ALAMYsay, well, you’re welcome to come
up with any answer you like, but
I’m going to answer it for you,
because it’s a metaphor. It’s a
very useful metaphor for human
psychology. I found it in The Secret
Commonwealth to be a very good
analogy for depression. You don’t
like your daemon. Or your
daemon wants to leave you and
go and live with someone else. It’s
a very tight, neat, easily graspable
way of picturing something that
isn’t easily picturable otherwise. ❚

HENRY DO/SOLENT NEWS/SHUTTERSTOCK EDITORIAL

Views Aperture

28 | New Scientist | 16 May 2020

Sun trackers

Photographer Henry Do

RISING proudly from the dry bed
of Ivanpah Lake, these solar power
towers are surrounded by glinting
seas of perfectly arranged panels.
They are part of the Ivanpah Solar
Energy Facility in the Mojave
desert in southern California,
one of the world’s largest solar
thermal energy plants.

The facility uses more than
170,000 devices called heliostats,
each consisting of two mirrors
that direct solar energy onto
boilers found on the three
centralised solar power towers.
The boilers then use the sun’s
heat to produce steam that drives
turbines to generate electricity.

Photographer Henry Do
from Las Vegas, Nevada, who
took this shot, thinks that the
concept behind the plant is
ingenious. “I love how massive
the system is and the pattern of
the mirrors seen from above and
how they track the sun.”

Spread out over 14 square
kilometres, the facility can
generate enough energy to power
140,000 homes every year. Due
to the scale of plants like Ivanpah,
solar energy is becoming cheaper
and could play a role in helping
renewables overtake fossil fuels
as the world’s preferred sources
of electricity.  ❚

Gege Li

16 May 2020 | New Scientist | 29

Features Cover story

May the
fifth force

be with you

The universe increasingly seems to be telling us there
is an unexplained presence on the cosmic stage,
says Daniel Cossins

TASKED with telling the universe’s Forces drive the cosmic narrative. They tell
epic story, cosmologists have put its various actors, from particles to planets,
on a compelling show. The curtain how to move and behave – things that would
rises with a bang before a sweeping, otherwise seem inexplicable (see “What is a
unstoppable narrative unfolds. Stars form force?”, page 32). The four fundamental forces
and explode, galaxies swirl their way into we know of are gravity, electromagnetism,
existence. Black holes munch and merge, the weak nuclear force and the strong nuclear
sending out ripples through the auditorium. force (see “The familiar four”, page 35). Of these,
gravity is the outlier, the only one with no
It is a ripping yarn – but the longer we quantum field or particle attached to it and
watch it, the more it seems not quite to which can’t be described by the “standard
add up. The story is inconsistent. The pace model” of particle physics. Yet gravity, described
changes arbitrarily. Some of the characters by Albert Einstein’s space-and-time-warping
are ill-drawn, do inexplicable things or are general theory of relativity, determines the
just plain not there on cue. All in all, there universe’s overarching plot lines.
is enough in this play that goes wrong to
make you think someone has lost the plot. The problems with the story of the cosmos
begin at the beginning. The big bang theory
Increasingly, we think we know how. suggests that temperature and matter density
We had assumed that just four fundamental in the universe should now be a hotchpotch,
forces keep the cosmic action bowling the result of early random quantum
along. But hints from theory and fluctuations being amplified as the cosmos
experiment are combining to suggest expanded. But viewed at the grandest scales,
it might not be just four, but five, six – or galaxies and the like seem remarkably evenly
maybe even more. Sketchy though these spread. To square that circle, in the 1980s
indications are, even one new force cosmologists invented cosmic inflation,
would be a turn-up for the books. “It would a split-second burst of growth during
be absolutely momentous,” says Philippe which the primordial cosmos ballooned
Brax at the Saclay Institute of Theoretical exponentially, flattening out its surface >
Physics in France.

30 | New Scientist | 16 May 2020

OWEN GENT

16 May 2020 | New Scientist | 31

WHAT IS A FORCE? “We don’t know wrinkles. A grand plot twist – but one
what new actor that is currently entirely inexplicable.
By holding this magazine, or swiping to expect, other
down a smartphone screen, you are than it must be Problem number two really became
exerting a force: one that operates a quantum force” apparent around the same time – the 1980s,
between two objects that are physically not the dawn of time – with the observation
touching. Drag forces such as friction that there isn’t enough visible matter in most
and air resistance are also such “contact galaxies to exert the gravitational pull required
forces”, which influence movement to stop them flying apart as their components
and acceleration, and can be described whirl around. Cosmologists’ second big
by Isaac Newton’s laws of motion. invention was some additional invisible stuff,
dark matter, to glue galaxies together – stuff
When physicists talk about we have failed to find.
fundamental forces, it is something
rather different: influences between The third implausible turn of events came
things that are apparently not in contact. in the late 1990s, when observations of far-off
This “action at a distance” perplexed exploding stars known as supernovae revealed
Newton when his universal law of that the universe’s expansion is accelerating.
gravitation first suggested it. It was, Naively, with only gravity pulling things
he wrote, “so great an absurdity that I together, you might expect it to be slowing.
believe no man who has in philosophical Our best stab at explaining the “dark energy”
matters a competent faculty of thinking we think is responsible for accelerated
can ever fall into it”. expansion invokes the power of quantum
particles popping in and out of empty space.
These days, we ascribe such mysteries But this comes up with an answer for the size
to the action of fields that fill empty of the effect roughly 120 orders of magnitude
space. “In the modern understanding, the too big. “The universe would have expanded
most basic things in the world are fields,” so rapidly, everything would have been
says theorist Frank Wilczek at the ripped apart,” says Clare Burrage at the
Massachusetts Institute of Technology. University of Nottingham, UK.

So what are fields? They are, says The simplest solution to these problems
Matt Strassler at Harvard University, might be just to say that gravity doesn’t work
“a fundamental intermediary between how we think it does. But general relativity has
two objects”. For three of the four
fundamental forces we currently know of,
they are quantum fields that come with
accompanying particles, called bosons,
that pop in an out of existence to mediate
influences across various ranges:
the massless photon, for instance,
mediating the electromagnetic force.

The odd one out is the gravitational
field. According to Albert Einstein’s
general theory of relativity, which
superseded Newton’s universal law,
gravity is the product of mass warping
space-time. The strength of the
gravitational field at any point is
essentially the degree to which a massive
object is curving space-time around it.

In all cases, what separates the
fundamental forces from the common-
or-garden ones we tend to notice is that
they can’t be reduced to another force
or field, as for example friction or air
resistance can ultimately be reduced
to electromagnetic interactions between
different bits of matter. But the question
of how many of these fundamental
intermediaries exist remains unanswered
(see main story).

32 | New Scientist | 16 May 2020

proved maddeningly difficult to edit, passing The tricky part is finding a force that fits at the University of California, Irvine, found
every test we have ever thrown at it, including the bill. For inflation, a one-off event some this hard to believe when he first heard it.
the recent detection of gravitational waves 13.8 billion years ago, whatever caused it might Similar anomalies crop up from time to time,
produced when black holes and other massive have long since left the stage – not that this has and are almost always down to experimental
cosmic objects collide. Meanwhile, ideas stopped people from coming up with inventive error. “But when I went through the paper
that try to alter gravity, such as modified new plot lines, even involving particles and trail, looking at how they did the experiment,
Newtonian dynamics or MOND – a popular forces we already know (see “The Higgs force I couldn’t see anything wrong,” says Feng.
way to explain away dark matter – don’t awakens”, page 34).
square with all cosmic observations. The plot thickened late last year, when the
When it comes to the other cosmic Hungarian team reported a similar anomaly in
That adds to the yearning for a new inexplicables, dark matter and dark energy, the decay of helium nuclei. Feng reckons both
character on the stage, and the belief that a fifth however, we seem to have some hot leads. results are consistent with the existence of a
fundamental force of nature must be waiting Perhaps the hottest, although controversial, “protophobic X boson” that interacts over
in the wings. “We have several indications,” lead dates from 2015, when a team led by Attila short distances with the neutrons within the
says Brax. “There’s definitely something there.” Krasznahorkay of the Institute for Nuclear atomic nucleus in a new way. That would be a
Research at the Hungarian Academy of startling find. “It would be huge,” he says.
The dark side Sciences spotted anomalies in the decay of “We’re talking about a once every half-century
short-lived nuclei of the unstable isotope sort of discovery.”
But we don’t know what new actor to expect, beryllium-8. These seemed to indicate the
other than a quantum force. This tallies with interference of an even shorter-lived, slow- The idea has its critics. Matt Strassler,
the idea that even if gravity can’t yet be moving particle. Its mass was about 17 MeV, a theorist at Harvard University, points out
described in quantum terms, most physicists a little more than 30 times the mass of an that making Feng’s proposed new force coexist
believe it eventually will be, in a long sought electron, and nowhere near that of any known with the ones we know about “requires some
after marrying of relativity and quantum particle. It also happened to look like a boson, complicated and not entirely plausible
field theory. “Any sensible physicist believes a force-carrying particle like the photon, but trickery”. The properties of the particle, with
gravity’s force-carrying particle exists,” one that interacts very weakly – just the thing an intermediate mass and a short range of
says Frank Wilczek, a particle theorist at the for explaining dark matter’s diffident interaction, are certainly surprising given what
Massachusetts Institute of Technology who interaction with the rest of the cosmos. quantum field theory suggests we should
won a share of a Nobel prize in physics for the The researchers speculated that it might be expect. “There are two kinds of things you can
quantum theory behind the strong nuclear a “dark photon”, a new particle that might add to the standard model that have not been
force. Follow that logic and any fifth force has transmit a force between dark matter particles. observed, but would be consistent with
to be quantum, too. everything we have observed,” says Wilzcek:
Like most observers, theorist Jonathan Feng very heavy particles, which would carry a
short-range force, or very light particles that
would mediate a long-range force.

The new particle seems to be neither. Still,
Feng says, we need to keep an open mind. “New
physics doesn’t have to come from the place
you expect it.” To really get theorists’ pulses
racing, the result needs first to be corroborated
in an independent experiment. That could
come soon, or not: researchers at PADME,
the Positron Annihilation into Dark Matter
Experiment in Frascati, Italy, for example, have
been collecting data for over a year now and
expect to have results sometime in 2021.

If confirmed, the particle would count
among the great surprises that experiments
occasionally throw at theorists – a new force
that interacted so weakly with ordinary
matter that we just hadn’t spotted it. Brax
and Burrage, meanwhile, are investigating
the possibility of a type of fifth force that
adopts a different disguise: it has large effects,
but those effects are screened by gravity.

It is known as a chameleon force, and the
idea is that the particle transmitting it changes
its mass depending on the local density of
matter. Chameleon particles would be heavier
where the average matter density is high, as for
example around Earth, meaning the force >

16 May 2020 | New Scientist | 33

THE HIGGS associated with them would have a smaller
FORCE AWAKENS range in our neighbourhood and so would be
practically invisible to us. The mass of these
As physicists close in on the discovery particles would be much smaller in the vast
of a fifth fundamental force of nature swathes of empty space between galaxies,
(see main story), a pedant might counter where they would have a larger range of
that we have already found it. And they influence – just the ticket to explain the
would be right, sort of. dark-energy effect of distant galaxies racing
away from us ever faster.
Discovered in 2012 at the Large Hadron
Collider – CERN’s powerful atom smasher “It is not quite as strange as it sounds,” says
near Geneva, Switzerland – the Higgs Burrage, pointing out that the massless photon
boson and its underlying field is famous undergoes a similar metamorphosis when
for giving all other known particles their passing through a plasma of charged particles,
masses. But the Higgs field isn’t only a experiencing a drag and effectively gaining
mass-giver. Under the right conditions, mass. Wilczek agrees in principle, while being
it can create a push and pull between sceptical of the models themselves. “That sort
two particles, too, which would make it of thing is allowed by the rules of quantum
another fundamental force of nature to field theory,” he says.
add to the four we already know.
And it might just work. In 2018, a group led
You won’t often hear physicists refer
to it as such, however, because the Higgs “A ‘chameleon’
force operates at such a short range that force would be
it is practically irrelevant – and possibly invisible to us
undetectable. That is why we had to find where matter
the Higgs particle to confirm the existence density is high,
of the field. “If we define the Higgs field like on Earth”
as the interaction, then we’ve already
discovered it,” says theorist Matt Strassler
at Harvard University. “But if we mean
the pull between two objects it induces,
then we’ve not seen it.”

All of which makes it a bit surprising
that theorists have suggested the Higgs
field could be the cause of cosmic inflation,
the split-second burst of mega-expansion
at the time of the big bang invoked to
account for the perplexing uniformity of
the universe at the largest scales. But it is
possible to tweak the properties of the
Higgs field, such that it could have been
temporarily strong enough to suddenly
inflate everything in that first moment,
before settling down to the barely
detectable strength it has now.

On further inspection, though,
it turns out the Higgs works in this way,
as an “inflaton”, only if you invent at least
one other field to regulate its strength.
So although the Higgs force alone probably
can’t explain inflation, it might plausibly
serve as a portal to new forces that could.

34 | New Scientist | 16 May 2020

by Baojiu Li at Durham University, UK, ran has collaborated with experimentalists to Given the changeable nature of chameleons,
simulations that showed that a universe with craft a bowling-ball-sized vacuum chamber it may not even be such an outrageous stretch
a chameleon force would form galaxies like with a marble-sized metal sphere at its centre to think that a chameleon force might, under
those we see. The challenge now is to identify designed to cancel out the effects of the known certain circumstances, change its strength
subtle differences in those galaxies compared forces. It is a trap for chameleons. A chameleon so it assists gravity, rather than counteracting
with general relativity’s predictions, so that field would be suppressed around the central it – and so bag two birds with one stone by
next-generation telescopes, such as the sphere and the walls of the chamber but active also addressing dark matter. “There have
European Space Agency’s EUCLID satellite, between them – so drop atoms into the been some attempts to see if the chameleon
set for launch in 2022, can look for them. vacuum and any acceleration of them in this can play a role on galaxy and galaxy cluster
region would betray its presence. scales, maybe replacing some of the need for
It’s a trap! dark matter,” says Burrage. Indications so far,
The team reported its first results last year. however, seem to suggest that chameleon
Burrage thinks we don’t need to wait. Even It was a bust, there was no sign of the forces can’t explain all the effects we ascribe
if a chameleon force is a master of disguise, chameleon. “That is obviously disappointing,” to dark matter, she adds.
it can still be exposed here on Earth, she says. says Burrage. But so far, the researchers have
“You just need to come up with a situation ruled out only one particular chameleon Anyhow, rather than a unification of forces,
where it can’t hide.” model, and there is plenty of room for an the smart money is on diversification. With the
upgraded experiment to uncover the real deal: four fundamental forces we already have, we
That situation is housed in a basement lab a weaker force ever so slightly stronger than have contrived to explain only normal atomic
at Imperial College London, where Burrage gravity that might explain dark energy. matter, which appears to make up only 5 per
cent of the matter and energy in the universe.
THE FAMILIAR FOUR “It seems unlikely that all the vast majority
of the universe would be made of just one or
We currently know of four fundamental two components,” says Brax. “I wouldn’t be
forces governing the basic workings surprised if we find more than one new force.”
of matter in our universe today.
Wilczek agrees, sort of. “I wouldn’t be
ELECTROMAGNETISM: Explains why scandalised,” he says. “I don’t know what to
atoms hold together and how light behaves expect, but certainly it would be nice to have
GOVERNING THEORY: Quantum more than one.” Indeed, he is pursuing another
electrodynamics (QED) candidate for an additional fundamental force:
MEDIATOR: Photon (predicted one associated with hypothetical, light, long-
by Albert Einstein in 1905) lived particles called axions. These would have
MAXIMUM RANGE: Infinite many of the properties associated with dark
matter, as well as helping to explain some
WEAK NUCLEAR FORCE: Accounts other thorny problems in particle physics,
for radioactive beta decay and the such as why events at the subatomic level look
nuclear fusion that fuels stars the same whether they run backwards or
GOVERNING THEORY: Electroweak theory forwards in time. “This is the fifth force that
(unified theory with QED at high energies) I think is most compelling,” says Wilczek.
MEDIATOR: W and Z bosons (predicted
in 1968, discovered in 1983) All these efforts speak to a wider truth,
TYPICAL RANGE: 10-18 metres says Brax: that what we have now with our
standard cosmological model is akin to a rough
STRONG NUCLEAR FORCE: Holds protons draft of the script for the story of the universe.
and neutrons together within the atomic nucleus “To embed our model in something larger,
GOVERNING THEORY: Quantum something we could call a theory, usually that
chromodynamics (QCD) involves new particles or fields, and those are
MEDIATOR: Gluons (predicted in 1962, going to give you new forces,” he says.
discovered in 1979)
TYPICAL RANGE: 10-15 metres Or to put it another way, even a smash hit
like our cosmological model starts to look a
GRAVITY: Keeps galaxies together, little tired after a while. A sprinkling of new
the planets moving around the sun and our players to add to the established figures is
feet on the ground starting to look like the best way to reaffirm
GOVERNING THEORY: General relativity why everyone found the story so compelling
MEDIATOR: None; gravitons if it were found in the first place. ❚
to be quantum
RANGE: Infinite Daniel Cossins is a feature
editor at New Scientist

16 May 2020 | New Scientist | 35

ALEX MUSTARD/NATURE PL Features

Seaweed farming could help clean
up the oceans and the atmosphere,
reports Michael Marshall

Kelp is on
the way

36 | New Scientist | 16 May 2020

“Seaweed’s
long-chain
molecules
are ideal for
making plastic
substitutes”

AS A CHILD in South Wales, I was dimly to define. Rather than being a single family, and some such bioplastics are already on the
aware that laverbread was a treasured they belong to a loose grouping of life forms
cultural asset. Nobody I knew ate any, called algae, which shares a common ancestor market. UK start-up Notpla, for example, uses
though, and it never turned up on my plate. with green plants like mosses and trees. All the
I would probably have turned my nose up at familiar seaweeds, from the nori used in sushi a mixture of seaweeds and plants to make
it if it had. Far from being bread as most of to bladderwrack and kelp species, belong to
us know it, this traditional Welsh foodstuff one of three groups of algae commonly materials it hopes could replace plastic water
consists of seaweed boiled into a mushy paste, known as reds, browns and greens.
often dipped in oatmeal and fried before bottles and ketchup sachets. You may already
serving. Not my childhood self’s ideal dish. Many of these species are already farmed on
a small scale or harvested wild, mainly for use have seen them in action: runners at the
For many people, seaweed is something as a foodstuff or as a source of useful chemicals.
we trip over on the beach, not take there 2019 London Marathon were given pouches
in our lunch boxes. But for thousands of Eating seaweed offers many benefits (see
years, humans have harnessed seaweed in “Super seaweed?”, page 36), but societies differ of sports drink made from Notpla’s bioplastic.
extraordinary ways. Our ancestors ate it, enormously in how much they consume. In
farmed it and used it as fertiliser. When China, Japan and Korea, seaweed is a major For now, though, seaweed harvesting
humans first entered North America from part of the national diet. But in many Western
Asia more than 13,000 years ago, their countries, consumption has historically been remains a relatively niche industry. “It’s a
survival may have depended on fish that less conspicuous. “It was kind of frowned upon
were plentiful thanks to coastal kelp. as ‘poor food’,” says M. Lynn Cornish at Acadian product that you cannot find easily in the
Seaplants in Dartmouth, Canada.
Today, we still rely on seaweed’s many supermarket,” says Francisco Barba of the
benefits. We use it as a delicacy to wrap Beyond food
round sushi, extract its chemicals for use in University of Valencia in Spain. According
industry and turn it into recyclable plastics. Many people do still ingest seaweed, or
But its potential doesn’t end there. Large-scale extracts of it, without realising it. Thickeners to a 2017 report co-authored by Cornish,
seaweed farms could clean up Earth’s oceans, in sauces and yoghurts, for example, are made
restoring biodiversity and increasing the of carrageenans, compounds found in red 32 countries actively harvest wild seaweed,
productivity of aquaculture. They could seaweeds. Often listed as E407 on packaging,
suck carbon dioxide from the air, and help they are also a common ingredient in many gathering more than 800,000 tonnes per
curb the emission of other greenhouse gases. cosmetics. “Nobody knows there is carrageenan
According to some researchers, it could even from seaweed in toothpaste,” says Susan Holdt year. That isn’t much compared with other
be crucial to saving civilisation. of the Technical University of Denmark in
Kongens Lyngby. The rise of veganism has crops: in 2018, farmers in more than
Seaweed still has a long way to go to fulfil also boosted demand, pushing more food
those lofty ambitions. Some wild populations manufacturers to ditch animal-based 60 countries grew more than 2.5 million
have been overharvested, and the potential ingredients like gelatine and turn to
for farming has barely been tapped. But even seaweed extracts instead. tonnes of cherries, for example.
if it fails to meet the enormous expectations
put on it, its versatility still makes it an Seaweed’s multitalented tendrils extend far Furthermore, some wild seaweeds have
incredibly valuable material. beyond food. The long-chain molecules they
contain are ideal for making plastic substitutes, been overexploited. Cornish points to Prince
Biologically speaking, seaweeds aren’t easy
Edward Island in Canada, where people used

to harvest a red seaweed called Irish moss

(Chondrus crispus), which is rich in

carrageenans. “It’s been overharvested,”

says Cornish. “That resource has pretty

much disappeared.”

If we want seaweed in large quantities,

we need to give it a helping hand by cultivating

it. That’s why there is now a push towards

creating and expanding seaweed farms.

In the US, a non-profit organisation called

GreenWave has been training seaweed farmers

since 2014. In the UK, SeaGrown has recently

launched a commercial farm in the North Sea.

The potential for open-ocean seaweed

farming is enormous. The 2019 paper “The

Future of Food from the Sea” by the High

Level Panel for a Sustainable Ocean >

16 May 2020 | New Scientist | 37

“Seaweed forests Economy, an international group that works a few months, then harvested by taking a boat
covering 9 per with governments and industry to promote out, lifting the lines with hooks and stripping
cent of the ocean sustainable use of the ocean, outlines a the crop off, with no fertilisers required.
could reduce sparkling future for seaweed. It envisages
atmospheric CO2 the ocean supplying 364 million tonnes of For Angela Mead, a marine biologist and
to pre-industrial animal protein – mainly in the form of fish and founder of Biome (Algae) Ltd in Salcombe, UK,
levels” shellfish – per year. This is more than two-thirds the challenge is to scale farms up. That means
the amount needed to feed the 9.1 billion a new kind of location. “Usually, seaweed
human beings expected by 2050, and farming will happen in a sheltered region,
seaweed could be crucial to achieving this. like a loch or an inlet,” she says. “There’s
very limited coastline that could support
Farming it, the paper says, “may in some that. But we have this mass of coastline
cases enhance wild fisheries by creating that is quite exposed and wild.”
artificial habitats”. This is a key element of its
appeal: seaweed fits well with other marine Mead also hopes to maximise the benefits
farming and harvesting. What’s more, seaweed of seaweed by farming it on an existing
farming is much more low-maintenance than mussel farm. This approach mimics that of
land agriculture. All it takes is weighted lines GreenWave, whose farms combine kelp on
seeded with seaweed floating a few metres lines with cultivated mussels, scallops and
below the surface, attached to buoys so they oysters. The kelp provides shelter for the
can be relocated. The seaweed is left to grow for shellfish, which in turn remove excess
nitrogen from the water. Similarly, in the
Super seaweed? Pacific nation of Kiribati, islanders farm
seaweeds alongside milkfish, sandfish and
The word “superfood” is a marketing Seaweed contains a lot of fibre, sea cucumbers, ensuring food security.
term that has no rigorous scientific which is good at binding to other
meaning. It is generally applied to chemicals. That may mean that the Such integrated farms promise large
foods that are unusually high in desirable trace metals and minerals and varied food yields, and can also restore
some nutrient that is considered stay trapped inside it rather than ecosystems. Many marine species shelter
particularly important to health. being taken up by our bodies. This around the seaweed lines, and the benefits
Examples include blueberries, which is a recurring problem with other don’t stop there, because seaweed helps keep
are rich in vitamin C; chia seeds, which supposed superfoods: they may the water hospitable. For example, if water
contain a lot of omega-3 fatty acids only give us vitamin-rich stools. becomes too rich in nutrients and minerals,
that help your heart; and kale, which harmful algae grow rapidly and deplete the
has lots of glucosinolates, pungent How we prepare the seaweed dissolved oxygen, killing fish. Seaweeds mop
chemicals tentatively proposed to makes a big difference, says Holdt, up excess nutrients, preventing this. They
offer some protection against cancer. as we don’t yet know which methods can also restore oxygen and combat ocean
maximise our nutrient intake. acidification. A 2019 study estimated that
By these standards, many 48 million square kilometres of the ocean
seaweeds would surely count as Still, while seaweed isn’t could be devoted to seaweed farming,
superfoods. For example, they are technically a superfood, neither providing benefits to 77 countries. As demand
high in iodine, which our thyroid is anything else. What’s more, for food grows, seaweed and other algae could
gland needs, and in supposedly it is thoroughly nutritious and become a major component of our diet.
beneficial chemicals such as an excellent thing to add to your
antioxidants. Some seaweeds diet for other reasons. If scaled up quickly enough, seaweed
also contain a pigment called farming could even contribute to stopping
fucoxanthin, which may have Seaweed species contain a dangerous climate change.
anti-obesity effects – in rats at least. lot of protein, so they are good
meat substitutes. There are other Cleaning the planet
The problem is that we may protein-rich foodstuffs that are
not absorb these substances in vegan-friendly, such as soya, but At present, one of the most significant sources
meaningful quantities when we they are often low in essential of greenhouse gases is livestock farming. Cows
eat seaweed. “What happens in amino acids. Not so seaweed. Holdt and other ruminants have microorganisms in
your intestines?” asks Susan Holdt highlights wakame and nori, a type their guts that break down fibrous material like
at the Technical University of of red seaweed that is wrapped hay, releasing nutrients that the animal can
Denmark in Kongens Lyngby. around rice in sushi, as being use. This process creates hydrogen gas, which
particularly rich in these nutrients. gut microbes called methanogens feed on,
releasing methane as waste. “The methane is
then belched out of the animal,” says Ermias
Kebreab at the University of California, Davis.
This is bad news for the planet.

However, since 2008, evidence has
accumulated that adding seaweed to ruminant

38 | New Scientist | 16 May 2020

CHINAIMAGES/SIPA USA/PA IMAGES Seaweed farms seaweed might offer a way to remove CO2
like this one off without any of those negative impacts.
ANNELI STIBERG/GETTY IMAGES the coast of
Rongcheng, China, A similar idea is championed by Tim
food reduces their methane emissions. Later are more low- Flannery at the Australian Museum in Sydney.
studies found that a genus of red algae called maintenance than Originally a palaeontologist who started his
Asparagopsis works especially well, but there land agriculture career by discovering new mammal species,
was a drawback: many of these experiments he has become a prominent advocate for
were performed on microbes incubated in a Seaweed and strong action on climate change.
lab, not in real cows. mussels could
benefit from being His plan is both simple and daring.
“I was a bit sceptical,” says Kebreab. “Just grown together He wants to create huge farms growing
because it works in the lab doesn’t mean it seaweed in the ocean and then sink the
works in the animal.” However, when his team atmosphere. A 2017 study found that biomass into the deep, along with all the CO2
tried feeding 12 cows the red seaweed with commercial seaweed farms remove 2.8 million it has absorbed. The idea has been proposed
their normal food, the results were dramatic. tonnes of CO2 every year. While they aren’t as before. In 2012, Antoine de Ramon N’Yeurt at
Over three weeks, methane emissions fell by efficient as forests on land, storing 1500 tonnes the University of the South Pacific in Suva, Fiji,
up to 67 per cent. In unpublished results, the of this greenhouse gas per square kilometre estimated that seaweed forests covering 9 per
team found that adding seaweed to their diet compared with more than 3600 tonnes, there cent of the ocean could reduce atmospheric
remained effective over several months. is far more unused space available for new CO2 to pre-industrial levels. That is an area
Kebreab is now on the advisory board of seaweed plantations than for forests. almost twice that of Russia, and more than
California start-up Blue Ocean Barns, which is 10 times today’s total space occupied by
trying to get the approach approved in the US. But how long the CO2 stays locked up will seaweed, both wild and farmed. Well aware
depend on what we do with the seaweed. this would be a monumental expansion,
Methane reduction, though an important If we eat it, the carbon will return to the air for now Flannery’s plans are more modest.
step in the right direction, is small change within months. Alternatively, the seaweed
by comparison with the elimination of could be processed to make biofuels, which He founded the Ocean Forests Foundation
carbon dioxide. It is CO2 that causes most could replace oil and gas. This is promising, to promote his idea, but has had to shutter it
global warming and bears the bulk of the but still results in CO2 being released. for lack of funding. Instead, Flannery wants to
responsibility for sea level rise. Remarkably, gather experts from relevant fields to figure
seaweed can help here too. More radical alternatives beckon. Of the out whether the idea is viable and how to
four emissions scenarios used by climate proceed. “We’re in a paused stage, trying to
For one thing, it is a photosynthesiser scientists to simulate possible futures, only get the funding that would be required to
just like plants, so can extract CO2 from the one keeps global temperatures from rising hold the meeting, and then waiting for the
more than 2°C. It does so by removing CO2 circumstances to arise so we can hold the
from the air and burying it underground. meeting,” he says, wearily citing the covid-19
In this scenario, crops grown on land would pandemic as an unexpected roadblock.
be converted into biofuels and the CO2 they
emit subsequently trapped and buried. He admits there are “any number” of
potential problems. “If you did it at scale,
This requires lots of land, threatening would you be disturbing the world’s nitrogen
biodiversity and straining food supplies. cycle?” he asks. “Are there issues with anoxia in
However, obtaining the biofuels from the deep ocean, if you’re introducing so much
decomposing material? Are the costs going to
be so considerable that you can’t do it?” At a
2019 conference where his idea was presented,
Peter Liss at the University of East Anglia in the
UK raised the objection that seaweeds release
halogen-containing gases that could interfere
with atmospheric chemistry.

All told, it remains to be seen whether
Flannery’s radical idea will float or sink. It is
quite possible that the less drastic approach
of using seaweed as biofuel and then burying
the CO2 released would be easier to manage.
But either way, we are discovering that seaweed
is nothing to turn your nose up at.  ❚

Michael Marshall
is a freelance writer
based in Devon, UK

16 May 2020 | New Scientist | 39

ANIMATED HEALTHCARE LTD/SCIENCE PHOTO LIBRARYFeatures

Under pressure

If we aren’t sure what causes hypertension, should
we really be medicating it, wonders Peter Judge

40 | New Scientist | 16 May 2020

LAST year, I was diagnosed with high blood in the circulatory system. He took solution. He used a stethoscope to listen to
blood pressure, otherwise known a simple and direct approach, inserting sounds in the artery beneath the cuff. When
as hypertension. “Why me?” I asked. a brass pipe into a horse’s femoral artery blood flow stops, there is no sound. When it
“I exercise regularly, I’m not overweight, and connecting it to a tall vertical glass tube. first comes back, there are distinct “tapping”
I don’t smoke and I don’t drink excessively. The column of blood went up almost sounds corresponding to systolic pressure.
I even meditate.” 2.5 metres. The horse died, of course. These die away when the flow is unimpeded,
giving the diastolic pressure. We use the same
At first, I doubted the diagnosis. Admittedly, By the 19th century, the condition we now basic principle today, although modern
my blood pressure had been up in a routine call hypertension had been described, and “oscillometric” monitors use electronics to
consultation. But when I monitored it at home doctors were looking for safe ways to measure analyse pulse vibrations.
over the following week, the measurements blood pressure. Some contraptions were rather
differed every time, even from one minute to impractical. One, for example, sealed the whole So, your blood pressure reading consists of
the next. Besides, the average of these readings arm in a tank of water and raised the pressure two numbers, measured in millimetres of
wasn’t much above the normal range. Yet my by lifting a movable reservoir. Then, in 1896, mercury (mmHg): the first indicating systolic
doctor had recommended pills to bring the pressure and the second diastolic. Anything
pressure down. Why act on such shifting “Worldwide, between 90/60 mmHg and 120/80 mmHg is
figures? How do the pills work? Are they around a billion considered healthy. In the UK, the National
safe? Is high blood pressure really a people have high Institute for Health and Care Excellence (NICE)
problem anyway? And, again, why me? blood pressure” defines high blood pressure as being more
than 135/85 mmHg. In the US, you can be
Now I know that hypertension increases an Italian doctor called Scipione Riva-Rocci diagnosed with hypertension if your blood
the risk of death from covid-19, I am even more created a device we would recognise today. pressure is 130/80mmHg or higher.
motivated to get to the bottom of it. And I am It used a pressurised cuff connected to a
surely not alone. One in four adults have high manometer – a J-shaped glass tube containing It all sounds very clear-cut and clinical, but,
blood pressure – that is some 16 million people mercury, which measures gas pressure. The as I discovered, blood pressure is notoriously
in the UK and around a billion worldwide – cuff was placed around the arm, inflated until variable. For a start, it changes according to the
and, globally, its prevalence is rising, especially blood flow was restricted, and then deflated time of day, being generally lower at night and
in the developing world. It is linked with stress until the pulse resumed. Thus the rising to a peak in mid-afternoon. In addition
and occurs more often among certain groups “sphygmomanometer” gave a reading of the to this circadian rhythm, it tends to dip slightly
of people, including smokers, heavy drinkers pressure at which the heart pumps blood after a meal. Your physical activity affects it
and those who are pregnant, inactive or through the arteries: systolic pressure. too: high blood pressure helps get more
overweight. But there is so much about this oxygen to your muscles and it isn’t unusual to
common condition that remains a mystery, Measuring the blood pressure between have a systolic pressure of 160 when exercising.
even to people diagnosed with it. That wasn’t heartbeats – the diastolic pressure – proved
good enough for me. I wanted answers, trickier. At first, doctors tried to detect For this reason, doctors try to get “resting”
so I decided to look into it myself. vibrations caused by the pulse. In 1905, Russian blood pressure measurements. But that can be
surgeon Nikolai Korotkoff hit on a better problematic too, because having your blood
The first thing I discovered was that the pressure taken can be stressful, which will affect
quest to quantify blood pressure has a the result. Recognising this “white coat effect”,
colourful history. English physician William medical professionals in the UK don’t act on
Harvey established that the heart pumps blood pressure measured in the clinic unless it
blood around the body in 1628, but it would is over 140/90 mmHg. Indeed, patients whose
be a century before another Englishman, readings appear elevated are increasingly asked
clergyman Stephen Hales, became the first to take their own measurements at home. And
to successfully measure the pressure of the a recently published study tracking 4 million >

16 May 2020 | New Scientist | 41

Everyday ways to people for a decade showed that self-
lower blood pressure assessment is just as effective in terms
of long-term health outcomes.
Modern drugs are highly effective at reducing
hypertension, but there are other things you My experience was typical. I was told to
can do to lower blood pressure record my blood pressure at two different
times each day. Each time I had to take two
STEP UP YOUR EXERCISE half of regular caffeine drinkers readings, about a minute apart, and then use
become inured to its hypertensive the second, which is presumed to reflect a
Researchers tracked 138 first-timers effect. Alcoholic drinks also increase more relaxed state. If there was a big difference,
entering the 2016 and 2017 blood pressure temporarily – I could take further measurements until the
London marathon. After running consuming about two standard numbers were steady. There was certainly a lot
between about 10 and 20 drinks a day doesn’t seem to cause of variability. Some mornings, my readings
kilometres a week in training, the harm but habitual, heavy drinking would fluctuate from 150/99 to 136/84, and
women completed the course in an raises blood pressure long-term. then back again. Nevertheless, overall they
average of 5.4 hours and the men in However, research reveals that averaged 140/91, some 5 mmHg – “5 points” –
4.5 hours. Tests revealed that their cutting back can reverse this. above the cut-off for high blood pressure.
arteries were less stiff and their It was official: I had hypertension.
blood pressure had gone down by GO GREEN
an average of 4/3 mmHg. The older Age-old risk factor
and slower the competitors, the Vegetarians and vegans tend to
more benefit they got. If training for a have  lower blood pressure than I wanted to know why. I knew that chronic
marathon sounds like too much hard meat eaters. That may be due to stress is a major cause of high blood pressure.
work, any kind of regular aerobic saturated fats in meat and dairy, Stress triggers the production of adrenalin,
exercise will do you good. which are linked to high blood which makes your heart beat faster, pumping
pressure, although we aren’t sure more blood through the system to gear you
PASS ON THE SALT how they cause it. In its dietary up for “fight or flight”. This response is crucial
approaches to stop hypertension, for survival, but when it fails to switch off, the
Despite some claims to the contrary the US National Heart, Lung, and result is hypertension. This helps explain
in recent years, eating too much salt Blood Institute recommends cutting why people living in low-income households,
is bad for you. Salt raises blood down on meat and dairy and eating deprived areas and developing countries are
pressure by making your body retain plenty of whole grains, fruit and veg. particularly prone to high blood pressure.
water. In the UK, average If vegetarianism is a step too far, try Inhabiting the most deprived areas of
consumption is 8 grams per day; swapping some meat for oily fish, England, for instance, increases the risk
NHS advice is 6 grams, or just over a which contains blood-pressure- by 30 per cent. And although the number
teaspoon. One way to cut down is by reducing omega-3 oils. of people with hypertension is falling in
avoiding pre-prepared foods, which developed countries, globally it has doubled
often contain concealed salt. Also, RELAX. REALLY RELAX since 1975 because of rises in developing
eat plenty of fresh fruit and veg countries. Long work hours are also linked
because the potassium within them When we are stressed, we produce with stress. And research published in 2019
helps your body excrete sodium in more adrenaline, which increases argues that strategies to cut them would lower
urine. The jury is still out on the our heart rate and blood pressure. the public health burden of hypertension.
benefits of replacing regular salt with We are also more likely to engage in
potassium-enriched salt, because of hypertension-inducing behaviours Fortunately, my life isn’t particularly
potential risks such as heart such as overeating, drinking too stressful, covid-19 notwithstanding. Nor do I
arrhythmias and worse, particularly much alcohol and smoking. drink heavily or smoke – two habits strongly
for people with kidney disease. Relaxation reduces stress but linked with hypertension. Being overweight
is notoriously hard to measure. or inactive also increases blood pressure but,
WATCH WHAT YOU DRINK Meditation, for example, seems again, that’s not me. And I certainly don’t fall
to help many people, but not into another high-risk group, pregnant
People at risk of hypertension are everyone benefits. We should all women: gestational hypertension affects
often warned to avoid caffeine, aim for good sleep habits, though. around 6 per cent of pregnancies and is
which results in a spike in blood Sleep seems to allow your body to particularly common in women who have
pressure that can last a few hours. regulate stress hormones, and if you diabetes and those who are older than 40
The problem arises if this increase is get less than 6 hours, you may wake or younger than 20.
sustained, which doesn’t happen for up still stressed.
everyone. A recent study found that However, there was a risk factor I hadn’t
been aware of. On average, between the ages
of 16 and 75, people’s systolic blood pressure
goes up by about 20 points, an effect that is
particularly marked in Western cultures. I am
58, so it would have been unusual if mine

42 | New Scientist | 16 May 2020

SCIENCE PHOTO LIBRARY Salt raises with nasty side effects, including early death.
blood Things began to change in the 1960s when
“Are drugs a good pressure by
option when you increasing the the US Veterans Health Administration,
can change your water your which runs a chain of hospitals, started to take
lifestyle?” body retains disease prevention seriously. Its first major
blood pressure study, published in 1967,
hadn’t increased somewhat since my youth. but I was still sceptical about medicating my showed that severe hypertension is treatable.
But is that really anything to worry about? condition. After all, my journalistic research This followed 143 patients with diastolic
To find out, I contacted Christine A’Court at has revealed that we still don’t really know the readings of between 115 and 129. Compared
the Nuffield Institute of Primary Care Health mechanisms by which age – and most other with those who got placebos, the patients
Sciences at the University of Oxford. risk factors – cause high blood pressure. given the most promising drugs available at
Are drugs really a good option when there are the time had fewer strokes and less congestive
“Multiple trials show that resting blood plenty of lifestyle changes people can make heart failure. And the drugs lowered their
pressure has a close relationship with (see “Everyday ways to lower blood pressure”, blood pressure by an average of 43/30.
cardiovascular outcomes, particularly stroke left)? In answering this question, I discovered
and hypertensive heart failure,” says A’Court. that blood pressure treatment might be the Other studies followed, showing that drugs
People with high blood pressure have more first instance of data-driven medicine. also benefit people with moderately high
chance of damage to their blood vessels, blood pressure, and older people – although
putting them at increased risk of all sorts of The earliest systematic records go back the latest results suggest that some very old
cardiovascular diseases from heart attack to to the 1920s when insurance companies, people would be better off without them.
chronic kidney disease and dementia. noting the connection between high blood Meanwhile, better drugs were being developed.
pressure and life expectancy, began taking Beta-blockers, first made in the mid-1960s,
That left me in no doubt of the dangers, readings from large numbers of potential were an early breakthrough. They regulate
clients – and refusing cover to anyone with heart rate by blocking the effects of adrenaline,
hypertension. Analysis of statistics like these and turned out to lower blood pressure as well.
left no doubt that hypertension is a killer.
However, most doctors considered it a Modern drugs are even more effective and
natural response to external factors – have fewer side effects. I am on a calcium
referring to it as “essential hypertension” – channel blocker called amlodipine, widely
and thought intervention was dangerous used in people of my age. It stops cells in my
and unnecessary. They had a point. Although arteries from taking up calcium, which would
treatment had moved beyond bloodletting stiffen them. People younger than 55 are
and leeching, at the time it included drugs such more likely to get ACE inhibitors. Angiotensin-
as potassium thiocyanate and barbiturates converting enzyme (ACE) is produced by the
body to help constrict blood vessels, and these
drugs reduce how much of it there is, helping
to relax arteries and veins.

Vast numbers of people take these drugs and
they are undoubtedly effective. Department
of Health figures indicate that in the UK the
average systolic pressure has fallen by 3 mmHg
over the past decade. That will be having
tangible effects. A review published in The
Lancet found that every 10 mmHg reduction in
blood pressure results in a reduction of 17 per
cent for coronary heart disease, 27 per cent for
stroke, and 13 per cent for overall mortality.

This success story is even more remarkable
when you consider one last fact. Except in a few
unusual illnesses, these drugs aren’t “curing”
the underlying cause of hypertension. “We do
not have a cure for high blood pressure,” says
A’court. “In 95 per cent of cases we simply try
to control the problem. That approach works,
fortunately!” It certainly has for me. ❚

Peter Judge is a science and
technology journalist based
in London. He no longer
eats crisps

16 May 2020 | New Scientist | 43

Essential Guide Extract

We humans have a problem with reality. We experience it all the time, but struggle
to define it, let alone understand it. We don’t know when it began, how big it is, where
it came from or where it is going, and we certainly don’t know why it exists.

In this classic New Scientist article, reproduced in our new Essential Guide: The Nature
of Reality, physicist Roger Penrose explains how modern physics suggests that what
we perceive and what exists may be two very different things – an intriguing mystery
at the intersection of physics, mathematics and our conscious experience.

W HAT do we understand by “reality”? view, arguing that it is conscious experience itself that
For those of us who consider ourselves
hard-headed realists, there is a kind of is primary. From this perspective, the “external reality”
common-sense answer: “Reality
consists of those things – tables, that appears to constitute the ambient environment
chairs, trees, houses, planets, animals,
people and so on – which are actual things made of of this experience is to be understood as a secondary
matter”. We might tend to include some more abstract-
seeming notions such as space and time, and the construct that is abstracted from conscious sense-data.
totality of all such “real” things would be referred to
as “the universe”. Some might even feel driven to the view that one’s

Some might well consider that this is not the whole own particular conscious experience is to be regarded
of reality, however. In particular, there is the question
of the reality of our minds. Should we not include a as primary, and that the experiences of others are
conscious experience as something real? And what
about concepts such as truth, virtue or beauty? Of themselves merely things to be abstracted, ultimately,
course, some hard-headed people might adopt a
doggedly materialist point of view and take mentality from one’s own sense-data.
and all its attributes to be secondary to what is
materially real. Our mental states, after all (so it would I have considerable difficulty with such a picture
be argued), are simply emergent features of the
construction and behaviour of our physical brains. of reality, which seems to me lopsided. At best, it
We behave in certain ways merely because our brains
act according to physical laws – the same laws as those would be difficult to convince anyone else of a theory
that are strictly obeyed by all other pieces of physical
material. Conscious mental experience, accordingly, of reality that depended upon such solipsism for its
has no further reality than that of the material
underlying its existence; though not yet properly basis. Moreover, I find it extremely hard to see how the
understood, it is merely an “epiphenomenon”, having
no additional influence on the way that our bodies extraordinary precision that we seem to observe in the
behave beyond what those physical laws demand.
workings of the natural world should find its basis in
Some philosophers might take an almost opposite
the musings of any individual.

Even if such a solipsistic basis is not adopted, so that

the totality of all conscious experience is to be taken

as the primary reality, I still have great difficulty.

This would seem to demand that “external reality”

is merely something that emerges from some kind

of majority-wins voting amongst the individual

conscious experiences of all of us taken together.

I cannot see that such an emergent picture could

have anything like the robustness and precision that

we seem to see outside ourselves, stretching away

seemingly endlessly in all directions in space and in ANXO VIZCAÍNO

time, and inwards to minute levels that we do not

directly perceive with our senses; all requiring many

different kinds of precision instruments to >



explore the universe over a vast range of different signals received from space and the overall predictions
scales. True, there is a mystery about consciousness of Einstein’s theory to an astonishing 14 decimal places,
itself, and it is profoundly puzzling how it could come even before the LIGO collaboration first directly
about from the seemingly purely calculational, detected a passing gravitational wave in 2015. At
unfeeling and utterly impersonal laws of physics that the other end of the size scale, there are multitudes
appear to govern the behaviour of all material things. of very precise observations that give innumerable
Nevertheless, among the basic laws of physics that we confirmations of the accuracy of quantum theory
know – and we do not yet know all of them – some are and also of its generalisation to the quantum theory
precise to an extraordinary degree, far beyond the of relativistic fields, which gives us quantum
precision of our direct sensory experiences, or of the electrodynamics, one of the underpinnings of the
combined calculational powers of all conscious standard model of particle physics. The magnetic
individuals within the ken of mankind. moment of an electron, for example, has been
precisely measured to some 12 decimal places, and
One example of an over-reachingly deep and the observed figures are matched precisely by the
precise physical theory is Einstein’s magnificent theoretical predictions of quantum electrodynamics.
general theory of relativity, which improves even
upon the already amazingly accurate Newtonian An important point to be made about these physical
theory of gravity. In the behaviour of the solar system, theories is that they are not just enormously precise
Newton’s theory is precise to something like one part but depend upon mathematics of very considerable
in 107: Einstein’s theory does much more, giving not sophistication. It would be a mistake to think of the
only corrections to Newton’s theory that become role of mathematics in basic physical theory as being
relevant when gravitational fields get large, but also simply organisational, where the entities that
predicting completely new effects, such as black holes, constitute the world just behave in one way or another,
gravitational lensing and gravitational waves – the and our theories represent merely our attempts –
analogues, for gravitation, of the light waves of sometimes very successful – to make some kind of
Maxwell’s electromagnetic theory. sense of what is going on around us. In such a view
there would be no particular mathematical order to
The agreement between theory and experiment the world; it would be we who, in a sense, impose
here has been extraordinary. Astronomers have, this order by describing, in an elaborate mathematical
for example, been monitoring the orbits of one scheme, those aspects of the world’s behaviour that
double neutron star system – known as PSR 1913+16 – we can make sense of.
since the 1970s. The emission of Einstein’s predicted
gravitational waves from this system has been To me, such a description again falls far short of
confirmed, and there was agreement between the explaining the extraordinary precision in the

“What substance does
the ‘reality’ around us
actually have?”

agreement between the most remarkable of the atoms. And the atoms? They have their nuclei, built
physical theories that we have come across and from protons and neutrons and glued together by
the behaviour of our material universe at its most strong nuclear forces; these nuclei are orbited by
fundamental levels. Take the example of gravitation electrons, held in by the considerably weaker
again. Newton’s beautifully simple mathematical electromagnetic forces. Going deeper, protons and
description was later found to remain accurate to a neutrons are to be thought of as composed of more
degree tens of thousands of times greater than the elementary ingredients, quarks, held together by
observational precision available in the 17th century further entities called gluons. Just what are electrons,
when he formulated it. Newton had needed to quarks and so on, though? The best we can do at this
introduce the procedures of calculus in order to stage is simply to refer to the mathematical equations
formulate his theory. In the 20th century, Einstein that they satisfy, which for electrons and quarks
added the sophistication of differential geometry – would be the Dirac equation. What distinguishes a
and increased the agreement between theory and quark from an electron would be their very different
observation by a factor of around 10 million. In each masses and the fact that quarks indulge in interactions
case, the increased accuracy was not the result of a new – namely the “strong” interactions – that electrons are
theory being introduced only to make sense of vast blind to. What, then, are gluons? They are “gauge”
amounts of new data. The extra precision was seen particles that mediate the strong force – which is again
only after each theory had been produced, revealing a notion that can only be understood in terms of the
accord between physical behaviour at its deepest level mathematics used to describe them.
and a beautiful, sophisticated mathematical scheme.
Even if we accept that an electron, say, should be
Mathematics all the way down understood as being merely an entity that is the
solution of some mathematical equation, how do we
If, as this suggests, the mathematics is indeed there in distinguish that electron from some other electron?
the behaviour of physical things and not merely Here a fundamental principle of quantum mechanics
imposed by us, then we must ask again what substance comes to our rescue. It asserts that all electrons are
does this “reality” that we see about us actually have? indistinguishable from one another: we cannot talk of
What, after all, is the real table that I am now sitting at this electron and that electron, but only of the system,
actually composed of? It is made of wood, yes, but what which consists of a pair of electrons, say, or a triple or a
is wood made of? Well, fibres that were once living cells. quadruple, and so on. Something very similar applies
And these? Molecules that are composed of individual to quarks or gluons or to any other specific kind of
particle. Quantum reality is strange that way.

Indeed, quantum reality is strange in many ways. >