The Week - UK (2022-05-28)

NEWS 19

There was much excitement in 2019 when

astronomers captured the first-ever picture

of a black hole, in the M87 galaxy 55 million

light-years away. Now the same team have

released a photo of a smaller black hole

rather closer to home: in our own galaxy, the

Milky Way. Like the 2019 picture, the new

image shows a dark shadow ringed by light,

produced by gases being whipped around the

black hole by its gravitational pull. The photo

of the black hole, which is named Sagittarius

A*, was captured by the Event Horizon

Telescope, a network of eight observatories

around the world that work together to

mimic a telescope the size of the Earth.

Although Sagittarius A* is closer to us than

the M87 black hole, the plasma encircling it moves quicker, so researchers had to take

several photos over several nights, and use a supercomputer to combine them.

“I’m personally happy about the fact it really drills home that there is definitely a

black hole at the centre of our galaxy,” said Dr Ziri Younsi, a co-author of the paper.

“It is key to our understanding of how the Milky Way formed and will evolve.”

Health & Science

28 May 2022 THE WEEK

Children are exercising even less

Children in the UK are less active now

than they were before the pandemic, a

study has found. By the latter half of 2021,

fewer than a third of children were doing

the recommended 60 minutes of moderate

to vigorous physical activity a day, the

research suggests; and on average they

were active for 56 minutes on weekdays

– eight minutes less per day than children

of the same age before the lockdowns.

The study involved 393 children and their

parents who were recruited from schools

in the Bristol area in May last year, a few

weeks after schools had reopened. Over

the next few months, participants wore

accelerometers, to gauge the intensity of

their activity, and were asked about their

lifestyles. This data was then compared

to that on 1,296 children from the area

who’d been assessed before the lockdown.

The results showed that the children spent

less time exercising, and were also more

sedentary: on average, they spent 25

minutes more sitting down each weekday

than the pre-lockdown cohort. However,

their parents’ activity levels were broadly

unchanged. The researchers said it was

surprising, and concerning, that children’s

activity levels had not returned to previous

levels when freedoms were restored.

Plants can grow in lunar soil

Plants have been grown in lunar soil for

the first time, raising hopes that crops

could one day be harvested on the Moon

– and in currently barren areas on Earth,

too. Researchers in Florida had waited 11

years for permission from Nasa to run the

study, and were finally allowed to use just

12g of loose soil known as regolith that

had been collected during Apollo missions

between 1969 and 1972. They planted

thale cress seeds in the moistened regolith,

which had nutrients added to it on a daily

basis. As a control, they also planted seeds

in volcanic ash from Earth. “After two

days, they started to sprout!” one of the

team wrote, in a press release. “Everything

sprouted. I can’t tell you how astonished

we were! Every plant – whether in a lunar

sample or in a control – looked the same

up until about day six.” After that, the

regolith plants started to grow less well,

but Nasa said that the research provided a

starting point for agriculture on the Moon,

and might lead to new insights into how

to improve the soil there, and on Earth.

“When humans move as civilisations, we

always take our agriculture with us,” said

co-author Prof Robert Ferl. “Showing that

plants will grow in lunar soil is a huge step

in being able to establish lunar colonies.”

Dogs could be Covid screeners

Dogs can be trained to detect coronavirus

to a high accuracy, which could make them

useful in settings where mass testing is not

practical, research has indicated. For the

study, four dogs that had already learnt

to sniff out drugs and cancer were trained

to identify Covid-19. Researchers then

presented them with skin samples from

114 people who had tested positive and

306 people who had tested negative. They

found that the dogs could identify both

those with, and without, the disease with

an accuracy rate of more than 90%. The

dogs were then tested in a real-life setting,

at Helsinki airport. Here, they smelled 303

incoming passengers, each of whom took

a PCR test. The dogs matched the PCR test

results in 98% of the cases. Writing in BMJ

Global Health, the authors said that dogs

could be deployed in sites of high Covid

prevalence, “such as hospitals (to prescreen

patients and personnel), as well as in low

prevalence sites, such as airports”.

Turtles are bad map readers

The question of how marine animals know

where to go when they’re migrating has

vexed scientists for centuries. There is some

evidence that sea turtles use the Earth’s

magnetic field to navigate, but the accuracy

of their internal “maps” has been unclear.

Now a team in Australia have established

that the turtles are really rather bad at

orientation. Researchers at Deakin

University attached GPS devices to 22

hawksbill turtles, to track them as they

swam from their nesting grounds on the

Indian Ocean island of Diego Garcia to

feeding sites elsewhere in the Chagos

Archipelago. They found that the turtles

took roundabout routes – one swam fully

812 miles to get to an island 109 miles

away. “Our results provide compelling

evidence that hawksbill turtles only have

a relatively crude map sense in the open

ocean,” the authors concluded.

Hawksbill turtles: lost at sea

Pollution claimed nine million lives in

2019, accounting for one in six deaths, a

study in The Lancet Planetary Health has

concluded. Researchers at the Global

Alliance on Health and Pollution in

Switzerland found that the figure had

barely budged since they last examined

the link between pollution and death in

2015, but that fatalities caused by

household air pollution – for instance by

burning wood indoors – had fallen from

2.9 million in 2015 to 2.3 million in 2019,

while deaths from outdoor pollution had

risen from 4.2 million to 4.5 million.

More than 90% of the pollution-related

deaths occurred in low- and middle-

income countries. “Nine million deaths

is a lot of deaths,” said co-author Philip

Landrigan. “We’re making gains in the

easy stuff and we’re seeing the more

difficult stuff, which is the ambient

(outdoor industrial) air pollution and

the chemical pollution, still going up.”

The global toll of pollution

What the scientists are saying...

A black hole in the Milky Way

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Sagittarius A*: close to home?