2019-06-22_New_Scientist

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News


Exomoons

Leah Crane

ABOUT 370 light years away, a
planet is being born, possibly with its
own set of rings or moons. In 2018,
astronomers spotted a young world
growing around star PDS 70. Now
they have observed what appears
to be a disc of debris orbiting the
planet, the same sort of disc that
we think can coalesce into a moon.
Faustine Cantalloube at the Max
Planck Institute for Astronomy
in Heidelberg, Germany, and his
colleagues used the Very Large
Telescope in Chile to examine the
spectrum of light coming from the
planet, PDS 70b, and found that
it appeared to be emitting more
infrared light than we would expect
for a planet alone.
The infrared light indicates that
something above the planet’s
surface is being heated as it absorbs
light from the planet and re-emits it
at a longer and redder wavelength.
The team compared the data with
models that included a planetary
atmosphere or a disc of dust and
gas, and found that the disc was a
far better match (The Astrophysical
Journal Letters, doi.org/c698).
“The planet is very young,
so it’s hot and bright and it’s
heating up this dust around the
planet,” says Cantalloube.
This is the first time we have
spotted a disc around a young
planet. Some material from the disc
is probably falling onto the planet
and helping it grow, but eventually
the disc may flatten out to form
rings like Saturn’s or clump up and
create moons. We have never before
definitively spotted a moon around
a planet outside our solar system. ❚

The live birth
of a planet and
its moons

Adam Vaughan

THE UK is to set itself the most
ambitious long-term climate
target of any major country: to
become carbon neutral by 2050.
It is being seen by many as a
bid by outgoing prime minister
Theresa May to build a legacy
beyond Brexit. “Now is the
time to go further and faster
to safeguard the environment
for our children,” she said in
a statement last week.
The net zero target is a
dramatic raising of ambition
from the existing UK target of
an 80 per cent cut in emissions
by 2050. Under net zero, some
industries are likely to still emit
carbon by mid-century, but
these would be offset by other
measures, such as tree planting,
that suck carbon from the air.
The decision to push ahead
with the tougher goal comes
despite grumbles about it from
parts of the government. Earlier
this month, the Treasury said
that moving to net zero would
cost in excess of £1 trillion by
2050 – more than government
advisers had said – and the

implications should be better
understood before enacting the
target. In an apparent nod to
these concerns, Downing Street
promised a review within five
years, to see if other countries
are taking similar action and
to check that “industries do
not face unfair competition”.
Boris Johnson and Jeremy
Hunt, two of the frontrunners in
the race to lead the Conservative
party and become the UK’s next

prime minister, have both said
they support the new goal.
It was also welcomed by the
government’s adviser on global
warming, the Committee on
Climate Change (CCC), which
had called for the stricter target
in May. And it follows months
of protests by school pupils and
campaigners calling for tougher
action (see “Do protests work?,
page 20). The Confederation of

British Industry also says it is
“the right response to the...
climate crisis”.
However, the government
says it would “retain the ability
to use international carbon
credits”. This can involve paying
other countries to make carbon
cuts on the UK’s behalf to count
towards the target. The CCC
advises against this, saying the
target should be met within the
UK’s borders.
The goal has been introduced
as a draft amendment to the
Climate Change Act 2008, but
MPs will need to vote for the
measure before it becomes law.
Only three MPs voted against
the original law 11 years ago.
One way to get close to net
zero by 2050 would be to replace
natural gas with hydrogen.
A report by the Institution of
Engineering and Technology
last week concluded that using
hydrogen for heating, power
and industry would be safe.
However, the report revealed
that this would require a hike
in hydrogen production to
10 times current levels.
Norway also made climate
moves last week, with its MPs
backing a decision to divest the
country’s $1 trillion sovereign
wealth fund from oil and gas
exploration firms and invest
more in renewable energy.
The fund, known formally as
the Government Pension Fund
Global, will gradually sell off an
$8 billion stake in 134 oil and
gas firms. But the shift will only
affect companies solely involved
in fossil fuel exploration, not
those such as Shell and BP
which also have renewable
energy business arms. ❚

UK raises climate goal to


net zero carbon by 2050


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Protesters want
more drastic
action on emissions

11
years since the UK’s last major
climate change legislation

Climate policy

Planet PDS 70b
(the light circle)
is forming in the
protoplanetary
disc of star
PDS 70

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10 | New Scientist | 22 June 2019
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