22 | New Scientist | 9 April 2022AstrophysicsA STAR more than 27 billion light
years from Earth is the most distant
individual one we have spotted.
Because light takes time to travel
across the universe, we are seeing
the star as it existed 900 million
years after the big bang, providing
a window on the early universe.
Brian Welch at Johns Hopkins
University in Maryland and his
colleagues found the star with the
Hubble Space Telescope using a
process called gravitational lensing.
This involves a relatively nearby
galaxy or cluster of stars warping
and magnifying the light from a
more distant object, behaving like
a lens through which we can view it.
The galaxy in which this distant
star resides is nicknamed the
Sunrise Arc for the shape into which
gravitational lensing stretched its
light, and the researchers dubbedthe new star Earendel, an Anglo-
Saxon word meaning “morning
star” or “rising light”. The star
(inside the square in the picture,
left) is probably between 50 and
100 times the mass of the sun.
The universe’s expansion means
that while the light from Earendel
took about 12.8 billion years to
reach us, the star is now likely to
be about 27.7 billion light years
away (Nature, doi.org/hn3v).
Further observations could reveal
how stars in the early universe were
different from ones formed more
recently, and help solve the mystery
of how supermassive black holes
formed in the early universe. If it is
a really massive star, “it could be
the sort of thing that could form an
intermediate black hole that could
be the seed to a supermassive black
hole”, says Welch. Leah CraneFurthest star ever seen
offers glimpse back in time
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News In brief
AFTER the asteroid-triggered
mass extinction 66 million years
ago that wiped out most of the
dinosaurs, small surviving
mammal species underwent
an evolutionary explosion. Now,
it seems that the beasts evolved
bigger bodies millions of years
before their brain size caught up.
Ornella Bertrand at the
University of Edinburgh, UK, and
her colleagues looked at CT scans
of mammal skulls from before and
after this extinction event at the
end of the Cretaceous. Some of
these are new discoveries from
places like the Colorado basin
that show mammal evolution
in the million years after the
likes of Triceratops went extinct.
It was already known that the
body size of mammals increased
immediately after the event.
Mammals at the time of the
extinction were no bigger than aEvolutionbadger – which tend to be under a
metre in length – while some were
the size of a black bear 10 million
years later. But Bertrand’s team
has discovered that the brain size
of the mammals stayed about the
same even as their bodies grew.
It wasn’t until about 56 million
years ago, during the Eocene
epoch, that the palaeontologists
detect sweeping changes in
mammal brains (Science, doi.org/
hn4f). “During this time,” says
Bertrand, “the part of the brain
that increases the most is the
neocortex where the integration
of complex senses such as
vision, hearing, motor control
and memory occurs.”
This increase in brain size
may be partly explained by the
lush forests that spread across
the world in the early Eocene.
Mammals underwent another
evolutionary burst as they began
to adapt to the thick vegetation,
which made navigating, finding
food and avoiding predators
more complex. Riley BlackBeasts’ bodies grew
faster than brainsWOOD-BURNING appliances in
people’s homes are a major source
of air pollution in the European
Union and the UK, responsible for
€17 billion a year in health-related
costs, a study has found.
Marisa Korteland at consultancy
firm CE Delft and her colleagues
calculated how much air pollution
is produced by heating and
cooking in homes based on
emissions data from Eurostat,Healththe EU’s statistical office.
They used this to estimate the
health cost based on a 2013 study
by the World Health Organization.
The estimate includes social costs
of higher illness rates and earlier
deaths as well as direct spending
on healthcare.
They say air pollution from
fossil fuels and wood burned in
homes for heating or cooking
results in €27 billion of health-
related costs a year in the EU and
UK. Wood-based home appliances
are responsible for 63 per cent
(€17 billion) of the €27 billion.
The average health costs
from using a wood stove for a
year are €750 per household,
says Korteland, compared with
€210 from driving a diesel car
and €30 from a gas boiler.
If countries swapped stoves and
boilers for heat pumps powered by
electricity from non-biomass and
non-fossil fuel sources, the health-
related costs from air pollution
from heating could be cut to zero,
PL the study says. Michael Le Page
AINPICTURE
/JOZE
F^ KUB
ICABurning wood brings
a hefty health bill