18 | New Scientist | 25 July 2020Solar systemWe have trampled on
most of AntarcticaLESS than a third of Antarctica is
still entirely pristine and free from
direct human influence, according
to an analysis that may bolster the
case for greater environmental
protection for the remote region.
To see if existing protections
are sufficient given increasing
human impact, Steven Chown at
Monash University in Australia
and his colleagues analysed
2.7 million records covering theArtificial spider web
keeps itself cleanTHREADS of artificial spider silk
are adhesive and shake off water,
just like the real thing. Their
creators hope that the work could
one day help robots self-clean.
Won Jun Song at Seoul National
University in South Korea and
his colleagues made threads of
artificial silk from a composite:
a highly conductive hydrogel
encapsulated in silicone rubber
with a hydrophobic coating.
“Hydrogels have several
outstanding features for spider
webs,” says Song. For instance,
they are transparent and
extremely stretchable.
The artificial threads are about
100 times thicker than typical
spider silk and 250 times less rigid.
Nevertheless, the webs can attract
objects, like a leaf or a piece of
glass, using electrostatic attraction.
This makes them adhesive.
Most importantly, in a similarTechnology EnvironmentTHE closest images ever taken of
the sun have spotted miniature
solar flares everywhere near its
surface. They were captured by the
Solar Orbiter probe developed by
the European Space Agency (ESA).
Dubbed “campfires”, these flares
are up to a billion times smaller
than the solar flares observable
from Earth. Researchers think the
campfires (yellowy white points in
the eight close-up images, left) may
be related to changes in the sun’s
magnetic field. But we don’t know if
they are tiny versions of solar flares
or are made another way.
“Because of their multitude,
they could contribute significantly
to heating the solar corona,” said
ESA’s Daniel Müller at a press event.
A joint mission between ESA
and NASA, Solar Orbiter was
launched on 10 February, carryingsix instruments to image the sun
and its surroundings. At its closest,
the craft was 77 million kilometres
from the sun – about half the
distance between the sun and Earth.
The campfires were captured
using an extreme ultraviolet imager
on 15 June, when the craft reached
its first perihelion, the point in its
elliptical orbit closest to our star.
“We’ve never been closer to the
sun with a camera,” said Müller.
However, other spacecraft
have been closer. NASA’s Parker
Solar Probe was just 18.7 million
kilometres away in January.
“Solar Orbiter is really the limit of
where cameras can take images of
the sun,” said NASA’s Holly Gilbert.
In the next mission phase, due
to start late next year, the craft will
get as close as 42 million kilometres
from the sun’s surface. Donna LuSun’s extreme close-up
reveals tiny solar flares
past two centuries of human
activity on Antarctica, including
newly digitised books by
explorers. Based on four accepted
definitions of wilderness, they
found that between 99.57 and
100 per cent of Antarctica could
be considered to be such.
But narrowing the definition
to areas never visited by humans
meant that figure fell to about
32 per cent (Nature, doi.org/d35x).
Such untouched areas are
considered important as a baseline
to assess our growing impact
on the region’s biodiversity, and
because 12 nations have promised
to protect them under the Antarctic
Treaty, which promotes scientific
cooperation in the region.
“If you trample through a
moss bed, the mosses can take
years to recover. If we really
want to keep Antarctica pristine,
which is what all the nations
signed up to the treaty have
said, are there any left for them
to keep? It turns out not much,”
says Chown. Adam Vaughanway to real spider webs, these
artificial webs can shake off
water and other contaminants
to maintain their ability to attract
objects. This is done by sending
time-varying electric fields
throughout the artificial silk,
resulting in the web vigorously
vibrating. After cleaning, the webs
recover up to 98.7 per cent of their
original adhesion force (Science
Robotics, doi.org/gg4296).
The webs work for a few
weeks, until the solvent in the gel
dissolves. The researchers are
currently working to increase
this active lifespan.
Song says these webs could one
day help robots self-clean. “Our
approach could be used wherever
cleanliness is critical for a device’s
reliable operation,” he says.
“Spider webs are marvels
of engineering in nature and
by analysing them we can learn
a lot about construction with
robots,” says Mirko Kovac at
Imperial College London.
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