20 | New Scientist | 15 August 2020TechnologyDirty snowballs cause
Jupiter’s odd lightningTHE JUNO spacecraft has spotted
lightning on Jupiter unlike
anything we have seen before,
and it may be caused by strange
slushy balls of ice and ammonia.
Planetary scientists have long
thought that Jupiter’s lightning
happens in much the same way as
Earth’s: through liquid water and
ice interacting within clouds and
building up electric charge. That
was supported by seeing lightningZombie microbes
extend the limits of lifeDEEP-sea microbes can survive
on less energy than previously
thought necessary for any living
thing, potentially changing the
definition of life as we know it.
James Bradley at Queen Mary
University of London and his
colleagues used data from
sediment samples collected from
beneath the sea floor to determine
the rate of energy use by the
microorganisms that live there.
Using a model that considered
various aspects of the habitat,
including the rate at which organic
carbon is degraded, the availability
of oxygen and the number of
microorganisms, Bradley and his
team calculated the rate of energy
use per microbial cell. The value
was 100 times lower than that
previously thought to be the limit
for life. A few cells survived on less
than 10-21 watts of power (Science
Advances, doi.org/d56f).Life Solar systemFLUORESCENT materials have
been created using a new technique,
and they can be 3D printed in any
shape you want. It may lead to solar
panels that are more efficient.
Some 100,000 different dyes
are able to fluoresce – or glow under
ultraviolet light – because individual
molecules in solution are physically
distant from each other, says
Amar Flood at Indiana University.
“But in solids, the particles are
closer together and so interfere
with each other, which stops
them behaving as individuals.”
Flood says this means materials
made using fluorescent dyes,
such as fibres for textiles, aren’t as
fluorescent as the starting solution,
which has been a recognised
problem in chemistry for 150 years.
His team has now tried mixing
doughnut-shaped molecules calledcyanostars with the dyes. The
cyanostars are able to hold the
positively charged dye molecules
apart from each other so they
maintain their fluorescent
properties, even when they are
in a solid state. Brighter individual
fluorescent materials exist, but the
team’s methods promise to make
it easier to make fluorescent solids
from a large range of dyes.
The technique can be used
with any positively charged
dye and in conjunction with
3D printing to make solids that
glow (Chem, doi.org/d56j).
Fluorescent material could
improve the efficiency of solar
panels by letting them convert
infrared rays or low-frequency
visible light from the sun into a form
that can be captured by solar cells.
Jason Arunn MurugesuBright fluorescent materials
3D printed in any shape
coming from a layer of water
clouds beneath the cloud tops
that we see as Jupiter’s “surface”.
But now, NASA’s Juno spacecraft
has spotted lightning much higher
in the planet’s atmosphere, where
it is too cold for liquid water. “It’s
very different from anything that
happens on Earth,” says Heidi
Becker at NASA’s Jet Propulsion
Laboratory in California, a
member of the Juno team.
The team found that this
strange lightning could be
caused by liquid ammonia
acting as an antifreeze. That
would create “mushballs” of a
slushy ammonia-water mixture
surrounded by water ice. The high-
altitude lightning could occur
when these mushballs collide with
ice particles and build up electric
charge (Nature, doi.org/d55s).
The balls could then drop into
Jupiter’s interior, explaining why
the interior doesn’t have as much
ammonia gas as we expected. The
missing ammonia may be hiding
in mushballs. Leah CranePrevious estimates for the
lower energy limit for life have
involved growing microorganisms
in the lab and starving them of
nutrients to determine the limit
for survival. But Bradley says these
experiments don’t fully represent
the range of environments that
microbes inhabit in the real world,
including beneath the sea floor.
Because of their extremely low
rate of energy consumption, the
microbes – mainly bacteria and
archaea – can survive buried for
millions of years. “That increases
the possibility of places which
we can go to search for life on
other planets,” says Bradley,
such as on Mars.
“I don’t think that we have
a good understanding yet of
the mechanisms by which
they survive in this incredibly
low-energy state for millions of
years,” says Bradley. “Possibly it’s
something to do with their ability
to reduce their metabolic rate...
and to enter into a kind of
zombie-like state.” Layal LiverpoolAM
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GILLNews In brief