Download Dark blue dot not so dark

News
Triplets become
wide binaries
Dark blue dot not so dark
Drills aim for
Lake Ellsworth
The origins of binary star systems
in wide orbits, sometimes as much
as a light-year apart, have been
something of a puzzle. Now simulations suggest that they could
start life as triple stars.
Simulations of star formation by the
NASA Astrobiology team at the University of Hawaii suggest that most
stars start life with a few others at
the edge of their cloud cores. Gravitational pull between the stars and
the gas often results in the least massive star being ejected from the system, while the more massive ones get
larger and closer together. In some
cases – and the team ran their simulations 180 000 times – the smallest
star is not ejected, but orbits far away.
If the two more massive stars then
combine, the result is a wide binary.
“This can happen if there is enough
gas in the cloud core to provide
resistance,” said the paper’s lead
author, Bo Reipurth of the Institute
for Astronomy at the University of
Hawaii at Manoa. “Sometimes there
is so much gas in the core that the
two close stars spiral all the way in
and collide with each other in a spectacular merging explosion.”
The wide binary nearest to Earth
is Alpha Centauri, which has a small
companion, Proxima Centauri,
which orbits at a distance of about
one-quarter of a light-year. All three
stars were born close together several
billion years ago, before a powerful
dynamic kick sent Proxima out into
its wide path, where it has been orbiting ever since.
This research was published in
December 2012 in Nature.
Imagery from the new NASA–NOAA Suomi National Polar-orbiting
Partnership satellite have been combined to give a realistic set of images
of the Earth at night, including sources of light as faint as a single ship at
sea. The day–night band of the Visible Infrared Imaging Radiometer Suite
(VIIRS) detects light in a range of wavelengths from green to near-infrared
and uses filtering to observe dim signals such as city lights, gas flares,
aurorae, wildfires and reflected moonlight. It can even pick out the edge of
the Antarctic ice, lit by the glow of the aurora australis, pictured above. The
images will give much improved data on the extent of human activity and how
it affects life at the Earth’s surface. VIIRS works at very high resolution – six
times better spatial resolution and 250 times better dynamic range than
previously available – making it useful for mapping storms and features
such as fog and clouds that are difficult to pick up with thermal imaging, and
it works through the night, adding useful data for weather forecasting.
In December a UK team of scientists and engineers was coming
close to its target of drilling into
Lake Ellsworth, an ancient lake
buried below more than 3 km of
ice on the West Antarctic Ice Sheet.
Finding life, or not, in the isolated
water will have profound consequences for astrobiology.
Members of the British Antarctic
Survey designed the high-pressure
hot-water drill that should penetrate
the ice after five days or so of continuous drilling. Then probes designed
at the National Oceanography Centre will collect water and sediment
samples. The team hopes to be able
to keep the borehole open for long
enough to send the two instruments
down it; they estimate that 24 hours
is the maximum time before refreezing makes it too narrow.
Hot-water drilling is not a new
technique, but the 3 km to Lake
Ellsworth is the longest borehole
attempted. The team also has to take
care not to contaminate the water,
possibly isolated for a million years,
using space industry standard clean
technology.
Lake Ellsworth principal investigator Martin Siegert from the University of Bristol said: “This British
mission is part of an international
effort to discover and explore subglacial lake environments. We are
about to explore the unknown and I
am very excited that our mission will
advance our scientific understanding
of Antarctica’s hidden world.”
The Lake Ellsworth Consortium is
funded by the Natural Environment
Research Council.
http://1.usa.gov/T9V8Wp
http://1.usa.gov/Ub42TJ
http://www.ellsworth.org.uk
Views
Risky business
From Garry Hunt
I read with interest the editorial
in the December 2012 edition of
A&G on communicating risk. This
is a topic which is both an interest
and concern for me as a scientist
and even more so as a businessman.
A major issue for scientists is
not simply one of communicating the results of their research,
but to understand to whom they
are communicating this information. Particular issues where this
is important which also involve
risk are climate change and global
warming, as well as those of
earthquake prediction. I would like
to use the former issue of climate
change and global warming as an
1.8
example of the problem for the
purpose of this letter.
For several decades, scientists
have been providing predictions of
the impact of climate change and
possible global warming. Hardly a
month passes without a new theory
and prediction of the change to the
Earth’s global temperature and the
associated consequences. Sometimes, the latest prediction contradicts a previous statement, so the
general public is left in a confused
state. Indeed, we have reached a
position where there are as many
people who believe the climate is
changing as there are people who
ignore it on the basis that it is simply a natural fluctuation which the
planet has experienced before. My
discussions with business and some
governments are far worse. Many
companies are simply ignoring the
problem, on the grounds that if the
scientific community cannot agree,
why should they bother to change
their working practices when the
current economic problems are
more serious. This is a foolish
attitude, but it is a massive problem
to attempt to reverse these attitudes
as the statements made by the
scientific community are considered
to be the gospel truth – and this is
often far from the case.
I have spoken to many business organizations and groups of
scientists over many years to stress
we need the scientific community
to keep quiet and not be so public
with their often “off hand” predictions. With climate change and
global warming, they have shown
there is a problem, but the details
remain necessarily imprecise. When
problems of this type which involve
risk are discussed, we should be
focusing on the action to be taken
by businesses and by everyone
rather than having a continued
dialogue in the open press. This
simply confuses the general public
and is then easier for businesses and
indeed governments to ignore.
The scientific community will
always have an important role to
play in communicating the results
of research, but needs to understand
and action its responsibilities more
carefully when the consequences of
its work can affect all mankind.
Prof. Garry E Hunt, Managing Partner,
Elbury Enterprises; [email protected]
A&G • February 2013 • Vol. 54