A close up image of comet
67P/Churyumov-Gerasimenko, taken at a distance of 130 km using the
OSIRIS camera on the Rosetta spacecraft. A range of features, including
boulders, craters and steep cliffs are clearly visible.
Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
Comet 67P/Churyumov-Gerasimenko,
studied in detail by the European Space Agency Rosetta and Philae
spacecraft since September 2014, is a body with distinct and unexpected
features. Now two astronomers have a radical explanation for its
properties -- micro-organisms that shape cometary activity. Dr Max
Wallis of the University of Cardiff set out their ideas today (Monday 6
July) at the National Astronomy Meeting in Llandudno, Wales.
Rosetta data have revealed an irregular 'duck shaped' comet with
about 4.3 by 4.1 km in extent. It appears to have a black crust and
underlying ice and images show large, smooth 'seas', flat-bottomed
craters and a surface peppered with mega-boulders. The crater lakes are
re-frozen bodies of water overlain with organic debris. Parallel furrows
relate to the flexing of the asymmetric and spinning double-lobed body,
which generates fractures in the ice beneath.
Dr Wallis, and his colleague Professor Chandra Wickramasinghe,
Director of the Buckingham Centre for Astrobiology, argue that these
features are all consistent with a mixture of ice and organic material
that consolidate under the sun's warming during the comet's orbiting in
space, when active micro-organisms can be supported.
In their model, the micro-organisms probably require liquid water
bodies to colonise the comet and could inhabit cracks in its ice and
'snow'. Organisms containing anti-freeze salts are particularly good at
adapting to these conditions and some could be active at temperatures as
low as -40 degrees Celsius.
Sunlit areas of P/67 Churyumov-Gerasimenko have approached this
temperature last September, when at 500 million km from the Sun and weak
gas emissions were evident. As it travels to its closest point to the
Sun -- perihelion at 195 million km -- the temperature is rising,
gassing increasing and the micro-organisms should become increasingly
active.
Dr Wallis said: "Rosetta has already shown that the comet is not to
be seen as a deep-frozen inactive body, but supports geological
processes and could be more hospitable to micro-life than our Arctic and
Antarctic regions."
Wallis and Wickramasinghe cite further evidence for life in the
detection by Philae of abundant complex organic molecules on the surface
of the comet and in the infrared images taken by Rosetta.
Professor Wickramasinghe commented: "If the Rosetta orbiter has found
evidence of life on the comet, it would be a fitting tribute to mark
the centenary of the birth of Sir Fred Hoyle, one of the undisputable
pioneers of astrobiology."
Story Source:
The above post is reprinted from
materials provided by
Royal Astronomical Society (RAS).
Note: Materials may be edited for content and length.
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