Organic 'Building Blocks' Discovered in Titan's Atmosphere

http://www.ucl.ac.uk/media/library/OrganicBuildingBlocks

Organic "building blocks" discovered in Titan's atmosphere
University College London
28 November 2007

Scientists analysing data gathered by the Cassini spacecraft have
confirmed the presence of heavy negative ions in the upper regions of
Titan's atmosphere. These particles may act as organic building blocks
for even more complicated molecules and their discovery was completely
unexpected because of the chemical composition of the atmosphere
(which
lacks oxygen and mainly consists of nitrogen and methane). The
observation has now been verified on 16 different encounters and
findings will be published in Geophysical Research Letters on November
28.

Professor Andrew Coates, researcher at UCL's Mullard Space Science
Laboratory and lead author of the paper, says: "Cassini's electron
spectrometer has enabled us to detect negative ions which have 10,000
times the mass of hydrogen. Additional rings of carbon can build up on
these ions, forming molecules called polycyclic aromatic hydrocarbons,
which may act as a basis for the earliest forms of life.

"Their existence poses questions about the processes involved in
atmospheric chemistry and aerosol formation and we now think it most
likely that these negative ions form in the upper atmosphere before
moving closer to the surface, where they probably form the mist which
shrouds the planet and which has hidden its secrets from us in the
past.
It was this mist which stopped the Voyager mission from examining
Titan
more closely in 1980 and was one of the reasons that Cassini was
launched."

The new paper builds on work published in Science (May 11) where the
team found smaller tholins, up to 8,000 times the mass of hydrogen,
forming away from the surface of Titan.

Dr Hunter Waite of the South West Research Institute in Texas and
author
of the earlier study, said: "Tholins are very large, complex, organic
molecules thought to include chemical precursors to life.
Understanding
how they form could provide valuable insight into the origin of life
in
the solar system."

The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. NASA's Jet
Propulsion Laboratory, a division of the California Institute of
Technology, manages the Cassini-Huygens mission for NASA's Science
Mission Directorate, Washington, D.C. The Cassini orbiter was
designed,
developed and assembled at JPL.

-Ends-

Notes to editors:

More information about the mission is available at
http://saturn.jpl.nasa.gov and
http://www.nasa.gov/cassini

If you wish to interview one of the scientists involved in the study
please contact:

Dave Weston, UCL Media Relations Office, tel: +44 (0)20 7679 7678,
mobile: +44 (0) 7733 307 596, out of hours +44 (0)7917 271 364, e-
mail:
d.weston@xxxxxxxxx

About UCL:

Founded in 1826, UCL was the first English university established
after
Oxford and Cambridge, the first to admit students regardless of race,
class, religion or gender, and the first to provide systematic
teaching
of law, architecture and medicine. In the governmentâs most recent
Research Assessment Exercise, 59 UCL departments achieved top ratings
of
5* and 5, indicating research quality of international excellence.

UCL is in the top ten world universities in the 2007 THES-QS World
University Rankings, and the fourth-ranked UK university in the 2007
league table of the top 500 world universities produced by the
Shanghai
Jiao Tong University. UCL alumni include Marie Stopes, Jonathan
Dimbleby, Lord Woolf, Alexander Graham Bell, and members of the band
Coldplay.
.

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