Flamsteed AS Dr Lewis Dartnell Astrobiology

Flamsteed Astronomy Society

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by Chris Sutcliffe

As part of the Flamsteed Society Christmas Party evening at the Royal Observatory Greenwich on 6 December 2010, a presentation with the title “Astrobiology: the hunt for alien life” was given in the Peter Harrison Planetarium.

Dr Dartnell is an Astrobiologist from University College London, looking for life beyond Earth. Lewis is also a science journalist writing for the Daily Telegraph, the New Scientist, The Guardian, BBC News, The Sun, Astronomy Now, and Spaceflight Now, amongst others.

Astrobiology studies the search for extraterrestrial life and the effects of outer space on living organisms. How do we define ‘life’? On Earth, we know life when we see it -- we have all evolved together and recognise it. All forms of known life consist of cells and Lewis showed a Harvard Biovision animated video with the title ‘A day in the life of a cell’ which can be viewed at http://multimedia.mcb.harvard.edu/

Even though we think life on Earth is familiar we continue to be surprised by how adaptable it is. Lewis described extremophiles which are organisms which thrive in physically extreme conditions eg heat or acid. A thermophile is an extremophile which thrives in high temperatures (60 to 80 degrees C) and is found in geothermal regions of the Earth such as the Yellowstone National Park in North America.

In the Arctic, there are hundreds of pockets of water under the ice, packed with bacteria at temperatures down to -20 degrees C. There are also advanced forms of complex animal life such as tube worms which have no mouth or stomach, raising the question how do they survive. Worms have been discovered which eat ice and methane but not carbohydrates; they survive on frozen “fart gas”, in the temperature range -20 to +12 C.

So life on Earth has shown it can adapt to conditions which we now know also exist elsewhere in the solar system. Using the wonders of the planetarium’s high technology, Lewis cleverly commenced a journey from Earth starting in Greenwich, first stop Mars!

In the late 1990s, NASA’s Pathfinder Mission to Mars landed a rover on the planet to analyse Mars’ atmosphere, climate and geology, and the composition of its rocks and soil, by taking measurements and images. The expedition confirmed the feasibility of landing expedition vehicles on Mars. As a further development the European Space Agency’s (ESA) probe ExoMars is currently being designed with the aim of going to Mars in 2018 to look for signs of life. The probe will include a drill to bring soil to the surface for analysis and look for organic molecules.

Pictures by Grey Lipley