Public Lectures for the Session 2002-2003 held in Room E7 of the Renold Building, UMIST.
Delivered to the Manchester Astronomical Society

21st November 2002

''The possibility of life in the Solar System''

Dr. Monica M. Grady
Head of Division, Petrology & Meteoritics, Department of Mineralogy. Natural History Museum, London

For life to exist elsewhere in the solar system, the basic chemistry of life, carbon, together with the universal solvent, water, had to be present within in an environment that would sustain the formation and evolution of large, complex organic molecules. Comet impacts were thought to have deposited large amounts of water onto the earth and other planets during the heavy bombardment phase in the formation of the solar system, about 3500 million years ago. However this did not imply that panspermia via comets had brought life itself to our planet from interstellar space.

There is increasing evidence that life can flourish in adverse conditions. On earth, 'Extremeophile' organisms are found living in extraordinary conditions of high and low temperture, pressure, acidity and salinity and even high radiation. Sunlight, once thought to be necessary for the evolution of life, was now shown to be unnecessary. Although earth occupies a comparatively favourable position in the solar system, these new discoveries support the idea that life could also have evolved elsewhere.

Dr. Grady examined the possibility that conditions on Mars and Europa might have allowed primitive organisms to evolve when conditions may have been more conducive. An expert in carbon analysis, she described how evidence for life on Mars might yet be gleaned from the forthcoming Beagle II landing mission. The Gas Analytical Package (GAP) experiment was designed to detect carbon in all its various compounds, including atmospheric gases and may yet show evidence of a carbon cycle indicative of extant Martian biology, even if this is beneath the surface of the planet. In spite of recent assertions, there was no direct evidence for micro-fossils in Martian meteorites.

Beyond the solar system, about a hundred, hot, Jupiter-sized planets are known to orbit other stars. A proposed, joint NASA/ESA project, the DARWIN Terrestrial Planet Finder, had been designed to look for the spectral signatures of ozone and carbon-cycle gases on alien, earth-like planets that might indicate the presence of life outside of our solar system. SETI projects, in which even the home computer user could participate, were designed to detect the remote possibility of radio signals from alien civilizations.

Monica ended her talk by saying that she had to return to Milton Keynes that evening as her husband, Dr.Ian Wright, senior scientist and designer of the GAP experiment was eagerly awaiting the results of space-readiness tests on the instrument. The launch of Beagle II aboard the Mars Express mission is scheduled for the end of May, with a landing just before Christmas, 2003.

Synopsis by Kevin J. Kilburn (Secretary)

Maintained by Michael Oates
Page modified 28 October, 2006