Comet's likely role as harbingers of life on Earth

Bengaluru, August 6 : Did a comet strike jump-start life on Earth? The findings of the European Space Agency’s Rosetta Mission tend to suggest this possibility. An instrument on board the Philae Lander of Rosetta Mission has identified 16 organic molecules on the surface of a comet that are potentially “prebiotic”, or necessary for life, the mission scientists have reported in a recent issue of the jourl Science. “These are the first organic molecules to be ever reported directly, from in-situ alyses, from the surface of a comet,” Chaitanya Giri, a co-investigator of Cometary Sampling and Composition Experiment (COSAC) of the Rosetta Mission and one of the authors, told IANS.

On November 12, 2014, Philae Lander became the first space probe to soft land on the surface of a comet called 67P/Churyumov-Gerasimenko. Besides COSAC, Philae carried several scientific experiments on board, with each trying to decipher the ture of the comet. COSAC - which is a gas chromatography-mass spectrometer - aimed to study the surface ‘organic’ chemical composition of the comet, said Giri, a post-doctoral research scientist in the Department of Planets and Comets at the Max Planck Institute for Solar System Research (MPS) in Gottingen, Germany.

According to the report, the Philae Lander bounced off the comet’s surface multiple times after the touchdown before coming to rest. The dust cloud kicked up from the bounces entered the COSAC instrument, which alysed the dust. “The entire COSAC team studied the mass spectra data generated by it,” Giri said. The COSAC team, led by Fred Goesmann, involved scientists from France, Germany, Ireland, the Netherlands, Spain, Switzerland and the United States. Giri, the only Indian on board, has been part of the team for the past five years in various capacities, beginning as a trainee doctoral student.

According to the Science report, as many as 16 molecules were identified by the experiment. Twelve of these had been reported earlier from remote ground-based telescopes and fly-by missions whereas COSAC has reported four novel molecules that have never been reported earlier, Giri said. These new molecules are acetamide, methyl isocyate, propioldehyde and acetone.

Other re-reported molecules include hydrogen cyanide, formamide and glycolaldehyde. “All these molecules are of great significance for triggering prebiotic chemistry - the precursor processes towards the formation of life,” Giri said.  (ians)