Conférence "The Long History of Preparing Our Comet Mission ROSETTA/PHILAE - on the Search for Life’s Roots beyond Earth"
de 11:00 à 14:00
|Où ?||Salle de séminaire Bât. Recherche-Chimie, Faculté des Sciences Campus Valrose 28 Av. Valrose, Nice|
Prof. Wolfram THIEMANN, University of Bremen (Germany)
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The ROSETTA/PHILAE mission on its route to comet Churyomov/Gerasimenko has a impressingly long history of preparation which the author wants to illustrate, in order to give the audience an idea of how scientific ideas may originate and mature years later into concrete results of high relevance: A young student of chemistry is introduced in his second semester of university latest into the fascinating world of organic chemistry, - this seems to be the worldwide accepted curriculum of chemical studies in higher education. He will be told among other subjects about the elementary building blocks of proteins, the amino acids.These can be synthesised by Strecker method rather easily from the small molecules aldehyde, ammonia, water, and cyanic acid, resulting in “racemic” mixtures of the L- and the D-enantiomers. A few weeks later only, mostly at the end of the semester the same lecturer will tell you, that the living world is made up of the same amino acids, yet, exclusively made up of the pure enantiomer L-amino acids only. Why this is so, is left in mystery, is it a hidden law perhaps? Be as it is, it appears immediately, that this “one-sided, dissymmetric” biochemistry of our terrestric living world is a characteristic signature of life as we know it. Looking for life outside Earth we assume that this dissymmetry is worth searching for on extraterrestrial objects. Exactly this is our mission to this comet, could life on Earth could have been triggered by some cometary organic dust in the early phase of Earth, being dissymmetric perhaps? Helmut Rosenbauer from the Max-Planck-Institute (formerly MPI for Aeronomy and Atmospheric Research, now renamed MPI for Solar System Research) at Katlenburg-Lindau took up our idea and integrated this into his earliest concepts of ROSETTA searching for organic stuff on the comet. The lander PHILAE to be released from the orbiter will land softly on the comet’s surface, grab some soil and inject it into some small oven, to be heated and analyzed by a chiral gas chromatograph coupled with a mass spectrometer, with the aim of identifying some enantiomer amino acids of biological importance. The time span from discussing first these raw ideas about (homo-)chirality being a signature of life, - a strong and very peculiar biological marker so to say -, over implementing an experiment to be performed on this ESA managed space vehicle up to the first sampling of cometary soil was more than two decades, maybe one of the longest periods of preparation and final realisation ever in the history of science projects and in particular of space exploration. In the second half of the year 2014 we will know in detail about the success of this ambitious mission!