Prebiotic Molecules in Space and Origins of Life on Earth

664. WE-Heraeus-Seminar

Veranstaltungsbericht

19 Mar - 23 Mar 2018

Where:

Physikzentrum Bad Honnef

Scientific organizers:

Prof. Paola Caselli, MPE München • Prof. D. Braun, LMU München • Prof. Cecilia Ceccarelli, U Grenoble/FRA • Prof. Pascale Ehrenfreund, U Washington/USA

How life originates is one of the outstanding questions of humankind. Different scientific communities, from astrophysicists to planetary scientists, from geochemists to biophysicists, all share the common aim of understanding how life on Earth originated and if life exists elsewhere in the Universe. Despite these common goals, it has been difficult to join forces and focus on the ‘big picture’, as different background and terminology often hinder fruitful interdisciplinary collaborations.  In this conference, we plan to bring together astrochemists working on the production of prebiotic molecules in space and their delivery to planet-forming regions; Solar System scientists working on the chemical composition of the most pristine material such as comets and primitive meteorites; the exoplanet community, in particular those working on exoplanet atmospheres; geochemists working on the primitive Earth and its conditions to host life; and biophysicists working on the very first steps that assembled pre-biotic molecules into the macromolecules used by terrestrial life.  We believe that fostering communication and interaction among the various groups is a pre-requisite to succeed in our quest on the origins of life.

In the past years there has been tremendous progress in astrochemistry, with the advent of the Atacama Large Millimeter and sub-millimeter Array (ALMA), the NOrthern Extended Millimeter Array (NOEMA), as well as on experimental and theoretical work. For example, complex organic molecules (with ≥ 6 atoms) have been detected in pre-stellar cores, branched alkyl molecules have been found close to our Galactic center, the first P-bearing molecule has been discovered in star forming regions, and the importance of gas-phase chemistry in the production of complex molecules in cold environment established. Links have been found between the deuterium and 15N fraction in interstellar clouds, around young stellar systems and that measured in comets and meteorites in our Solar System. Organic molecules found in young stellar systems have abundances similar to those measured in comets, suggesting a common mechanism in their production across the Galaxy. Glycine, important precursors of pre-biotic molecules and P-bearing species have been detected in the comet visited by Rosetta. A large number of amino acids, nucleobases and fatty acids are contained in the most pristine family of meteortites, once again suggesting important connections with early phases during the process of star and planet formation. Tremendous progress has also been made in detecting atmospheric signatures of exoplanets through spectroscopic methods, which provide important constraints on the atmospheric physical structure and chemical composition. The higher sensitivity of the future-generation telescopes, such as the James Webb Space Telescope (JWST) and the European Extremely Large Telescope (E-ELT), will revolutionize the exoplanetary research and open up new quantitative studies on planetary habitability; theoreticians are getting ready for the challenge, by providing quantitative predictions for future high sensitivity observations.

In the fields of geochemistry and biophysics, discoveries in recent years include the combination of replication and accumulation to overcome Spiegelman's survival of the shortest RNA string, sequence selection by phase transitions with DNA using non-equilibrium driving, the usage of non-equilibrium to drive polymerization of long lengths, managing a Polymerase Chain Reaction (PCR) like reaction only with an RNA ribozyme, enhanced modes of polymerization and ligation to create cofactors and ligate RNA, establishing a chemical synthesis network towards pyrimidines and amino acids from simple components in impact craters and the usage of crystallization as a mode of early purification and chiral selection.

The seminar is also supported by