Prebiotic Organics in Extraterrestrial Samples: An Inventory for the Origin of Life

Meteorites provide a record of the chemical processes that occurred in the early solar system before life began on Earth. The delivery of complex organic compounds by carbonaceous chondrites to the early Earth and other planetary bodies could have been an important source of prebiotic organic compounds required for the emergence of life. Of particular interest is the study of meteoritic amino acids and their enantiomeric compositions since these molecules are the monomers of proteins common to all life on Earth. The single chirality observed in biological molecules — left-handed amino acids and right-handed sugars — is a property important for molecular recognition processes and is thought to be a prerequisite for life. In contrast to biology, all known non-biological reactions result in equal mixtures of left- and right-handed (L = D) amino acids and sugars. Therefore, how the nearly exclusive production of one hand of such molecules arose from what were presumably equal mixtures of L and D molecules in a prebiotic world has been an area of intensive research. A predominance of left- over right-handed amino acids (up to ~60%) has been found in some meteorites, but how this large amino acid asymmetry came about remains unclear. In this seminar, the possible chemical origins of asymmetric amino acids and other prebiotic organic molecules in meteorites and the implications for the origin of life on Earth will be discussed. I will also talk about the plans for both current and future sample return missions and their importance in our search for evidence of life in the solar system.

Speaker: Daniel Glavin (NASA Goddard Space Flight Center)

Talks are held in the STScI John N. Bahcall Auditorium. Light lunch (provided) starts at 12pm; talk starts at 12:30pm.

Planets, Life, and the Universe Lecture Series presentations are also webcast live. Webcasts can be viewed at the STScI webcast site during the scheduled presentation, and can be found afterward in the STScI webcast archive.

STScI is located in the Muller Building on the Johns Hopkins University Homewood campus. View a JHU map and directions.