Organic Matter in Meteorites: Molecular and Isotopic Analyses of the Murchison Meteorite

Freudian abstracts

“…The same isotope ratios that distinguish Murchison amino acids from their terrestrial counterparts imply that these molecules or their chemical precursors originated in interstellar clouds 1,8 . Why should chemistry in such a cloud have a bias towards onehandedness?…”

“…In the cat, more robust disparity signals are produced by so-called complex cells at a later stage of processing. But, even for some complex detectors, the sign of the disparity signal is inverted when the contrast sign is reversed such that white regions in one eye are superimposed on black regions in the other 8 .…”

“…But periodic stimuli, even when in register, can contain regions of opposite contrast. Under these circumstances, complex cells that accept opposite-contrast stimuli could use them to improve their response 8 .…”

“…These authors had previously 7 used the carbon isotope ratio 13 C/ 12 C of alanine in Murchison to argue for an excess of L-alanine over D-alanine, but reservations about these measurements persisted 8 . In their present letter 1 , they instead examine the 15 N/ 14 N ratio of individual Murchison amino-acid enantiomers.…”

Space as a Tool for Astrobiology: Review and Recommendations for Experimentations in Earth Orbit and Beyond

“…Today, the fact that meteorites, and in particular the carbonaceous chondrites, contain organic compounds is very well established (Ehrenfreund and Sephton 2006). The extraction and analysis of organic compounds like amino acids and nucleobases from meteorites has provided important information on processes and conditions prevalent in the solar nebula (Callahan et al 2011;Cronin and Chang 1993;Martins et al 2008;. Investigating the influence of weightlessness on the Miller-Urey experiment could also simulate conditions in the solar nebula.…”