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Of interstellar carbon and extraterrestrial nitrogen.
Posted: May 5, 2006
Meteorites Discovered To Carry Interstellar Carbon. "The tell-tale signs are lots of deuterium and 15N chemically bonded to carbon," commented co-author Larry Nittler. "We have known for some time, for instance, that interplanetary dust particles (IDP), collected from high-flying airplanes in the upper atmosphere, contain huge excesses of these isotopes, probably indicating vestiges of organic material that formed in the interstellar medium. The IDPs have other characteristics indicating that they originated on bodies--perhaps comets--that have undergone less severe processing than the asteroids from which meteorites originate." "The scientists found that some meteorite samples, when examined at the same tiny scales as interplanetary dust particles, actually have similar or even higher abundances of 15N and D than those reported for IDPs. "It's amazing that pristine organic molecules associated with these isotopes were able to survive the harsh and tumultuous conditions present in the inner solar system when the meteorites that contain them came together," reflected co-author Conel Alexander. "It means that the parent bodies--the comets and asteroids--of these seemingly different types of extraterrestrial material are more similar in origin than previously believed." http://www.sciencedaily.com/releases...0505192530.htm Both the carbon and nitrogen are inferred to be of interstellar origin. It is notable then that nitrogen in relationship to organic carbon has been proposed as a signature for extraterrestrial life: Extraterrestrial Life. "Fri, 05 May 2006 - When searching for life, most researchers have been hunting the Solar System for signs of liquid water; past and present. But geobiologists from the University of Southern California think that more effort should be spent looking for evidence of nitrogen. Since nitrogen isn't a major component in rocks and minerals but an essential component of life, any concentration of this element would strongly indicate life's fingerprint." http://www.universetoday.com/am/publ...rrestrial.html It is notable as well that organic nitrogen has been found abundant in carbonaceous meteorites: NITROGEN AND CARBON ISOTOPIC MEASUREMENTS OF CARBON NANOGLOBULES FROM THE TAGISH LAKE METEORITE BY SECONDARY ION MASS SPECTROMETRY. J. W. Ashley1,2, G. R. Huss1, L. A. J. Garvie1, Y. Guan1, P. R. Buseck1,3, and L. B. Williams1. 1Department of Geological Sciences, Arizona State University, Box 871404, Tempe, AZ 85287-1404; 2Minor Planet Research, Inc., Box 17131, Fountain Hills, AZ, 85269-7131; 3Department of Chemistry/Biochemistry, Arizona State University, Box 871404, Tempe, AZ 85287-1604. Lunar and Planetary Science XXXVI (2005) http://www.lpi.usra.edu/meetings/lpsc2005/pdf/2205.pdf Bob Clark |
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