Results 101 to 110 of about 965 (142)

Carbonaceous chondrites as bioengineered comets

SPIE Proceedings, 2012
The discovery of microfossils on carbonaceous meteorites has electrified the public with the first concrete evidence of extraterrestrial biology. But how these organisms colonized and grew on the parent body–the comet–remains a mystery. We report on several features of cyanobacteria that permit them to bioengineer comets, as well as a tantalizing ...
Robert B. Sheldon, Richard Hoover
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Carbonaceous chondrites—I. Characterization and significance of carbonaceous chondrite (CM) xenoliths in the Jodzie howardite

Geochimica et Cosmochimica Acta, 1979
Mineralogical, chemical, textural, and isotopic studies of the abundant carbonaceous inclusions in the Jodzie howardite which are consistent with carbonaceous chondrite (CM) characteristics are examined. These CM xenoliths show regolith alteration comparable to the Murray and Murchison meteorites but less than Nogoya, flow-oriented development of ...
T.E. Bunch, S. Chang, U. Frick, J. Neil, G. Moreland   +4 more
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Origin of organic compounds in carbonaceous chondrites

Advances in Space Research, 1989
Carbonaceous chondrites, a class of primitive meteorite, have long been known to contain their complement of carbon largely in the form of organic, i.e., hydrocarbon-related, matter. Both discrete organic compounds and an insoluble, macromolecular material are present.
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Fluorescent organic matter in carbonaceous chondrites

Advances in Space Research, 1999
Fluorescent organic matter in carbonaceous chondrites was investigated using a microscope equipped with a fluorescence spectrophotometer. Fluorescent particles were observed in powdered CM2 carbonaceous chondrites (Y-74662, Y-7791198, and Murchison) without carbon enrichment by acid treatments. Although it was difficult to find fluorescent particles in
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THE CARBONACEOUS CHONDRITES—A SELECTIVE REVIEW

Meteoritics, 1971
The presently known carbonaceous chondrites are listed, and their densities and contents of Fe, Si, and Mg recorded. A review of classification schemes indicate that Wiik's (1956) division into Types I, II, and III reflects basic differences in chemical and mineralogical composition and structure, and is preferable to the Van Schmus‐Wood (1967 ...
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Organic constituents of the carbonaceous chondrites

Space Science Reviews, 1963
Organic constituents, such as hydroxylated aromatic acids and hydrocarbons, in carbonaceous chondrites, and their possible extraterrestrial ...
MichaelH. Briggs, Gregg Mamikunian
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On the Q-phase of carbonaceous chondrites

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1999
One of the unresolved puzzles of meteoritics is the nature of the carrier of the so-called heavy planetary gases. Apparently, these gases reside mainly in a minor fraction, which has been dubbed Q by Lewis et al. in analogy of the naming by Papanastasiou et al. of a minor glassy phase in lunar rocks highly enriched in trace elements such as Pb and U. Q
Vis, R.D., Heymann, D.
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Organic constituents of carbonaceous chondrites.

Life sciences and space research, 2002
From a brief discussion of forms of meteorite carbon it is concluded that almost all the carbon in the carbonaceous chondrites is present as organic matter. Attempts to extract and identify this organic matter are then reviewed. It is shown that only 25 per cent has been extracted and only about 5 per cent chemically characterized.
M H, Briggs, G, Mamikunian
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Carbonaceous Chondrite

2011
Tilman Spohn, Frank Sohl
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The Loongana (CL) group of carbonaceous chondrites

Geochimica Et Cosmochimica Acta, 2021
Knut Metzler, Dominik C Hezel, Jens Barosch   +2 more
exaly