ABSTRACT
Table 6.1 shows the general organic composition of the Murchison meteorite, which fell in a large size (over 100 kg) in 1969s and has been extensively studied since. The larger portion of meteoritic organic carbon is sometimes described as kerogen-like because, like terrestrial kerogens, it is an insoluble macromolecular material made up of N, O and S besides C and H and has a complex composition that is not known in much molecular detail. The bulk of this material has been inferred mainly from spectroscopic analyses15 and decomposition studies, where it is pyrolyzed by heat or oxidized into its fragments. It is believed to have the hypothetical structure shown in Figure 6.3 and to be composed of clusters of aromatic rings, bridged by aliphatic chains containing S, N, O, with peripheral branching and functional groups. The insoluble carbon is not homogeneous, however and ~ 10% is found as self-contained nanostructures, spheres and nano tubes of diverse elemental composition; also found within it are minute amounts o f“exotic” carbon, so called because it was likely formed in the envelopes of stars (i.e., prior to the formation of Solar System). In addition, it was discovered recendy that the material is not completely
nicotinamide, is the co-enzyme of a large group of oxido-reductases), several monocarboxylic acids (such as formic, acetic and butyric acids that take their names from being found in ants, vinegar and spoiled butter, respectively), sugar-like compounds (components of many ter restrial polysaccharides) and a complex amphiphilic material (having both polar and hydrophobic moieties) that is extracted from meteorite powders by chloroform and forms membrane-like vesicles in water.4
