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Science Frontiers ONLINE No. 65: Sep-Oct 1989 |
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Fossil from mars?
Who would have thought that the dreary Antarctic wastes would harbor a piece of Mars, much less a fossil of Martian life? Yet, British scientists, I.P. Wright et al, in Nature, come close to such a conclusion.
"The meteorite EETA 79001, which many believe to have originated on Mars, contains carbonate minerals thought to be Martian weathering or alteration products. Accompanying the carbonates are unexpectedly high concentrations of organic materials (defined here as carbonaceous matter that has a low stability towards oxidation, and so combusts at less than 600�C; the term 'organic' does not necessarily imply an origin by biogenic processes.) Although the carbon isotope composition of these materials is indistinguishable from terrestrial biogenic components, and so cannot be used to assess the source, we argue here that their occurrence in an interior sample of a clean Antarctic meteority militates against a wholly terrestrial origin. A sample of Martian organic materials may thus be available for further study in the laboratory."
(Wright, I.P., et al; "Organic Materials in a Martian Meteorite," Nature, 340: 220, 1989.)
But there are many "buts":
- Meteorite EETA 79001 may not have come from Mars after all, even though many scientists think it did.
- The organic material in EETA 79001 may have come instead from the comet that supposedly blasted the meteorite into space from the Martian surface, although the carbon-isotope ratios do not favor a cometary origin.
- The organic material may only be terrestrial contamination, despite the careful handling of the meteorite.
Nevertheless, EETA 79001 has revived speculation about life on Mars. Could not the calcium carbonate, for example, have come from the shell of some Martian water creature? I.P. Wright does not avoid this possibility.
"There is a remote chance that we're looking at some (extraterrestrial) fossil life form."
(Amato, I.; "Meteorite May Carry Organic Martian Cargo," Science News, 136:53, 1989.)