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Meteorite_Conflict

2013-11-13 来源: 类别: 更多范文

Meteorite Conflict There is still uncertainty pertaining to the matter of fossilized bacteria, from other planets, being discovered in Earths atmosphere. Most of the uncertainty lies in the discovery of the meteorites found in the town of Murchison, Australia, in 1969. Scientists believe they discovered eighteen different amino acids in the fragment. Six of which are commonly found in proteins, whereas twelve others were unknown to terrestrial life, as in it can’t be found in Earths atmosphere. Although, there are also scientists that believe the meteorite was contaminated by terrestrial forms of bacteria upon it entering our atmosphere. They claim that the electron microscope and morphology techniques are inconclusive as to whether or not the fragment contains extraterrestrial life. Scientists that believe the fragment to contain extraterrestrial life, do so with sound reason. On July 29,1997, Richard B. Hoover of NASA’s Marshal Space Flight Center announced he had made a pivotal finding. He observed and photographed the Murchison meteorite microfossils that resemble microorganisms. The chemical evidence around the fossils is most readily explained as the result of biological activity. He observed the potential fossils in freshly broken pieces, so the chance they spawned due to terrestrial contaminants is unlikely. The most interesting and notable form of the microfossils curls to a tapered end. The observed, would curl, or retract, further into the fragment under the heat of the electron microscope. It would ten relax to its previous state after being removed from the heat. In addition, there is also the finding of amino acids in the meteorite fragments. Eighteen different amino acids were found in the fragment, six of which are commonly found in our atmosphere, and twelve that do not occur in terrestrial life. Meaning that it cannot be found in Earths atmosphere. All of these amino acids appeared in both dextrorotatory and laevorotatory form, suggesting they were not the result of Earthly contamination. The meteorite also contained hydrocarbons, which appeared abiogenic in character and was enriched with a heavy carbon isotope, confirming its extraterrestrial organic origin. Although, there are scientist that believe that the appearance of fossilized life is due to contamination by Earthly atmospheric conditions. Dr. Matthew Genge, a meteorite researcher from the Natural History Museum in London believes that the Murchison meteorites are even more likely to have experienced contamination since they allegedly fell in a farmyard, and that some of the fragments were recovered in a ditch of manure. He said that any meteorite recovered outside of Antarctica has ample opportunity to be contaminated. He also stated that terrestrial bacteria and fungi infest meteorites almost instantaneously upon landing on Earths surface. That the fungus worms its way into the meteorites along cracks and pores, and burrow into the carbonaceous material as they eat is. Dr. Andrew Steele from the University of Portsmouth added that the meteorites become contaminated within days of entering Earths atmosphere, and yet some of the Murchison meteorites were allegedly left in the open for four to five months before being collected for research. In conclusion, in the matter concerning whether or not the Murchison meteorites legitimately contain fossilized versions of extraterrestrial life is still uncertain. Both sides of the argument present compelling arguments, and only the future, with the refinement of our knowledge and technology, will help us to understand what exists in the universe outside of Earths orbit.
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