ALH84001

the Mars meteorite ALH84001 (photo: NASA)
Electron microscope admission of ALH84001. Relikt of a Mars bacterium? (Photo: NASA)

ALH84001 is a 1.94 kg heavy meteorite, which was already found 1984 in the Allan Hills Eisfeld in the Antarctic, but only 1993 as SNC meteorite (Mars meteorite) were identified. Itmainly therefore a new sub-group of the SNC meteorites of coarse-grained kataklastischen Orthopyroxenit and defines, which is called SNC Orthopyroxenit, consists. Compared with other Mars meteorites, which have usually a relatively recent geological age, ALH84001 already originated in zirka 4 billion years ago. In accordance with measurement of the irradiation age becameALH84001, probably by the Impakt of a Asteroiden on Mars, approximately 15 million years ago away from the Mars surface and landed before approximately 13,000 years on earth.

In the year 1996 found David S. McKay and its coworkers structures in Mars meteorites the ALH84001,they as traces of fossil bacteria interpreted (Lit.: McKay et. aluminium, 1996). Their arguments for traces of fossil life in ALH84001 are:

  • Structures in electron microscope photographs, which are interpreted as fossilierte bacteria. It is however objected that these structures also artifacts of the used recording technology itscould. Besides the size of the structures is only within the range of some nanometer and thus many smaller than usual terrestrial bacteria. „Nano-bacteria “allegedly also on earth discovered, so far is this findings however still disputed.
  • Carbonate inclusions, which magnetite in oneForm contain, as it is produced on earth by bacteria. It is so far however not to be excluded that this not also by not-biological processes can be produced for magnetite.
  • Polyzykli aromatic hydrocarbons (PAH, of English. P olycyclic A romatic H ydrocarbons) within the carbonates, which withDecay of bacteria to develop know. It is difficult also here to point that there are no not-biological processes, which the same sample by PAH's as it to ALH84001 was found produced.

The theses of McKay and its co-authors are discussed until today controversially. Becamein the meantime also in two other Mars meteorites, Shergotty and Nakhla, possible Relikte of earlier life found. Among other things on these structures the theory of the Panspermie constructs , after which the life on earth resulted from germs from the universe.

See also: List ofMeteorites

literature

  • D. S. McKay, E. K. Gibson, K. L. Thomas Keprta, H. Vali, C. S. Romanek, S. J. Clemett, X. D. F. Chillier, C. R. Maechling, R. N. Zare: Search for past would run on Mars: Possible relic biogenic activity in Martian meteoriteALH 84001, in Science, volume. 273 (1996), S. 924-930.

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