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Life on Martian Meteorites

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ABSTRACT

In this paper, the great dispute of whether or not there is real evidence of life on martian meteorites is discussed. Findings of carbon globules, nanocrystal magnetites, and rod-shaped objects on ALH84001, Nakhla and Yamata 593 suggest biogenic processes once occurred on Mars. Furthermore, past atmospheric conditions and a current abundance of methane gas build more justification to martian life. Many of these discoveries are accused of being accounted for by either terrestrial contamination or abiotic processes, but composition analysis and model experiments show that contamination cannot be held fully responsible. It is concluded that martian meteorites do provide insight and valid evidence for extraterrestrial life.

INTRODUCTION

The question of life beyond Earth has been debated upon since over 2000 years ago, when Greek scholars first discovered that our planet was not alone the universe. Out of the eight current planets in our solar system, Mars is said to be the most similar to Earth, suggesting that it is the most probable planet to have encompassed life, if any. Although today it is cold and arid, the red planet was once warmer and wetter with a thicker atmosphere and could very well have allowed life to form.

Martian meteorites that have landed on Earth contain evidence that justifies the presence of life in space. First, we are certain these meteorites are in fact from Mars from measuring and matching their noble gas ratios to that of Mars (McKay et al. 1996). Findings within the Allan Hills (ALH84001) meteorite by a team of NASA researchers ignited immense interest in the subject of martian life in 1996. The team discovered polycyclic aromatic hydrocarbons (PAHs) as well as globules of carbonate a...

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...rites to the atmosphere of Mars. Earth Planet Sci. Lett. 288, 382-385.

Friedmann, E. I., Wierzchos, J., Ascaso, C., & Winklhofer, M. (2001) Chains of magnetite crystals in the meteorite ALH84001. Proceedings of the National Academy of Sciences 98, 2167-2181.

Gillet, Ph. et al. (2000) Bacteria in the Tatahouine meteorite: nanometric-scale life in rocks. Earth Planet Sci. Lett. 155, 161-167.

Mckay, D. S. et al. (1996) Search for past life on Mars: possible relic biogenic activity in martian meteorite ALH 84001. Science 273, 924-930.

Scott, E.R.D. (1999) Origin of carbonate-magnetite-sulfide assemblages in Martian meteorite ALH84001. Jour. Geophys. Res. 104, 3803-3813.

Thomas-Keprta, K.L., Clemett, S.J., McKay, D.S., Gibson, E.K. & Wentworth S.J. (2009) Origins of magnetite nanocrystals in martian meteorite ALH84001. Geochimica et Cosmochimica Acta. 73, 6631-6677.
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