What evidance show if there was water and life on mars

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Alpheus Danson

1 June 2007

Life on Mars

For decades , scientists have pondered upon the possibility of life in other planets . Striking similarities have been discovered between Mars and Earth like the presence of certain chemicals and minerals that support life . Liquid water was once stable on the surface of Mars attesting the presence of an atmosphere capable of decelerating C-rich micrometeorites . Therefore , primitive life may have developed on Mars as well and fossilized microorganisms may still be present in the near subsurface (Brack A Pillinger C

, 313-9 . The environment of Mars 3 .5 to 4 .0 Gyr ago resembled that of the Earth at this time since both contained liquid water (Mckay CP , 41-50 . Though the Viking Mission provided no definitive clues to suggest past or present life , Martian meteorites showed evidences of conducive chemical composition (Brack A Pillinger C , 313-9

Brack A Pillinger C (313-9 ) also say that

Despite the volcanic nature of the samples , some of them have been found to contain carbonate inclusions and a carbon iso composition indicative of an origin from Martian atmospheric carbon dioxide . The oxygen iso composition of these carbonates deposits enables calculation of the temperature regime that existed when a fluid that dissolved the carbon dioxide was formed . Since the composition of the fluid is yet undetermined , only the temperature range

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could be estimated . The range between 0 degree and 90 degrees C is appropriate for life processes

Dasch

Kross J (27-9 ) state that

The recently found meteorite ALH84001 indicates towards the possibility of life on Mars . Presumed to have left Mars 16 million years ago , the meteorite was discovered on an Antarctic ice shelf in 1984 . Carbonate globules that contained microfossils and unusual mineral compounds were found . NASA researchers believed they discovered single-celled fossils resembling nanobacteria fossils found on Earth . However , they also maintained that further research would be needed to lend more credibility

Additionally , Oro J Holzer G (77-86 ) have written that

An analysis of the top layer of the Martian regolith at the two Viking landing sites hadn 't revealed any indigenous organic compounds . However the existence of these compounds , as we go deeper down , cannot be dismissed . Various potential sources for organic matter , like comets and meteorites , are indicated by Cosmochemical considerations . The disappearance of organic matter from the top layer could have been the result of a degradation processes on the surface of Mars by destructive agents like ultraviolet light , oxygen and metal oxides

McKay CP (27-33 ) writes that

Pictures of Mars that were taken from Viking and Mariner 9 missions show evidence of liquid water in Mars ' past , indicating a warmer climate . It has been

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speculated that outflow channels and valley networks were formed 3 .5 to 4 billions years ago . This was the time when life was developing on Earth . Present

theories suggest that chemical reactions in Mars ' early atmosphere had exhausted the original amounts of carbon dioxide and there was no mechanism to recycle it back into the atmosphere . Ecosystems in the cold , dry Antarctic valleys replicate models of Mars on Earth and are an indicator that if life evolved on Mars there may be organic or fossil evidence under the surface

These revolutionary discoveries raise hopes of finding life on other planets . The closest that any planet seems to have arrived at the potential of supporting life has , by far , been Mars . To sustain life planets need to have an atmosphere that is similar to that of earth . For life , liquid water has to be present on the surface . The inner edge of the habitable zone is determined by loss of water via photolysis and hydrogen escape and the outer edge is determined by CO2 clouds that cool a planet 's surface by increasing its albedo and by lowering the convective lapse rate (Kasting JF , Whitmire DP Reynolds RT , 108-28 Research is still on to discover if there are planets that meet these criteria

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Works Cited

Brack A Pillinger C , Life on Mars : chemical arguments and clues from Martian

Meteorites , Extremophiles . 1998 Aug 2 (3 :313-9

Dasch

Kross J , My favorite Martians : NASA uncovers evidence of ancient life on

Mars , Ad Astra . 1996 Sep-Oct 8 (5 :27-9

McKay CP , Past , present , and future life on Mars Gravit Space Biol Bull 1998

May 11 (2 :41-50

Oro J , Holzer G , The effects of ultraviolet light on the degradation of organic

compounds :a possible explanation for the absence of organic matter on Mars . Life Sci Space Res . 1979 17 :77-86

McKay CP Did Mars once have martians ? Astronomy . 1993 Sep 21 :27-33

Kasting JF , Whitmire DP Reynolds RT , Habitable zones around main sequence

stars .Icarus , 1993 Jan , 101 (1 :108-28...