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Orson Welles 1939 broadcast of Martians invading New Jersey only served to perpetuate the mythology of the Martians. Unfortunately, the media really does have a powerful effect on people.
The Viking Lander Mission on Mars (1976) sampled the soil and found evidence of a highly chemical reactive soil and environment. There was no unambiguous evidence for biological processes. Worse still was the mass spectrometer measurements which detected no organic molecules down to a concentraction of less than 1 part in 10 million.
So what about the Martian Meteorite?
By analogy with the development of early life on the earth, starting which chemical processes that synthesized organic molecules and rained them into the oceans, we believe that oceans are required for the development of early life:
Was there water on Mars?
The ability for liquid water to exist on the Martian surface depends upon the atmospheric pressure. Current atmospheric pressure is 1/1000 that of the earth - way to thin of atmosphere for water to exist.
However, in the early history of Mars there was enough Carbon Dioxide present to form an atmosphere that was 2 times as thick as the present day atmosphere of the Earth (note the early earth's atmosphere was 50 times its present capacity).
At this pressure, water could exist as a liquid on the Surface. The questoin is, how long did these "oceans" exist. On earth we know it took 800 million -- 1 billion years for the first cells to evolve. It is highly unlikely that oceans on Mars existed for that long - it is mostly likely that they only existed for a few 10's of millions of years before the atmospheric pressure lowers to the point that liquid water can longer be sustained
Where does the atmosphere go?
The most probably explanation of the morphological features seen in the Martian Meteorite is a chemical reaction. Factors that work against the biological interpretation are the following: