I doubt that there is any life on Mars, even microbes. Mars has a very thin atmosphere. I don't think that this can support life at any form. NASA's Phoenix lander will arrive Mars this coming May. If the robotic digger doesn't malfunction and lands safely then it will be able to do many fascinating things. It could analyze the soil and the bacteria. If it discovers any microbial life then it would become a huge headline. It will eventually change my opinion at one point. However, I know that it has failed to advance beyond its own level.
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Claim of Martian Life Called 'Bogus'