Pardon me, but when did researchers discover that life _used_ to exist on
Mars? If I recall correctly, researchers recently re-studied a Martian
rock, which had been sitting here on Earth for a good while (centuries?
millennia?), and found microscopic structures and mineral deposits which
might have resulted from the presence of bacteria of some kind, at some
time. The conclusion of the researchers was that this finding could
support the existence of bacterial life on Mars at one time. They pointed
out that the study is not conclusive in any way, and a large number of
scientists (most?) are very sceptical about drawing such a conclusion,
because a number of equally satisfactory alternate hypotheses exist. I
believe Scientific American has carried articles on the subject in the past
months, and I would recommend this as a good start for finding more
reliable information on scientific issues.
As for solar wind blowing microbes to Mars, is there any support for this
theory? Do microbes typically get blown off the Earth by solar wind? If
this is a common occurrence, why didn't the Viking lander find any of our
microbes on its visit to Mars?