-> -> 3) If Mars was at one time worth life bearing then why only Microbes?
-> -> What halted further development of life? Is one of the bigger craters a
-> -> kin to the crater that wiped out dinosaurs? If yes then where is the
-> -> evidence for the impact besides the crater?

-> What halted further development of life on Mars was it's core cooled,
-> magnetic field disappeared and it's atmosphere was literally
-> blown away by the solar wind in the absence of that magnetic field.



Decrease in core temperature = loss of magnetic field?

Isn't the atmosphere held in place by gravity? And gravity is directly
dependent on the mass of a body. So unless Mars lost a lot of mass, why
would it be unable to make the atmosphere stick? I don't see how your
suggestion could be true unless the atmosphere was rarified enough to
begin with. A low mass atmosphere is more likely to be blown away by
solar wind.

But even if what you say is accurate ... well, it doesn't feel right to
me. Life begins in a weak atmophere, reaches the microbe level and fails
to adapt to an increasingly difficult atmosphere. If it could evolve to
the Microbe level in a relative (to Earth) hostile environment, surely
it should have evolved further. At least our evolution time scale has
been faster than the geological time scale. And Mars is right next to
us, not in some remote art of the galaxy. Conditions could not have been
SO drastically different.

Is there a book on this?

---
Jitender Saan