The seldom considered ramifications of a sterile Mars are explored.
Very much is now known about the environment on Mars. Herein, the individual and
collective environmental parameters are examined with particular consideration of those that
might be inimical to life as we know it, or as might reasonably be assumed to be so to alien life.
It is shown that no single measurement or combination of them precludes the ability of Mars to
support even a wide number of terrestrial microbial species, let alone the likely greater
tolerance and/or adaptability of possible alien life forms. Some yet unknown factor or
combination of factors would have to be responsible for Mars' failure to generate life or to
successfully harbor viable forms received from space. Since Mars is so Earth-like, the red
planet's sterility could deliver a fatal blow to the growing concept of a cosmic Biologic
Imperative, and would raise the daunting prospect that Earth is a unique or a very rare habitat.