Life And Mars

There is an inherent tenson between searching for life on Mars and protecting the Martian atmosphere from contanimation by Earthly microbes that hitched a ride to the Red Planet.  If we go to those places on Mars most likely to harbor life, the risk of contanimation is higher precisely because Earthly life could survive in those areas.  If we stay away from such spots, however, the chances of finding Martian life likely decrease.

So, it's a balancing act.  The strategy used so far has been to send sterilized machines to the planet.  Sterilized, but possibly not completely without tiny, live passengers.  When human explorers reach Mars, bringing along all the bacteria that live within our bodies, our strategy for keeping them away from a possible Martian ecosphere will need to be much more sophisticated.