ABSTRACT
Mars has been at the center of exobiological explorations. is is partly because of easy accessibility and partly because conditions on early Mars were wetter and possibly conducive to the origins of life. Today, however, Mars is an extreme cold desert. If life originated there, some organisms may have adapted to the drastically changing planet and survived, perhaps even to the present. It is in this context that scientists have been exploring the Antarctic Dry Valleys, one of the coldest and driest places on Earth, for the last 60 years and more recently the Atacama, one of the driest. Much is known about the organisms that survive there. Sucient information indicates that in Antarctica, the cold limit is approached but may not be crossed. In the Atacama, the dry limit is reached in the hyperarid core.
