Salt and Life on Mars

Too much salt isn't good for a person, nor, according to scientists, is it good for the evolution of life.

Studies of four billion year old rocks on Mars using data from orbiting probes as well as direct measurements using instruments on the rover, Opportunity, suggest that the water that once flowed on Mars was extremely salty. Though there are life forms on Earth that thrive in brine, scientists think they evolved from forms that originated in less salty water. Salt complicates the chemistry of life, thus making it less likely life would arise in extremely saline environments.

Less likely, however, is not impossible, as the scientists involved with the study acknowledge. Fresher water may also have flowed some places on Mars at some point, they say. That would've given life an opportunity to establish itself, and perhaps adapt to too much salt.