Martian Life Increasingly Likely

Searching for E.T.: Possibility of Life on Mars

"Kral and his colleagues recently published a paper detailing their work with a class of organisms known as methanogens -- methane-producing organisms that some scientists believe may hold the key to whether or not Mars conditions can support life. For the past several years, Kral and his colleagues have been testing the organisms' ability to survive under Mars-like conditions."

Martian exobiology has followed a compelling trajectory. First, it was thought merely possible that Mars had life -- in the remote geological past. Then it was thought probable that Mars once harbored life.

Later, scientists realized it was entirely possible that Mars was home to extant lifeforms instead of mere fossils. More recently, with the discovery of methane in the Martian atmosphere, it seems the case for contemporary Mars life has shifted into the "probable" phase.