NASA scientist expands list of habitability possibilities for exoplanets

WASHINGTON, June 10 (UPI) -- Increasingly, scientists are discovering that life is capable of enduring even more extreme conditions that previously thought.

Accordingly, NASA is looking to relax some limits placed on planets being considered as hospitable to life.

In a new paper published in the Proceedings of the National Academy of Sciences, NASA scientist Chris McKay has established a new checklist of habitability possibilities based on recent discoveries of life's durability and adaptability.

In the paper, McKay outlines a number of ways life could get by on planets, moons or even other celestial bodies previously thought to be inhospitable.

McKay points out that some microorganisms have been found to live in environs featuring temperatures well below freezing or well above the boiling point of water. Ruling exoplanets out simply based on temperature would be misguided.

Furthermore, as McKay's paper highlights, even trace amounts of water can support life; and an atmosphere that's just one-tenth oxygen is enough to sustain living things.

McKay's study offers new thoughts on the proper probable limits for life on another planet, including updates to the limitations of temperature, atmospheric pressure, availability of water, amount of oxygen, possibility of photosynthesis, levels of radiation, and more.