Astronomy
Biochemical Constraints on Life in Deep Subsurface Martian Aquifers
Quick fact
In the deep subsurface of Mars, the biochemical challenge may be not freezing but the combination of high salt, strong water-binding perchlorate ions, and a trickle of energy from rock radioactivity—so slow that a single bacterial cell might only divide once every thousand years.
Why this is interesting
Imagine an ocean hidden miles beneath the red desert, sealed off from the sun for billions of years—could anything be alive down there? The answer depends on hurdles deeper than darkness.