Billions of years ago, pockets of water became trapped deep underground on Earth. Having just found some of these water pockets, scientists have discovered that they contain not only water, but are also abundant in life-sustaining chemicals.
What's more, the rocks that have been holding this primordial water hostage for billions of years are reminiscent of the sort of rocks that scientists have observed somewhere else in the solar system. Mars. This has the scientific community looking to our little red neighbor with renewed hope: if Earth can be home to such ancient, watery time capsules then maybe — just maybe — Mars is too.
The theory is that these isolated, subterranean pools could be home to life similar to that which resides near to hydrothermal vents upon the deep-ocean seafloor. Gasses, such as hydrogen, helium, neon, and xenon could provide the energy microbes would need to survive. Even if they've been removed from sunlight for billions of years. So if Martians exist today, maybe they're tiny little beings, living in pockets of water trapped far beneath the barren surface of their world.