An artist illustration of NASA's InSight lander on Mars.NASA/JPL-CaltechMars just scored another point in favor of alien life.Scientists discovered signs of an ocean's worth of liquid water miles below Mars' surface.The findings, based on Marsquake measurements by NASA's InSight lander, could help solve a mystery.Mars is looking more and more like a place for NASA to find the first signs of alien life.Scientists discovered evidence of a reservoir of liquid water seven to 13 miles below the Martian surface, lingering in the pores of the planet's crust.They believe there's enough to cover the entire planet with an ocean about one mile deep.The water, if it exists, is too deep to access in the foreseeable future.