Ridges on Mars suggest ancient flowing water

Fossilized hydrology

A 3-D image of an impact crater in the Nilosyrtis area on the Martian surface shows long pipe-like ridges, fossilized evidence of ancient subsurface water flow. Credit: NASA Mars Reconnaissance Orbiter

Ridges in impact craters on Mars appear to be fossils of cracks in the Martian surface, formed by minerals deposited by flowing water. Water flowing beneath the surface suggests life may once have been possible on Mars.