Is K2-18b Covered in Oceans of Water or Oceans of Lava?

Water may have flowed intermittently in Martian valleys for hundreds of millions of years. Using impact craters as a dating tool, researchers determined maximum timescales for formation of Martian valley networks shaped by running water - which has big implications for early Mars' habitability.

Discovery changes understanding of water's history on the moon. New research shows the early lunar crust, which makes up the surface of the moon, was considerably enriched in water more than 4 billion years ago, counter to previously held understanding.

Half of this Exoplanet is Covered in Lava