Mars’ Gale Crater once held a lake of liquid water. (Credit: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS)

Mars was a very different place as a young planet. Liquid water dotted the Red Planet’s landscape with lakes and rivers. But the planet’s climate changed drastically in the past few billion years. Today, scientists see the remains of the planet’s bodies of water in dried-up river channels and salts left in its rocks.

Now, new data from the Curiosity rover show that the planet’s waters wer