A NASA rover exploring the foothills of a Martian mountain has found rippled rocks, offering scientists the clearest evidence yet of ancient water waves on the Red Planet.
Curiosity, a car-size robot that has been rumbling over Mars for a decade, took photos of the peculiar geology in mid-December(Opens in a new tab). The rocks are like the undulating patterns one might find when the tide reels the ocean back from a beach, revealing wobbly tracks on the temporarily exposed sand.
Mission scientists say waves of water lapping on the surface of a shallow lake created these grooves, perhaps billions of years ago. The movement on top churned up sediment from the bottom, they suspect, forming the combed texture.
