Smooth, round pebbles found by NASA's Mars rover Curiosity provide more evidence that water once flowed on the Red Planet, according to a new study. The Curiosity rover snapped pictures of several ...

There is something peaceful and calming about river pebbles. These smooth, moss-covered stones can provide an appearance of order, fitting together like a natural mosaic, which is probably why they ...

There is now even more evidence that Mars was once covered in oceans, lakes and rivers. A group of small rounded pebbles found in the Gale Crater are shaped in such a way that suggests they once ...

Smooth, round pebbles found by NASA's Mars rover Curiosity provide more evidence that water once flowed on the Red Planet, according to a new study. The Curiosity rover snapped pictures of several ...