Unusual rocks on an Icelandic beach were dropped there by icebergs, adding to evidence that an unusually cool period preceded ...

The Perseverance rover has found some intriguing samples on the red planet. Here's what they might reveal about the origins ...

Some of the unusual rocks carry stories about water on Mars. One has hints of long-gone microbes. All tell of a dynamic, complex planet.

A strange rock covered in tiny spheres may hold secrets to Mars’ watery — or fiery — past.

But Curiosity wasn't the only one with a geological mystery. At the same time, roughly 2,300 miles away on the other side of ...