It’s as close as we can get to Mars without leaving the planet—and it’s up for sale. If you didn’t make the list for Blue ...

People have long wondered what life was first like on Earth, and if there is life in our solar system beyond our planet.

Gigantic hidden fortresses discovered 1,800 miles underground in Earth's mantle, rewrite how the planet's interior works.

The origins of plate tectonics on Earth are hotly debated, but evidence from Australia now shows that parts of the crust moved in relation to each other as early as 3.5 billion years ago ...