Science has a funny way of humbling certainty. Most of us carry a mental picture of how Earth works that was assembled in school, reinforced by documentaries, and rarely questioned afterward. The ...

Billions of years ago, Earth was an uninhabitable rock covered in magma. Scientists are still working to decipher the tale of how it transformed into a blue and green orb teeming with life. However, ...

An illustration shows how, about 65 million years ago, a large asteroid collided with Earth. It hit what is today Mexico and created the Chicxulub crater. Mark Garlick/Science Photo Library/Getty ...