astrobiology

Earth, Mars and Venus all looked pretty similar when they first formed. Today, Mars is dry, cold, and dusty; Venus has a hot, crushing atmosphere. Why did these sibling planets turn out so different?

Scientists are thrilled with the tiny asphalt-black rocks, and most of the sample hasn't even been revealed yet.

Astronomers have found about 2,000 planets beyond our solar system. Now, some scientists are expanding the search to look for distant moons, too, in the hunt for signs of life.