happened to collide with the Earth. The best-known episode is that in which the dinosaurs died 65 million years ago, but there have been many other catastrophic impacts both before then, and since.

On August 23, 1966, NASA’s Lunar Orbiter 1 captured the very first photograph of Earth from the vicinity of the Moon, showing our planet as a delicate crescent rising above the lunar horizon. While ...

Continental clues: Modern continental rocks carry chemical signatures from the very start of our planet’s history, challenging current theories about plate tectonics. Researchers have made a new ...

The discovery that helium and iron can mix at the temperatures and pressures found at the center of Earth could settle a long-standing debate over how our planet formed. When you purchase through ...