Last year, scientists detected a mysterious, powerful burst of radio waves originating from within our galaxy. Now, astronomers think it was caused by a long-dead NASA satellite — but they're not sure ...

Unplanned' picture of Earth captured by NASA's Orbiter 1 from Moon in 1966, became defining moment in space photography. For ...

"That Mars is habitable by beings of some sort or other is as certain as it is uncertain what these beings may be," wrote Percival Lowell in the early 20th century. While other astronomers had their ...