At a Glance NASA has announced the discovery of water under the icy surface of two moons.Both moons have underwater vents, which suggests a heat source capable of sustaining life.Life has not been discovered on either moon; additional missions will be needed to find living organisms. Plumes spewing from Saturn moon Enceladus and Jupiter moon Europa are proof of vast oceans of liquid water underneath their icy surfaces, NASA announced at a Thursday news conference. Hydrogen, a key building block...

The image above is an artist's rendition of an asteroid approaching Earth. (Getty Images) On Wednesday, an asteroid almost a mile wide will sail past Earth, coming closer than it ever has within the last 400 years. According to NASA, the , or roughly 683,508 miles, of Earth. It will be one of the strongest asteroid radar targets of this year. The flyby will be the closest of an asteroid of this size since a September 2004 encounter with an...

A security camera captures a fireball streaking across the sky in Cornelius, North Carolina. ...