Crucial chemical for life can form in conditions found on early Earth

Last images of ESR-2 satellite look like TIE starfighter from Star Wars. ESR-2 returned to Earth in an uncontrolled reentry this week after nearly three decades (corrected link)

'Intruder' stars have changed Earth's climate over the eons. Here's how.

An asteroid the size of a bus will fly near Earth on Feb. 22 — but don't worry (video)