Because a teacher was going to space, millions of schoolchildren watched the Challenger lift off on Jan. 28, 1986. It exploded 73 seconds later.

Swift observations with the European Southern Observatory's Very Large Telescope (ESO's VLT) have revealed the explosive death of a star just as the blast was breaking through the star's surface. For ...

A nuclear winter is a theoretical concept, but if the climate scenario expected to follow a large-scale nuclear war, in which smoke and soot from firestorms block sunlight, came to fruition, global ...