... In a nova, a nuclear detonation on the surface of a compact white dwarf star blasts away material that has been dumped on its surface by a companion star. ... Photographed from the approaching Space Shuttle Endeavour, the Mir space station floats above the clouds of planet Earth. ... This sequence of false color X-ray images captures a rare event - the passage or transit of planet Mercury in front of the Sun. ... NGC 1808: A Nearby Starburst Galaxy . ... NGC 1808 is a galaxy in turmoil. ...