Scientists have discovered that a supervolcano likely created a mysterious rock formation on Mars some 3 billion years ago.
New observations have helped astronomers identify the source of a 2,000-year-old supernova explosion. But this blast, and the neutron star that created it, seem to have a curious history that defies explanation.
The RXTE satellite, which reentered Earth's atmosphere over the tropics on April 30th, leaves behind a legacy of discoveries and data.
Curiosity spotted polygonal shapes on the surface of rocks on Mars — now, analysis of these mud cracks is revealing the history of the long-ago lake that once filled Gale Crater.
Astronomers have discovered a newborn neutron star in a rare pairing with an old red giant companion.
The infrared Spitzer Space Telescope peers into hidden star-forming regions to see the illuminated insides of dark cocoons.
It's taken some 10 billion years, but a compact group of small galaxies is at last merging into a single big one.