The asteroid belt, a ring of rubble between Mars and Jupiter, has sometimes been written off as discarded leftovers from the solar system's start. But new research published in the journal Nature shows that the belt actually formed during an unruly later era, when planets themselves were on the move.
An aurora as seen over the Poker Flat Research Range north of Fairbanks, Alaska.
Skies across Colorado will offer a rare opportunity for seeing the Northern Lights — typically seen in places like Canada and Alaska. The impetus for this natural phenomenon comes from a powerful geomagnetic storm caused by an eruption from the sun.
For the scientists who have emotionally traveled with NASA's Voyager mission for decades, 2013 will be remembered as the year they knew Voyager 1 had finally become the first explorer from Earth to enter the mysterious realm of interstellar space.
Voyager 1 and its twin, Voyager 2, both blasted off in 1977, more than 35 years ago. Voyager 1 flew by Jupiter, then Saturn — and then on toward the unknown region that lies between stars.