The image shows a simulation of a collision between two shells of matter ejected by a massive star in two subsequent pulsational pair-instability supernova eruptions, only years apart, just before the star dies. Image released Feb. 7, 2013. (Ke-Jung Chen/School of Physics and Astronomy, Univ. Minnesota) Forecasting when stars will die in giant explosions may one day be possible by looking for the warning outbursts they release beforehand, researchers say. Supernovas are the most powerful stellar explosions in the universe,...

This image provided by NASA/JPL-Caltech shows a simulation of asteroid 2012 DA14 approaching from the south as it passes through the Earth-moon system on Friday, Feb. 15, 2013. (AP Photo/NASA/JPL-Caltech) CAPE CANAVERAL, Fla. -- The world is safe - at least from one asteroid. A 150-foot cosmic rock hurtled safely past Earth on Friday. Note: Tune into The Channel Channel tonight at 9pm for an encore of Deadliest Space Weather - Meteors. (MORE: Hundreds Hurt after Meteor Hits Earth) It...

This image provided by NASA/JPL-Caltech shows a simulation of asteroid 2012 DA14 approaching from the south as it passes through the Earth-moon system on Feb. 15, 2013. The 150-foot object will pass within 17,000 miles of the Earth. (AP Photo/NASA/JPL-Caltech) Although the 150-foot (45 meter) rock will zoom harmlessly by our planet on its record near approach this week, it is just one of up to a million "near-Earth objects" which astronomers believe could one day pose a serious threat....