A meteor's vapor trail above the city of Chelyabinsk, Russia, on Friday. Vyacheslav Nikulin /EPA /LANDOV hide caption

itoggle caption Vyacheslav Nikulin /EPA /LANDOV

An illustration of what asteroid 2012 DA 14 may look like as it approaches Earth. NASA/JPL-CalTech/EPA /LANDOV hide caption

itoggle caption NASA/JPL-CalTech/EPA /LANDOV

An artist's impression of a gamma-ray burst, a powerful jet of energy lasting from less than a second to several minutes. The most powerful events in the universe, they are thought to be mostly associated with the explosion of stars that collapse into black holes. A. Roquette/ESO hide caption

itoggle caption A. Roquette/ESO