NASA’s Wide-Field Infrared Survey Explorer (WISE) is an infrared telescope in space, designed to survey large areas of the sky at a time, using infra-red light to detect objects that are too dim and faint for normal telescopes to detect.  Part of its mission is finding and mapping the millions of asteroids which orbit our Sun, and identifying those which pass near Earth.  More than three months into its mission, WISE is detecting hundreds of new asteroids every day!  With all this extra information, we are now far more likely to spot potential collisions in time to work out a plan to do something about it.  Bruce Willis presumably has been placed on 24 hour standby, just in case.