Worried about Earth-threatening asteroids? One of NASA's newest space telescopes has spotted 25,000 never-before-seen asteroids in just six months. Ninety-five of those are considered “near Earth,” but in the language of astronomy that means within 30 million miles (48 million kilometers). Luckily for us, none poses any threat to Earth anytime soon. Called WISE for Wide-field Infrared Survey Explorer, the telescope completes its first full scan of the sky Saturday and then begins another round of imaging. What's special about WISE is its ability to see through impenetrable veils of dust, picking up the heat glow of objects that are invisible to regular telescopes. By the end of the year, researchers expect to have a cosmic census of millions of newfound objects that should help answer questions about how planets, stars and galaxies form. Besides all those asteroids, WISE has also sighted 15 new comets. It has spied hundreds of potential brown dwarfs - stellar objects that are bigger than a planet but much smaller than a star - and confirmed the existence of 20 of them, including some of the coldest ever known.
