Ninety-five of those are considered "near Earth," but in the language of astronomy that means within 30 million miles. 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 on 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.
"Most telescopes focus on the hottest and brightest objects in the universe," said Richard Binzel of the Massachusetts Institute of Technology. "WISE is especially sensitive to seeing what's cool and dark, what you could call the stealth objects of the universe."
Mission team members are elated with the discoveries of the $320 million project, which launched in December. 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.
The telescope also detected what's thought to be an ultraluminous galaxy, more than 10 billion light years away and formed from other colliding galaxies.
WISE's 16-inch telescope was built by Utah State University's Space Dynamics Laboratory. It circles the Earth 300 miles high and takes snapshots every 11 seconds over the whole sky.