National Public Radio notes:
WISE should find many previously unseen asteroids, including ones that might be threatening to smack into Earth. Amy Mainzer, deputy project scientist for WISE, says a visible light telescope tends to see sunlight bouncing off of bright, shiny asteroids, but WISE will be able to detect dark asteroids that would go unnoticed — even if they're large. She says a dark asteroid may stand out more when WISE takes a look, "because what you're seeing is the heat that's being radiated from the asteroid."That's good news for everyone worrying that the Mayans might have been correct and that civilization will end in 2012. We can cross off "asteroid impact" from the list of possible causes of that mythical catastrophe. That still leaves worldwide pandemics, economic meltdowns, nuclear holocaust, and presidential elections.
(Photo courtesy NASA/JPL-Caltech/Space Dynamics Lab)
WISE, by the way, is a pretty cool contraption. As you can see in the photo above from NASA, it's encased in a hydrogen ice-cooled container so it doesn't mistakenly read its own heat signature.
Once launched, WISE will circle earth's poles, "scanning the entire sky one-and-a-half times in nine months. The mission will uncover hidden cosmic objects, including the coolest stars, dark asteroids and the most luminous galaxies," according to NASA.