Every night of the year, telescopes around the world watch for deadly invaders. Not the kind that come in spaceships and fire deathrays, though. Instead, they're looking for asteroids that could someday slam into our planet, devastating life on a regional or even global scale.
The newest and most powerful of these telescopes joined the hunt last year. Called Pan STARRS, it features one of the world's largest digital cameras: each image is 1.4 gigapixels. And it'll snap hundreds of pictures every night.
The targets for its quest are Near-Earth Objects -- asteroids and comets that come close to Earth's orbit around the Sun. Impacts by large asteroids or comets may be responsible for the demise of much of the life on Earth several times in the remote past -- including the extinction of the dinosaurs.
Astronomers have discovered almost 8,000 Near-Earth Objects, none of which are on a collision course with Earth. But thousands more await discovery.
Over the next few years, as many as four Pan STARRS telescopes will scan the sky from their home in Hawaii. They'll snap hundreds of pictures each night, allowing them to scan the entire sky every few nights. Their images should reveal every Near-Earth asteroid that's a kilometer in diameter or bigger, and many of the ones that are as little as a third of a kilometer across. Early detection should give us time to prepare a defense against these celestial invaders.
Script by Damond Benningfield, Copyright 2011
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