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Environment: Killer Asteroids!

UH astronomers are preparing to scour the skies for signs of impending doom.

Remember the 1998 movie, Armageddon, in which Bruce Willis, Ben Affleck and a team of oil drillers travel into space to destroy a deadly, Earth-bound asteroid? Just another hyped-up sci-fi scenario, or could mankind really face such a cataclysmic ending?

photo: Dan Durda

Rolf Kudritzki, the director of the University of Hawai‘i’s Institute for Astronomy (IFA), says asteroid collisions are nothing new. The moon is littered with craters, thanks to multiple asteroid impacts. In the Arizona desert, a massive crater proves that an asteroid hit our planet 50,000 years ago. And Kudritzki points out that dinosaurs were likely extinguished by a catastrophic impact in Yucatan, Mexico, some 65 million years ago.

photo: Brett Simison

In fact, an IFA astronomer has predicted hat, in 2029, an asteroid 400 meters in diameter will just barely miss the Earth. If it were to hit us, though, you’d be saying buh-bye to Honolulu and hello to a global catastrophe.

“Astronomers have come to the conclusion that it would be important to survey our own solar system for these potentially dangerous objects,” says Kudritzki. “To find asteroids, you need to build a telescope which can see a very wide area of the sky, and then you also need a huge camera so that you can take pictures of what you’re seeing.”

Astronomers at IFA are doing just that. By 2010, four such telescopes with four giant cameras—comparable to 10,000 regular digital cameras, with 1.5 billion total pixels—will be placed on Mauna Kea, at the site of an existing UH telescope. Called PS4, Kudritzki notes, “When it goes into full operation, PS4 will take a picture every 30 seconds of one field of view in the sky, which is very large, something like 100 times the diameter of the moon, then it’ll move to the next field, then the next, and in a about a week we’ll have a full picture of the totally available sky from Hawai‘i. This way we’ll be able to find all moving objects in our solar system, determine their orbits and then we’ll be able to tell whether they are going to hit Earth or not.”

photo: Rob Brunswick

To test the technology before the project gets under way, a prototype telescope called PS1 went up last June inside the dome of an old laser ranging facility at Haleakala.

What happens if astronomers do find a killer asteroid? Ed Lu, a NASA astronaut and former IFA solar physicist, has co-developed a proposal for a spacecraft, aptly dubbed the “gravity tractor,” that could slightly change the asteroid’s orbit by creating a gravitational pull with the deadly mass, causing it to miss Earth. “It hasn’t been tested and is only a proposal at this point, but it’s a very serious one that shows a lot of promise,” says Kudritzki. God speed, gravity tractor.

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,June

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