Friday, October 9, 2009

Close encounters of the asteroid kind; this could be exciting

Our state and our planet can expect some astronomical excitement in coming years, with close asteroid encounters in the next three decades, and a (vaguely) possible impact within 50 years.

The asteroid is called Apophis. It swings near the Earth in 2029, 2036 and again in 2068.

(Image: The little circle marks Apophis in this University of Hawai'i Institute for Astronomy photo.)

The best and latest calculations have it missing the surface of the planet by just 20,000 miles in 2036.

"Our new orbit solution shows that Apophis will miss Earth's surface in 2036 by a scant 20,270 miles, give or take 125 miles. That's slightly closer to Earth than most of our communications and weather satellites," said David Tholen, of the University of Hawai'i Institute for Astronomy.

The calculation still isn't perfect, and scientists figure the odds at four in a million that it could hit the Earth.

The estimates are calculated from observations at Mauna Kea observatories by Tholen, former Hawaii astronomer Fabrizio Bernardi of the University of Pisa, Italy, and University of Hawai'i graduate students Marco Micheli and Garrett Elliott. From those observations, Steve Chesley, of the Jet Propulsion Laboratory in California, calculated the positions of Apophis.

But after that really near miss, the new calculations suggest Apophis has a three in a million chance that it could crash into the Earth in 2068. Researchers will be making more detailed calculations about that possibility in 2010 when Apophis—which disappears behind the Sun during part of its orbit—swings back into view.

Tholen, Bernardi and University of Arizona astronomer Roy Tucker discovered Apophis only in 2004.

The initial orbit calculations suggested it had a small chance of impact with the Earth as early as a Friday the 13th in April 2029, but further calculations showed that would not happen.

Apophis is a couple of hundred yards across. If it did hit, that would be a big issue. But the odds are against it.

"The refined orbital determination further reinforces that Apophis is an asteroid we can look to as an opportunity for exciting science and not something that should be feared," said Don Yeomans, manager of the Near-Earth Object Program Office at JPL. "The public can follow along as we continue to study Apophis and other near-Earth objects by visiting us on our AsteroidWatch Web site and by following us on the @AsteroidWatch Twitter feed."

The information in this post was drawn from the following two press releases.

Here's the Jet Propulsion Laboratory's release on the event.

And here's the university of Hawai'i Institute for Astronomy release.

Other resources:

© Jan TenBruggencate 2009

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