Small asteroid headed for light show over Africa

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Small asteroid headed for light show over Africa

By SETH BORENSTEIN, AP Science Writer

Mon Oct 6, 6:21 PM ET

A small asteroid was headed for a fiery but harmless dive into

Earth's atmosphere early Tuesday morning over Africa, astronomers

said in a first of its kind advance warning.

Harvard scientists announced late Monday afternoon that the asteroid

2008 TC3 would burn up in the sky, making a fireball potentially

visible to people in northern Africa. Measuring between 3 feet and 15

feet in diameter, the rock was expected to enter Earth's atmosphere

above Sudan at 10:46 p.m. EDT Monday, just before dawn in Africa.

Harvard astronomer Tim Spahr said the asteroid was so small it

wouldn't reach the ground before burning up and wouldn't hurt anyone,

but the fireball should be seen heading from west to east.

" It's the first time we've been able to predict an impactor in

advance and it'll be quite a celestial show for the world, " said

Yeomans, manager of NASA's Near Earth Object program, which

tracks asteroids and comets that come close.

There are 5,681 such objects, but only 757 of them are large enough

to cause any damage if they hit Earth.

This object, spotted by an Arizona telescope late Sunday and

calculated on Monday to be heading toward Earth, isn't one of them.

Astronomers don't know precisely how big it is or what it is made of,

but they know that it is small enough that it will burn up

harmlessly. As it enters the atmosphere becoming a meteor, it

compresses the air in front of it, which then gets hotter, causing a

fireworks display.

Rocks this size hit Earth's atmosphere about two or three times a

year, but without warning, Yeomans said.

Astronomers were only able to give the world about six hours notice

because the rock is so dark and small. It was spotted a little

farther away from Earth than the moon, said Spahr, director of the

International Astronomical Union's Minor Planet Center. Astronomers

hope by scanning the sky they can eventually give Earth warning for

more worrisome rocks that come this way.

" If this were something larger and it was going to hit the ground we

would be able to get people out of the way, " Spahr said. But with

something this size, they can tell people to look up for a sight that

could be " pretty cool from the ground, " he said.

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On the Net

NASA's Near Earth Object Program: http://neo.jpl.nasa.gov/

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