Threats from the asteroid belt

10:46, 23 February 2009
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Earth in the past has...

Keeping an eye out for asteroids ought to be of interest to all earthlings, given the known hazards inherent in collisions with space objects, according to Charleston Post Courier, Congress shouldn`t allow a relatively low-cost mission to identify hazards languish for lack of funds.

Earth in the past has collided with asteroids and other cosmic debris to devastating effect. Some scientists think one such collision about 65 million years ago contributed to the extinction of the dinosaurs.

In 1908, a meteoroid about 100 yards across struck Siberia, and flattened trees for hundreds of square miles around. Had it struck a populated area, the necessity for tracking Near Earth Objects (NEOs) would be more readily apparent.

Four years ago astronomers discovered an asteroid on a potentially devastating future collision course with Earth. That kicked off an effort by NASA to identify all NEOs that might hit Earth, and to come up with proposals for avoiding or coping with collisions.

A recent report by the Association of Space Explorers` International Panel on Asteroid Threat Mitigation, chaired by former Apollo astronaut Rusty Schweikart, warns that "dozens" of space objects pose a threat to earth.

The panel`s findings, briefed last month to representatives of the United Nations, note that our planet is bombarded daily from space, and every century or so is struck by objects large enough to cause serious damage. But the authors add, "For the first time in our planet`s 4.5-billion-year history, the technical capacities exist to prevent such cosmic collisions with Earth."

If Asteroid Apophis 99942 hits Earth, the estimated impact would be equivalent to a nuclear explosion more than 33,000 times as destructive as the atomic bomb that flattened Hiroshima. Astronomers estimate it will pass close to Earth in 2029 and return on an even closer course in 2036, though with a remote 1 in 45,000 chance of hitting.

The panel urges the U.N. to begin thinking now about how to deal with Apophis and similar threats. A blue-ribbon scientific panel appointed by Congress is also looking at the problem. So far, NASA has spent about $40 million on its long-term tracking effort.

Astronomers say it is not a question whether Earth will be hit again, but when, and at what cost to human life. Technology exists to improve protections for the planet, and should be put to use. This isn`t science fiction.

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