December 3, 2008

Global Action Needed To Stop Asteroid Threat

According to Professor Richard Crowther, a leading analyst for the United Nations, the international community must work together to stop the threat of asteroids colliding with Earth.

A group of space experts called the Association of Space Explorers (ASE) have called for a coordinated response to the threat and say missions to stop asteroids will need global approval.

The UN will discuss the issue in February.

In the ASE report, the group points to history to show the dangers of asteroid impacts.  An asteroid impact 65 million years ago wiped out the dinosaurs, and the Tunguska impact of 1908 produced a fire large enough to engulf the city of New York.

According to the group, the next major threat could occur within the next 20 years. Asteroid Apophis is expected to come near Earth, with a one in 45,000 chance of impact.

An impact by Apophis would be at least 100 times more powerful than the Tunguska impact in Siberia.

"The issue is it's a single event, potentially causing a large number of casualties," said Professor Crowther, chair of the UN Working Group on Near Earth Objects.

The UN agrees that action is necessary but the group is unsure about the form of action. The group plans to use the ASE report as a resource.

"A lot of what's in the report is consistent with what we're suggesting anyway, there needs to be effective scientific coordination, enough observatory time, and people looking in the right place at the right time," said Professor Crowther, who welcomed the ASE report.

The report says that asteroids larger than 200m in diameter need to be deflected away from the Earth, while asteroids smaller than 200m will likely burn up upon entering Earth's atmosphere.

Some of the proposed methods of deflecting the asteroids include crashing spacecraft into the object, or setting it off course with a nuclear explosion.  Researchers agree that dealing with the threat early will mean a less drastic course of action.

Crowther believes the natural force of gravity can be used to deflect asteroids.

"We can use the natural attraction of a probe to one of the bodies, to slowly pull the object away."

If done from a sufficient distance from Earth, the orbit of the asteroid could be changed enough to remove it from a collision path, Crowther added.

The ASE report proposes that scientific monitoring be combined with a global political strategy to find the best way to deal with asteroids.

According to Crowther, the scientific consensus is in place, but the political consensus will be more difficult.

"We have to decide on a political framework, who's going to act and under what authority. That's clearly a role for the UN within the next two to three years. The key is to get it done before it's needed, when people are much more reasonable, rational and objective."

Image Credit: NASA/JPL-Caltech/T. Pyle (SSC) 


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