An asteroid discovered three years ago could be a threat in 2029 when it crosses Earth's orbit, a Russian astronomer said Monday.

Boris Shustov, director of the Institute of Astronomy, said at a forum that the Apophis asteroid could have a bigger impact than an asteroid that hit Siberia in 1908, the Novosti news agency reported.

The Tunguska astral event affected 830 square miles and blasted 80 million trees. The force of the impact was about 1,000 times more powerful than the atomic bomb the United States dropped on Hiroshima, Japan, at the end of World War II and measured 5.0 on the Richter scale.

Apophis' predicted track would take it within 17,000 miles of Earth in 2029, Shustov said.

He said if the asteroid proves to be a threat, the Hollywood scenario of destroying it is likely to be more harmful than helpful. Instead, a micro-satellite could nudge it into a safer orbit.

"To blast an asteroid, as some hot shots suggest, is quite an unpredictable step, and a more cautious approach is welcomed now," he said.

Copyright 2007 by United Press International

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