Newspaper article The Christian Science Monitor

If Asteroids Drop in, Will We See Them Coming? Today, Congress Looks at How to Avoid Hollywood's Asteroid- Meets-Earth Scenarios

Newspaper article The Christian Science Monitor

If Asteroids Drop in, Will We See Them Coming? Today, Congress Looks at How to Avoid Hollywood's Asteroid- Meets-Earth Scenarios

Article excerpt

The films are vintage Hollywood, but the villains - comets and asteroids - are plucked from the pages of Earth's geologic past.

As moviegoers flock to theaters to see Earth and its inhabitants take it on the chin in "Deep Impact" and await the release of the other anticipated summer blockbuster, "Arma-geddon," a congressional panel has summoned astronomers and NASA officials to testify today on real-life asteroid hazards.

At issue is whether detection efforts are sufficient and whether enough attention is being paid to ideas about diverting comets and asteroids if that ever becomes necessary. The hearings before the House Subcommittee on Space and Aeronautics come at a time of heightened public awareness that Planet Earth spins through a rough neighborhood. In March, for example, the International Astronomical Union's Minor Planet Center in Cambridge, Mass., warned that an asteroid discovered last December could pass as close as 40,000 kilometers (24,800 miles) to Earth in October 2028. Within 24 hours, that distance grew to 950,000 km after researchers found earlier images of the object and refined its projected orbit. Even discounting this high-profile reversal, "we've had a number of 'fair warnings,'" says a congressional staff member who focuses on space issues. From the Arizona desert and Yucatan Peninsula to the forests of Siberia, Earth's surface displays the weathered dents and flattened forests of past collisions. The hazard came into stark focus in 1994, when comet Shoemaker-Levy 9 broke apart and plunged into Jupiter, punching Earth-sized holes in the Jovian atmosphere. Heading our way Earth will get a more subtle reminder of these cosmic hazards in November, when the planet enters a cloud of debris that has boiled off comet Temple-Tuttle. The comet orbits the sun once every 33 years and made its closest approach to the sun in February, adding more material to the cloud. Known as the Leonid meteor shower, the storm of cometary leftovers - most no bigger than grains of dust and sand - threaten to pummel satellites at speeds approaching those of a .22 caliber bullet, pitting solar panels and even causing electrical failures. "Normally, you'll see 50 meteors an hour during a typical meteor shower, but we expect that rate to go up to as much as 5,000 an hour" during the Leonid's peak, says William Ailor, director of the Aerospace Corp. Center for Orbital and Reentry Debris Studies in El Segundo, Calif. "This will be a new experience for spacecraft," he adds, noting that satellites are larger and more numerous than during the comet's last pass. "You just can't simulate these {meteoroid} impact speeds on Earth." Growing effort This year the National Aeronautics and Space Administration is spending $3 million on efforts to locate comets and asteroids whose orbits cross or approach Earth's orbit. …

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