The Great Asteroid Scare
(from "What's Up", April 1998)
On March 11, Brian Marsden of the
Central Bureau of Astronomical Telegrams announced that a mile-wide asteroid,
1997 XF11, could pass within 30,000 miles of our world in 2028, and stood a
slight chance of actually hitting the Earth. The report emphasized the
uncertainty of the orbit and the need for astronomers to make further
observations, but the news media picked up and ran with the doomsday scenario.
(A collision with the asteroid would destroy human society as we know it.) The
next day, Donald K. Yeomans and Paul Chodas of JPL announced, based on their
analysis of the same data, that there was no chance of XF11 hitting Earth, and
it probably wouldn’t pass within 600,000 miles of us. The planet breathed a
collective sigh of relief. Still, astronomers will scour prediscovery images and
pay close attention to the asteroid’s passages in 2000 and 2002 to determine
exactly how far away it will pass in 2028. This event did serve to raise public
awareness of the potential danger of near-Earth asteroids (ironically just
months before the release of Deep Impact and Armageddon, two films with a
collision scenario), as well as stimulate discussion of how to deflect these
menaces. If the 600,000-mile figure is correct, the asteroid would briefly reach
the fringe of naked-eye visibility. A 30,000-mile passage would be a spectacular
sight (if a bit close for comfort), with the asteroid exceeding zero magnitude
as it passed through the evening skies over Europe on October 26, 2028, crossing
a third of the heavens in a few short
hours.
To My
AstroWeb
tonyhoffman@earthlink.net