Updated 6:07 PM ET March 12, 1998
NASA Says Asteroid Won't Hit Earth
By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - An asteroid that is headed toward
Earth is not going to hit us after all, NASA said Thursday.
It will miss the planet by 600,000 miles, NASA researchers said.
The International Astronomical Union (IAU), which keeps track
of such objects, said late Wednesday that an asteroid would pass
very close to the Earth in the year 2028 and might conceivably hit it.
The IAU appealed for astronomers to have a look at the asteroid,
dubbed 1997 XF1, and see if they could get more information
about its size and orbit.
NASA spokesman Don Savage said a team at the space agency's
Jet Propulsion Laboratory (JPL) had done just that.
"The latest numbers are in -- 600,000 miles from the Earth is the
latest determination of the orbit," Savage said.
That is far outside the orbit of the moon, which is about 240,000
miles from the Earth.
Savage said JPL scientists Don Yeomans and Paul Chodas had
taken a second look at what data there was on 1997 XF1, which
was first spotted last year. Thay also went through old
photographs that astronomers had taken of the sky, some of
which showed the asteroid, which no one had noticed at the time.
Savage said astronomers would still be trying to see the asteroid,
which orbits the sun erratically but will pass by the Earth again in
about two years.
The IAU's Brian Marsden had said it could pass as close as
200,000 miles and maybe even as close as 30,000 miles. At such
a close distance, it would be visible from the Earth.
But Savage said it would still be quite close and would offer
excellent research opportunities. "We really don't know much
about asteroids. They are very small," he said. "They are so small
that you don't get a very good look at them."
Astronomers still are not sure whether they are large pieces of
rock, or stuck-together piles of rubble.
But many have hit the Earth in the past. A five-mile wide asteroid
that landed on what is now the Yucatan Peninsula in Mexico 65
million years ago caused worldwide disturbances that may have
sent the dinosaurs into extinction.
Either a small asteroid or a large meteorite caused an explosion in 1908 near Tunguska, Siberia. Whatever it was vaporized before it hit the ground but it flattened hundreds of square miles of trees.
Experts say a large bomb could probably be used to deflect any
asteroid heading towards Earth.
Last October, President Bill Clinton used his line-item veto to cut
several projects, one of which was the $30 million "Clementine"
Asteroid Intercept Technology Demonstrator. The project
involved tracking three asteroids this year and next and sending
spacecraft to intercept them.
On Thursday Wisconsin Representative James Sensenbrenner
issued a statement calling on Clinton to reinstate the program.
"This project would have been a low-cost proof of concept for
any future attempt to protect our planet from an asteroid
collision," Sensenbrenner, who chairs the House Committee on
Science, said.
Duncan Steel, a former astronomer at Australia's University of
Adelaide, has been warning of the asteroid danger for years.
Hehelped set up the Rome-based Spaceguard Foundation to
heighten awareness of the asteroid danger. He wants to set up a
global chain of telescopes watching for the danger.
Steel says any one person's risk of being killed by such a collision
is four times higher than that of being killed in an air crash,
although this was due to how statistics work.
The risk is assessed assuming that everyone in the whole world
would be killed, which raises the stakes considerably compared
to a plane crash in which only a few hundred die. The risk of an
actual asteroid collision is much lower than the risk that a
passenger jet will crash. |
