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> 1998
> March
> March 13, 1998:
Hour Two: An Approaching Asteroid:
What is the threat from asteroid 1997 XF11 - and what, if anything, can we do about it?
| Astronomers announced on Wednesday that in thirty years, a mile-wide asteroid might come very close to Earth - only 30,000 miles, a hair's breadth by stellar standards. Astronomers from the International Astronomical Union's Central Bureau for Astronomical Telegrams said that the asteroid, named 1997 XF11, has only a slight chance of colliding with the Earth - but such a collision, no matter how unlikely, could cause widespread devastation on Earth - from tidal waves to global climate change. |
Another asteroid, Gaspra, seen in a
close fly-by by the Galileo spaceprobe.
(NASA/JPL photo) | Then, just one day later, came a new message from a team of astronomers at NASA's Jet Propulsion Laboratory. Recalculations of the asteroid's orbit, made using older, better data taken in 1990, show that the asteroid may only come within 600,000 miles of Earth. That's still relatively close by astronomical standards - but far enough away that it reduces the risk of a collision with Earth to near zero.
Other teams from around the world are scrambling to make more observations of the potential visitor in the next few months, before it moves out of view of telescopes to refine the orbit data still more. In the year 2000, the next time the asteroid comes near the Earth, scientists will again be able to improve their measurements and calculations about just how close the asteroid will come during the October 26, 2028 encounter.
There are currently 108 objects that astronomers have spotted that the International Astronomical Union classifies as "potentially hazardous," meaning that they are both destined to come dangerously close to the Earth in the next few centuries and that they are of a size large enough to do some damage. One joint NASA/Air Force project is attempting to catalog all the asteroids that approach the Earth, and numerous other groups, like the University of Arizona team that initially spotted asteroid 1997 XF11, regularly scan the skies looking for potential threats.
On this hour of Science Friday, we'll take a look at the risks from this asteroid, and from asteroids in general. We'll also talk about ways that people might protect the Earth from an asteroid threat should one ever arise - and about the politics and policies that might affect asteroid defenses.
So just how concerned are our listeners?
Read some of their comments here.
Guests:
Steve Pravdo
Project Manager and Co-Investigator, Near Earth Asteroid Tracking Program
Jet Propulsion Laboratory, NASA
Pasedena, CA
Brian Marsden
Director, Central Bureau for Astronomical Telegrams
International Astronomical Union
Associate Director, Minor Planet Center
Harvard-Smithsonian Center for Astrophysics
Cambridge, MA
Representative Dana Rohrabacher (R-CA)
Chairman, Space and Aeronautics Subcommittee
House Science Committee
U.S. House of Representatives
Washington, D.C.
Books/Articles Discussed:
Related Links:
Science Friday,
January 17, 1997: Stray Asteroids - Real Audio Link
Want to see the asteroid? Look HERE.
Asteroid defense plans:
Planetary defense page
U.S. mirror site
of the Spaceguard Foundation
Groups that monitor asteroids.
Spacewatch
NEAT
AMOS
Victoria
Klet
Ondrejov
ODAS |
