[meteorite-list] Task force to monitor asteroid threats

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Fri Aug 18 00:18:03 2006
Message-ID: <frfae2taa27fjg4pkjfa9l56k0o35toddm_at_4ax.com>

http://www.msnbc.msn.com/id/14395543/

Task force to monitor asteroid threats
Astronomers focus on worries about impact catastrophe
The Associated Press


Updated: 3:14 p.m. ET Aug 17, 2006
PRAGUE, Czech Republic - They?re out there, hidden among a haze of stars ?
killer asteroids. Now the world?s astronomers are keeping a wary eye to the
skies for giant objects on a collision course with Earth.

Experts say there are about 1,100 comets and asteroids in the inner solar system
that are at least a half-mile (1 kilometer) across, and that any one of them
could unleash a global cataclysm capable of killing millions in a single
blinding flash.

On Thursday, the International Astronomical Union said it has set up a special
task force to sharpen its focus on threats from such ?near-Earth objects.?

?The goal is to discover these killer asteroids before they discover us,? said
Nick Kaiser of the University of Hawaii?s Institute for Astronomy, which hopes
to train four powerful digital cameras on the heavens to watch for would-be
intruders.

There are no asteroid busters to stop one right now, but scientists believe that
one day a defense could be devised, such as using spacecraft to divert a killer
comet.

Congress wants defense plan
Congress has asked NASA for a plan to comb the cosmos for even smaller, more
distant objects, including asteroids just 1? football fields (150 meters)
across. The space agency is to catalog their position, speed and course by 2020.
Already, there are 103 objects on an ?impact risk? watch list.

Scientists warn there are as many as 100,000 of these ?smaller? heavenly bodies
with the potential to take out entire cities or set off a tsunami like the
killer wave that swept through the Indian Ocean in December 2004.

Earth?s craters bear silent witness to what can happen even when a smallish
asteroid slams home. In 1908, one struck remote central Siberia, unleashing as
much energy as a 15-megaton nuclear bomb. Fortunately, it wiped out 60 million
trees, not people. Had it hit a populated area, the loss of life would have been
staggering.

Good news: Risk reduced
There?s some recent good news too: Earth?s most pressing threat ? the asteroid
99942 Apophis ? appears to have eased. Scientists initially gave it a 1-in-5,500
chance of hitting the planet in 2036, with enough power to wipe out the New York
City metro area. But experts said Thursday the latest observations suggest those
odds have dwindled to 1-in-30,000.

They won?t be sure until it makes an earlier pass in 2029, when it?s expected to
come within 18,640 miles (30,000 kilometers) of Earth. If that sounds
comfortably distant, consider this: It?s closer than many commercial satellites
and a good deal nearer than the moon.

Although close encounters are unnerving, they give astronomers a unique
opportunity to get a better glimpse of asteroids and comets ? the leftover
building materials of the universe ? and gain a better understanding of the
origins of the solar system.

Scientists say expanding their database of the objects crowding Earth?s
neighborhood could help produce a permanent warning system like those that now
monitor the Pacific for tsunamis or keep tabs on volcanoes and earthquake zones.

Give the world a decade or so of lead time to deal with a specific threat, they
say, and it stands a chance of getting out of harm?s way ? perhaps by sending up
a spacecraft to nudge an asteroid off-course.

?Right now, unfortunately, there are no ?asteroid busters? or hot lines. Who ya
gonna call?? said Andrea Milani Comparetti, a professor of mathematics at
Italy?s University of Pisa.

Worrying about a scare
To be on the safe side, astronomers trying to determine the odds of one hitting
Earth work with computer models that surround it with thousands of ?virtual
asteroids.? Experts then map out the likely orbits for each one and factor those
in to come up with the probability of an impact.

But widening the search for threatening objects creates a problem: Discoveries
could become commonplace, either creating unnecessary panic and confusion or
lulling the public into a false sense of complacency.


?We?re now going to be finding such objects once a week instead of once a year,?
said David Morrison, a NASA scientist who will chair the new task force.

?Only in Hollywood do asteroids arbitrarily change orbits,? he said. ?But there
is great potential for misunderstanding. Dealing with probability and risk is a
problem for all of us, whether we?re dealing with asteroid impacts or terrorist
attacks.?

Bottom line: Mankind may not be able to dodge every cosmic bullet.

?It?s through collisions that planets are born,? said Giovanni Valsecchi of
Italy?s National Institute of Astrophysics. ?And it?s through collisions that
planets die.?

? 2006 The Associated Press. All rights reserved. This material may not be
published, broadcast, rewritten or redistributed.
Received on Fri 18 Aug 2006 12:19:07 AM PDT