[meteorite-list] Skywatchers Search For Asteroids

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:08:19 2004
Message-ID: <200209010533.WAA04448_at_zagami.jpl.nasa.gov>

For JPL internal use only.

http://www.floridatoday.com/news/space/stories/2002b/090102asteroid.htm

Skywatchers search for asteroids

Only handful of people stand between Earth and disaster

By Chris Kridler
FLORIDA TODAY
August 31, 2002

There's a select club of people who are awake while you're asleep, scanning
the skies all night for a bright spot or smudge that could be the next big
rock that threatens Earth.

One scientist said there are more people working in your typical McDonald's
than there are working full-time to save the planet with their telescopes.

Asteroid hunters and comet hunters have to deal with a vast universe, low
budgets, highly competitive quests for grants and bone-headed media
reactions to initial discoveries that suggest impending doom before the
findings are refined by mathematics and time.

"I think you can expect more reports of potential impactors as time goes on,
because more asteroids are being discovered," said Robert McMillan,
principal investigator for the Spacewatch project, which uses two telescopes
45 miles southwest of Tucson, Ariz., to scan.

"So the ones that zing past the Earth at relatively close distances have
always been doing that, it's just now we've become more aware of it."

Under a mandate by Congress, partly spurred by the spectacular collision of
comet Shoemaker Levy 9 with Jupiter in 1994, skywatchers are looking for the
kind of rock that could make us extinct.

Efforts such as Spacewatch and the joint NASA-Air Force Near-Earth Asteroid
Tracking project in Maui, Hawaii, have to sort through a lot of rocks to
find what McMillan calls "potentially hazardous asteroids."

50 worth watching

Spacewatch spots about 100,000 asteroids a year, but most are in the solar
system's main asteroid belt. Only about 50 are near-Earth asteroids.

They send their discoveries to the Minor Planets Center in Cambridge, Mass.,
and post them on technical Web sites. Other professional and amateur
astronomers can follow up on the discoveries by tracking the objects' orbits
and refining predictions of where they'll end up.

Sometimes, though, a scientist won't communicate a finding clearly, or a
journalist will rush ahead with a story about an Armageddon rock, before
additional calculations can rule out an Earth-crossing orbit.

"It's a more complicated problem than blaming some journalists," said
asteroid expert Clark Chapman, with the Southwest Research Institute in
Boulder, Colo. "First, the issue is inherently difficult for people to
grasp," particularly the enormous odds against a collision.

The most recent example was reporting on asteroid 2002 NT7, which caused a
media frenzy in Britain when initial calculations showed it had a chance of
hitting Earth on Feb. 1, 2019. Later calculations showed it wouldn't.

Such reversals hurt the credibility of scientists, who really aren't trying
to get attention by crying doom, observers say.

"I worry about it. I encounter people on the street who are kind of unhappy
about this stuff," Chapman said. "I was just in my dentist's chair yesterday
morning, and he said, 'What's with this asteroid that was going to hit the
Earth?' I think scientists as a whole need to work to preserve their
credibility, because there's so many voices in our lives saying so many
foolish things, people who are peddling so many kinds of crazy things,
pseudo-scientists and what-not."

Even though they always go through a process of refining their forecasts,
"it certainly comes across like we're making mistakes," he said.

Meanwhile, skywatchers labor while engaging in "friendly competition" for
scarce grants, some of which are too short-term to make long-term plans.

"It's a very small community," Chapman said. "The total funding in the world
is mainly the funding by NASA, which is a couple of million dollars."

More funding could help astronomers find smaller asteroids that might not
cause a global crisis but could, say, take out South Florida.

"There are arguments for increasing the coverage down to smaller asteroids,"
McMillan said. "Currently the goal of NASA is to find 90 percent of
Earth-approaching asteroids larger than 1 kilometer within 10 years of
surveying, but of course, asteroids that are smaller than that can still do
a great deal of damage."

The problem is that expanding the effort would be taxing and expensive, said
Richard Kowalski of Zephyrhills, moderator of the online Minor Planet
Mailing List, which is frequented by asteroid hunters.

"You would have to spend billions and billions of dollars per year, and the
threat is not that large, so it's hard to justify spending that money," he
said.

Amateur astronomers help fill the gap, and what they spend is equivalent if
not greater than funding given to official searchers, Kowalski said.

When it comes to amateurs, "in the case of comets, they're a crucial part of
it," said Michael A'Hearn of the University of Maryland, the principal
investigator for the Deep Impact comet probe.

"The professional surveys are doing very well at what they're trying to do,
which is finding and cataloging all the asteroids," said A'Hearn, who will
be speaking at a NASA-sponsored asteroid conference in Virginia this week.
"People often assume that comets will be found as a natural byproduct of all
of that, but the point is, they won't be."

It's difficult to track comets, because many have much longer orbits than
asteroids do.

"The asteroids are the largest part of the hazard," A'Hearn said, "but we
just don't know what fraction of the hazard is due to comets. It's certainly
less than half, and it could be as small as one percent."

"To satisfactorily find comets in time to do anything about it is a major
challenge," said Chapman, who also is speaking at the conference. "It's
probably technically possible to do, but it's nothing that's at all easy. It
would maybe involve launching major space telescopes out in Jupiter's
orbit."
Received on Sun 01 Sep 2002 01:33:24 AM PDT