- IRVINE, California (AP) -- Following March's false alarm about an asteroid
coming dangerously close to Earth in the 21st century and two Hollywood
summer blockbusters about cosmic collisions, experts met Saturday to plan
asteroid warnings that won't trigger mass panic.
-
- "Collisions with the Earth is a
topic that is so prone to sensationalism that we must be extremely careful
about how we communicate new discoveries," said Richard P. Binzel,
a planetary science professor at the Massachusetts Institute of Technology.
"It took the (March) event to wake us up."
-
- A March 11 report that Asteroid 1997XF11
was headed to within 30,000 miles of Earth's center -- and could hit in
October 2028 -- was front page news and the top story on evening TV news
broadcasts.
-
- The report from the International Astronomical
Union was quickly debunked by astronomers at NASA's Jet Propulsion Laboratory
in Pasadena who recalculated the asteroid's likely path and found it would
miss the Earth by 600,000 miles.
-
- "There's a great misperception in
the public that for one day there was a possibility that the asteroid would
hit in 2028," said Paul W. Chodas, the JPL astronomer whose calculations
put those frightened by the report at ease. "According to our calculations,
there never was a chance the object would hit the Earth."
-
- Chance Of Possible Collision In Rare
-
- In the aftermath, scientists began thinking
about how they could avert another scare, although efforts to delay release
of data could be difficult given the increasingly free flow of scientific
information through the Internet.
-
- Since that time, Hollywood has put killer
asteroids and comets into the public mind with the "Deep Impact"
and "Armageddon," as well as made-for-TV movies earlier this
year.
-
- In light of the heightened awareness,
the National Research Council's Committee on Planetary and Lunar Exploration
brought together astronomers who identify and track asteroids, experts
in risk management, seismologists with experience in earthquake and volcano
warnings and reporters.
-
- The main problem in reporting new asteroid
discoveries is that only a fraction that initially seem potentially hazardous
turn out to be headed close to Earth once scientists refine orbital calculations.
-
- "It is extremely unlikely that we're
going to have an asteroid come with a real possibility of a collision,"
Chodas said, adding that 15 minutes after he had the XF11 data in hand,
his calculations found "zero threat."
-
- Scientists agree that peer review of
initial observations -- standard procedure in science -- is essential.
-
- In April, the National Aeronautics and
Space Administration drafted "Interim Roles and Responsibilities for
Reporting Potentially Hazardous Objects," which recommends consultation
and coordination among experts before any public announcements.
-
- NASA Wants Longer Delay Before Any Announcement
-
- It might take up to 48 hours for experts
to consult with each other, Chodas said. NASA wants an additional 24 hours
before the information is released.
-
- Chodas, who computes orbits for asteroids
and comets, went into the meeting with an open mind about giving NASA the
extra 24 hours, although he wondered what the agency planned to do during
that time.
-
- But participants suggested eliminating
the delay. They also suggested encouraging, rather than requiring, scientists
to contact NASA.
-
- An earthquake expert urged openness about
any potential threat, as long as the uncertainty of initial observations
is clearly explained.
-
- "You can't control the flow of news
but you can be as truthful as possible up front," said Allan Lindh
of the U.S. Geological Survey. "The press, public and public officials
seem to deal well with uncertainty, but they don't deal well with the suggestion
you might hold out on them."
-
- Controlling False Alarms
-
- Binzel, who opposes mandating a set waiting
period, suggested that NASA or the International Astronomical Union establish
a code of conduct under which amateur or professional astronomers would
seek verification from colleagues before going public.
-
- Without that, false alarms will create
"total loss of credibility among the astronomers."
-
- Scientists have so far identified 123
potentially hazardous asteroids that could pass within 5 million miles
of Earth. They've discovered 200 of the estimated 2,000 large asteroids
that could pass within 30 million miles of Earth.
-
- Chodas noted that just Friday, scientists
using a radar antenna in Goldstone, California, observed that a 100-foot-
wide asteroid discovered days earlier will pass within 476,000 miles of
Earth on Monday. That's the closest future passage of any asteroid now
being tracked, he said.
-
- NASA is spending more money in the next
decade to scan space for others.
-
- One of the giant rocky chunks is thought
to have slammed into Mexico's Yucatan Peninsula 65 million years ago, wiping
out dinosaurs and most species.
-
- Scientists know that in 1908, an asteroid
exploded over Siberia, flattening nearly 1,000 square miles of forest.
-
- Harry Y. "Hap" McSween, the
University of Tennessee geologist who chaired the daylong workshop, said
it was important that the event was getting U.S. scientists talking, but
added that "this is going to have to be an international discussion."
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