- WASHINGTON -- A dangerous asteroid will whiz by Earth today in a cosmic
close call. Similar near misses are expected March 2, 18, 26 and April
1.
-
- Astronomers are discovering potential
killer asteroids at a record pace.
-
- The public's flirtation last year with
fear of menacing space rocks -- fueled by two fictionalized movies and
one widely reported threat -- has faded. But astronomers scanning the sky
with new technology are finding more asteroids than ever.
-
- There are almost weekly additions to
science's official list of "potentially hazardous asteroids."
In 1998, scientists found 55 of the would-be killers -- more than in the
previous six years combined. Now the all-time list is at 163 and growing.
-
- None of these rocks is expected to hit
Earth directly. But they are too close for comfort.
-
- "It's crazy," said University
of Arizona astronomer Tim Spahr, scientist for one of three teams of sky
searchers. "It's not even active, it's just insane."
-
- Caution, read with care!!!!
-
- Here are a few recent examples:
-
- This afternoon, a half-mile-wide asteroid
discovered in January will whiz by Earth at a distance of 3.4 million miles.
That rock, called 1999 BJ8, is expected to give Earth its closest call
in the next 22 months, according to the ever-changing list of dangerous
objects.
-
- On Feb. 4, 30-foot-wide rock came incredibly
close to Earth. It was only 632,000 miles away (2 1/2 times the distance
from here to the moon), and scientists didn't notice until it had already
passed and was moving away.
-
- For a few brief hours Feb.16, it looked
as if a two-thirds-of-a-mile-long asteroid discovered in January could
come even closer than that -- maybe even hit us in 2066 or 2073. But new
photographs showed that the rock with an unusual orbit would be close,
but not that close.
-
- The biggest reason that astronomers are
finding more of these near-miss asteroids is the redirection of Air Force
technology from tracking killer satellites to spotting killer rocks.
-
- Massachusetts Institute of Technology's
Lincoln Laboratory, a federally funded national security research center
outside Boston, changed the asteroid tracking world last March when it
began using Air Force technology to scan the sky with a telescope based
in New Mexico. The lab's program, called LINEAR, has found 38 of the last
59 asteroids.
-
- "We have it down to a point where
we're in a groove," LINEAR chief Grant Stokes said.
-
- But even as new threats are being found
much more frequently than before, "we're way behind," said Don
Yeomans, manager of NASA's Near Earth Object program.
-
- That's because last year, NASA set a
goal of finding most potential asteroid threats within 10 years. Asteroids
are considered a threat if they are bigger than half a mile wide and are
going to come within five million miles of Earth.
-
- Astronomers guess there are 2,000 such
asteroids out there, and so far they have found about 8 percent of them.
So even though the number of asteroids being found is soaring, it's not
growing fast enough, experts said.
-
- NASA, which spends $3.5 million a year
on asteroid tracking, is speeding up the process. A second LINEAR program
goes on-line this spring. With a second LINEAR, astronomers should find
90 percent of those killer rocks in about 16 or 17 years.
-
- The last time a big asteroid hit was
65 million years ago. That was the asteroid that landed in the Yucatan
and is thought to have wiped out the dinosaurs.
-
- Of course, there are millions of others
that could cause major disasters, like a 150-foot-wide one that exploded
over Tunguska, Siberia, in 1908 and leveled thousands of square miles of
forests.
-
- "If you were going to find every
object that's going to threaten the Earth with a Tunguska, you're talking
millions, not thousands." said researcher Jeff Larsen of the University
of Arizona's Spacewatch tracking program.
|
