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(meteorobs) NASA Science News: "Weekend Fireballs"
------- Forwarded Message
From: Ron Baalke <baalke@zagami.jpl.nasadot gov>
Subject: Weekend Fireballs
Date: Tue, 4 Dec 2001 08:00:47 -0800 (PST)
http://science.nasadot gov/headlines/y2001/ast03dec_1.htm
Weekend Fireballs
NASA Science News
December 3, 2001
Pieces of a Proton rocket disintegrated in Earth's atmosphere this weekend,
startling sky watchers in western Europe and at least seven US states.
On Saturday night, Dec. 1st, around 10:15 p.m. CST, a sensational fireball
glided over the US Midwest. Automobile traffic stopped. Airline pilots
peered in amazement through cockpit windows. And emergency phone lines were
jammed.
"It was breathtaking!" said Greg Bakker of Hull, Iowa. "My wife and I were
driving home around 10:30 CST when I saw the lights. I pulled the vehicle to
the side of the road and we sat there awestruck. There were about 8 objects -
fiery yellow in color and slow-moving, much slower than any of the Leonid
meteors I saw last month."
Indeed, what Bakker saw was no meteor. It was the remains of a Russian
Proton rocket that had left Earth only 10 hours earlier carrying three
navigation satellites to orbit. The satellites were deployed successfully,
but pieces of the rocket fell back to Earth and disintegrated.
Rick Bordignon was in a commercial airliner bound for Las Vegas when he saw
them. "I was looking out the left window into the starry night when I
noticed an approaching light," he recalled. "I was thinking... Hmmmmm, looks
like a missile. But rather than raise a general sense of panic by yelling
'Incoming!,' I did the next best thing and got out my camera.
"I snapped one picture (above), but my camera is poor in low light. So I
stopped to adjust the settings. When I looked out again I was amazed by what
I saw: hundreds of objects with colorful glowing tails! So I snapped another
one (inset) but it only picked up the brightest fragments -- and it was
shaky, too.
"The light plume [seemed to] go up and over our plane. After it was gone I
looked around to judge the reactions of the other passengers -- and I swear
everyone was sleeping!
"When I got off the plane, I tracked down the pilot. He said every pilot in
the Midwest saw it and it was the 'buzz of the frequencies.' They had never
witnessed anything like it before."
The eye-catching display had actually begun hours earlier. Alan Pickup, a
satellite decay expert who works at the United Kingdom's Astronomy
Technology Centre at the Royal Observatory in Edinburgh, explains:
"The rocket, a Proton or 'SL-12', was launched from the Baikonur Cosmodrome
in Kazakstan at 18:04 UT on Dec. 1st. An 800 kg metal casing from the fourth
stage of the rocket was on its third orbit around Earth when it burned up in
the atmosphere over southern England and France at about 22:35 UT."
Welshman Chris Evans was just stepping out of a restaurant in the French
countryside when the casing soared overhead. "At first it was a single large
fireball," says Evans, "but then it broke into about 30 or 40 smaller ones,
like a giant fireworks display. It was absolutely magnificent." Other
observers in the region noted a lingering trail and a "smoky halo" around
the Full Moon.
Meanwhile, another even bigger piece of the rocket -- its 4,200-kg third
stage -- was decaying. The third stage hadn't dropped as fast as the casing
had done. But finally, about six hours later, it too began to glow.
Shannon Rudine at the University of Texas McDonald Observatory spotted the
rocket at 10:18 p.m. CST on Dec. 1st (0418 UT on Dec. 2nd). "When I first
noticed it, it had already broken into dozens of slow-moving incandescent
fragments. Several were brilliant white, each nearly as bright as the planet
Jupiter," he recalled
The flaming debris continued from there northeast over Oklahoma, Kansas,
Nebraska, Missouri, Iowa and South Dakota -- dazzling thousands of onlookers
along its path.
Many witnesses saw the fireball because it moved in such a leisurely way
across the sky. There was plenty of time to pull over and step out of the
car, or call a friend to the window. What a change of pace from the Leonids!
Genuine meteors zip across the sky in a few seconds or less. The difference
is mainly speed: Manmade space debris returns to Earth traveling 7 or 8
km/s, while Leonid meteoroids strike the atmosphere at 72 km/s -- ten times
faster.
Furthermore, meteoroids, which are fluffy bits of comet dust, are mostly
smaller than grains of sand and less massive than a gram. They disintegrate
quickly. A Proton rocket, on the other hand, weighs thousands of kg. Such a
massive object can burn and glow for a long time, especially when it skims
almost horizontally through the atmosphere as this one did.
Even so, some sky watchers missed the spectacle.
"I was sitting in my living room on Saturday night when I heard a thunderous
boom," says Matt Hilger of David City, Nebraska. "It was loud, but not quite
loud enough to pull me away from Sports Center on TV. Moments later, a
friend phoned to tell me about the event, but," he lamented, "it was too
late...."
"Next time I hear a sonic boom late at night," he says, "I'll definitely
look out the window."
Editor's note: After this story was published we received reports that sky
watchers in New Mexico also saw the fireballs, adding to the list of US
states already mentioned above.
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