[meteorite-list] Leonids: Wild Storm of Shooting Stars Seen Sunday Morning

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:47:12 2004
Message-ID: <200111182329.PAA25696_at_zagami.jpl.nasa.gov>

http://www.space.com/scienceastronomy/astronomy/leonids_wrap_011118.html

Leonids: Wild Storm of Shooting Stars Seen Sunday Morning
By Robert Roy Britt
space.com
18 November 2001

Vivid streaks of light, sometimes several at a time, zipped across the early
Sunday morning sky as the 2001 Leonid meteor shower reached a stunning
crescendo. A few of the meteors exploded into dazzling fireballs as
skywatchers in North America and elsewhere witnessed ancient space dust
plunging into Earth's atmosphere and vaporizing.

The event was well documented by scientists, and it will live forever in the
memories of thousands of amateur astronomers and first-time viewers who
braved sometimes chilly weather and fought off sleep.

"It was a fabulous show," said Jim Graham of New York City, who traveled
about 100 miles north to view the Leonids under darker skies. "At one point
we saw six at once, in about a second. Some seemed to have a punctuation
mark at the end, with a little trail that blows up. We saw one that lit up a
big piece of the sky and just exploded at the end."

"It was unbelievable," said Robin Lloyd, who works at the American Museum of
Natural History in New York and watched with Graham and his son. "It was the
most beautiful thing."

It's too soon to say for sure whether the 2001 Leonid meteor shower, which
peaked before dawn, will qualify as a storm as scientists had predicted. But
early indications point to a storm designation. A meteor storm is defined as
a shower that exceeds an hourly rate of 1,000 meteors.

Either way, it was unlike anything seen on Earth since 1966, professionals
and casual observers agreed. And astronomers say it won't be repeated for
nearly a century.

Reports from many locations

Early risers from California to Ohio to Virginia and elsewhere described
similar experiences -- an occasionally wild show with peaks and lull, all
lasting from shortly after midnight until dawn.

Some witnesses described fast-moving meteors, zooming across all parts of
the sky and sometimes leaving smoky trails.

In rural Maryland under fairly dark skies, this reporter counted four
meteors per minute during a five-minute stretch at 4 a.m., but by 5 a.m.
that count grew to more than eight per minute. That equates to an hourly
rate of 480. But many meteors went unseen on a foggy horizon.

A group of scientists reported an hourly rate of 800 shooting stars above
New Mexico. A Texas observer counted dozens in a few seconds -- and did so
several times. Other groups observing in the Southwest reported preliminary
estimates in the neighborhood of 2,000 meteors per hour for a short stretch
of time.

A stronger display was expected in Australia and parts of eastern Asia. One
preliminary report from a group of NASA scientists claimed an hourly rate of
1,250 meteors in Hawaii. One early and rough report from China indicates
rates may have reached 2,000 or more.

Behind the show

The display was the result of space dust vaporizing in Earth's atmosphere.
Most of the shooting stars were created by stuff no larger than sand grains.
The debris is the exhaust of comet Tempel-Tuttle, which orbits the Sun every
33 years. Earth passed through several separate trails of this debris over
the weekend. Some of the trails had been laid down centuries ago.

Four different research groups had predicted when and where various peaks of
activity would occur, and how many meteors per hour would be visible at the
peak time. But meteor shower forecasting is in its infancy. Serious Leonids
forecasts go back to just 1998.

The predictions for North American ranged from 800 meteors per hour to
4,200. In parts of Asia and Australia, a peak hourly rate of 8,000 or more
was expected. The hourly rates were expected to be achieved during short
bursts that would last 30 minutes or less.

The show is not entirely over. Though the peak is past, the Leonids will
wind down through Nov. 21. Each morning until then offers an opportunity to
see some shooting stars, both those associated with the Leonids as well as
others.

This time of year is a busy one for shooting stars in general.

Monday morning observers with dark skies can expect to see up to 35 total
meteors per hour in the Northern Hemisphere and 20 in the Southern
Hemisphere, according to Robert Lunsford of the American Meteor Society.
Unpredictable bursts of Leonid activity could send the rates higher for
short stretches. Similar activity was spotted early Friday and Saturday.

While the Leonids are also visible in Europe and elsewhere, the strong
bursts of activity were confined to a few regions of the globe.

Next year's Leonids are expected to equal or exceed this year's count, but
the show will be largely drowned out by a full Moon.

Satellite threat

Satellite operators have been watching the Leonids with wary eyes. A
fast-moving Leonid meteor can damage or disable a satellite. NASA scientist
and meteor forecaster Bill Cooke said before the shower that there would be
between 1-in-10,000 and 1-in-1,000 chance of at least one satellite being
significantly damaged during the full duration of the shower.

So far, there have been no reports of satellite damage.

Defense officials have said military satellites are more robust than most
and are capable of withstanding an impact. Measures were taken to protect
spy satellites and other spacecraft critical to military operations, but
officials would not say what those precautions were.
Received on Sun 18 Nov 2001 06:29:34 PM PST