Leonids_20012002 Leonid Meteor Shower: Visit our new Special Report
The 2001 Leonid meteor shower peaked early Sunday, Nov. 18 and was the best shooting star show in 35 years. This page archives our entire coverage.
|  This Leonid fireball was caught on video by George Varros on Nov. 17, 2001, from Mount Airy, MD. The bright dot at the top is Jupiter.
 See the full animation
EXCLUSIVE
Time-Lapsed Video!
Astrophotographer Wil Milan captured about 4.5 hours of the 2001 Leonid meteor shower from northwestern Arizona, near the Burro Creek Wilderness. His video is compressed into about 35 seconds. How the Video was made
Wil Milan also took photos of this year's Leonids. Top, a fireball. Below, several meteors at once. 
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A Grand Diversion: The 2001 Leonid Meteor Shower in Words & Pictures
19 November 2001: See more images like this, from SPACE.com visitor Brian Scott, in our four 2001 Leonid Photo Galleries.
POST-GAME ANALYSIS
'It Looks Like We All Were Wrong'
27 November 2001: Shooting star tallies and interviews reveal that while strides were made in the young science of meteor forecasting, nobody got it right in 2001. EARLY RESULTS
Wild Storm of Shooting Stars Seen Sunday Morning
18 November 2001: Scientists and amateurs report in from around the world. WHAT DID YOU SEE?
Share your Leonid experience with the world!
The Leonids From Space
 Check out this composite satellite shot, taken during the 1997 Leonids meteor shower. |
| Don't miss another celestial event! |
The information below was provided prior to Nov. 18, when the Leonids peaked.
2001 PREDICTIONS
30 U.S. Cities & World Forecast
SATELLITE THREAT
Military Satellites Prepared
Odds of an Impact Soar
MAKING A LEONID
What Causes the Shower?
THE 2001 STORM
How it Stacks Up Against History
By Robert Roy Britt
Senior Science Writer
Posted July 27, 2001 and updated Nov. 6
Few cosmic events in modern history have equaled the 1966 Leonid meteor shower. Residents in the western United States saw a storm of shooting stars estimated to rain down at a rate of 100,000 per hour during a brief peak.
One eyewitness, who was 14 at the time, said he was frozen in place for 30 minutes, "watching an alien fireworks display."
This November, the wildly varying Leonids are expected to produce another storm. Though not likely to rival the 1966 spectacle, the 2001 version of the Leonids may offer a meteor storm unlike anything since, with hundreds or even thousands of meteors -- on a per hour basis -- raining down at the busiest stretch.
The Leonids run from Nov. 14-21 and will peak in the early morning on the 18th.
2001 Leonid Meteor Shower Predictions
Here is one of the leading predictions for how many Leonids will streak across the sky. It is from researchers Rob McNaught and David Asher, who say the totals could be higher. Other reserachers predict other rates. All time are for Nov. 18, 2001. Note that the peaks may last less than 1 hour. This chart is updated as of Oct. 30:
| Where | When | Meteors |
| North & Central America | 4:55 a.m. EST | 800 per hour |
| Australia; East Asia | 17:24 UT | 2,000 per hour |
| Western Australia; East, Southeast & Central Asia | 18:13 UT | 8,000 per hour |
| NOTE: 4:55 a.m. EST = 3:55 a.m. CST, 2:55 a.m. MST, and 1:55 a.m. PST
UT=Universal Time, same as GMT; Eastern Australian daylight saving time is UT +11 hours |
| VIEWER'S GUIDE |
Leonids Viewer's Guide
Simple advice for an event anyone can see The best viewing was in the early morning hours of Sunday, Nov. 18. The mornings surrounding the peak, from Nov. 14-21, could produce bursts of activity worth watching. Leonids cannot be seen in the evening. No special equipment is required, so anyone who lives where the peaks are forecasted to occur can enjoy the event. |
Maybe Even More?
06 November 2001: Another forecaster, Peter Jenniskens of the SETI Institute and NASA's Ames Research Center, has predicted that up to 4,200 meteors per hour could be visible from North America at 5:09 a.m. EST.
Jenniskens bases his predictions in part on observations of the 1999 and 2000 Leonid storms he and colleagues made from aircraft. On Nov. 3, he told SPACE.com that he figures Earth will pass closer to the densest part of the dust trail that is expected to cause the U.S. peak. More dust, more meteors.
Jenniskens predictions are not included in the city-by-city listings, though he expects higher numbers than any of the other three sets of predictions for some locations.
Europe and South America
06 November 2001: Several SPACE.com visitors from around the world have asked, "What about us?" So we asked Robert Lunsford of the American Meteor Society, who said Europe and most of South America will be bathed in sunlight during the peak. Only the "normal background rate" of 10-15 meteors per hour will be visible in the early morning hours of Nov. 18.
What Causes the Leonids?
The Leonid meter shower is caused by the comet Tempel-Tuttle, which swings around the Sun every 33.2 years and leaves behind a trail of dust and debris. When Earth passes through this stream of material, the small bits -- most no larger than a grain of sand -- burn up in the atmosphere and create shooting stars.
Predicting the Leonids is a challenge because each year Earth passes through different portions of the debris stream, which itself moves through space, mingling and spreading the densest areas which are refreshed every 33.2 years.
The comet is named after Ernst Tempel and Horace Tuttle, who spotted it in 1865 and 1866. Tempel-Tuttle has a nucleus that's about 2.5 miles (4 kilometers) in diameter.
Improving Predictions
The activity of the annual Leonids was accurately predicted in 1999 and 2000, boosting confidence that a forecast for this year will be on target also. This year, hundreds or possibly thousands of shooting stars are expected to zoom through Earth's atmosphere each hour.
The most widely watched Leonid predictions are made by Rob McNaught of the Australian National University and David Asher of the Armagh Observatory (see above chart). Even these two researchers, however, admit that prior to 1999, meteor forecast had a checkered past.
"But a new theory is able to explain the historical events and should thus be able to make sound predictions for the near future," McNaught says. "Prospects appear good for a moderate storm visible in dark skies from Australia and eastern Asia in 2001, and in moonlit skies over Europe, west Africa and North America in 2002."
America will not be left out this year, either.
"It seems certain that the America's and the Far East will be treated to a grand display without interfering moonlight in 2001," said Robert Lunsford of the American Meteor Society, shortly after reviewing last year's event and noting that predictions were on target.
McNaught and Asher study comet Tempel-Tuttle's dust trails to make their predictions about the Leonids. Until recent weeks, they had expected a peak this year of up to 15,000 meteors per hour over Australia and East Asia and as many as 2,500 per hour over North and Central America.
Without completely ruling out those numbers as possible, they revised their predictions in late October, calling for an hourly rate of 8,000 over Australia and East Asia and some 800 over North and Central America (see chart above).
Why the revision?
On Oct. 30, David Asher told SPACE.com why the revision had been made. He said another meteor forecaster, Esko Lyytinen, had worked with another team to explore how the Sun's radiation might push comet debris around, widening the trails over the years.
"So we added an 'aging parameter' to our model, to allow for a possible effect of each trail getting slightly wider with age," Asher said via e-mail. "This made a bit of a difference to the estimated meteor rates, without any dramatic change in the conclusions."
He said previously forecasted peak times won't change -- the center of a trail is still the center -- but there may be fewer meteors during those peaks if the debris is spread more widely. Asher said the revision was made in the past week or two and would soon be published in the the Journal of the International Meteor Organization.
Importantly, Asher also said he had not ruled out the possibility that the previous estimates -- for rates as high as 15,000 meteors per hour over Australia and East Asia and as many as 2,500 per hour over North and Central America -- are "within the bounds of possibility." He said the uncertainty for how many dust grains are in a trail is very high.
If the downward revision proves accurate, however, it would demote the American version of the show from storm status to shower status -- though still one heckuva meteor shower. Bill Cooke, a NASA meteor forecaster, said a rate of 1,000 meteors per hour is commonly considered the threshold for a storm.
More Meteor Info
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