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Celestial Light Show Tonight as Earth Clips Comet's Wake
By HENRY FOUNTAIN


The Leonid meteor shower, that middle-of-November, middle-of-the-night celestial light show, may give 
sky watchers in eastern North America a double dose of shooting stars tonight.

The shower, which takes place every year around Nov. 18 as Earth travels through streams of dust left 
behind by the comet Temple-Tuttle, is expected to have two peak periods. The first will occur about 
11 p.m. Eastern time on Monday, and European observers should have the best view. The second comes 
some six hours later, around 5:15 a.m. Eastern time on Tuesday, when North Americans get the best view.
 
The forecast for tonight in the New York region is for clear skies around the time of the 11 p.m. 
encounter and for some clouds by 5 a.m. on Tuesday.

Gary W. Kronk, an amateur astronomer who runs a Web site about comets and meteors 
(comets.amsmeteors.org), said that for North Americans, the late show should be grand, but 
Easterners willing to do a double shift of sky watching may witness some fireworks at 11 p.m. as well.

At that time, the part of the sky the meteors appear to come from (to the east near the 
constellation Leo, which is why they are called the Leonids) will be below the horizon, 
but Easterners may be able to see the trails of dust particles that are just scraping the 
upper atmosphere at 158,000 miles an hour.

Unlike the relatively short, white streaks of light of most shooting stars, these trails may 
be longer and reddish.

Temple-Tuttle orbits the Sun every 33 years, and during its closest approach the heat of the 
Sun causes some of the comet's ice to bubble off, taking some dusty debris with it. 

This year, which some experts believe may feature the most intense meteor storm until the end 
of the 21st century, the early peak will be caused by a dust stream from Temple-Tuttle's 
approach in 1767. The late peak involves a cloud from 1866. A later cloud generally has had 
less time to spread, so it has a higher concentration of dust particles, which should make 
for more meteors. Earth will also hit this stream more head-on than the 1767 one. 

These factors mean that the later peak should have more activity than the earlier. Estimates 
of the rate of meteors during the late peak are as high as 5,000 per hour, although Mr. Kronk 
notes that, because the moon will be nearly full, a peak of about 3,000 is more likely.

Of course, cloud cover will mean no meteors at all, and that is what Mr. Kronk, who lives 
in a small town in southern Illinois, saw last year.

For those who suffer Mr. Kronk's fate this year, NASA will provide something of an alternative, 
a live television and Web cast offering reports and images of meteors zipping through the skies 
around the world. Details are available at www.nasa.gov/ntv/ntvweb.html.