for National Geographic News
Shooting stars should be visible tonight, the traditional climax of the Leonid meteor shower. Sky watchers in the Americas, however, will observe peak activity early Wednesday morning.
The shower climaxed for viewers in eastern Asia late last week, but the nearly full moon washed out some meteors that would have otherwise been visible in a dark sky.
The shower's peak early Wednesday morning "will be better" than last week's, said Bill Cooke, an expert on meteor showers with the Space Environment Group at NASA's Marshall Space Flight Center in Huntsville, Alabama.
Weather permitting, residents in the northeastern United States, for example, may witness 17 meteors every 15 minutes as the shower peaks at around 2:30 a.m. ET on Wednesday.
While still impressive, Leonid activity is returning to normal after several years of spectacular displays, said Michael Bakich, an associate editor with Astronomy Magazine in Waukesha, Wisconsin.
"This year will not be one of the super showers as it has been over the last few years," he said. "It's coming back to normal." Bakich said sky watchers won't discern much difference in shower activity tonight and early Tuesday morning, the traditional Leonid peak, versus tomorrow night and early Wednesday morning.
Cooke maintains that while the 2003 Leonids will be less intense than in recent years, tomorrow night's peak will still see a ten-fold increase over normal shooting star activity, making that the optimal night to catch sight of a meteor.
The Leonids are caused by the comet Tempel-Tuttle, which swings through the inner solar system every 33 years. With each pass, the sun cooks off the comet a bit of dusty debris that trails in the comet's wake.
Earth orbits through this debris zone every year. When the planet passes through a stream, or trail, of debris, meteor showers grace the skies as the dusty particles vaporize in Earth's atmosphere.
"We always intersect multiple streams of Leonids. For the past few years, we've been intersecting up to six streams," said Cooke. "What makes this [year] unusual is the streams are so spread out so far in time."
In 2001, Earth directly hit a dense stream, sparking a meteor storm. The occasional phenomenon occurs when Earth encounters at least 1,000 meteors per hour. However, this year's peaks are separated by six days and will produce no more than 100 per hour, said Cooke.
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