Skywatchers brace for a storm of meteors

If astronomers’ predictions are correct – and if Wisconsin gets a break from its chronically cloudy November weather – skywatchers will be in for a rare treat next Tuesday, Nov. 19, as the annual Leonid meteor shower has been upgraded to a show of stormy proportions.

“We’re really looking for a meteor storm rather than a shower,” says James Lattis, director of the UW Space Place.

The difference between a meteor shower and a meteor storm, says Lattis, is that a storm produces thousands of meteors per hour compared to hundreds, at best, for a shower.

The difference, Lattis explains, is determined by the angle of the Earth as it passes through streams of icy debris left in the wake of Comet Tempel-Tuttle, a comet that regularly sweeps through the inner solar system and is the source for the meteors that make up the annual Leonid meteor shower.

Like all comets, Tempel-Tuttle sheds particles of ice, mostly, and dust as it traverses a long elliptical orbit around the sun. As the Earth passes through the trail of junk shed by the comet, the particles burn up as they fall through the Earth’s atmosphere and create the distinctive streaks of light we know as meteors or, colloquially, as shooting stars.

“This comet orbits the sun approximately every thirty-three years,” Lattis explains. “Every time it passes through the inner part of the solar system, it leaves a trail of debris. But the comet doesn’t retrace its path exactly, so what you have is a braided tangle of filaments from many passes of the comet.

“If we hit one of those square on, we get a real meteor storm. This year, the calculations put us going right through the middle of a filament left by the comet in1866. We should get a pretty good display.”

Tempel-Tuttle last visited our part of the solar system in 1998.

According to Lattis, clear skies permitting, those looking for meteors will get a show that may not be rivaled until the end of the century. The conditions for a storm arise right after the comet passes through the inner solar system, which happens every 33 years. But the next two Leonid meteor storms may not be as good because the Earth will pass farther from the orbit of the comet.

“The year 2099 will be the next time the Earth will pass through this thick part of the swarm of comet trails,” says Lattis. “This is a rare opportunity.”

Lattis will help host a meteor-watching party near the boathouse at Wingra Park early next Tuesday morning when the storm is expected to be at a peak. The predicted peak of the storm will be at about 4:30 a.m., with optimal viewing an hour on each side of the peak.

The party, co-hosted by the Madison Astronomical Society , UW-Extension and the Friends of Lake Wingra, is free and open to the public. In addition to meteor watching, the Madison Astronomical Society will have telescopes available for viewing planets and other objects in the early morning sky.