Meteor fun — luck of locale

LITTLE MOUNTAIN — Cars parked every-which-way, vehicles cruising up with headlights a-glare, Tori Amos songs playing loudly through the warm night, a group of young men making off-color jokes — it wasn't your typical meteor shower.

The scene early Thursday was an impromptu star party to observe the annual Perseid meteor shower. But some of the dozens of folks visiting this site at the top of Emigration Canyon seemed to ignore the "star" part and simply partied.

Infrequently, those paying attention to the sky would ooh and ahh, as bright streaks flashed across the star fields. But others merely continued with their summer frolic.

Perhaps they would have been more attentive to the astronomical wonders had the meteor shower been more amazing. But despite predictions this could be one of the best Perseid displays, for much of the night it was unimpressive, at least this close to Salt Lake City's light

pollution.

Also, Venus and the sliver of a moon rose above the mountains around the time when the shower's peak was supposed to start. Their light, reflecting from a thin cloud cover, further washed out the view.

In other locations, the fireworks were much better. Why the difference?

"It's really the luck of the draw," said Patrick Wiggins, NASA solar system ambassador to Utah.

Most meteor showers result from cometary debris burning up in the atmosphere. In the case of the Perseid (the name comes from Perseus constellation, the area of the sky from which the meteors seem to originate), the parent comet was one dubbed Swift-Tuttle.

On its long orbital path, whenever a comet nears the inner solar system it heats up and begins to blaze and shed bits of debris. This material, which may stretch out as a long tail, tends to remain in space as tiny particles in the comet's orbit.

When Earth passed through that orbit, sometimes centuries later, grains of comet dust strike the atmosphere and friction makes them burn up. Their searing destruction is the meteor display that watchers enjoy.

"The meteorite material . . . is not of uniform density," Wiggins said. In the comet's orbit, "there are places where it's very dense, so if you hit that place you get many, many, many meteorites.

"But there're also places that are quite sparse." If Earth happens to run through the comet's orbit in one of the sparse regions, few meteors will light up the sky. If it goes through a denser area, the show is better.