If the sky is clear, the annual Perseid meteor shower could rock this year, astronomers predict.
Weather permitting, St. Vincent College's School of Natural Science, Computer Science and Mathematics will hold an open house for stargazers from 9 to 11 p.m. Wednesday, the onset of peak viewing time.
Physics club and department members will be on hand outside the physics building to talk about the celestial event.
"This promises to be one of the better ones in recent years," said John Smetanka, assistant professor of physics at the college in Unity Township.
"The moon is a waning crescent and will not rise until after 2:30 a.m.," he said. "Astronomers are also predicting that the Earth will be passing through a relatively new and dense cloud of debris from comet Swift-Tuttle."
The comet is the source of the space dust trail that causes the Perseid shower. The display of "shooting stars" occurs every year in mid-August, when Earth travels through Swift-Tuttle's orbital path.
"In 1862, a new filament of dust boiled off the comet and, if predictions are correct, the earth could plow through this new filament on Wednesday evening," said Kim Bonenberger, of the Carnegie Science Center's Henry Buhl Jr. Planetarium & Observatory in Pittsburgh.
Smetanka said this "could enhance the number of shooting stars we see from 60 to 100 per hour to several hundred per hour."
The meteor shower takes its name from the constellation Perseus, found in the northern sky. Many of the shooting stars appear to be streaming from a point near the constellation.
Most meteors are "really the size of a grain of dust," Smetanka explained.
The bright trails we see from the ground are atoms being vaporized by friction as those particles enter Earth's atmosphere at amazing speeds.
"A larger, say gravel-sized, piece looks like a big ball of fire shooting across the sky," he said. "But few ever make it to the ground because they burn up very high in the atmosphere."
Most of the meteors are "fairly faint," Smetanka added. But with the new moon, "the sky will be much darker, so it will be easier to see them."
A fair number of meteors should be visible in the weeks before and after the shower's peak date -- from now through Wednesday and Friday through Aug. 17.
"For best results ... lie down on your favorite lawn chair and look toward the northeast," Bonenberger advised.
"The best viewing will be after 2 a.m. Thursday, from a location free of lights," Smetanka added. "But even city dwellers should be able to see some meteors Wednesday evening."
