SOUTHERN UTAH — The Sky Report is presented as a public service by the Stellar Vista Observatory, a nonprofit organization based in Kanab, Utah, which provides opportunities for people to observe, appreciate and comprehend our starry night sky. Additional information is available online. Send questions and comments to [email protected].
The main event this week is the annual Perseid meteor shower, which peaks on the evening of Aug. 11.
Meteors, also called “shooting stars,” are the flash of light you see when a piece of dust from outer space falls through our atmosphere. They fall so fast – in this case, at 37 miles per second or 130,000 miles per hour – that friction with the air burns them up in seconds at a height of 50 miles or more. Faint meteors are caused by dust-size particles, while brilliant meteors come from something the size of a marble. Every night, random meteors fall at the rate of approximately six per hour.
A meteor shower happens when the Earth moves through a swarm of particles shed by a comet long ago. The tail of Comet NEOWISE, which we saw recently, is made of dust shed by the evaporating dirty-ice nucleus, and those particles drift away, following in the comet’s orbit. When we pass near that orbit, we plow through a swarm of dust and see a meteor shower.
These meteors come from dust shed by Comet Swift-Tuttle. We pass through the swarm at the same point in our orbit each year, in mid-August. The shower lasts all week but peaks on the night of Aug. 11.
Most meteors are faint, so for best effect it’s essential to have a dark sky. Dress warmly, lie comfortably and look up. These meteors appear to radiate from the direction of the constellation Perseus (hence their name, Perseid), which is very low in the northeast after dark.
As the hours pass and Perseus rises higher, you’ll see more meteors. The best time to look is the morning hours of Aug. 12, when you might see up to one meteor per minute. Most people will look on the night of Aug. 11, when meteors fall at the rate of one every few minutes.
While watching for meteors, notice four bright planets. Jupiter and Saturn are in the southeast as the sky grows dark; Jupiter is the brighter of the two. Mars rises in the east around midnight. Venus rises at 4 a.m. and is a third of the way up the eastern sky at sunrise. The crescent moon is near Venus on the morning of Aug. 15 in a nice pairing – and photo opportunity.
Written by JOHN MOSLEY. John Mosley was program supervisor of the Griffith Observatory in Los Angeles for 27 years and is the author of “Stargazing for Beginners” and “Stargazing with Binoculars and Telescopes”. He and his wife live in St. George where he continues to stargaze from his retirement home while serving on the advisory committee for Stellar Vista Observatory.