The Perseid meteor shower peaks at 6:00 pm, MDT, on Thursday, August 12, 2010. Predictions are for a healthy 90 meteors per hour at peak. A waxing crescent Moon will set early and give meteor watchers a good dark sky on the nights of the 11th and the 12th.
Regardless of the predicted peak hour, the best time to watch for meteors is during the pre-dawn hours (after midnight), your local time, when your position on the Earth is moving into the meteoroid stream. Meteors (commonly called ‘shooting stars’ or ‘falling stars’) are actually little more than grains of sand, dust and small pebbles that burn up high in the atmosphere as they fall down to Earth at very fast speeds. The Perseids are traveling at around 60 kilometers per second (130,000 miles per hour!).
Meteor showers are the result of a passing comet. Comets are mountain-sized objects made of frozen gasses, water, and dirt. As the comet approaches and rounds the Sun, it sublimates (turns from a solid directly into a gas, like dry ice), creating a cloudy sphere, called the coma, around the nucleus. The solar wind pushes on the coma forming the long comet’s tail, which always points away from the Sun. It is the gritty particle material of the comet that we see as meteors when the Earth passes through this debris field left behind long after the comet has passed. The comet may not come back for many years, but we will enjoy the meteor shower at about the same time every year. The Perseids are the result of comet Swift-Tuttle, which last passed the Sun in 1993 and won’t be back for another 118 years.
The name ‘Perseids’ comes from the comet Perseus. As you watch Perseid meteors, all over the sky, you can trace backward the familiar streak of light seen. No matter which direction the meteor is headed, the streak of light can be traced backward toward the constellation Perseus. Doing this for several meteors will show that there is a point of convergence for all these backward-traced paths. This point, called the ‘radiant,’ which will be in Perseus.
No need for a telescope or binoculars. Just get comfortable, get out of the city if you can, and enjoy the Perseid meteors this week.