The days of summer are starting to wane, the back-to-school ads are running on television and the meaningless NFL preseason games are about to begin. But there is one good thing you can look forward to this time of year, the Perseid meteor shower.

There are about a dozen meteor showers per year, but the Perseids are special because of two things: the abundance of meteors and the fact that you can watch the show without freezing your rear off.

This week is the best time to catch the show. After midnight - and especially from 2 a.m. to 5 a.m. - is the best time to view the Perseids.

The peak of the show will be Friday morning, and it will be extra special because the moon will have already set, leaving us with dark skies. Of course, the absence of the moon won't do you a lot of good in the middle of an urban or well-developed area. But if you can get out to the suburbs or countryside, you may see 50 to 70 meteors or "shooting stars" per hour.

Many people call meteors shooting stars because they literally look like stars falling from the sky. But they're actually just grains of dust and pebbles. The biggest ones may approach the size of small walnuts. This is all debris left behind by comets that have passed by the Earth and our sun.

Comets basically are dirty snow/ice balls that partially melt when they get close to the sun. Debris from these partially melted comets is left in their wake and gravity between the particles keeps the debris trail intact.

Meteors from meteor showers are best seen after midnight because, at that time, we'll be on the side of the Earth that's heading into the debris trail. It just like taking a drive on a summer night. You get more smashed bugs on your front windshield than you do on the rear.

The debris trail that causes the Perseids is from the comet Swift-Tuttle that comes by this part of our solar system about every 130 years and last passed by in 1992. There is some thought that Swift-Tuttle could possibly collide with the Earth in 2126, but that's been played down by a lot of astronomers. I guess time will tell.

In the meantime, tiny pieces of Comet Swift-Tuttle will slam into our atmosphere at speeds over 40 miles per second, easily incinerating them before they can get anywhere near you.

Most of the light you see from meteors as they streak across the sky is not caused by their flaming death, but by ionization. These debris particles are zipping through our atmosphere so fast that the column of air they are going through is being destabilized. Zillions of electrons are temporarily bounced away from the nucleus of zillions and zillions of atoms, and that produces energy in the form of light.

The Perseids are called the Perseids because all of the meteors seem to emanate from the general direction of the constellation Perseus the Hero. In the early morning hours, Perseus rises high in the northeastern sky. Does that mean you just look toward the northeastern sky? Nope. If you do you'll miss a lot of good meteors.

My advice for watching the Perseids, or any other meteor shower, is to lie back on the ground or a reclining lawn chair and roll your eyes all around the sky. Watching a meteor shower with family and/or friends is lot of fun because you have that many more eyes watching the big sky.

Once again, Friday morning is the peak and you could see over 60 meteors per hour, or about one per minute, but you have to watch the sky closely. The Perseids are famous for the number of meteors you can see, but most of them are faint and rapidly rip across the sky.

Oh yeah, and while you're sitting out in the dark, don't forget the bug spray.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the new book, "Pennsylvania Starwatch," available at bookstores and at his Web site

www.lynchandthestars.com