Pure Perseids

A pair of glowing trails left by meteors.
Picture courtesy of Carter Roberts.They're called "shooting stars"--and I'm not referring to John Wayne or Clint Eastwood. I mean meteors, and they'll be spicing up the skies near you in less than two weeks.

First the news flash: The Perseid Meteor Shower, August 12, by the dark of the Moon! Be there. This year's Perseid shower coincides with the night of New Moon, so there will be no moonlight brightening the night, and it will be much easier to spot the fainter meteors and achieve a high sighting count for the night. How many meteors you count is the measuring stick of your success….

A "Perseid" is a meteor--shooting star, falling star, what have you--belonging to the Perseid Meteor Shower, an annual flurry of these brilliant atmospheric streakers that takes place on and around August 12. Their name comes from the fact that these meteors appear to come from the direction of the constellation Perseus.

The Perseid shower is notable in that it boasts one of the highest meteor rates of any of the annual showers. I've read different figures, but under good viewing conditions (no clouds, dark sky), one might expect to see as many as 50 or 60 meteors per hour. The ones you miss when you blink don't count, though.

Most meteor showers actually take place over a spread of days surrounding the expected shower peak date, sometimes spanning a couple of weeks or more. But these showers tend to start off slow, rise toward a peak activity night, and then taper off--so generally the best time to view a shower is within a day or so of the peak.

This year, the Perseids are expected to peak sometime on August 12, so you can expect a good show in the wee morning hours of Sunday the 12, Sunday night, and again in the wee morning hours of Monday the 13. For best viewing results, find a nice comfortable spot where you can see a broad swath of the sky--preferably in a location free from as much urban light pollution as possible (a "dark sky" sight). Look toward the northwest…and stare. Stare for hours. And don't blink. You will be rewarded.

A meteor is a small bit or rock or metal from space that burns up in Earth's atmosphere and leaves a glowing streak of hot vapor in its path. Meteors burn up completely in the atmosphere, and do not reach the ground. If a rock from space actually reaches the Earth's surface, it is called a meteorite.

Meteor showers occur when the Earth flies through a trail of dust left behind by a comet. Earth, moving along in its orbit at 18 miles per second, runs into these dust clouds much as a car speeding along the highway might run through a cloud of insects. Earth's "windshield" is our atmosphere--and instead of seeing streaks and blotches of bug guts all over the glass, we see streaks of light and flash across the sky. I have referred to meteors in a shower as the "dandruff of comets."

Now, get ready, make a pot of coffee, break out a chaise lounge, sit back and relax. Let the streaking begin….

Benjamin Burress is a staff astronomer at The Chabot Space & Science Center in Oakland, CA.