Fiery Skies of August

8/5/07 – 8/11/07
by C. Zaitz

Every August, the earth passes through a part of its orbit where a vast cloud of debris awaits. The debris consists of tiny particles, many no larger than a mote of dust or grain of sand, left behind by a comet. As earth plows through the cloud, the tiny bits of rock are jammed into the thick atmosphere and create spectacular plasma trails as they incinerate. These are the Perseid meteors, and the nights of August 11th and 12th will be the peak this year.

I find it odd that particles so very tiny can make such a fiery fuss in the sky. So do other scientists, and it hasn’t been completely clear what is actually making the light. Scientist study the light from meteors to find out if it comes from ionized gas as the meteorite interacts with the air and melts and sublimates, or if it’s from the compressed and heated air that the meteorite creates as it slams in at over 40 miles per second. It may be both, but meteor spectra tell us that most of the light contains ionized bits of meteorite, making the first explanation more plausible as the main cause.

This year, the event of the Perseid meteor shower is predicted to be good. The moon will not be around to outshine the sometimes faint streaks of light, and if you can find a spot where the sky is not tainted by artificial lights, the chances are great for you to see several meteors a minute. Perseids can go off in any direction, but if you trace the streak back to the source, you will be somewhere near the constellation Perseus. Though the average sighting may be one per minute, often you will see a “clumping effect” where you may see 3-5 in a minute but then experience a lull.

The very best time to see them is always between midnight and sunrise, but that’s inconvenient for most of us. Luckily, anytime after twilight is fine, though if you can stay up, the view will get dramatically better towards morning. You don’t have to know where Perseus is, which is handy since he’s not the most spectacular of all constellations. Look toward the northeast in the early evening, and higher in the north more overhead as night turns to morning. All you really need is a fairly dark sky, perhaps a lawnchair, and some patience.

Meteor showers are one of the most fun things to watch in astronomy. You do not need the aid of binoculars or a telescope to enjoy a meteor shower, but you can try to photograph them if you’re a gambler or just very patient! You can stay out late with friends and count them or just try to be the first to see the biggest and brightest one of the night. It’s always fun to hear someone shout “There’s one” and have everyone sigh because by the time someone says those words, the meteor is usually gone. Meteor showers are social events, and a great way to watch the sky with your loved ones and friends. I encourage you to take your children or parents out for the evening and enjoy the natural show of the Perseid meteor shower.

Until next week, my friends, enjoy the view.