A second chance? Not in astronomy. Once you’ve seen a storm of meteors explode across the heavens, or a total eclipse fall over Nutley, New Jersey, you’ve usually got to wait a lifetime for a shot at seeing it again. But we’ve been granted a rare boon: a reprise of the great Perseid meteor shower that was so anticipated last summer. Now it’s Take Two-- except that conditions are even better this time around.
You probably remember what happened. The long-lost comet Swift- Tuttle dashed through our neighborhood late in 1992, leaving behind a swarm of debris that reinforced the hailstorm through which our planet crashes every August.
All this cometary rubbish produces the Perseid meteors, so named because they seem to fly away from the constellation Perseus, whose obscure pattern rises in the northeast around midnight. In years when the moon isn’t too bright, the resulting one-per-minute display of shooting stars provides summer’s finest night for stargazing.
With our planet bulldozing its way through the newly enhanced cometary stream, the shower should be unusually rich this year. It could even become a storm--a striking phenomenon that rewards people situated on the right part of Earth with dozens of meteors per second.
Last year Europe was favored as the best viewing area, with an outside chance that the place to be would be the East Coast of the United States. But few who live in either region got the opportunity to find out, since both places were extensively overcast.
New calculations suggest that the best chance for a meteor storm wasn’t 1993 after all, but 1994, and that the region most likely to get the fireworks will again be somewhere around the Atlantic--very possibly the eastern United States! (Other astronomers believe 1995 or 1996 will be the optimum year; it all depends on the thankless, imprecise science of figuring out where Swift-Tuttle ejected its densest swarm of debris.)
Even with such uncertainty, this month’s Perseids should again be better and brighter than normal no matter where you live, with 100 or more ultrafast meteors during each peak hour. Perseids are exceptionally fast because they meet our planet head-on, entering our atmosphere at 37 miles per second, some 80 times faster than high-velocity bullets. (For comparison, the November Andromedid meteors lope along at just 12 miles per second.) It’s no surprise, then, that few of the raisin-size visitors last longer than two seconds as they transmute into glowing sky dust.
This really is our best shot until 1996. The moon, an unobtrusive crescent, will set well before midnight, which is when the display normally starts cranking up. (Next year a full moon will spoil things no matter what else happens.) If the weather cooperates, we may witness one of the sky’s finest shows.
You can try on two nights, since the maximum effect is likely to occur during daylight hours over the United States and Canada. Catch the performance Thursday, August 11. If it’s cloudy or less than spectacular, you’ll get a second chance shortly after maximum, on the following night. A few simple tips will give you the best seats in the house.
First, choose a dark site. This is a good time to visit those friends in the country. And park yourself in a place with a wide-open sky-- don’t sit under a tree. To avoid a stiff neck, bring a lounge chair. Or spread a blanket and take another one along for warmth. This is one time when the sequel--Perseids II--should be better than the original.
