Illustration by Victor R. Erickson
A meteor isn’t what its nickname implies. It’s not a “shooting star.” Our Sun is a star, large enough to fit 109 Earths across its diameter. The average meteor is the size of a grain of sand. But when that grain zips through our upper atmosphere at up to 50 miles per second, its flare-out is stunning.
I’ve seen Perseid meteors spewing flaming green tails, and ones with no tail, tumbling through the night like glowing knuckleballs. I’ve seen cigar-shaped Perseid meteors flying sideways, and chunks that split in two as Earth’s atmosphere found chinks in their armor. I’ve seen flameouts so bright they made me blink, and fireballs that fell to the horizon slowly, dripping molten gold in their wake.
Earth collects about 400 tons of meteoric debris every day, the lion’s share of which is so microscopic that it can float around for years before descending to our planet’s surface. A tiny minority of the debris is large enough to create that brilliant burst we see from ground level. And yet on an average night under a clear sky graced by low light pollution, the patient sky watcher can spot three or four meteors per hour, increasing to seven or eight by dawn. There’s a lot of stuff up there.
The light show gets serious when Earth in its voyage around the Sun passes through a special kind of debris. For billions of years, fragments left over from the formation of the outer planets have crossed the plane of Earth’s orbit in their long and elongated journey around the Sun.
As these mountains of ice approach our star, solar radiation begins to vaporize their surfaces and solar winds blow the gas and dust rearward, creating comas many times the diameter of Earth and tails millions of miles long. You might have seen two shining examples of these ice mountains back in 1996 and ’97. Their names were Hyakutake and Hale-Bopp, and their tails were magnificent. We know those ice mountains as comets.
One comet in particular, labeled 109P/Swift-Tuttle, slingshots around the Sun every 130 years on a path proximate to the plane of Earth’s orbit (its next sweep past the Sun will occur in 2126). Its detritus – grist for the meteor mill – is spread through long, narrow corridors of space like permanent oil spills.
Meteor watching is easy – no knowledge of astronomical facts or figures required. The Perseids’ radiant area is the constellation Perseus, but meteors scoot in from all points of the sky. All you need is a good pair of eyes and clear skies.
Scope out an open spot as far from city lights as feasible. Bring a blanket and pillow, a thermos of your favorite hot beverage and a portable recliner. The ultimate posture for meteor watching is the one that allows for the widest field of vision: flat on your back. (The naked eye is a far better meteor-sighting instrument than binoculars or a telescope.) So stretch out with your feet to the east, relax your focus and take in the whole sky at once.
And enjoy the show.
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