One night this August, my
husband Richard and I woke at 3:30 am and headed groggily outside
to our back deck to watch for meteors. As I stepped out the door,
Richard said, “There’s one!” I looked overhead and caught the
tail end of a white line fading in the black sky over our small
town in south-central Colorado.
The meteor shower we
roused ourselves to watch was the Perseids, the most reliable
shower of the year, which begins in late July and peaks the second
week of August before tapering off. This celestial drizzle of
shooting stars is named for the constellation Perseus since the
meteors seem to radiate outward from its location near the Milky
Way.
The source of the falling stars is not the
constellation, however, but a trail of dust laid down by Comet
Swift-Tuttle. Earth passes through this debris-laden plume each
summer, producing fireballs that streak across the heavens.
Comets are celestial construction junk, writes astronomer
Chet Raymo, giant snowballs of ice and space debris left over from
the formation of our solar system. They hang out in the fringes of
our neighborhood until dislodged by passing stars and sent hurtling
on pendulum-like orbital paths around the sun.
I curled
up on the chaise lounge Richard had unfolded next to his and
scanned the night sky, too dazzled by the abundant stars to notice
meteors. As I began to pick out the familiar shapes of
constellations, I was reminded of how lucky I am to live in the
rural West, where the heavens remain dark, relatively unbleached by
light pollution.
Soon, a meteor zipped across the hazy
band of the Milky Way before burning out; an instant later, another
whipped away in the opposite direction, leaving a straight and
faintly reddish trail. After a few minutes with no meteor activity,
a really bright one streaked halfway across the sky before
vanishing in darkness.
Meteors begin as bits of debris
left behind by a comet on its swing through our solar system. The
sun boils the outer layers of the comet’s icy nucleus into a
halo of shimmering gases; solar winds whip the debris into a
streamlined “tail.”
This powdery tail persists like the
plume of dust trailing behind a pickup on a dirt road —
except the comet-detritus is not as harmless as rural dust; in the
zero gravity of space it never dissipates.
When earth
passes through this trail of floating comet trash, bits of debris
collide with our planet’s atmosphere. Heated instantly by the
friction of their sudden encounter with gaseous air, the particles
— most no bigger than a sand grain — flare as they
shoot across the heavens, and are vaporized, all in less time than
it takes to read this sentence.
The Perseid meteor shower
can be counted on to produce a trickle of fiery comet-debris each
summer. And in years when Earth brushes through a particularly
dense portion of Comet Swift-Tuttle’s gritty plume, the
trickle turns to a shower.
Humans have long read portents
in such stellar rains, interpreting meteor showers as mythical
beings like dragons or angels bearing messages from the heavens.
One cannot help but be awed and a little bit frightened when it
appears as if stars flare and fall.
If a meteor is large
enough to survive its plunge through our atmosphere, the celestial
detritus is dangerous indeed. Meteors have crashed through roofs,
started forest fires, even killed people.
As Richard and
I watched the bright streaks cross the star-freckled sky in the
chill of night, I shivered, thinking of the skies over Iraq, where
the artificial shooting stars of missiles and bombs split the
darkness, their explosive tracings cruel imitations of
meteors’ stunning beauty and deadly potential.
My
small town in the Upper Arkansas River Valley is a long way from
war-torn Iraq. But meteor showers bring that violence close in a
way television images and news stories cannot. When our planet
brushes across a debris-laden comet trail, sending flaming
projectiles cascading in all directions, I can almost feel the
searing power of those streaks of light. They provide evidence of
something we usually cannot grasp: our own fragility in the course
of Earth’s hurtling journey through space. In the momentary
illumination as meteors flare in the night skies over my small
town, the immensity of the universe seems very real, and our lives
very brief and blessed indeed.
Susan Tweit is a
contributor to Writers on the Range, a service of High
Country News (hcn.org). She writes books and essays in
Salida, Colorado.
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