by Ruth Ann Grissom
September 23, 2015
Now that the autumnal equinox has passed, our nights will become increasingly longer until the winter solstice, but three major meteor showers will brighten our skies in the coming months: the Orionids, Leonids and Geminids. This year, the moon shouldn’t interfere with any of these events at their peak, so conditions will be optimal as long as the weather cooperates.
Meteor showers are named for the constellation from which they seem to emanate. They
The 2010 Perseids over the VLT by ESO/S. Guisard – http://www.eso.org/public/images/potw1033a/. Licensed under CC BY 4.0 via Commons – https://commons.wikimedia.org/wiki/File:The_2010_Perseids_over_the_VLT.jpg#/media/File:The_2010_Perseids_over_the_VLT.jpg
appear in the same part of the sky at the same time every year thanks to the earth’s annual orbit around the sun. Comets have a more elliptical path around the solar system, so we regularly encounter their icy detritus. When this debris enters our atmosphere, the pieces are usually as small as a grain of sand or a hunk no larger than a baseball. They heat to more than 3000 degrees Fahrenheit, causing them to glow and vaporize. Despite being known as falling or shooting stars, the meteors aren’t moving; we are.
The Leonid mega-storm of 1966, which at one point produced thousands of meteors per minute, made some observers feel as though “they needed to grip the ground, so strong was the impression of Earth plowing along through space,” according to an account on the EarthSky website (http://earthsky.org). Alas, that’s an exceedingly rare event. Most range from showers of 10 to storms of 100 per hour. The intensity is surprisingly hard for astronomers to predict due to small variations in the paths of the comet and Earth induced by the gravitational pull of other planetary bodies. Until it’s upon us, we never know if we’re heading into a particularly sparse or dense stretch of a comet’s tail.
The other variable is weather. The Persied meteor shower in mid-August is popular with those who hate the cold, but in the Uwharries, summer skies are often fuzzy with humidity or obstructed by towering cumulonimbus clouds, so it’s not reliably spectacular in our neck of the woods. This year, I watched the Persied from the deck of a rustic cabin in Lassen Volcanic National Park. This was the first time we’d planned our annual reunion with my husband’s family to coincide with the meteor shower. It’s a popular time – I had to book the cabins a year and a half in advance. In California, where it seems to never rain these days, the skies are likely to be clear in August, but there’s always the risk of smoke from forest fires. In fact, the week before we arrived, the park had suffered reduced visibility due to nearby fires, but luckily for us, the winds shifted just in time.
We were there three nights around the peak. Above our mile-high valley, the skies were dark and clear. Our deck offered a view of Scorpio sauntering across the southern horizon, and we soon realized there was no need to turn and focus on Perseus, the constellation at the source of the shower, in the northeast. Meteors blazed across the valley. They seemed so close, I might have felt the urge to duck if I’d been standing on the ridge. It was thrilling enough to keep me up till midnight, despite the jet lag and three-hour difference in time.
But I’ve witnessed fall and winter meteor showers in the Uwharries that are just as impressive. Several years ago, my mom, dad, sister and I loaded up the bed of the truck with pillows, pads and blankets and drove to the corner of our darkest field. Conditions were perfect that night. The sky above us was deep enough to give us a glimpse of infinity. The four of us huddled together, sharing a thermos of coffee. I don’t know how we managed to endure the cold so long. Each meteor we spotted gave us hope for the next. We were insatiable. Just one more, we promised ourselves and each other. But that one wasn’t enough. We craved another, and another after than. We waited patiently for the flashes and streaks of light as we hurtled headlong into the path of cometary detritus, filled with awe at its passing.
For more information about meteor showers, including viewing tips and the dates of our fall events, go to the McDonald Observatory’s Star Date website (https://stardate.org/nightsky/meteors).