For more than 2000 years, we have records of humans enjoying a spectacle of white streaks across the night sky about this time of year. We call it the Perseids meteor shower. Though it lasts a couple of weeks, tonight is the peak viewing time with the highest number of meteors per hour, so clear your calendar and find a clear view of the night sky.
What is a Meteor Shower?
As a kid, I had the fortune of spending a lot of time camping in the mountains. I relished the time around the campfire looking towards the stars, and dreamed that they were large rocks burning up as they entered the atmosphere.
As an adult, I learned that while larger rocks occasionally do enter the atmosphere, the majority of meteors are small specks. They are actually the size of a grain of sand. It is the speed of their entry into the atmosphere which causes the streaks. At 59 km/sec, the visible white “tail” we see crossing the sky is the air vaporizing around that grain of sand-sized particle.
These flying grains of sand typically come from comets orbiting around the sun. They are best described as a dirty snowball of frozen ice with lumps of rocks, debris, gas and other things frozen into it. When the orbit of a comet is closest to the sun, part of that snowball melts and releases the debris that travels to our little planet and which will eventually burn up in our night sky.
In the case of the Perseids, the debris for the meteor shower comes from the Swift-Tuttle Comet (which takes 133 years for one orbit of the sun). Because comet debris travels in roughly the same direction, meteors of a shower typically appear to come from a single point. The Perseids earned its name from having a radiant point within the Perseus constellation, and it usually peaks on or near August 12 every year.
Viewing the Perseids
Last year, I was camping in the mountains during the Perseids. With an exceptionally clear view of the night sky without haze or city light interference, our small group of campers counted over 100 meteors within a few hours. The quantity of meteors may vary depending upon the time and your location of viewing them—but, this meteor shower is the real deal with a prediction of nearly 60 meteors/hour at the peak viewing time tonight.
All you will need to see the Perseids tonight is a clear view of the sky, a warm jacket and maybe a blanket! Though you may start seeing them as soon as it gets dark, the moon will be out of the way for North American viewers after midnight.
Set your alarm, get outside and look up—it should be beautiful!
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