The Perseids, Falling Stars over Lake Tahoe

Perseid meteor show during one of the observing sessions at Northstar California. | Courtesy Ryan Berendsen

Every year the Earth passes through a field of comet debris from late July to August causing a shower of falling stars we call The Perseids. The comet causing the shower, at 16 miles in diameter, is the largest solar system object (besides the moon) to regularly come near the Earth. It’s bigger than the asteroid that took out the dinosaurs and is traveling twice as fast: about 134,000 mph.

“Oh, the silent dust of tail
Round and round
As planets tour
Until almost like hail
The streaks of light
Fill the sky and mind
With sprite anticipation.”
– Tony Berendsen

The comet, named Swift-Tuttle after two American astronomers, was discovered independently in 1862. Records indicate it has been orbiting around the sun for more than 2,000 years with recorded sightings dating back to 322 B.C.

There are two great things to know about Comet Swift-Tuttle: It’s not going to hit the Earth for at least another 2,000 years and it causes a terrific showing of falling stars during the warm summer nights of August.

I’ve used the term falling stars purposely. A more correct term is meteor, but there really isn’t a difference in common meaning of either term, except that a meteor isn’t a star falling into the atmosphere.

Stars look small to us in the sky because they are very distant. The sun is a star, about 1 million times larger than Earth. It looms big in our sky because it is so close to us. If a star collided with Earth, well, that would be the end of all of us. The term falling star came to be at a time when humans thought stars were just points of light in the night sky.

A falling star is caused by a piece of debris from an asteroid or a comet burning up in our upper atmosphere, about 60 miles high. In the case of The Perseids, it is comet debris causing those beautiful fleeting streaks of light in the night sky. They are no larger than the tip of your finger and some are only the size of a grain of sand.

The Perseids are a periodic shower of falling stars returning every year. Comet Swift-Tuttle has left a trail of particles in its 133-year orbital path through the Solar System and when Earth travels through them we see falling stars. This year Aug. 11, 12 and 13 are the peak mornings to observe, since Earth will be traveling through the center of the trail of comet particles.

I suggest the best time to get out and observe this year are the evenings of Aug. 11 and 12, since the moon will be rising about midnight and its light will over shine the light of most of the falling stars in the morning hours. Luckily, there will be a couple of hours after sunset before the moon rises of dark skies for viewing.

Watching for falling stars is about both anticipation and patience. They appear in any part of the sky and will appear when they will — not any sooner. A fun way to enjoy the shower is to find a dark location with an unobstructed horizon. Bring blankets and a pillow to lay flat on the ground. Make yourself comfortable and look up to count how many you see in an hour.

I used to do this every year with my daughter Alisha when she was young. One year we decided to meet one of my astronomy mentors, Jessie Huntsman, out in Red Rock near Reno, Nev. We laid out among the manzanita and sagebrush for a couple hours listening to him talk about the constellations and stars while we were dazzled by streaks of light in the dark night sky.

As an added treat to enjoying the shower this year, Mars, Jupiter and Saturn will be above the horizon. Bring an astronomy app on your phone to help find them and binoculars or telescope to see them closer. |