Elizabeth Jeffery, Ph.D., is an astronomer and former researcher at the Space Telescope Science Institute in Baltimore City. She is currently a professor of Physics and Astronomy at James Madison University in Harrisonburg, VA.
Sometimes the world's best shows go on behind the curtain. This will certainly ring true Thursday night and into the early morning Friday, as the Leonids meteor shower peaks on the other side of cloud cover.
This upcoming show will appear to hail from the constellation Leo the Lion.
So, what causes the meteor shower?
As I explained in a previous article, a meteor is created when a tiny piece of space junk (for example, a bit of dust or rock) enters the earth's atmosphere. As this small piece of debris flies high through the air, it encounters friction that makes it so hot it will burn up. As a result, a meteor appears as a quick, bright streak across the sky, and will then disappear. The brighter and longer the streak, the bigger the rock or dust particle that burned up.
On an average night, if you are away from city lights, with a dark, moonless sky, you will see an average of six random meteors an hour (mostly faint ones). But several times a year, we are treated to a meteor shower. Meteor showers are when the number of meteors we see are considerably greater than average. These additional meteors will also appear to be coming from approximately the same spot in the sky.
The predictable timing of some meteor showers is due to some of Earth's messier neighbors, comets. Comets go around the sun, just as the Earth does, but follow a different path. Sometimes comets will cross the orbit of Earth, and when they do, they leave behind them a trail of dust, rock and ice. Every time the Earth passes through this dirty spot (even after the comet is long gone), there is an increased amount of debris that enters our atmosphere and burns up, creating more meteors.
The comet that created the reserve of space junk for this upcoming shower is known as Comet 55P/Tempel-Tuttle, a comet that takes 33 years to make a complete orbit around the Sun. This year's shower is expected to produce 10-15 meteors per hour at its peak.
A meteor shower is named after the constellation where the meteors appear to be coming from. This shower will appear to be coming from the constellation Leo the Lion, hence its name—the Leonids.
You don't need any fancy equipment to view a meteor shower. In fact, it's better if you don't use a telescope or binoculars to watch for meteors because you want to be able to see a large area of sky all at once. Meteors will appear unexpectedly, and sometimes you will see one out of the corner of your eye, so you don't want anything narrowing your vision.
So, if you're lucky enough to spend the night in an area without cloud cover, grab a lawn chair and some blankets (bundle up, it will be cold!) and enjoy the show.