Ranger Steve’s Nature Niche
“Shooting stars” create fire in a black sky. To celebrate my birthday, the Perseid meteor shower reoccurs annually with a peak fire performance from August 11-13. I pretend the fireworks are a personal birthday celebration but I know scientifically we all share this annual nature niche event equally.
Why does the Perseus meteor shower gain prominence as my birthday approaches and diminish afterward?
Most of us are aware the sun is the center of our solar system with planets that revolve around it and are held by its gravity. It takes the Earth about 365 days for a trip around the sun and we call it a year. The time it takes planets to go around the sun is their year but it is easier to compare their orbits to our year. It takes Jupiter nearly 12 Earth years to go around the sun once and only 88 days for Mercury.
Earth’s path around the sun brings the planet into contact with space debris that becomes “shooting stars” (meteors) nightly. During mid-August, the Perseid meteor shower light show might have 200 shooting stars an hour because there is massive debris in Earth’s orbit at that location. A comet likely passed through Earth’s path and left billions of rock, iron, or nickel bits floating in space.
Comets orbit the sun making large oval loops. We can predict return dates for some but adequate data is not present for others. Some may not return. Little is known about the source of debris for the Perseus meteor shower. Perhaps a comet passed through Earth’s path and it may or may not return.
Think of Earth’s path as a tube that the planet is in as it travels around the sun. When debris drifts into the tube, it gets caught by Earth’s gravity and is pulled to the surface. As the material within the tube is drawn toward Earth, it heats, glows, and vaporizes. Material farther outside the tube continues to float in space and next year it might drift close enough to be caught by gravity.
Material left by a passing comet is called a meteor swarm. It is a mass of material that is mostly very small. The average size of a meteor is .0005 (5 ten thousands) of an ounce. That is the size of sand grain. When the Earth passes, it draws particles that heat, glow, and vaporize. Some larger pieces glow very bright and may even survive to land on Earth as a meteorite.
My friend Bob and I went to see the “Old Woman” that is kept hidden away in recesses of the Smithsonian National Museum. We received permission to have someone escort us to see her because she is not in a public access area. The Old Woman is the largest meteorite found in California and the second largest found in the United States. It was named for the location it was found (The Old Woman Mountains).
This week spend time watching the sky for meteors. It is best to look between midnight and dawn when Earth faces the direction of travel and collides with more debris. Before midnight, we can see many but it is like backing into debris instead of hitting it face on. Think of it like driving a car forward into insects or backing into them. You will notice most when looking and driving forward as you hit them. The front windshield gets splattered and the back does not.
Shooting stars are usually about 50 to 75 miles over head but emit bright light for a tiny sand-sized particle. Meteor showers are named for the constellation where they appear to originate. The constellation Perseus can be found in the northeast sky and moves west during the night. Perseus stars are light years away and have no relationship to the meteor shower that originates in Earth’s orbit. Look before the moon rises or after it sets because the sky will be darkest. Get away from lights that impair the ability to enjoy a dark night sky. You have a couple weeks for watching the Perseid Meteor shower.
Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at firstname.lastname@example.org – Ody Brook Nature Sanctuary, 13010 Northland Dr. Cedar Springs, MI 49319 or call 616-696-1753.