Make a wish upon a falling star? That will be an easy task this weekend as the annual Orionid meteor shower brings a dazzling display of shooting stars.
If skies are clear, Orange County residents will be treated to one of the year's most beautiful aerial shows as the meteor shower peaks, according to NASA scientists.
Those looking skyward Saturday night and Sunday morning will see earthbound Orionid meteors, particles left behind by Halley's comet burning up as the planet crosses through the swath of debris left by the comet.
"We expect to see about 25 meteors per hour when the shower peaks on Sunday morning," says Bill Cooke, the head of NASA's Meteoroid Environment Office. "With no moon to spoil the show, observing conditions should be ideal."
The Orionid meteor shower happens each year in late October when the Earth drifts through debris from Halley's comet, which last passed through the inner solar system 1986 and won't be back until 2061.
Because these meteors streak out of the constellation Orion, astronomers call them "Orionids."
Cooke suggests going outside one to two hours before sunrise when the sky is dark and the constellation Orion is high overhead. Orionids will appear from a small area near the shoulder of Orion, but spray across the entire sky, according to NASA.
"Be prepared for speed," Cooke said. "Meteoroids from Halley’s Comet strike Earth's atmosphere traveling 148,000 mph. Only the November Leonids are faster."
To view the meteor shower, follow these viewing tips from Tammy Smecker-Hane, director of the UCI observatory:
- Find as dark a location as you can, away from street lights, shopping plazas, etc., and lie back in a chair or on a blanket and look up at the sky. Some of the best places to go are ball fields or grassy parks where you have no lights and no trees or houses nearby to block your view.
- No telescopes are needed and most cameras have such a small field of view (unless you have a special fish-eye lens) that photographing the meteors is very difficult.
- The meteors will happen all over the sky. However, if you trace their path backward, all will seem to intersect at the Orion constellation. This is just an optical illusion but it gives this shower its name, Orionid.
- Whether it is easy to see shooting stars during a meteor shower depends on whether the Earth crosses through a lot or a little of the comet's debris, which can vary each year, and whether the moon is out or not. When the moon is bright, it makes the night sky brighter and harder to see fainter meteors. The darker the sky, the more fainter ones you'll see. Fortunately, this year, the moon is in the crescent phase and sets around midnight, so the sky will be relatively dark. As long as the clouds stay away, your chance of seeing some great meteors is good.
According to Smecker-Hane, most of the particles that give rise to the meteors are only the size of a few grains of sand. Despite their small mass, they have high kinetic energy as they hit the Earth's atmosphere because they're traveling at speeds of about 50,000 mph.
As the debris hits molecules in the atmosphere, the atmosphere glows, forming a bright trail across the sky known as a meteor or "shooting star," Smecker-Hane said.
Meteoroids must originally be bigger than the size of a fist to survive the trip through Earth's atmosphere and strike the surface of the Earth, Smecker-Hane said.
"We can find these meteorites easily in Antarctica and in deserts where their charred, black surfaces make them easily stick out against the ground. However, most of the Earth's surface is covered with water so most meteorites land harmlessly in the ocean," she said.
Even when there is no meteor shower, 800 meteorites weighing more than 100 grams (about a quarter-pound) hit the Earth every day, she said.
"But the Earth is so large that most hit harmlessly, and there's absolutely no need to worry about you or your home getting struck by one," she added. "The fact that the frequency of meteors striking Earth is larger during a meteor shower means the frequency of shooting stars is higher than normal, which makes for some exciting observing."