Written by Tony Phillips
Science at NASA
Washington, D.C. – Waking up before sunrise is a good way to get a head start on the day. On October 21st, waking up before sunrise could stop you in your tracks.
Blame Halley’s Comet. Every year in mid-to-late October, Earth passes through a stream of dusty debris from Comet Halley, and the pre-dawn sky can light up with a pretty display of shooting stars.
“We expect to see about 20 meteors per hour when the shower peaks on Tuesday morning, October 21st,” says Bill Cooke, the head of NASA’s Meteoroid Environment Office. “With no Moon to spoil the show, observing conditions should be ideal.”Because these meteors streak out of the constellation Orion, astronomers call them “Orionids.”
“The Orionid meteor shower is not the strongest, but it is one of the most beautiful showers of the year,” notes Cooke.
The reason is its setting: The shower is framed by some of the brightest stars in the heavens. Constellations such as Taurus, Gemini and Orion provide a glittering backdrop for the display. The brightest star of all, Sirius, is located just below Orion’s left foot, a good place to point your camera while you’re waiting for meteors.
To see the show, Cooke suggests going outside one to two hours before sunrise when the sky is dark and the constellation Orion is high overhead. Lie down on a blanket with a broad view of the heavens. Although Orionids emerge from a small area near the shoulder of Orion, they will spray across the entire sky.
“Be prepared for speed,” he adds. “Meteoroids from Halley’s Comet strike Earth’s atmosphere traveling 148,000 mph. Only the November Leonids are faster.”
Speed is important because fast meteors have a tendency to explode. Occasionally, Orionid fireballs will leave incandescent streams of debris in their wake that linger for minutes. Such filaments of “meteor smoke” twisted by upper atmospheric winds into convoluted shapes can be even prettier than the meteors themselves.
“It really is a wonderful morning to be awake,” says Cooke. “Just don’t plan on going anywhere in a hurry.”
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