Halley’s Comet showed up in the inner part of our solar system in 1986 and won’t be visible again until 2061, but its traces remain. The debris strewn in the comet’s wake broke off from Halley as it was warmed by the sun.
As our planet passes through the remnants of the comet, bits and pieces of debris will hit our atmosphere and fall, heating up and causing bright white, green and orange streaks.
"We expect to see about 25 meteors per hour when the shower peaks on Sunday morning, Oct. 21," Bill Cooke, the head of NASA's Meteoroid Environment Office, said in a statement. "With no Moon to spoil the show, observing conditions should be ideal."
The Orionids get their name, because they appear to originate from the constellation of Orion.
The lack of moonlight isn’t the only reason this year’s Orionid shower is expected to dazzle. Other bright stars and planets will frame the meteor display. This weekend, the constellations Taurus, Gemini and, of course, Orion will be in view, while Venus, Jupiter and Dog Star Sirius will form a bright triangle in the eastern sky. On Sunday morning, the Orionids will be streaking straight through this celestial trio.
In order to view the Orionids, you may have to get up a little early. Cooke suggests going out one or two hours before dawn, in an area away from city lights. Look for the constellation Orion, with its characteristic “belt” made of a line of three stars.
Also, “be prepared for speed,” Cooke says. “Meteoroids from Halley’s Comet strike Earth's atmosphere traveling 148,000 mph. Only the November Leonids are faster.”
It's likely this year's show will be especially dazzling. Since 2006, the Orionids have been one of the best meteor showers of the year, with up to 60 or more meteors per hour in some years, according to Cooke.
The fast-flying Orionids often explode in our atmosphere, leaving behind lingering streams of smoke and debris that can be twisted by the wind into pretty shapes.
And if you can’t get to a suitably dark stargazing spot this weekend, NASA will be streaming a webcast of the meteor shower online starting at 8 p.m. Eastern time on Saturday. Astronomer Mitzi Adams will also be on hand to answer questions from the audience via chat.