However, several times each year Earth encounters a stream of debris left by a passing comet, and the result is a meteor shower. You'll notice the difference if you watch the sky for a half hour or so: not only do the number of meteors you'll see go up, but also the meteors seem to fly away from a common point in the sky called the radiant.
A shower gets its name from the constellation where this radiant lies — for example, August's well-known Perseid shower has its radiant in Perseus. The higher a shower’s radiant, the more meteors it produces all over the sky. One notable exception to this rule is the Quadrantid shower, named for the now-defunct constellation Quadrans Muralis. Instead, its radiant lies in the constellation Boötes.
Meteor showers peak during the predawn hours on the dates listed below, though they're typically active a few nights before and after the peak date. Note that the rates are for ideal conditions: very dark skies free of moonlight or light pollution; most likely you'll see somewhat lower rates than those listed. Following the table are specific predictions for each shower's prospects during 2009.
For the best possible viewing experience, find a dark location, make yourself comfortable in a reclining chair, and wear plenty of warm clothing. And for more information on watching and studying meteors, see Meteors: A Primer and the other articles in the Meteor section of our website.
|Major Meteor Showers in 2010|
|Shower||Radiant and direction||Morning of maximum||Hourly rate||Parent body|
|Quadrantid*||Draco (NE)||Jan. 4||100||2003 EH1|
|Lyrid||Lyra (E)||Apr. 22||10-20||Thatcher (1861 I)|
|Eta Aquarid*||Aquarius (E)||May 6||20-40||1P/Halley|
|Delta Aquarid*||Aquarius (S)||July 29||20||96P/Machholz|
|Perseid||Perseus (NE)||Aug. 13||60||109P/Swift-Tuttle|
|Orionid*||Orion (SE)||Oct. 21||10-15||1P/Halley|
|Leonid*||Leo (E)||Nov. 18||10-20||55P/Tempel-Tuttle|
|Geminid||Gemini (S)||Dec. 14||100||3200 Phaethon|
* Moonlight will wash out fainter meteors in these showers.
January 4: The Quadrantids
The good news is than the Moon won't be a factor for this year's edition of usually dependable Quadrantids. The bad news is that the peak of this short, sharp shower occurs during daylight hours for North America on January 3rd, the usual date for its maximum. But head out anyway — you should still see dozens of meteors per hour streaming from its radiant in northern Boötes.
April 22: The Lyrids
This isn't one of the year's strongest showers, and what few meteors you'll see will have to compete with a waxing gibbous Moon. Best bet: wait until the Moon sets (after midnight), or get up extra early. By then the radiant, near the Hercules-Lyra border, will be high up.
May 5: The Eta Aquarids
This shower is spawned by none other than Halley's Comet. It's typically a good one for Northern and Southern Hemisphere observers, though the radiant, in the Water Jar of Aquarius, rises late for northerners. Once these meteors start arriving they'll be sharing the sky with the last-quarter Moon, so don't expect to see more than 10 or so per hour.
July 29: The Delta Aquarids
Skywatchers in the Southern Hemisphere see the Aquarid showers best because their radiant is below the celestial equator. Light from a just-past-full Moon will wash out many of the predicted 20 or so Delta Aquarids per hour.
August 12–13: The Perseids
The Perseid shower is a popular display because it offers up to 60 meteors per hour under a summer sky. Showtime usually begins as soon as the radiant (near the Double Cluster in Perseus) clears the horizon, an hour or so before midnight. With a peak predicted for 8 p.m. Eastern Daylight Time on the 12th, you'll want to catch them early. A thin waxing crescent Moon won't be a spoiler this year.
October 21: The Orionids
This is another modest shower spawned by Halley's Comet. Ordinarily you might see 10 to 15 meteors per hour streaming from the shower’s radiant, located above Orion’s bright reddish star Betelgeuse. But light from a nearly full Moon will drop even those modest counts precipitously.
November 17: The Leonids
Typically the Leonid shower is a weak display, with fewer than a dozen meteors per hour radiating from Leo’s Sickle. But the parent comet, 55P/Tempel-Tuttle, tends to create narrow concentrated streams that can produce brief but prodigious displays (as was the case during the late 1990s). In contrast to 2009, which featured an exciting but brief pulse of meteors ejected by the comet in 1466 and 1533, no such bonus is in the offing for 2010. A waxing, nearly full Moon will wash out most of the 20 or so per hour that would normally be visible.
December 14: The Geminids
With an average of 100 meteors per hour radiating from near the bright star Castor, this end-of-the-calendar shower is usually one of the year’s best. Better still, you don't have to stay up until the wee hours to see them — at mid-northern latitudes, the radiant is well up in the sky by 9 p.m. However, for this year's performance, the Moon will be just past first quarter. So expect this shower to be at its best in the wee hours of December 14th, after the Moon has set. Geminid meteors come from 3200 Phaethon, an asteroid discovered in 1983.