Spend even an hour under a dark, Moonless sky, and you'll likely catch sight of a meteor as it suddenly and unexpectedly paints a bright streak across the dark firmament. "Shooting stars" can occur at any time on any night. Most nights a half dozen of these sporadic (random) meteors appear hourly.
The flashes come more often, and the heart pounds a little quicker, during a meteor shower. These occur several times a year, whenever Earth encounters a stream of debris left by a passing comet. During one of these 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. 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.
In any case, the higher a shower’s radiant, the more meteors it produces all over the sky. Each shower has its own characteristics, due in part to the mix of sizes within the stream and in part to the velocity at which its bits of matter slam into Earth's atmosphere. As the chart here shows, even pea-size particles can create startlingly bright meteors.
Meteor showers peak during the predawn hours on the dates listed below, though they're typically active one or two nights before and after the peak. Note that the rates are for ideal conditions: very dark skies free of moonlight or light pollution, and with the radiant theoretically directly overhead. Most likely you'll see somewhat fewer meteors than those listed, but bright ones can dazzle you no matter what your conditions might be. Following the table are specific predictions for each shower's prospects during 2011.
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 2011|
|Shower||Radiant and direction||Morning of maximum||Hourly rate||Parent|
|Quadrantid||Draco (NE)||Jan. 4||60-120||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|
|Draconid*||Draco (NW)||Oct. 8||100?||21P/Giacobini-Zinner|
|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
With new Moon falling on the same night as this shower's peak, prospects are good for a fine show from this short, sharp shower. The peak is predicted to occur at 8 p.m. Eastern Standard Time on January 3rd, which is a little too early to be optimal because the shower's radiant doesn't climb high over the northeastern horizon until after midnight. Click here for more details.
April 23: The Lyrids
Rates aren't dramatic from this shower, whose particles come from Comet Thatcher (1861 I). However, this year the predicted peak favors North American viewers as it falls during the evening hours of the 22nd. Count on seeing roughly a dozen or so meteors per hour emanating from a radiant near the Hercules-Lyra border, espceically in the window after the radiant clears the horizon (about 9 p.m.) and before a waning gibbous Moon rises (2 a.m.).
May 6: 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. Moonlight won't be an issue this year, so observers with dark skies might see a meteor every minute or two.
July 29: The Delta Aquarids
Skywatchers in the Southern Hemisphere see the Aquarid showers best because their radiant is below the celestial equator. The Moon is new during this year's peak, so figure on seeing about 20 Delta Aquarids per hour.
August 13: The Perseids
The Perseid shower is perennially popular with Northern skywatchers because it offers up to 60 or more 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. Unfortunately, this year's preformance will be muted by the bright light from a full Moon. The Perseids' parent comet is 109P/Swift-Tuttle.
October 8: The Draconids
Ordinarily, the Draconid shower (formerly called the Giacobinids) puts on a so-so celestial show, delivering no more than 20 meteors per hour at best. However, celestial prognosticators predict that, this year, Earth will clip a dense stream of particles ejected in 1900, yielding Draconid rates that could top 600 per hour — 10 per minute — for ideal viewing conditions. Unfortunately, the timing of this short-lived pulse favors observers in Europe, and the shower's many faint meteors will be obliterated by a nearly full Moon that night. Click here for more details.
October 21: The Orionids
This is another modest shower due to Halley's Comet. You'll have a couple of moonlight-free hours to observe with the radiant over the horizon before a fat waning crescent rises. Watch for 10 to 15 hourly meteors that stream from above Orion’s bright reddish star Betelgeuse.
November 18: The Leonids
this shower's parent comet, 55P/Tempel-Tuttle, tends to create narrow concentrated streams that produces brief but prodigious displays — most recently during the late 1990s. But no such luck this year: expect the more typical weak display, with fewer than a dozen meteors per hour radiating from Leo’s Sickle. Lght from a last-quarter Moon won't help.
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, this year's performance will be partly spoiled by a just-past-full Moon that rises not long after the radiant clears the northeast horizon. Geminid meteors come from 3200 Phaethon, an asteroid discovered in 1983.