Meteor showers provide some of the most awe inspiring celestial events of the year. As would agree any stargazer fortunate enough to have seen a particularly prolific meteor shower raining down dozens of “shooting stars” from the sky each hour. Every now and then, we’re even treated to a meteor storm, which is a truly remarkable display in which thousands of meteors can be seen per hour. A spectacular example of this phenomenon is provided by The Great Leonids Meteor Storm of 1833.
Most meteor showers are the result of comets leaving behind an icy, dusty debris trail as they orbit the Sun. As the Earth makes it annual trek around the Sun, it travels through these various streams of small cometary fragments that burn up in Earth’s atmosphere. This in turn produces visible meteors. If the fragments are big enough, very bright meteors called fireballs may result. Or alternatively a “bolide” may be created, which is when a fireball explodes or breaks up in the atmosphere.
Each particular annual meteor shower typically last weeks. And while their meteors can appear anywhere in the night sky, they are often seen in the same region of sky associated with a particular constellation. This region is known as the radiant. The Geminids, for instance, are meteors that appear to originate from a point within the constellation of Gemini. The Earth passes through many of these comet debris trails as it orbits the Sun once a year. There are currently more than 900 known meteor showers, of which around 100 are well-established, visual showers. In this article, however, we will focus on the 10 biggest meteor showers of the year listed in chronological order.
10 Most Prolific Annual Meteor Showers
- Radiant: Constellation Boötes
- Parent body: Minor planet 2003 EH1
- Usual peak date: January 3
- Best viewed from: Northern hemisphere (party visible down to 50 ° S)
- Maximum zenithal hourly rate: 120
- Meteor velocity: 41 km/s
The Quadrantids can deliver at least as many meteors per hour as the Geminids and the Perseids. However, the debris trail that creates the Quadrantid shower is exceeding narrow. Consequently, most years more than 50% of the total Quadrantid meteor count occurs within only an 8 hour period or so. Moreover, many meteors in this shower go undetected as a result of being relatively dim, generally falling into the 3-6 magnitudes range.
The name “Quadrantids” derives from a former constellation known as Quadrans Muralis created in 1795. Although this contrived constellation is now a part of the constellation Boötes, an Italian observer reported in January 1825 that “the atmosphere was traversed by a multitude of the luminous bodies known by the name of falling stars [that] appeared to radiate from [the constellation] Quadrans Muralis”.
- Radiant: Constellation Lyra, near the star Vega (Alpha Lyrae)
- Parent body: Comet Thatcher (C/1861 G1)
- Usual peak date: April 22
- Best viewed from: Northern hemisphere, under dark skies
- Maximum zenithal hourly rate: 18
- Meteor Velocity: 48 km/s
The Lyrids have recorded sighting dating back to 687 BC, making them the oldest known meteor shower. They are also the richest meteor shower created by the debris of a long-period comet. Or more specifically by the comet C/1861 G1, which is classified as an intermediate long-period comet. Comets in this class typically have orbital periods that range from 200 years to more than 10,000 years. But since comet C/1861 G1 has an orbital period of only 415 years, the dust trail it creates is replenished more often than the trails of other long period comets.
Occasionally, the Lyrids produce a particularly rich display. Examples of such outburst occurred in 1922 and 1982 as a result of the planets “pushing” the comet’s debris trail closer to Earth. Under these conditions, which happen on average once every 60 years, the Lyrids can produce meteor counts of several hundred per hour. In 1803, for instance, observers counted more than 700 meteors per hour.
- Radiant: Constellation Aquarius, near the star Eta Aquarii
- Parent body: Halley’s Comet
- Usual peak date: May 6
- Best viewed from: Northern hemisphere, in hours just before sunrise
- Maximum zenithal hourly rate: 55
- Meteor velocity: 66 km/s
Unlike most other meteor showers, the Eta Aquariids do not produce a sharply defined peak. Instead, a slightly increased meteor count occurs for about a week centered on May 5.
The Eta Aquariids are reasonably consistent from one year to the next in terms of meteor counts. However, the current orbit of Halley’s Comet is too far from Earth to produce rich displays. As a result, during its week of peak activity this year just 1 meteor per minute is the best that we can expect from this shower. And even then only under dark skies from mid-northern latitudes.
Nonetheless, the 2013 Eta Aquariids produced a significantly richer display than usual. This is thought to be a result of a very old dust trail left behind by Halley’s Comet that had somehow become trapped into an orbital resonance with Jupiter. On this occasion, the Eta Aquariids produced about 135 meteors per hour. However, it is not certain when, or if this display will repeat itself to the same extent.
- Radiant: Constellation Capricornus
- Parent body: Comet 169P/NEAT
- Usual peak date: Mid-July until mid-August
- Best viewed from: Northern hemisphere
- Maximum zenithal hourly rate: 2-5/h. Sometimes flaring meteor outbursts of 5-9/h.
- Meteor velocity: Variable
The Capricornids rarely produce more than 9 meteors or so per hour. It does, however, produce many bright fireballs as a result of its debris trail containing fairly massive particles.
In 2005, comet 169P/NEAT was identified as the shower’s parent body. Scientists believe the meteor shower was created between 3500-5000 years ago after the comet broke apart. Nevertheless, Earth will only start to encounter the main debris trail on an annual basis in about 400 years’ time. The Capricornids are subsequently expected to become richer than any of the currently known meteor showers.
- Radiant: Constellation Perseus
- Parent body: Comet Swift–Tuttle
- Usual peak date: August 12
- Best viewed from: Northern hemisphere during the pre-dawn hours
- Maximum zenithal hourly rate: 60-100
- Meteor velocity: 58 km/s
The Perseid debris trail is known for being among the widest of all known cometary debris trails, stretching as it does across around 10% of the Earth-Sun distance. Most of the trail dust that Earth now encounters has been in the trail for around a thousand years. Furthermore, one particularly young filament of dust created in 1865 can sometimes create a noticeable peak about one day before the primary peak occurs on August 12 each year.
The Perseids typically run from about mid-July to about August 14, with a broad peak that usually occurs from August 9 to August 14. During this time, up to 60 meteors per hour can be seen coming from outside the showers’ radiant in the constellation Perseus.
- Radiant: Constellation Orion, near the red giant star Betelgeuse
- Parent body: Comet 1P/Halley
- Usual peak date: October 21
- Best viewed from: Mid-northern latitudes
- Maximum zenithal hourly rate: 20, but 50 -70 during some years
- Meteor velocity: 66.9 km/s
Of all the meteor showers that have Halley’s Comet as the parent body, the Orionids is by far the richest. The Orionids sometimes deliver up to 70 meteors per hour during the peak period, which usually occurs over roughly a week during the second half of October. The Orionids’ radiant lies at a point between the constellations Orion and Gemini.
- Radiant: Constellation Taurus
- Parent body: Comet 2P/Encke / Asteroid 2004 TG10
- Usual peak date: Southern Taurids (Oct. 10), Northern Taurids (Nov. 12)
- Best viewed from: Northern hemisphere
- Maximum zenithal hourly rate: 5
- Meteor velocity: 28 km/s
The Taurids are actually a complex of meteor showers, consisting of clearly identifiable northern and southern components. The southern component originates from Comet Encke, and the northern component originates from the asteroid 2004 TG10.
Comet Encke is believed a remnant of a much bigger comet which disintegrated between 20,000-30,000 years ago. In terms of volume, the resulting dust trail is the biggest known in the inner solar system. In fact, this dust trail is so wide that it takes Earth several weeks to pass through it. Moreover, this dust trail is particularly rich in bigger particles, with many the size of small pebbles. This helps explain the Taurids’ famous bright fireballs.
The Taurids have a complex pattern of peaks. For instance, the shower will have a particularly rich peak once every 2,500 to 3,000 years when Earth passes through a denser than usual part of the debris stream’s core. In addition, the northern and southern branches have peaks that overlap once every 3,000 or so years. This seems to be somewhat synchronous with the construction of megalithic structures such as Stonehenge. The next such peak will take place around the year 3000 AD.
- Radiant: Constellation Leo
- Parent body: Comet 55P/Tempel–Tuttle
- Usual peak date: November 17
- Best viewed from: Northern hemisphere. Also partially from mid-to high southern latitudes
- Maximum zenithal hourly rate: 15 to about 1000 during prolific outbursts
- Meteor velocity: 71 km
The Leonids are perhaps the most iconic of all meteor showers. This is no doubt a result of outbursts that have on occasion delivered several hundred thousand meteors per hour. It’s interesting to note that even in usual displays, the Leonids can deposit as much as 13 metric tons of material across the planet.
The Leonids shower is famous for producing bright, magnitude -1.5 fireballs. This is a result of particles that can be as big as 10 mm across, and weigh as much as 0.5 grams. However, the appearance of bright fireballs is not consistent from one year to the next because the main debris trail has split up into several discrete trails by gravity and solar radiation pressure. The effect of this? While the Leonids usually peaks on the 17th/18th of November each year, it often happens that a broad peak spanning several days on either side of the usual peak dates occurs.
- Radiant: Constellation Gemini, near the star Castor
- Parent body: Asteroid 3200 Phaethon
- Usual peak date: December 14
- Best viewed from: Northern hemisphere soon after sunset. Also in southern hemisphere at about local midnight
- Maximum zenithal hourly rate: 120
- Meteor velocity: 35 km/s
Apart from the Quadrantids, the Geminds are the only major meteor shower that does not have a regular comet as its parent body. Instead, it originates from a rocky minor planet. One interesting aspect of this shower is that it seems to be intensifying each year. In fact, recent hourly maxima have increased consistently to reach about 160 meteors per hour.
Geminids are also slow moving, with most meteors rarely exceeding velocities of around 35 km/s. This makes them very easy to spot and track as they move across the sky.
- Radiant: Constellation Ursa Minor, near the star Kochab (Beta Ursae Minoris)
- Parent body: Comet 8P/Tuttle
- Usual peak date: December 22
- Best viewed from: Northern hemisphere
- Maximum zenithal hourly rate: 10
- Meteor velocity: 33 km/s
Although the Ursids are fairly consistent in terms of peak dates, they are not a particularly rich shower. In some years, their meteors may even be impossible to distinguish from usual background meteor activity. When comet 8P/Tuttle is at aphelion, though, outbursts can occur which typically produce up to 170 or so meteors per hour. At this point, part of the debris trail becomes trapped into a 7:6 orbital resonance with the planet Jupiter.
Note though that the Ursids debris trail is particularly narrow. This means it is possible to miss the peak altogether if you are not actively looking for increased activity within a period of 12 hours from the expected peak.