What is a Meteor Shower?

Several times a year meteor showers light up the sky. Find out everything you need to know about these celestial fireworks, including the yearly dates of important meteor showers, and when and where to view them from, in this handy guide.

Illustration image — Geminid Meteor Shower of 2012.

Many times a year, hundreds of shooting stars lighting up clear night skies. But they don't really have anything to do with stars. These small space particles are meteoroids and are literally celestial debris.

Meteor, Meteoroid or Meteorite?

Whenever a meteoroid enters the atmosphere of the Earth, it generates a flash of light called a meteor, or "shooting star". High temperatures caused by friction between the meteoroid and gases in the Earth’s atmosphere heats the meteoroid to the point where it starts glowing. It is this glow that makes the meteoroid visible from the surface of the Earth.

Meteoroids generally glow for a very short period of time - they tend to burn up before hitting the surface of the Earth. If a meteoroid does not disintegrate while passing through Earth’s atmosphere, and hits the Earth’s surface, it is known as a Meteorite. Meteorites are thought to originate from the asteroid belt, though some meteorite debris have been identified as belonging to the Moon and Mars.

What is a Meteor Shower?

Sometimes, meteors occur in clusters known as a meteor shower. Meteor showers occur when a comet comes close to the sun and produces debris - meteoroids - that spread around the comet’s orbit. Anytime the Earth’s and the comets orbit coincide, the Earth experiences a meteor shower.

Since meteoroids that create a meteor shower all move on a parallel path, and at the same velocity, they seem to originate from a single point in the sky to observers on Earth. This point is known as the radiant. By convention, meteor showers, especially the regular ones are named after the constellation that the radiant lies in.

Prominent Meteor Showers

While meteors can occur at any time of the year, some meteor showers occur at the same time every year. Some of the more famous meteor showers have been observed by humans for hundreds and thousands of years.

Quadrantids

Quadrantids is the first meteor shower of every year, usually occurring between the last week of December, and January 12. It peaks around January 3 and January 4, and is best seen from the Northern Hemisphere. The radiant point for the Quandrantids lies in the constellation Boötes, close to the Big Dipper.

Lyrids

The radiant point of the Lyrids lie in the constellation Lyra. This meteor shower occurs between April 16 to April 26th of every year and can seen from the Northern and Southern Hemisphere.

Eta Aquarids

The next major meteor shower of year, the Eta Aquarids, occurs between late April and mid May, peaking around May 5-6. It is best seen from the Southern Hemisphere, though observers in the Northern Hemisphere can also enjoy a sparser display. Meteoroids in the Eta Aquarids are actually remnants from Halley’s Comet. The radiant for this shower lies in the constellation Aquarius.

Perseids

The Perseid meteor shower occurs in mid August, reaching peak activity around August 11-13. Its radiant lies in the constellation Perseus, and is associated with the comet Swift-Tuttle.

Draconids

The Draconid meteor shower, occurs every October, peaking around October 7-8. The name of this shower comes from the constellation Draco the Dragon.

Orionids

The Orionid meteor shower, which is also associated with debris from Halley’s comet, occurs every October, peaking around October 21-22. The name of this shower comes from the constellation Orion.

Leonids

Leonids occur during the month of November, usually peaking around mid-November. It is associated with the comet Tempel-Tuttle and is named after the constellation, Leo.

Geminids and Ursids

The month of December is good for meteor shower watchers, with the Geminids gracing the skies in early December, peaking around December 13-14, and the Ursids that peak around December 22-23. The Geminids owes its name to the constellation Gemini and are the only major meteor shower that is not associated with a comet, but with an asteroid. Ursids on the other hand get their name from the constellation Ursa Minor.

Viewing a Meteor Shower

Meteors are best viewed during the night, though meteoroids can enter the Earth’s atmosphere at any time of the day. They are just harder to see in the day light. Any ambient light, even from the moon, is a bane for meteor watchers. Meteors can be best seen away from city lights, on a new moon day.

Since meteors seem to come from the constellation they are named after, meteor watchers should try and find the direction of the constellation in the sky and look there for meteors.

July and August are some of the best months to observe meteor showers. Along with the Perseid, these months experience several minor meteor showers. December is another good month for meteor watchers.

Topics: Astronomy, Meteors