December 12, 2012
What Are The Geminids And Where Do They Come From?
[ Watch the Video: What is a Meteor? ]
John P. Millis, Ph.D. for redOrbit.com — Your Universe Online
Meteor showers are fascinating events - streaks of light across the darkness of night. While such displays struck fear into our ancestors, they provide wonderful entertainment today.
These celestial shows are rather common, with some 50 showers in 2012 alone (though not all of them are observable everywhere on Earth). One of the most brilliant events is the Geminid meteor shower, which arrives around the second week of December.
With an estimated 120 events per hour (roughly two per minute), the Geminids are usually one of the best showers of the year. But more than that, the Geminids are also special because they don´t come from the usual source.
Meteor showers are almost always the result of a comet passing through Earth´s orbit.
As a comet approaches the Sun it leaves a trail of dust in its wake. These tiny particles of rock and dust enter Earth´s atmosphere on its way around the Sun. As the grains heat up in our atmosphere, due to friction, they glow hot, creating the telltale streaks of light.
While the Geminid shower is still the result of dust particles entering our atmosphere, it wasn´t a comet that left them behind. Instead, researchers believe that an asteroid, called 3200 Phaethon, is responsible for the trail of dust.
This particular asteroid is part of a class known as Palladian asteroids, which have comet-like orbits around the Sun. The Geminids, along with the Quadrantids, are one of only two major meteor showers known to arise from an object other than a comet.
Where Do the Geminids Get Their Name?
The Geminid meteor shower gets its name because of the location of its radiant — the location in the sky where the meteors appear to be originating. In this case, the meteors seem to be emerging from the constellation Gemini (specifically, near the star Castor - one of the brightest stars in the sky).
Though, in reality, because of the nature of the Geminid shower, the meteors can appear almost anywhere in the night sky.
When to See the Geminids
The Geminid meteor shower is visible on clear nights in December, usually beginning around the 7th and extending into the middle of the month. The best time to catch them is at their peak, when the number of events climbs to more than two meteors per minute, which usually occurs around the 13th or 14th of December.