The past few months have been busy with meteor showers ranging from the Perseids in August, the Orionids in October, the Leonids in November, and the Gemenids which peak tonight (Dec. 13) and will continue into next weekend. With all the talk and Facebook events about the showers it's only be appropriate to talk a bit about meteors.
What causes meteors?
As the Earth travels through space it encounters debri clouds. As we travel through one of these clouds, the Earth's gravity will "pull" on pieces, causing them to encounter the atmosphere on their journey downward. When this happens the atmosphere puts friction on the meteor and causes it to burn up, usually completely, before reaching the surface of the planet. This happens daily, but most debri is small and burns up in the upper atmosphere. When there is an increase in this activity, it is called a meteor shower.
Meteor showers are usually caused by debri that falls off of comets. Chunks of material that are large enough will fall through the atmosphere and get closer to Earth's surface before burning up. As friction slows down the material it glows; this is what we see as a meteor, or shooting star as it has popularly been coined. Meteor showers are usually named for the constellation that they appear to originate from (e.g. the Gemenids appear to shoot out from the constellation Gemini).
The best place to watch a meteor shower is in a very dark area away from city lights or any other local luminescence that can cause light pollution and obstruct your eyes from adjusting properly to level necessary for viewing meteor showers. The consensus is that once you can view all the stars in the little dipper constellation, your eyes have properly adjusted.
When is a meteor a meteor?
Astronomers have different terms for a meteor depending on where it is in its travel. When the material is just floating through space, it is called a meteoroid. Once it enters our atmosphere and starts burning up, it is called a meteor. If a piece of the material makes it through without burning up and hits the surface, it is called a meteorite. Happy viewing!