What is a Shooting Star?
Written by Fraser Cain
A shooting star is another name for a meteoroid that burns up as it passes through the Earth's atmosphere. So, a shooting star isn't a star at all.
Most of the shooting stars that we can see are known as meteoroids. These are objects as small as a piece of sand, and as large as a boulder. Smaller than a piece of sand, and astronomers call them interplanetary dust. If they're larger than a boulder, astronomers call them asteroids.
A meteoroid becomes a meteor when it strikes the atmosphere and leaves a bright tail behind it. The bright line that we see in the sky is caused by the ram pressure of the meteoroid. It's not actually caused by friction, as most people think.
When a meteoroid is larger, the streak in the sky is called a fireball or bolide. These can be bright, and leave a streak in the sky that can last for more than a minute. Some are so large they even make crackling noises as they pass through the atmosphere.
If any portion of the meteoroid actually survives its passage through the atmosphere, astronomers call them meteorites.
Some of the brightest and most popular meteor showers are the Leonids, the Geminids, and the Perseids. With some of these showers, you can see more than one meteor (or shooting star) each minute.
We have written many articles about stars on Universe Today. Here's an article about the Quadrantid meteor shower, and here's an article about the Geminids.
Want more information on stars? Here's NASA's World Book on Stars, and more information from NASA's imagine the Universe.
We have recorded several episodes of Astronomy Cast about stars. Here are two that you might find helpful: Episode 12: Where Do Baby Stars Come From, and Episode 13: Where Do Stars Go When they Die?
Filed under: Astronomy
