The science behind meteor showers
A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth’s atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the ground. Meteor showers are named after the constellation from which the meteors appear to originate; for example, the Leonids shower appears to radiate from the constellation Leo.
The science behind meteor showers is fairly simple. Meteoroids are pieces of cometary debris that are in orbit around the sun. As a comet orbits the sun, it sheds bits of itself; these bits eventually form a stream of debris that follows the comet’s orbit. Earth passes through these streams of debris, and as the debris enters our atmosphere, it burns up, creating the streaks of light that we call meteors.
There are generally two types of meteor showers: those associated with comets, and those associated with asteroids. The most famous comet-associated meteor shower is the Perseids, which is caused by debris from Comet 109P/Swift-Tuttle. The most famous asteroid-associated meteor shower is the Leonids, which is caused by debris from the asteroid 3200 Phaethon.
Meteor showers are typically annual events. However, there are some that occur more than once per year, and there are also some that have not been observed for many years. The reason for this is that the orbit of a comet or asteroid can change over time, which affects the position of its debris stream. When the debris stream and Earth’s orbit intersect, we see a meteor shower.
So, the next time you see a meteor shower, remember, you’re seeing bits of comet or asteroid burning up in Earth’s atmosphere!