A meteor shower happens when Earth passes through a trail of small space debris. As those particles enter Earth's atmosphere, they burn up and create bright streaks called meteors.
Where the debris comes from
Many meteor showers come from debris left behind by comets. Some are linked to asteroids. The particles are usually tiny, but they move fast and glow as they heat the air.
Why showers return each year
Earth follows a regular orbit around the Sun, so it can pass through the same debris streams around the same time each year.
A meteor shower is different from a single comet or asteroid, though those objects can create the debris.