Mysterious and magical, meteor showers are some of the most spectacular celestial events visible from Earth, but what lies behind nature’s year-round firework display?

It can feel special to see a shooting star. Maybe they’re a reminder of the infinite vastness of the universe, or perhaps it’s just that Jiminy Cricket promised they’d make our dreams come true in The Adventures of Pinocchio. Either way, they’re an awe-inspiring sight that has inspired thinkers from Aristotle to Stephen Hawking and poets from Sappho to Sylvia Plath.

But shooting stars are not stars at all. They come from meteoroids – fragments of space rock left in the wake of a comet, asteroid or, more rarely, other larger bodies such as the moon. In their elliptical orbits, comets and asteroids periodically pass close to the sun, which burns off some of the ice from their surface, leaving a trail of dust and rocks. When it enters the Earth’s atmosphere at speeds of more than 11km per second, this cosmic debris burns up and meteoroids become meteors – the glowing streaks we know as shooting stars.

Raining fire

Meteor showers occur whenever the Earth passes through the dust-laden orbit of a comet or asteroid. Because comets and asteroids move around the sun on a fixed path, just like Earth does, we pass through each one’s trail at the same time each year; although as the distribution of rocks and particles within the meteor’s trail is random, the peak can vary within that time.