Meteor showers occur when Earth passes through trails of dust and debris left behind by comets or asteroids. The Perseids come from a comet called Swift–Tuttle, which orbits the Sun once every 133 years. The comet's dust particles enter Earth's atmosphere at speeds of about 37 miles (59 kilometres) per second.

The annual Perseid meteor shower will peak this Tuesday and Wednesday. Here's everything you need to know: Head out after midnight, and before 5 a.m. to look for the meteors at maximum activity. They could be visible as early as 10 p.m. Tuesday.