How do astronomers know when a meteor shower will peak?

Meteor showers happen when Earth crosses a trail of small particles shed by a comet or, in some cases, an asteroid. These particles enter the atmosphere at high speed and burn up as streaks of light. Astronomers can predict shower peaks because the debris stream follows the parent body’s orbit, and Earth crosses the same path at roughly the same time each year. The Perseids, linked to Comet Swift-Tuttle, usually peak in August, while the Geminids, tied to asteroid 3200 Phaethon, peak in December. The number of meteors visible depends on the stream density, moonlight, and your viewing location.