Along Earth’s orbit, how long is the nearby Perseid debris cloud during the 2026 shower?

Along Earth’s orbit, the nearby Perseid debris cloud extends for about 0.8 astronomical units during the 2026 shower. This is an estimate of the stream’s length in the direction Earth travels around the Sun.

Comet Swift–Tuttle has left particles along much of its elongated orbit over many returns to the inner Solar System. Those particles do not remain concentrated at the comet’s current position. Instead, solar heating, orbital motion and gravitational interactions spread them into a broad meteoroid stream.

The stream’s long extent helps explain why the Perseids are an annual shower rather than a single-night event. Earth begins encountering Perseid material in July and remains in or near the stream into August. The strongest activity occurs when Earth passes through the densest portion, usually around mid-August.