How wide is the Perseid debris cloud near Earth’s orbit in the 2026 shower’s source stream?

The Perseid debris cloud is estimated to be about 0.1 astronomical units wide near Earth’s orbit.

The cloud is a broad stream of dust and small particles released by Comet Swift–Tuttle over many passages through the inner Solar System. Earth does not encounter a narrow, perfectly defined line of debris. Instead, our planet crosses a distributed region whose particles have been spread along the comet’s orbit by the comet’s motion, gravity, and repeated encounters with the Solar System.

An astronomical unit is the average distance between Earth and the Sun, approximately 149.6 million kilometers. Thus, 0.1 astronomical unit is roughly 15 million kilometers. The cloud’s estimated length along Earth’s orbit is much greater, about 0.8 astronomical unit.

These dimensions help explain why the Perseids recur annually. Earth intersects the stream at nearly the same part of its own orbit each August, while the dust cloud remains extended enough to produce activity over several weeks rather than a single instant.