Comet Swift–Tuttle is in a 1:11 orbital resonance with Jupiter during the era of the 2026 Perseids.
An orbital resonance occurs when the periods of two orbiting bodies form a simple numerical relationship. In this case, Swift–Tuttle completes approximately one orbit for every eleven completed by Jupiter. The relationship is not a physical tether; it is a recurring timing pattern created by gravity and orbital motion.
Swift–Tuttle’s resonance is unusual because the comet travels on a retrograde orbit, meaning it moves around the Sun in the opposite direction to the planets’ general motion. The comet is described as the first object in a retrograde orbit found in such a resonance.
Resonances can influence the long-term evolution of small bodies by repeatedly altering their orbital paths. They help explain why the comet’s return intervals vary over time and why its orbit must be calculated carefully when predicting future appearances.