Video encyclopedia

Orbital resonance


Students explain Orbital Resonances


Orbital Resonance of Jupiter's Moons - As a Beat


Orbital Resonances


Artist’s animation of the TOI-178 orbits and resonances (sound on!)


TRAPPIST Sounds : TRAPPIST-1 Planetary System Translated Directly Into Music

In celestial mechanics, an orbital resonance occurs when orbiting bodies exert a regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly this relationship is found for a pair of objects. The physics principle behind orbital resonance is similar in concept to pushing a child on a swing, where the orbit and the swing both have a natural frequency, and the other body doing the "pushing" will act in periodic repetition to have a cumulative effect on the motion. Orbital resonances greatly enhance the mutual gravitational influence of the bodies, i.e. their ability to alter or constrain each other's orbits. In most cases, this results in an unstable interaction, in which the bodies exchange momentum and shift orbits until the resonance no longer exists. Under some circumstances, a resonant system can be stable and self-correcting, so that the bodies remain in resonance. Examples are the 1:2:4 resonance of Jupiter's moons Ganymede, Europa and Io, and the 2:3 resonance between Pluto and Neptune. Unstable resonances with Saturn's inner moons give rise to gaps in the rings of Saturn. The special case of 1:1 resonance between bodies with similar orbital radii causes large Solar System bodies to eject most other bodies sharing their orbits; this is part of the much more extensive process of clearing the neighbourhood, an effect that is used in the current definition of a planet.
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    • History 

    • Types of resonance 

    • Mean-motion resonances in the Solar System 

    • Mean-motion resonances among extrasolar planets 

    • Coincidental 'near' ratios of mean motion 

    • Possible past mean-motion resonances