The rotation of a non-solid body in which different parts turn at different speeds. Stars and planetary atmospheres rotate differentially. For example, the equatorial regions of the Sun rotate about 25% faster than the polar regions, and the rotation of Jupiter is divided into System I (the equatorial region) and System II (the rest of the planet). Disk-like systems such as the rings of Saturn, accretion disks around stars, and disk galaxies also rotate differentially because they are composed of individual parts, each with a separate orbit.
Subjects: Astronomy and Astrophysics.