KnowraPolar motionLinked fromLinked fromThe 8 pages that link to Polar motion, each with the reason it gives.All 8Broader topic 1Related 4Compared with 3Earth’s rotationRelated: Earth’s spin axis shifts slightly as mass moves within and across the planet.South PoleRelated: It causes the exact surface location of the rotational pole to vary slightly over time.Universal TimeRelated: Its effect on observed rotation is corrected when deriving UT1 from UT0.Celestial poleRelated: It produces small changes in the precise celestial pole direction.