Encke, the comet

The observations, physical studies, and orbital investigations of Encke's comet are reviewed and its significance in the quest for understanding the evolution and nature of comets is discussed. Attention is given to Encke's study on the comet's anomalous orbital motion and the hypothesis of a resisting interplanetary medium. Consideration is given to recent major changes in both dynamic and physical investigations of the comet, including studies of its precession and rotation, the nature of the nongravitational anomaly, and the evolution of discrete active regions on the nucleus.