Perihelion

Perihelion, in astronomy, the point in the orbit of a planet, comet, or other body that is closest to the Sun. When Earth is at its perihelion in early January, it is about 4,800,000 km (3,000,000 miles) closer to the Sun than when at its aphelion (farthest point from the Sun) in early July. Corresponding terms for describing the most distant orbital point of bodies moving around centers of force other than the Sun include “perigee” (for closest point to Earth) and “perijove” (for closest point to Jupiter). The perigee of Earth’s Moon, for instance, is about 50,000 km (31,000 miles) closer to Earth than its farthest orbital point (apogee). The word “pericenter” is a general term for the closest point in a body’s orbit from the body it circles.