Please Enter Your Search Term Below:
 Websearch   Directory   Dictionary   FactBook 
  Wikipedia: Apsis

Wikipedia: Apsis
From Wikipedia, the free encyclopedia.

This article is about the astronomical term. In architecture, apsis is also the plural of apse

In astronomy, an apsis is the point of greatest or least distance of the elliptical orbit of a celestial body from a center of attraction. The point of closest approach is called the periapsis and the point of farthest approach is the apoapsis.

According to Kepler's laws of planetary motion, as a body approaches the periapsis it will increase in velocity and as a body approaches the apoapsis it will decrease in velocity.

When the body the orbit is around is known, more specific names are often used.

Body being orbitedClosest approach Farthest approach
Earth perigee apogee
The Sun perihelion aphelion
The Moon perilune apolune
a black hole perimelasma apomelasma


From Wikipedia, the free encyclopedia. 
Modified by Geona