The curved path of a celestial object around a star, planet, or moon under gravity's influence. Orbits can be circular, elliptical, parabolic, or hyperbolic. Johannes Kepler first described planetary orbit laws in the early 1600s.
The point in the orbit of a planet, asteroid, or comet at which it is farthest from the Sun. Earth reaches its aphelion ...
The point in an orbit at which the object is closest to the Sun. Earth reaches perihelion around January 3rd at approxim...
A unit of measurement equal to the average distance between Earth and the Sun, approximately 149.6 million kilometers (9...
Dive deeper into orbit and related concepts on Cosmos Observatory.