Orbital Plane (astronomy)
The orbital plane of an object orbiting another is the geometrical plane in which the orbit lies. The orbital plane is defined by two parameters, Inclination (i) and Longitude of the ascending node (Ω). Three non-collinear points in space suffice to determine the orbital plane. A common example would be: the center of the heavier object, the center of the orbiting object and the center of the orbiting object at some later time.
All of the planets, comets, and asteroids in the Solar System are in orbit around the Sun. The orbital planes of all those orbits nearly line up with each other, making a semi-flat disk called the invariable plane of the Solar System.
By definition the inclination of a planet in the solar system is the angle between its orbital plane and the orbital plane of the Earth (the ecliptic). In other cases, for instance a moon orbiting another planet, it is convenient to define the inclination of the moon's orbit as the angle between its orbital plane and the planet's equator.
Read more about Orbital Plane (astronomy): Artificial Satellites Around The Earth
Famous quotes containing the word plane:
“Even though I had let them choose their own socks since babyhood, I was only beginning to learn to trust their adult judgment.. . . I had a sensation very much like the moment in an airplane when you realize that even if you stop holding the plane up by gripping the arms of your seat until your knuckles show white, the plane will stay up by itself. . . . To detach myself from my children . . . I had to achieve a condition which might be called loving objectivity.”
—Anonymous Parent of Adult Children. Ourselves and Our Children, by Boston Women’s Health Book Collective, ch. 5 (1978)