Definition
| Planet | rH (Gm) |
|---|---|
| Jupiter | 51 |
| Saturn | 69 |
| Uranus | 73 |
| Neptune | 116 |
There is no widely accepted precise definition of an irregular satellite. Informally, satellites are considered irregular if they are far enough from the planet that the precession of their orbital plane is primarily controlled by the Sun.
In practice, the satellite's semi-major axis is compared with the planet's Hill sphere (that is, the sphere of its gravitational influence) . Irregular satellites have semi-major axes greater than 0.05 with apoapses extending as far as to 0.65 . The radius of the Hill sphere is given in the adjacent table.
Read more about this topic: Irregular Moon
Famous quotes containing the word definition:
“Scientific method is the way to truth, but it affords, even in
principle, no unique definition of truth. Any so-called pragmatic
definition of truth is doomed to failure equally.”
—Willard Van Orman Quine (b. 1908)
“I’m beginning to think that the proper definition of “Man” is “an animal that writes letters.””
—Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)
“... we all know the wag’s definition of a philanthropist: a man whose charity increases directly as the square of the distance.”
—George Eliot [Mary Ann (or Marian)