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:
“Beauty, like all other qualities presented to human experience, is relative; and the definition of it becomes unmeaning and useless in proportion to its abstractness. To define beauty not in the most abstract, but in the most concrete terms possible, not to find a universal formula for it, but the formula which expresses most adequately this or that special manifestation of it, is the aim of the true student of aesthetics.”
—Walter Pater (1839–1894)
“One definition of man is “an intelligence served by organs.””
—Ralph Waldo Emerson (1803–1882)
“Mothers often are too easily intimidated by their children’s negative reactions...When the child cries or is unhappy, the mother reads this as meaning that she is a failure. This is why it is so important for a mother to know...that the process of growing up involves by definition things that her child is not going to like. Her job is not to create a bed of roses, but to help him learn how to pick his way through the thorns.”
—Elaine Heffner (20th century)