Structure
At its fullest extent, including its outlying regions, the Kuiper belt stretches from roughly 30 to 55 AU. However, the main body of the belt is generally accepted to extend from the 2:3 resonance (see below) at 39.5 AU to the 1:2 resonance at roughly 48 AU. The Kuiper belt is quite thick, with the main concentration extending as much as ten degrees outside the ecliptic plane and a more diffuse distribution of objects extending several times farther. Overall it more resembles a torus or doughnut than a belt. Its mean position is inclined to the ecliptic by 1.86 degrees.
The presence of Neptune has a profound effect on the Kuiper belt's structure due to orbital resonances. Over a timescale comparable to the age of the Solar System, Neptune's gravity destabilises the orbits of any objects which happen to lie in certain regions, and either sends them into the inner Solar System or out into the scattered disc or interstellar space. This causes the Kuiper belt to possess pronounced gaps in its current layout, similar to the Kirkwood gaps in the asteroid belt. In the region between 40 and 42 AU, for instance, no objects can retain a stable orbit over such times, and any observed in that region must have migrated there relatively recently.
Read more about this topic: Kuiper Belt
Famous quotes containing the word structure:
“With sixty staring me in the face, I have developed inflammation of the sentence structure and definite hardening of the paragraphs.”
—James Thurber (1894–1961)
“Slumism is the pent-up anger of people living on the outside of affluence. Slumism is decay of structure and deterioration of the human spirit. Slumism is a virus which spreads through the body politic. As other “isms,” it breeds disorder and demagoguery and hate.”
—Hubert H. Humphrey (1911–1978)
“The philosopher believes that the value of his philosophy lies in its totality, in its structure: posterity discovers it in the stones with which he built and with which other structures are subsequently built that are frequently better—and so, in the fact that that structure can be demolished and yet still possess value as material.”
—Friedrich Nietzsche (1844–1900)