Archives - Astronomy: Page 21
Author: paul carson (Wed Sep 27, 2006 2:06 am)
Title: Kuiper Belt Objects
More than 1,100 Kuiper Belt objects have been found so far. Astronomers estimate that half a million bodies larger than 20 miles wide are floating out there. At least one appears to be mostly rock with a coating of ice. Some are mostly ice. Some are less dense than ice, indicating a Swiss cheese like structure. A surprising number of them have moons.
Some move in clockwork with Neptune; Pluto, for example, is in what is called a 3:2 resonance, taking 1.5 times as long as Neptune to loop the Sun. Many Kuiper Belt objects have been flung into orbits crazily tilted to the rest of the solar system.
The distribution of Kuiper Belt objects has already provided decisive evidence that Neptune was once perhaps nearly a billion miles closer to the Sun and was then gravitationally nudged outward. Astronomers also hope that the Kuiper Belt preserves a frozen record of the earliest building materials of the solar system.
grow and be kind