Kuiper Belt

Circling the solar system like a large ring is a group of objects named after the astronomer who proposed their existence, Gerard Kuiper (rhymes with "viper"). The Kuiper Belt is the home for many asteroids (the Trans-Neptunians) as well as the short-period comets (long-period comets come from the Oort Cloud).

Several objects in the Kuiper Belt have been discovered recently solidifying the evidence that the belt actually does exist. Astronomers believe that the gravitational pull from the larger, outer planets sometimes tears objects out of the Kuiper Belt and sends them heading out of the solar system (and sometimes into the solar system).


The Oort Cloud
The Oort cloud is an immense spherical cloud surrounding the planetary system and extending approximately 3 light years, about 30 trillion kilometers from the Sun. This vast distance is considered the edge of the Sun's orb of physical, gravitational, or dynamical influence. Within the cloud, comets are typically tens of millions of kilometers apart. They are weakly bound to the sun, and passing stars and other forces can readily change their orbits, sending them into the inner solar system or out to interstellar space. This is especially true of comets on the outer edges of the Oort cloud. The structure of the cloud is believed to consist of a relatively dense core that lies near the ecliptic plane and gradually replenishes the outer boundaries, creating a steady state. One sixth of an estimated six trillion icy objects or comets are in the outer region with the remainder in the relatively dense core.


The Heart of Darkness, or the Solar Cradle? or both?