2.  The Kuiper belt is a region of the solar system that starts just beyond the orbit of Neptune, contains dwarf planets like Pluto and Eris and other small celestial bodies made mostly of ice, and forms a flat ring.  A dwarf planet is any object that is round because of it’s gravity and orbits the sun but has not cleared it’s orbital path.  It takes Kuiper Belt objects about 12,000 year to orbit

3.  Short –period comets are comets that take less than 200 years to complete an orbit.  Astronomers believe that most short-period comets are found in the Kuiper belt.

4.  A spherical region that surrounds the solar system that extends from the Kuiper belt to nearly half way to the nearest star. There are billions of comets in the Oort cloud, astronomers think that most comets are from the Oort cloud.

5.  The Oort cloud contains billions of comets.  Along with other ice and dust particles it is estimated to be 10 – 40 earth masses.  This material is suspected to be left over from the formation of the solar system.

6.  Objects in the Oort take a few million years to orbit the sun because it is so far away.  Nearby passing stars can knock comets out of their orbit and fall into a more elliptical orbit around the sun.  These are called long period comets because it takes them more than 200 years to complete an orbit.

7. Oort cloudKuiper Belt SizeFrom the Kuiper Belt it extends halfway to the nearest star Starts just outside the orbit of Neptune Color, surface featuresVaries Rotation / RevolutionA few billion year revolution About 12,000 years to revolve DensityVaries GravityVaries Atmospheric CompositionNA Surface CompositionVaries Interior CompositionVaries Magnetic fieldNA MoonsNA Unique featuresContains billions of comets Contains dwarf planets and comets and other small celestial bodies