In 1994 the comet Shoemaker-Levy 9 put on an amazing display for Earth observers when it crashed into Jupiter.
The Kuiper Belt and Oort Cloud extend out far beyond the planets and are full of icy objects that may become comets like Shoemaker-Levy 9.
Photo: The asteroid Ida taken by the Galileo probe (NASA/JPL/USGS)
Minor planets orbit between Mars and Jupiter.
Leftover building material orbits the Sun.
Icy objects beyond Neptune may be a source of comets.
The Solar System's outer edge is predicted to be a source of comets.
Once a planet, Pluto is now a Kuiper Belt dwarf planet.