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The tiny blue and purple dots in this picture show where Kuiper Belt Objects are. See how they are out past Neptune, near Pluto?
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Image courtesy NASA/JPL-Caltech.

The Kuiper Belt

You might think that space out near Pluto is pretty empty and lonely. Guess what, it isn't! There are thousands and thousands of giant balls of ice and rock out there. Those giant balls are called Kuiper Belt Objects, or KBOs for short. The Kuiper Belt is a bit like the asteroid belt.

The Kuiper Belt is much farther from the Sun than the asteroid belt. The Kuiper Belt is out near Pluto. There are thousands and thousands of KBOs. Some are small. Some are bigger. Some might be as big as Pluto, or even bigger! Scientists aren't quite sure whether big KBOs are planets or not.

Pluto is a planet, but it is also a KBO. Other than Pluto, the first KBO was discovered in 1992. It has a weird name. Its name is name "1992 QB1". Astronomers have found hundreds more KBOs since 1992.

The Kuiper Belt is named after Gerard Kuiper. Gerard Kuiper was an astronomer. Before the Kuiper Belt was found, he said that some comets probably came from the Kuiper Belt. He was right.

The Oort Cloud is another part of the edge of our Solar System. The Oort Cloud is not the same as the Kuiper Belt. The Oort Cloud is much, much further away. Sometimes people talk about the Oort Cloud and the Kuiper Belt together. They call the whole combined thing "Trans-Neptunian Objects", or TNOs for short. All of the TNOs are further from the Sun than the planet Neptune.

Most KBOs have weird names. Some of the most famous KBOs are Pluto, 1992 QB1, Orcus, Quaoar, Ixion, and Varuna.

Last modified January 31, 2006 by Randy Russell.

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