by Daniel B

Created on: March 25, 2007   Last Updated: May 02, 2007

When Clyde Tombaugh discovered Pluto in 1930, he wanted to make sure it - and he - received appropriate amounts of publicity and attention. Being perhaps as good a promoter as he was an astronomer, he therefore proclaimed that he had discovered a rather large new planet. This seemed logical enough to everyone else: the other known planets in the outer solar system - Jupiter, Saturn, Uranus, Neptune - were all known to be much larger than earth.

In 1951, astronomer Gerard Kuiper wrote a paper proposing that since Pluto was another giant planet, the area of space around its orbit should be fairly clear of asteroids or other smaller rocks, which would have been pulled in by its gravitational field, just as happens with Jupiter and the other giant planets, or flung out to the far outer reaches of the solar system - an area we now call the Oort Cloud.

Both Tombaugh and Kuiper turned out to be completely wrong.

Bigger and better telescopes, space probes and other advances in astronomy revealed Pluto to be a rather tiny planet. Though spherical like the Earth, it wasn't the size of Jupiter, Saturn, Uranus or Neptune - in fact, it wasn't even as big as Earth's moon! It began to seem less likely that Pluto would have cleared the space around it like a giant planet should.

Then in 1992, using the University of Hawaii's 2.2-meter telescope on Mauna Kea, David Jewitt and Jane Luu discovered there was something else out there "in Pluto's space." It wasn't anything terribly special, just a small object they named "1992 QB1" - but Pluto was no longer alone. Over the next dozen years, using the same telescope and others, astronomers discovered hundreds more objects in orbits a similar distance from the sun. Far from being empty, Pluto's neighborhood was positively crowded.

A variety of names were proposed for this growing assortment of new objects. The scientifically preferred name wound up being "Trans-Neptunian Objects," or "TNOs" for short, but even today, many people both within and beyond the astronomical community refer to them collectively as the "Kuiper Belt," ironically using the name of the man who predicted that they wouldn't be there at all!

Around the turn of the millennium, David Jewitt advised a graduate student from Illinois named Chadwick Trujillo. During his time as a doctoral candidate, Chad worked with Jewitt to chart the orbits of hundreds of Trans-Neptunian Objects. After receiving his Ph.D., he moved to the California Institute of Technology as a postdoctoral

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