Giant Leaps 10,000,000,000 km

1013 meters = 10,000,000,000 kilometers

All the planets in our solar system come into view. But at this distance, only Jupiter and Saturn would be visible with the naked eye.

Faraway dwarf planet Pluto orbits the sun at an average distance of 5.9 billion kilometers (3.7 billion miles). Pluto was the first of a large collection of small worlds, now known as the Kuiper Belt, to be discovered.

Dr. Kuiper's Belt begins just outside the orbit of Neptune, at a distance from the sun of 30 to 100 AU. There are probably more than 35,000 objects here with diameters greater than 100 kilometers (60 miles). There could be 100,000 or more!

Other than Pluto, the first Kuiper Belt Object (KBO) was detected in 1992. And the list is growing fast. In early 2004, an object 1,770 kilometers (1,100 miles) in diameter was found in this region of space. Sedna, as this dwarf planet is now known, may be the largest object in the Kuiper Belt after Pluto, which is 2,274 kilometers (1,413 miles) in diameter.

Most periodic comets—those that return on predictable orbital timetables—come from the Kuiper Belt. The most famous example is Comet Halley.