One of the implications of the discovery of the Kuiper Belt and its many small planets is that many scientists now think of the solar system as having not two but three zones.

I tend to think of Pluto and its moons as presents sitting under a Christmas tree. They're wrapped, and from Earth all we can do is look at the boxes to see whether they're light or heavy, to see if something maybe jiggles a bit inside. We're seeing intriguing things, but we really don't know what's in there.

There are lots of really interesting little planets out there in the Kuiper Belt, but Pluto's the only one that's got all the cool attributes.

Alan Stern Quotes