The Kuiper Belt is the largest mapped structure in our planetary system, three times as big as all the territory from the sun out to Neptune's orbit.
Every type of ring behavior we have seen around Jupiter, Uranus, or Neptune can be found in orbit around Saturn. And Saturn's ring system offers the greatest promise of understanding processes in operation within all disk systems, not just those found around planets.
No one planet can tell us everything about the universe, but Neptune seems to hold more than its share of information about the formation of our own solar system - as well as the solar systems beyond.
When Hubble was launched, it became clear very shortly thereafter that there was a problem with the optics.The mirror was not quite the right shape. And the one program that I had really been looking forward to doing with Hubble was studying outer planets in our solar system, the planets Uranus and Neptune.
To be taken into account were some years of schooling, where I studied with diligence Neptune's laws, and these laws I tried to obey when I sailed overseas; it was worth the while.