Neptune and Pluto
How does Neptune's moon system differ from those of the other Jovian worlds? What do these differences suggest about the origin of Neptune's moon system?
What causes Triton's geysers?
What is the predicted fate of Triton?
How do the rings of Neptune differ from those of Uranus and Saturn?
Will Pluto and Neptune ever collide?
How were the mass and radius of Pluto determined?
In what respect is Pluto more like a moon than a Jovian or terrestrial planet?
In what sense were astronomers fortunate to discover Pluto?