Hi Stuart,

As you probably know there has recently been a lot of debate over Pluto's status as a planet. The problem arises from the definition of "planet".... there are some controversies about what the definition should be. So it is possible that at some time in the future, if scientists agree that Pluto fits into the definition of "planet" (this definition might change with time), it could once again be considered to be a planet. If Pluto falls back into the definition of "planet", then there are a few other objects in our solar system that are similar to Pluto which would also be considered a planet. The problem is really in the definition, and as that might change with time, so might Pluto's (and other objects in space) status. Science is always evolving and part of that evolution sometimes requires changes in definitions.

Holly