Do you see any value in questioning and ultimately changing Pluto's planet status?

Answer 1

There was not any good reason for the International Astronomical Union (IAU) to define the term "planet" as it did, or WHEN it did. There had never been a formal definition of the word "planet". The IAU defined "Planet" with three criteria;

1. Orbits a star, not another planet

2. Has reached hydrostatic equilibrium; meaning, its own gravity has squashed it into a spherical shape (or nearly so).

3. Has "cleared its orbit" of other objects, meaning that there are no other objects traveling in the same orbital path.

It is this third requirement that caused Pluto to be demoted from "planet" to "dwarf planet". There are other objects in the Kuiper Belt which potentially could match Pluto's orbit. In fact, by this third criteria, the Earth itself doesn't really qualify as a "planet"; there are near-Earth asteroids that orbit in paths that are not dramatically different from ours.

Part of the controversy has been that "recent" (at the time) discoveries of other Kuiper Belt objects which are larger than Pluto itself is. Haumea, Eris, and Makemake orbit further out from the Sun and are larger than Pluto. For that matter, the former asteroid Ceres is also larger than Pluto. All five of these objects are now called "dwarf planets".

It seems likely that the next meeting of the IAU will reconsider the status of Pluto, but there's no way of knowing what the decision will be. The IAU is open to any astronomer, but only the ones who attend the meetings get to vote; last time, about 3% of the members actually attended and voted.