There are news articles bouncing around about the discovery of a “10th” planet which might be larger than Pluto and might displace Pluto from the ranks of planets.
BBC News says,
>The discovery of a new planet in our Solar System could have an unintended consequence – the elimination of Pluto in the list of planets everyone has in their heads. Is it time to wave this distant, dark piece of rock farewell?
Saturn is a planet and it is really a large gas cloud with a chunk of stuff in the middle. It generates more heat than it receives from the Sun which makes it more star like but we consider Saturn a planet because it is big (really big) and because ancient astronomers watched it move through the night sky.
Mercury is a small hot rock that is much more like our moon freshly removed from a blast furnace than our Earth and yet we consider it to be a planet. See the Ancient Astronomers discussion above.
If Pluto was formally demoted from planetdom, then all of the science classrooms would have to pull the little Pluto ball off of their solar system models. Towns would have to change their Solar System Models. The cost would be enormous. The disruption would be worse than the conversion to the metric system (for us in the USA) could ever promise to be. What would happen to Mickey’s dog? Would Disney have to rename him UB313?
Here is my solution. On almost all of the Solar System models, Pluto is out of whack. It is kind of like Hawaii and Alaska on maps of the USA. If we really represented Alaska like it should be, Alaska would take up 1/4 of the map and we would have to unfold most of Canada to see it. We would have to have a spare glove compartment to store the ocean pages between us and Hawaii. So instead, we throw them on a corner of the map – out of scale and in the wrong spot.
For many of our solar system models we say, “We are putting Pluto here because if we put it were it should actually go, you would have to run outside and climb up on the roof of the Dairy Queen down the street and look for the little thing that looks like a grain of rice.”
So here is my solution to the problem. It is really simple. The outermost, largest chunk of planet-like stuff will always be called Pluto. Discover a bigger piece of planet-stuff beyond Neptune? It is now called Pluto. The old Pluto will become a non-planet with a catchy name like UTBP4 (Used To Be Pluto number #4).
All of the models are always correct as long as they have one disclaimer – PLUTO’S LOCATION AND SIZE MAY BE INCORRECT OR CORRECT – IT DEPENDS ON THE ASTRONOMERS AND WHAT THEY HAVE FOUND. EVERYTHING ELSE IS FINE.
Sometimes, it is the simple solutions that are hardest to accept.