No, Pluto is not a planet and that's ok


Pluto is not a planet, it's a dwarf planet and you should either be happy about that or you shouldn't care at all.

As New Horizons has closed in on Pluto there have been new calls to re-classify it as a planet. This has included online petitions and even a few headlines from dubious sources claiming that it had already returned to planet status.

This issue has had more staying power than I ever thought it would and I can only assume that it stems from an overall fear of change. For generations, people were told in school that there were nine planets and that one of them was Pluto. There is also, I think, a certain attachment because of the Disney character.

If you feel, somehow, ripped off by Pluto's re-classification just imagine how people felt when they found out that the Earth was neither flat, nor the center of the universe.

The thing is that planet or not, Pluto hasn't changed and it hasn't moved any more than it would have otherwise. It's still right where it has always been, going around the sun incredibly slowly. However, scientists like to classify things and after no small amount of debate, the International Astronomical Union (IAU) decided that it was important to make a distinction between planets and dwarf planets.

The Laboratory for Atmospheric and Space Physics (LASP) describes the difference like this: "The only difference between a planet and a dwarf planet is the area surrounding each celestial body. A dwarf planet has not cleared the area around its orbit, while a planet has."

This means that the stuff in the orbit of the planet is either in orbit around it or has merged with the planet. If you understand where Pluto is, in the Kuiper Belt, you will understand that it would be almost impossible for an object of its size to ever 'clear the area around its orbit'.



Really, once you fully understand, you'll be happy that Pluto has been reclassified. There are currently five known dwarf planets in our solar system but there may be as many as 200 in the Kuiper belt alone to say nothing of the Oort cloud. So, imagine trying to make that model of the solar system for the science fair if you have to include 200+ little balls. For that matter imagine the time that would have to be devoted, in the early grades, to learning all of their names.

In the end, if you're not a scientist and you really ever loved Pluto, the classification shouldn't matter to you. If you're making a salad do you leave out the tomatoes because, technically, they're a fruit and you're not making a fruit salad? Do you have a crippling fear of insects, except for spiders and scorpions because they're arachnids? Have you signed a petition asking that dolphins be reclassified as fish because they live in the ocean? Most people ignore scientific classifications all the time. Pluto is still Pluto and its feelings haven't been hurt by the "demotion".

So relax, whatever the IAU calls Pluto it is no less interesting and the universe is no less spectacular for the change.

    
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