back in my day i was taught that pluto was a planet
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back in my day i was taught that pluto was a planet
So was I. But the thing with sciences is that they make revisions when it's called for. In the case of Pluto, there were asteroids being found that were almost as large as Pluto, but they didn't behave as planets. So the definition was revised in 2006, and according to the new definition Pluto is no longer a planet.
Read these:
- http://en.wikipedia.org/wiki/Planet#2006…
- http://en.wikipedia.org/wiki/IAU_definit…
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Back in the day of everyone older than kindergarten it was considered a planet.
The problem is that it is smaller than some other things out about the same distance and smaller than a couple of asteroids, so if it is a planet, so are at least four or five other things we know about, so the definition of a planet was made precise and Pluto didn't meet it.
The problem is that it is smaller than some other things out about the same distance and smaller than a couple of asteroids, so if it is a planet, so are at least four or five other things we know about, so the definition of a planet was made precise and Pluto didn't meet it.
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"A rose by any other name is still a rose"
Pluto still is exactly the same body that it always has been, since its discovery in 1930, and since its origins billions of years ago.
When we talk about Pluto not being a planet, we really are just talking about how we define the word "planet".
Having discovered numerous bodies in the same zone as Pluto, of comparable size, it brings in to question whether Pluto is king of these small bodies (actually Eris is king of them), or whether Pluto is just a really small planet.
The line needs to be drawn somewhere, and Pluto simply didn't make the cut.
Officially, there is the clearing the neighborhood requirement that Pluto "failed to meet". There is more mass worth of stray smaller bodies (meteors, dust, gas) in Pluto's orbit than there is mass worth of the body of Pluto itself.
Pluto still is exactly the same body that it always has been, since its discovery in 1930, and since its origins billions of years ago.
When we talk about Pluto not being a planet, we really are just talking about how we define the word "planet".
Having discovered numerous bodies in the same zone as Pluto, of comparable size, it brings in to question whether Pluto is king of these small bodies (actually Eris is king of them), or whether Pluto is just a really small planet.
The line needs to be drawn somewhere, and Pluto simply didn't make the cut.
Officially, there is the clearing the neighborhood requirement that Pluto "failed to meet". There is more mass worth of stray smaller bodies (meteors, dust, gas) in Pluto's orbit than there is mass worth of the body of Pluto itself.
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Because "back in your day" (and in the day of everyone over 5 years of age) we didn't know nearly as much about the solar system as we do now. Once we started discovering a lot more objects out there we realized that a new definition of "planet" had to be come up with or we'd just keep finding more and more "planets" and eventually every kid in 3rd grade would be memorizing the names of a dozen or more balls of rock and ice that just happen to orbit the Sun. Back in your day we also thought Pluto had 1 moon, Charon. We know know that Pluto orbits a point in space outside of itself and that Charon, Nix, and Hydra (we didn't even know Nix and Hydra existed back then) orbit it as well along with a bunch of other Kuiper belt junk. We also know that there's a bunch of junk orbiting the Sun in the same area as Pluto. The fact that Pluto is no longer a planet has NOTHING to do with its size, which is a common misconception. It has to do primarily with the fact that it has not cleared its orbit of other junk orbiting in the same area, due primarily to its weak gravity. If we still considered Pluto a planet we'd also have to consider Eris, Makemake, Sedna, Orcus and a bunch of other Kuiper belt objects planets, and we'd also have to consider Ceres, in the asteroid belt, a planet. So we'd actually have 13 planets at least right there with who knows how many more to be discovered. When you compare the attributes of these objects with the 8 true planets it becomes obvious that none of them, Pluto included, should be classified together with the planets.