For the vast majority of human history the term "planet" which means "wanderer" included all permanent objects in our sky that did not have a fixed position against the other stars. Our ancestors identified 7 of them and our corresponding days of the week are named after them. I'm a bit upset about the demotion of the sun and moon from the list personally. Neither the IAU nor any other body has control over how language develops. If you want to call it a planet do so. The name we call an object does not change its properties. As a linguist I can tell you that language is directed by those who use it. In other words, over time those who talk about planets most will determine what the word will actually mean and your voice is no less authorative than the IAU or Neil Degrass Tyson on the matter. By the way dictionaries do not define words, cultures define words and dictionaries, a relatively modern invention, attempt to record those definitions. Our bizarre authority driven culture has oddly inflated the importance of dictionaries and grammarians as governing bodies of language. As a side note, I personally will not support adding 3 additional days to our week to account for modern discovered planets unless those days are considered "weekend" days. On Tue, Jul 21, 2015 at 5:23 AM, Chuck Hards <chuck.hards@gmail.com> wrote:
The *definition of planet* set in Prague <https://en.wikipedia.org/wiki/Prague> in 2006 by the International Astronomical Union <https://en.wikipedia.org/wiki/International_Astronomical_Union> (IAU) states that, in the Solar System <https://en.wikipedia.org/wiki/Solar_System>, a planet <https://en.wikipedia.org/wiki/Planet> is a celestial body <https://en.wikipedia.org/wiki/Celestial_body> which: 1. is in orbit <https://en.wikipedia.org/wiki/Orbit> around the Sun <https://en.wikipedia.org/wiki/Sun>, 2. has sufficient mass to assume hydrostatic equilibrium <https://en.wikipedia.org/wiki/Hydrostatic_equilibrium> (a nearly round shape), and 3. has "cleared the neighbourhood <https://en.wikipedia.org/wiki/Clearing_the_neighbourhood>" around its orbit. Pluto lacks the mass to clear the neighborhood in the vicinity of it's orbit. On Mon, Jul 20, 2015 at 12:58 PM, <baxman2@q.com> wrote:
I would personally favor Pluto being returned to official Planet status for the following reasons. It is spherical, has five months, and surface geological activity. The only argument against it, is Pluto's size being smaller than Earth's Moon, making it somewhat comparable to a number of known minor planets.
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