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Our New Solar System

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pendragon

 


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Three days ago in Prague, the International Astronomical Union voted on and passed a new definition of Planets, which demotes Pluto to a new classification of Dwarf Planet. The actually definition for a Planet is:


"A “planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit."


Which means our solar system is now made up of 8 planets, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The IAU also defined a new classification: a dwarf planet. The formal definition is:


"A “dwarf planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape , (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite."


Which means Pluto, Ceres and 2003 UB313(nicknamed Xena) are the first dwarf planets. The IAU also defined all other objects except satellites orbiting the Sun shall be referred to collectively as “Small Solar-System Bodies”.


Now I have been reading articles and blog posts objecting to the demotion of Pluto from full Planet status. Whats the big deal. Pluto has never enjoyed full planetary status since it was discovered about a hundred years ago. It's about time they finally classified it.  Our knowledge of the Universe and especially our Solar System is growing, so why can’t our classifications change also. 


Anyways, this classification could change in the future, depending on what data the New Horizons spacecraft sends back to earth.  The spacecraft lifted off in January of this year, at the time headed for the ninth planet, now it is headed for the first Dwarf Planet.  Who know what we will have learned by then. We might have to except more of that horrible ... "change".

Comments (8)

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codemonkey·
I think this is a result of people assuming what they read in books is correct.\r \r Unlike historical facts, talking about space and the planets is a constantly changing thing. People hate change, but worse than that? What is the root of all the uproar?\r \r When I was in school I had to pass tests that told me to memorize the planets, to write them down and my answers were graded. Now, years later, my answers are wrong. Worse of all? It dates me. \"When I was a boy, we had this planet called Pluto.\"\r \r Doesn't that make you feel uncomfortable? It is almost like being told the earth isn't flat. All you learned...and much of it becomes useless or falls into question.\r \r Regardless, I love space!\r \r CodeMonkey
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biorod·
I've got news for the International Astronomical Union: the Universe doesn't care.
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DreadPirate75·
I hear Uranus is like a black hole. \r \r Sorry, man..I couldn't resist! hehe. Nice article. Im a small time space geek. Good read.
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DaddyToe·
Isn't referring to Pluto as a dwarf planet going to upset the dwarfs? Not very PC by the astro dudes. That crazy little axe weilding dude in LOTR is not gonna take this well and after watching his movie he is likely to kill people over this.\r \r My apologies I have no ability to comment on space related blogs but this being your first blog post I had to make a comment.\r \r Make me a new sig, NOW.
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DaddyToe·
Just kidding about the sig thing, sorry.
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pendragon·
My first Blog. I didn't even expect any responses.\r Thanks for reading.
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BATMANKM·
Nice first Blog Pendragon! I found this particularly aggravating . My daughter is a very advanced 4 year old. I have been teaching her all about the solar system at night while getting ready for bed. She recently learned all the 9 planets. Now i have been trying to explain how Pluto isn't really a planet anymore...its completely \"F'ed\" up her mind :lol: Anyway great post. - BAT
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fecknmental·
Hahahaha know the feeling well my wee boy is space mad :lol:\r \r This is a major change though for scientists and even astrologers i wonder what the changes will be.\r \r Great first post very very original and entertaining :)