And Then There Were Eight…

Planets, that is.

Pluto Stripped of Its Title

I remember the debate started in 2003 with Xena (which, if I recall correctly was also named ‘Planet X’).  For quite some time, there were those who said our solar system now had ten planets.

Being resistant to change as I occasionally am (and unwilling to talk about ‘Planet X’ because it seemed stupid), I never acknowledged the concept of ten planets.  But apparently, behind the scenes, a war raged.

And the result?  Not only is ‘Xena’ not a planet, neither is Pluto.  The new rules are simple:

- It must be large enough for its own gravity to pull it into a nearly spherical shape, and it must have cleared the neighborhood around its orbit.

- A planet’s orbit cannot cross another planet’s orbit.

Sadly, Pluto’s orbit crosses Neptune’s.  I can’t exactly say that was even my first clue, as Pluto was the only non-gaseous ‘planet’ outside the Asteroid Belt, and it’s orbit is an elongated ellipse which does not follow the solar system’s ecliptic, or plane.

So what is Pluto, exactly?  A dwarf planet.  One of three classifications for objects which are not satellites.  The other two are planet, and small solar system body.

So long Pluto.  You were an icy little reject planet for 76 years, but you were still a planet.


13 Responses to “And Then There Were Eight…”  

  1. 1 Jason

    2003 UB313 has never been referred to as Planet X; that name is typically understood to mean a hypothetical Earth-sized (or larger) planet beyond the orbit of Neptune. Planet X is a favorite of Usenet cranks, many of whom belive that it passed through the inner solar system within recorded history (!) and that the ancients observed this passage (!?!?!).

  2. 2 Jason

    Also, I’m glad Pluto isn’t counted among the planets any more, since there are a very large number of TNOs just like Pluto out there, and I don’t like the idea of having to memorize the names of 106 “planets”, 99.999% percent of which are ~2000 km diameter balls of ice.

  3. 3 Big Remy

    Astronomers suck. Pluto forever. Anyone who says Pluto isn’t a planet is a communist and hates science.

  4. 4 Dave

    Teh Ellis agrees with you, Rem.

    You’ll Have To Pry Pluto Out Of My Cold Dead Education

    I will fight anyone who tells me that Pluto is not a planet.

  5. 5 Big Remy

    YEAH BOY!!!!!!

    F’king astronomers. I didn’t mention it before, but that second criteria about not crossing another planets orbit is the dumbest goddamn thing I’ve ever heard. It sounds like someone at NASA got bored and decided to start making up rules because they had nothing better to do.

  6. 6 Jason

    I agree that the new “definition” for planets is ill-considered. But I also think Pluto shouldn’t be called a planet, since it’s not unique; if you call Pluto a planet, what will you call all the other objects just like Pluto that we will probably find over the next few decades?

  7. 7 Big Remy

    “Planets: The Next Generation” or perhaps Planet V1.1?

  8. 8 Jason

    “Planets: The Next Generation”

    That reminds me — if I ever discover an exoplanet, I am naming it after a Star Trek: The Next Generation character, and I firmly expect that any and all objects later discovered in the same system will also be named after Star Trek characters.

    And no, you can’t name anything after characters from Enterprise. Ever. No one can; it’s like an unwritten rule of the cosmos.

  9. 9 Russtopher

    You know, my daughter has been running around telling everyone her newest learned fact, that our solar system has NINE planets, which she learned from her Blue’s Clues game.

    This is really going to piss her off.

  10. 10 Colin

    Hey, its never too early to learn that blue dogs are all liars and shouldn’t be trusted.

  11. 11 Dave

    And already, the plut is a planet merchandising is there…

  12. 12 Dave

    pluto, even. damn crappy hp keyboard…

  13. 13 Big Remy

    Awesome. F’UCK DA ASTRONOMERS!!!

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