Astronomers have recently discovered a body orbiting the sun at a distance beyond the orbit of Pluto but larger than the diminutive ninth planet. The object is whips around the sun in an elliptical orbit that is 45 degres to the plane of the ecliptic and is 97AU out at its furthest point, but only 36AUs (and inside the orbit of Pluto) at its closest. It was discovered by a trio of astronomers working at the Palomar Observatory in San Diego on January 8th. The group studying it had planned to hold off on announcing it until they had completed their observations (for example, the team isn’t exactly sure how it big is and I have yet to see the duration of its year or day) but hackers had found a personal web site setup by one of the researchers and so the team decided they had better go public now before somebody else tried to claim credit for their discovery.

Until the International Astronomical Union agrees that it is indeed a planet (and not just another nameless Kuiper Belt object) it isn’t officially the 10th planet in the solor system and it doesn’t have a name beyond the refernce object name listed in this blog entries title. Here’s hoping the official name is a little more catchy than 2003UB313. Most astronomers now believe that Pluto probably shouldn’t be classified as a planet but instead listed as a denizen of the Kuiper Belt – but if Pluto is a planet then it would seem that anything bigger than Pluto also ought to get planetary status. I think they better start updating all those school science texts.

What I find most interesting about the news coverage (and there has been plenty today) of the discovery is the need to discuss what the surface might be like. I guess to me anything out that far and that small is preordained to be without an atmosphere and more like a giant junk of rock than a true planet. The good news is all the artists renderings I’ve seen (which make for good TV I guess) do paint that picture for you – it’s cold and rocky.

15 thoughts on “2003UB313”

  1. 2003UB313 might have an atmophere, after all, there’s an atmospere on pluto, so why not this new planet.:):D(6):-@:-P:-S:^)(H);-):-$|-):O:(8o|

  2. The Mode of Eight Major Planets of the Solar System

    Yi-Fang Chang

    Department of Physics, Yunnan University, Kunming 650091, China

    Since Pluto was discovered in 1930, it and other major planets are called to nine major planets. In 2002 astronomer M.Brown, et al., discovered a new planet Quaoar (2002LM60). In 2004 they discovered again a new planet Sedna[1]. The diameters of two planets are about 1250km and 1700km. That should be tenth major planet in the Solar system? We compare respectively Terrestrial and Jovian planets (the units of mass and diameter are kg and 4880, 49500km), and calculate quantitatively to obtain results:

    Terrestrial Planets:Mercury,Venus,Earth,Mars,Ceres;



    Jovian Planets:Jupiter,Saturn,Uranus,Neptune,Pluto;



    From two tables, Pluto as ninth major planet is unsuitable, whose mass is too small and only a sixth of the Moon, and whose diameter is 2240km smaller than 3476km of the Moon. Therefore, the structure of the Solar system should be a symmetric mode of eight major planets[2,3]:

    Terrestrial Planets:Mercury,Venus,Earth,Mars; Asteroids.

    Jovian Planets:Jupiter,Saturn,Uranus,Neptune;Kuiper Belt(including Pluto).

    It should be a conclusion of astronomic observation. Moreover, the eccentricity of Pluto is bigger; it is also analogy with planetoid. This statement may include new 2003UB313.


    1.R.Irion, Science. 2004, 303(5669):1743.

    2.Yi-Fang Chang, Planet predicted by Liu Zihua and the mode of eight major planets of the Solar system. Journal of Anyang University. 3,1,6-7(March 2004).

    3.Yi-Fang Chang, Evolutionary direction of spiral galaxies described by theory of density wave and the mode of eight major planets of the Solar system. Journal of Hunan City University. 13,4,46-49(2004).

  3. All…I have to admit it…is the previous post a complaint, something saying that ‘HA! We found it first!’, or just another crafty communist plot to make me scratch my head and go ‘huh’? If so..I think he pulled the latter off….:O

  4. At some point we argue semantics – what is a planet, what is a planetoid, what is an asteroid? It doesn’t matter tremendously – those of us with a modicum of interest know the objects are there.

    It does matter what is taught in schools though, and how the common person thinks about the solar system. I personally believe that this new discovery won’t be classified as a planet and that Pluto will remain so (if only due to the historical nature of it and the reverence people hold towards Percival Lowell.)

  5. Actually most folks hold less reverence towards Lowell than they do to Clyde Tombaugh, the man who found Pluto. Lowell may have built the observatory, but Tombaugh is the person who took thousands of plates and compared them two-by-two in order to find the small moving dot. I highly recommend David Levy’s biography of Tombaugh!

  6. The New planet is twice the size of Pluto so i think that it should be called a planet. And the astronomers have made sure it is not a moon, like Planet X. It also switches orbits with Pluto.

  7. 2003 UB 313 isn’t to inspiring– How about DECIOUS (means the 10th one, . Must be classified as a planet, it does orbit the Sun . Very elliptical orbit I understand but that’s not unusual – all the planets orbits are elliptical to an entent. Pluto’s orbital path comes inside Neptune’s:after all. Must be gravitationally bound to the Sun and Solar System,so Planet it is (in my opinion).


    Sam Manoah,


  8. This is pretty weird crap man. To know that there is another unknown planet out there that we didnt find untill recently it makes you wonder what eles could be out there. Altho this artical dosent give much info I think it is still weird. I would like to learn more information about this planet.(H)

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