Astronomy Sedna 10th Planet Yes/No?

Discussion in 'Astronomy' started by Icewolf, Sep 22, 2004.

  1. Icewolf

    Icewolf Premium Member

    Has sedna officially been added to our Solar System as the tenth planet, many argue that if Pluto counts as a planet then Sedna should as well even though it is quite a distance away.
  2. JcMinJapan

    JcMinJapan Premium Member

    Well, not sure if you read my Pluto Page or not, but if we were to just find Pluto today, it would not be classified as a Planet, but a planetoid.

    Well, not too many facts, but here we go.

    Sedna is considered a planetoid. It is also the 2nd reddest object in the sky. It is behing Mars in Redness. This is strange indeed. As you will read below, there are a few strange things about this planetoid.

    Sedna was discovered on March 15 by Mike Brown of the California Institute of Technology, Pasadena, Calif..

    It is our Solar System's farthest known object with a year consisting of 10,500 Earth Years. Sedna is 130 billion kilometers from the sun, that is around 900 times Earth's distance from the Sun.

    It is 800-1100 miles in diameter. Pluto is 1400, so as you can see, this is very small.

    From observations with the Hibble Telescope, the estimated rotation perios of the Sedna is equal to 40 earth days. If this is correct, then it would be the slowest rotating object in the solar system. But, this is strange because most objects this size rotate in a matter of hours.

  3. amantine

    amantine Premium Member

    I think we should no longer call Pluto a planet. Instead, we should make a new class of solar system objects called Kuiper Belt Objects, KBOs. Pluto, Sedna, Quaoar, 2004 DW and Varuna would all belong to that new category. That would solve the confusion and problem.
  4. JcMinJapan

    JcMinJapan Premium Member

    I would agree with you. A long time ago, Pluto was considered a Planet, now it just fits in the Planetoid arena. By todays standards, it is not a planet. I see no real harm in removing it as an official planet. Things will just get more confusing as we learn about the solar system/universe/cosmos.