Solar Week - Ask a Question

Come here during Solar Week (next one: March 22-26, 2021) to interact. To post a question, click on your area of interest from the topics below, and then click on the "Ask New Question" button. Or EMAIL or tweet or plant in Answer Garden your question about the Sun or life as a scientist to us -- and watch for it to appear here.  You can also visit our FAQs (frequently asked questions). In between Solar Weeks in October and March, you can view all the archives here.

PrevPrev Go to previous topic
NextNext Go to next topic
Last Post 10/9/2009 8:16 AM by  Kris Sigsbee
Lisa T
 1 Replies
You are not authorized to post a reply.
Author Messages



10/9/2009 6:49 AM

    Do any of you believe Pluto will regain its status as a planet? Didn't hubble find more moons orbiting the planet around a year or so back, if this was true, could an argument be made to re-classify it as a planet, thank you..

    Tags: Pluto, Dwarf Planets, 2003 UB313, Kuiper Belt, Eris

    Kris Sigsbee

    Basic Member

    Basic Member

    10/9/2009 8:16 AM

    Hi Lisa,

    I don't believe that Pluto will be reinstated as a planet anytime soon. Having "moons" is not a sufficient condition for a solar system object to be classified as a planet under the current definition of a planet used by astronomers and space scientists. Many asteroids in our solar system may have other asteroids or objects orbiting around them like a moon. If having a moon was the only requirement, then we would have to reclassify every asteroid found with a "moon" to be a planet. Instead, we are now calling these objects binary or double- asteroids. Here is a link to some examples of asteroids that have "moons:"


    Pluto is considerably larger than these asteroids, but that also is not a sufficient condition for reinstating Pluto as a planet. Objects that are nearly as large, or possibly larger, than Pluto have recently been found beyond the orbit of Neptune. The largest of these objects, 2003 UB313, is now called Eris, after the Greek goddess of discord and strife. Eris appears to be larger than Pluto. If Pluto is reinstated as a planet because of its size, then we would also have to give Eris status as a planet. However, Pluto, Eris, and other similar objects are believed to have more in common with objects from the Kuiper Belt than they do with the terrestrial planets (Mercury, Venus, Earth, and Mars), so it seems unlikely that we will add these objects to the list of planets in our solar system. Instead, Pluto and Eris are often referred to as "dwarf planets." Here are some links where you can read more:



    You are not authorized to post a reply.

    Twitter Feed

    Scientist Leaderboard

    Name # of replies
    Multiverse skin is based on Greytness by Adammer