Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Hubble discovers two new satellites of Pluto

  1. Oct 31, 2005 #1

    Using NASA's Hubble Space Telescope to view the ninth planet in our solar system, astronomers discovered Pluto may have not one, but three moons.

    If confirmed, the discovery of the two new moons could offer insights into the nature and evolution of the Pluto system; Kuiper Belt Objects with satellite systems; and the early Kuiper Belt. The Kuiper Belt is a vast region of icy, rocky bodies beyond Neptune's orbit.


  2. jcsd
  3. Oct 31, 2005 #2
    Has an atmosphere even been detected yet on Pluto, other than methane?
  4. Oct 31, 2005 #3
    A quote from http://www.nineplanets.org/pluto.html" [Broken]

    "Little is known about Pluto's atmosphere, but it probably consists primarily of nitrogen with some carbon monoxide and methane. It is extremely tenuous, the surface pressure being only a few microbars. Pluto's atmosphere may exist as a gas only when Pluto is near its perihelion; for the majority of Pluto's long year, the atmospheric gases are frozen into ice. Near perihelion, it is likely that some of the atmosphere escapes to space perhaps even interacting with Charon. NASA mission planners want to arrive at Pluto while the atmosphere is still unfrozen."
    Last edited by a moderator: May 2, 2017
  5. Oct 31, 2005 #4
    http://i.a.cnn.net/cnn/2005/TECH/space/10/31/pluto.moons.reut/vert.pluto.moons.jpg [Broken]
    http://www.cnn.com/2005/TECH/space/10/31/pluto.moons.reut/index.html [Broken]
    Last edited by a moderator: May 2, 2017
  6. Nov 2, 2005 #5


    User Avatar
    Gold Member

    Oh great. Two more moons around something that might not even be a planet. If Pluto happens to end up categorized as 'not a planet', what would the satellites around it be considered? (Or has the planet/not a planet issue been firmly resolved?):confused:
  7. Nov 3, 2005 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Satellites of a Kuiper Belt object, I would imagine. There are non-planetary objects in the solar system that have one or more satellites. For example, the asteroid Ida has a moon called Dactyl.

    I don't think it has. I suspect you'll see Pluto demoted eventually.
  8. Nov 3, 2005 #7


    User Avatar
    Gold Member

    Thanks, Tiger. I hadn't heard of Ida/Dactyl before. I guess it just never crossed my mind that a non-planetary body would have enough gravity to maintain a satellite. Now for something even weirder that just popped into my head while I was typing that:
    Would it be possible for a large moon such as Titan to have a satellite of its own, sort of like a scaled down version of the sun/Earth/moon system? I know that it can be done artificially, such as the Apollo lunar orbiter, but could it form that way naturally given the overpowering gravity of the host planet?
  9. Feb 1, 2006 #8


    User Avatar
    Staff Emeritus
    Science Advisor

    Update -

    New 'Planet' Is Bigger Than Pluto

    Apparently this month, scientists will use Hubble Space Telescope (HST) to make additional measurements of Pluto and its 'partners'. The objective is to add data to what has already been collected in order to confirm that there are indeed other small bodies out there.

    From www.Stardate.org, February 1, 2006
  10. Feb 1, 2006 #9
    Is it possible that Pluto is an escaped moon of Neptune, and its odd plane of orbit is due to an unseen celestial body such as a brown dwarf?
  11. Feb 2, 2006 #10


    User Avatar
    Science Advisor
    Gold Member

    The Hill Sphere is how you would determine that. Here's a calculator for you: http://orbitsimulator.com/cmc/HillSphere.html . Keep your units in meters and kilograms.

    I believe in the Apollo missions, the discarded waste bags orbited the command module. (or maybe I bought into the myth).

    Titan... possible, yes. There's certainly room for a stable satellite in its Hill Sphere. But whether or not the Hill Sphere of Titan has been stable over its history as it migrated to its current position may make it unlikely.

    To date we know of no natural objects that orbit an object that orbit an object that orbits the Sun.
    Sorry for responding to a November post :blushing:
    Possible? Sure. Probable, no. For starters, it has moons. Read my reply to Danger. You'd also have to wonder how it escaped Neptune and then got locked into a resonance with it.
  12. Feb 2, 2006 #11
    I recently saw a program about Pluto and the New Horizons spacecraft, and it said that Pluto and Charon orbit around an axis (not inside pluto, but closer to it than charon), so I was wondering if it was possible that pluto's and charon's gravity wells connected to from the orbiting thingy (i forget the name) where they both orbit around a singular axis
    Last edited: Feb 2, 2006
  13. Feb 2, 2006 #12


    User Avatar
    Science Advisor
    Gold Member

    They orbit their common barycenter, as do all objects. Earth and the Moon have a common barycenter which is below the Earth's surface. Pluto & Charon's common barycenter is unique among planets because it is above the surface of Pluto. Several asteroids share this trait, as does the Sun and Jupiter. Thanks to Jupiter, the solar system barycenter is slightly outside the Sun's photosphere, in its corona.

    Here's an animated GIF of the Pluto and Charon orbiting their common barycenter. Pluto is purple, Charon is white:

  14. Mar 2, 2006 #13
    and that wobble is the way the first exosolar planets were discovered.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook