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

Ecliptic Plane's relation to Galactic Plane

  1. Nov 26, 2003 #1
    Hi,

    What is the orientation of the ecliptic plane of our solar system in relation to the plane of the galaxy?

    One source I found said they were aligned to within 5.5 degrees. http://www.earthsky.com/2000/es000304.html

    Another source I found stated that the orbital planes were 63 degrees apart. http://www.essex1.com/people/stauffer/MLS/solarsys.html

    Does anyone know for sure?

    Also, are all of the orbital parameters of our solar system around the galactic core known?

    Thanks,
    Glenn
     
  2. jcsd
  3. Nov 26, 2003 #2

    Labguy

    User Avatar
    Science Advisor

    The nearest bright star to the North Galactic Pole is Arcturus, in the constellation Bootes. I haven't made a measurement, but this is far more than 5.5 degrees; sounds like the 63 degrees is about right.

    http://www.site.uottawa.ca:4321/astronomy/index.html#galacticcoordinatecomponent says:

    "North galactic pole is a part of Coma Berenices
    has galactic latitude 90 degrees
    is opposite of south galactic pole
    has acronym NGP
    has definition A point in the constellation Coma Berenices where we look perpendicular to and above the Galactic Plane. The nearest bright star to the North Galactic Pole is Arcturus, in the neighboring constellation Bootes."

    Labguy
     
    Last edited: Nov 26, 2003
  4. Nov 26, 2003 #3

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    From your first link:
    I don't know who these guys are, but I don't think either of those statements is correct.

    - Warren
     
  5. Nov 26, 2003 #4

    Nereid

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    not 5.5 degrees!

    Here are two short pages with explanations and formulae:
    http://www.ess.sunysb.edu/fwalter/PHY515/coords.html
    http://scienceworld.wolfram.com/astronomy/GalacticCoordinates.html

    An all-sky summary of the IRAS (infrared astronomy satellite) observations:
    http://coolcosmos.ipac.caltech.edu/image_galleries/IRAS/allsky.html
    This is an Aitoff projection, in galactic coordinates. See the blue band running across the middle, at an angle of ~60o? That's the ecliptic plane, blue because the fine particles which lie in the ecliptic plane (and give us the zodiacal light) are hot compared with the dust etc which gives rise to the galactic emission.
    I'm not sure what you're asking Glenn. We know the distance to the galactic centre, the distance above the mid-plane of the disk, the time it takes to make one revolution, ... the eccentricity isn't well known though.
     
  6. Nov 28, 2003 #5
    Re: not 5.5 degrees!


    Do we know the inclination? Is there an inclination or does our solar system maintain a fixed distance above the mid-plane of the galactic disk?

    Basically I am asking if the solar system actually "orbits" the center of the galaxy?

    Thanks,
    Glenn
     
  7. Nov 28, 2003 #6

    Nereid

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    not that kind of orbit!

    AFAIK, the motion isn't a simple ellipse.

    For example, there is a 'vertical' oscillation, about the mid-plane of the disk. I don't remember what the period of this oscillation is, but it's unlikely to be a simple fraction of the rotation period. The amplitude is modest, only a few tens of parsecs, IIRC.

    Then there are encounters with giant molecular clouds, which don't necessarily orbit the centre of the galaxy in the same way the Sun does.

    Lately nearby galaxies in the process of being canabalised by the Milky Way have been discovered (Saggitarius, Carina); the extent to which they affect the orbit of the Sun is, as yet, unknown.
     
  8. Nov 28, 2003 #7

    Labguy

    User Avatar
    Science Advisor

    Re: not that kind of orbit!

    There are a bunch of interactions (pertubations) as you say, but most sites quote a 225 to 250 million year "orbit" for our solar system around the galaxy. That's a long time, but still very short on the time scale of galactic collisions.

    http://www.chron.com/content/interactive/space/astronomy/news/1999/ds/990602.html
    states 226 million years.

    Labguy
     
    Last edited: Nov 28, 2003
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Ecliptic Plane's relation to Galactic Plane
  1. Super-galactic plane (Replies: 7)

Loading...