Results 1 to 7 of 7

Thread: Gravitational interactions are the ultimate cause for the spiral Arms in the Galaxy.

  1. #1
    Join Date
    Sep 2015
    Posts
    534

    Gravitational interactions are the ultimate cause for the spiral Arms in the Galaxy.

    We have found that gravitational interactions are the ultimate cause for the spiral Arms in the Galaxy.

    We have also found that about 20% of the mass in the spiral arms participate in this gravitational interactions.

    So, how do we know which star in the spiral arm is part of this gravitational interaction?

    This is a list of stars that lie within 20 light years as known in the year 2006. (I assume that there are about 100 stars)

    http://www.atlasoftheuniverse.com/nearstar.html

    Based on statistics, about 20 might have gravitational interaction with other stars in the arm?
    So, how can we find them?

  2. #2
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    6,990
    Quote Originally Posted by Dave Lee View Post
    We have found that gravitational interactions are the ultimate cause for the spiral Arms in the Galaxy.
    Please provide a reference to this claim. The spiral pattern is conventionally held to be due to a density wave which is due to correlations in the orbits of objects in the spiral galaxy. The initial impetus for this is likely gravitational, and gravity is ultimately why things orbit from from your following statements this is not what you mean. So please provide a detailed, mainstream, reference for the model you are basing this claim on.

    Quote Originally Posted by Dave Lee View Post
    We have also found that about 20% of the mass in the spiral arms participate in this gravitational interactions.
    Please provide a reference to this claim. It is absolutely not what the mainstream model says. In fact it should intuitively be obvious that this is a suspect statement. All objects in the galaxy experience gravitational interactions. No current mainstream model has a special 'make spiral arm' set of interactions that are only applicable to a few stars.

    So the rest of your questions, unless you can provide the model they are based on, cannot be answered as they are based on flawed concepts.

  3. #3
    Join Date
    Sep 2015
    Posts
    534
    Please see your answer:
    https://forum.cosmoquest.org/showthr...N-Body-Problem
    Quote Originally Posted by Shaula View Post
    Gravitational interactions are the ultimate cause for the spiral Arms in the Galaxy. Not just the ones between matter in the spiral arm. Whether it is down to the bar/disk interactions or the effect of mergers/companions it is these interactions that drive the formation and stability of the density wave pattern. The actual internal interactions of the bodies in the overdensity may have a second order effect but it is not the main driver for the pattern forming or persisting.
    With regards to the 20%:
    http://articles.adsabs.harvard.edu/c...;filetype=.pdf

    "We found that 10 percent of the local mass is participating in the spiral arm, half from the gas and the other half from the stellar population. Clearly, the errors due to uncertainty in observations and the errors due to various approximations in the theory are unavoidable. Therefore, all the numerical values used in this paper may be subject to changes with the observational data and the galactic model to an extent of about 20 percent, but the qualitative features would be expected to remain the same."
    Last edited by Dave Lee; 2018-Jun-03 at 03:43 PM.

  4. #4
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    6,990
    Please read my answer.

    "Gravitational interactions are the ultimate cause for the spiral Arms in the Galaxy. Not just the ones between matter in the spiral arm. Whether it is down to the bar/disk interactions or the effect of mergers/companions it is these interactions that drive the formation and stability of the density wave pattern. The actual internal interactions of the bodies in the overdensity may have a second order effect but it is not the main driver for the pattern forming or persisting."

    Also, from the rest of that thread, it was said repeatedly and very clearly that gravitational interactions were what drove the formation of the spiral structure through the formation of a density wave. The density wave and associated star formation is then why you see spiral arms. The interactions between stars in the arm are not why the spiral arm forms or persists as you seem to be implying in your follow up.

    Your second link is broken. But from memory what it was saying was that 20% of the matter in the area was involved in the star formation which made the spiral arm visible. It absolutely did not say that 80% of matter in the area suddenly became immune to the force of gravity.

  5. #5
    Join Date
    Sep 2015
    Posts
    534

  6. #6
    Join Date
    Mar 2010
    Location
    United Kingdom
    Posts
    6,990
    Right, so what they are saying is just that you see 10% or so of the local mass in a spiral arm is part of the correlated structure that forms the density wave. Not that 90% of the mass is not undergoing gravitational interaction.

  7. #7
    Join Date
    May 2008
    Location
    The Netherlands
    Posts
    14,922
    Dave Lee: while one of your threads is closed for moderator discussion, do NOT open another thread on the same topic again!
    ____________
    "Dumb all over, a little ugly on the side." -- Frank Zappa
    "Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson
    "This is really very simple, but unfortunately it's very complicated." -- publius

    Moderator comments in this color | Get moderator attention using the lower left icon:
    Recommended reading: Forum Rules * Forum FAQs * Conspiracy Theory Advice * Alternate Theory Advocates Advice

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •