What hold galaxies together?

Discussion in 'Hydrodynamics and Aerodynamics' started by Sailor Al, Aug 3, 2022.

  1. Sailor Al
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    Sailor Al Senior Member

    It's not "a claim".
    I just said I would be surprised if it even got as high as 5%, the implication is that I suspect it will be way lower than that.
    And it's precisely because "we" are using the sail as the frame of reference that the confusion has arisen.
    Changing the FoR to the apparent wind and think in terms of helium bubbles and it all becomes very simple and clear.
    Please provide a reference to support that claim.
    Yes, a velocity gradient occurs outside on a windy day at different heights. No one is disputing that.
    I am disputing the fact of a velocity gradient in the air above the wing. There's no theoretical explanation and there's no experimental evidence.
    Take another look at my post:
     
  2. gonzo
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    gonzo Senior Member

    Helium bubbles?:confused:

    Take some time to read:
    The measurement of velocity gradients in fluid flow by laser light scattering - Experiments in Fluids https://link.springer.com/article/10.1007/BF00189887
    https://www.researchgate.net/public...ocity_gradients_in_laminar_and_turbulent_flow
    Measurements of the velocity gradient in a microscopic region using a transmission grating https://opg.optica.org/ao/abstract.cfm?uri=ao-24-5-641
    Energy Dissipation Rate, Velocity Gradient, and Mixing — AguaClara Textbook v1.4.8 documentation https://aguaclara.github.io/Textbook/Fluid_Deformation_and_Energy_Dissipation/FDED_Intro.html
     
  3. seasquirt
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    seasquirt In the beginning there were waters.

    You engineers have missed the obvious. The answer is SAE bolts and nuts and other fasteners. And some of those old Galaxies are still going strong.
    My other theory on what holds galaxies together has no experimental proof, but I could make up some numbers to support it: it's like frog's eggs trapped and held in place in jelly, but much thinner, and stuff invisible and 'un-detectable' to us makes connections between big things, and groups of little things, connecting everything, in all rotations, in a network of forces, which allows movement accordion to laws we cannot ascertain, yet. More like a living elastic web of electro/physical communication than a pure 'mass attraction' type of force like gravity. Sometimes a King wave messes things up a bit, but modified local equilibriums are established again. No - not Orgone.
    I'll put my aluminium foil hat back on.
    P.S. Someone please tell the red underscore line that aluminium is correct spelling !
     
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  4. gonzo
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    gonzo Senior Member

    Make sure the aluminium alloy is the correct one to stop alien spy rays. We get ours from the NSA; certified to reduce brain interference by 97.6%.
     
  5. rangebowdrie
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    rangebowdrie Senior Member

    "Gravity"
    Now I know why the earth is attracted to me. ;)
     
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  6. Sailor Al
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    Sailor Al Senior Member

    I'm not sure that adds to the discussion.
     
  7. rangebowdrie
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    rangebowdrie Senior Member

    I used a smiley, to add a little levity to the discussion.
     
  8. gonzo
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    gonzo Senior Member

    I see it now, levity is what keeps galaxies from collapsing. Otherwise, gravity would make them very sad.
     
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  9. seasquirt
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    seasquirt In the beginning there were waters.

    We don't want sad galaxies, or they might turn into black holes.
    Coincidence: just listening to Hawkwind - Levitation Levitation Levitation.
    Side tracked, is there levitation in deep space ? Relative to surrounding borderline nothingness. In space, no one can hear jokes.
    Maybe the folded dimensions inside quarks, tied up with super strings, holds galaxies together. I'm still on topic !
     
  10. baeckmo
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    baeckmo Hydrodynamics

    Yeahh... but considering your geoposition relative to mine, one of us is upside-down -- or ... another dilemma for "SA"?
     
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  11. Ad Hoc
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    Ad Hoc Naval Architect

    Makes 3 of us!!
     
  12. Will Gilmore
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    Will Gilmore Senior Member

    The biggest problem I have noticed in my interactions with scientist (physics professors, chemists, and others who are highly educated in the theoretical, cutting edge science of the day) is they seem to believe we have accounted for all phenomenal forces. I mean by that, that if they find that the application of well understood principal's to poorly understood events doesn't yield expected results, then their initial reaction is to believe the principal's or theories are at fault, not that there may be some unaccounted for relationships. For instance, take the idea of dark matter. An idea that came about to fill in the missing mass that we believe is necessary to hold a galaxy together. But, has it been considered that gravity and electromagnetism may not be the only attractive forces at work? Maybe there could even be a repelling force at work. Perhaps the clumping of matter at the cosmological level might generate a repelling force similar to electron repulsion, that matter in a galaxy isn't only being held together entirely by gravity, but it is also being pushed into organized clumps by the existence of other organized clumps. Stars, for instance, attract mass and create solar systems through gravity, but inertia and tangential movement may keep them from crashing together in a single growing mass of blazing plasma; but consider, as well, stars emit photons and electrons that push on matter, in opposition to the gravitational attraction.

    I'm not proposing my suggestions here as a serious possible answer in alternative to what we currently are exploring, only suggesting it is the limitations of our imaginations that may lead to some of the most absurd, but working models to explain things we don't yet understand. As a trained computer scientist, I understand that simple on/off switches arrayed together in vast numbers can lead to highly complex actions. Yet, ultimately, the fundamental principal mechanism is as simplistic as binary math.

    -Will
     
  13. gonzo
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    gonzo Senior Member

    If experimental results or observed behavior does not follow a theory's predictions, then the scientific method requires to question the theory. In that case the theory may have limits within which it is valid, or it is wrong.

    This is a real mishmash. Stars do not attract mass. All masses (bodies) attracts each other. When one mass orbits another, it is not about inertia and tangential movement. In a stable orbit, the masses are in free fall. Photons and electrons may hit matter (they are composed of matter too) and there will be a reaction force. However, there is no limit for the force to be opposite for that created by the acceleration of gravity on a mass. Finally, gravity does not attract, it accelerates.
     
  14. Will Gilmore
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    Will Gilmore Senior Member

    Huh! See what you did there?
    Symantecs. You are getting picky about how something is said when you are simply restating the same idea.
    Whether you want to state there is an acceleration without a force, the fact is, there is no suggestion in any science report I have heard, that gravity accelerates without a very specific direction toward the bodies of mass. That is, by definition, an attraction.

    You are letting your insistence on minor accuracies distract you from the point of my post.

    We often fail to consider that we may not be aware of or account for the possibility that there could be forces unaccounted for in the Universe. We are perfectly happy to satisfy our ignorance with labels such as "singularity" or "dark matter" and then act like we know, when what we really mean is, "we don't know what it is, but this is what we will call it."

    Suddenly, everyone is good with geometry/time causing 'acceleration' when we all understand that a change in movement requires a change in something else, a force, an acceleration, something that causes that change. Simply changing the shape of the sidewalk you are standing on doesn't cause you to move towards or away from the house it leads to, no matter how much time passes. Something has to act upon you, or you have to walk, to get to that house.
     
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  15. seasquirt
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    seasquirt In the beginning there were waters.

    I believe there are too many approximations and variables for 'science' to ever be intentionally absolutely correct.
    For a long time half of the world did mathematics and science without a zero in their equations, and they were often 'close enough' for the usages at the time.
    How many interpretations of infinity are there, I've read of two - a) between zero and one. and b) between one and everything. So what difference does the order of magnitude make, when it's the same stuff being accounted for, in the same imaginary extrapolation ?
    I was taught that during W W I I at least two different methods of calculus were developed by different countries, which gave the same answers, but maybe there's another more precise method we don't know about. Like Spherical mathematics.
    We are limited by our physical senses, feeble brains, de-education systems, and cultures, etc., so of the complete spectrum of knowable things, we will never be able to know much, in the great scheme of things, even if it is spelled out for us, we are too limited. Maybe future tools will make things quicker and easier to understand, like replacing log tables with scientific calculators, then A.I. computers.

    Not so long ago, learned people believed worms grew spontaneously, and anything unexplained was the work of god, or evil, depending on if you profited from it or not. The Earth was flat, or else. The Earth is at the centre of everything, or else. A land with no christians in it supported only animals, and was empty. A man would die if he traveled faster than 40 miles per hour. Light doesn't bend. Radioactivity isn't very dangerous. The Earth and sea are endless and will absorb garbage forever.
    Sects and Guilds with secretive agendas still exist, hiding secrets of truth, and promoting mis-information for gain.

    We are always proved wrong eventually. Even if all scientists repeated their experiments, and agreed on what held galaxies together, in ten years it would be a joke, or mark another turn in research directions. The truth is out there; use the 'force'; shazbot nanu nanu.
    At least we benefit from the research sometimes, like breast cancer scanning, satellite communications, satellite photos, solar weather reports, etc., so it's still good to wonder and experiment and test. But Never believe that you have The answer.
    And never forget, we are all still crapping in our own nest and filling it with s--t; how clever is that ?
    Hominid Stupidus destructor
     
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