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If you could see gravity what do you think it would it look like?

  1. Mar 22, 2013 #1
    If you could see gravity what do you think it would it look like? The trampoline, or fabric example doesn't seem right to me. I guess I've always imagined gravity as a 'fluid' for lack of a better term. I just imagine the gravitational field expands in all directions creating a sphere of gravity around the object. What are your opinions on this? Does my idea sound like a correct visualization?
     
  2. jcsd
  3. Mar 22, 2013 #2

    Bobbywhy

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    jt3213,

    Your visualization "the gravitational field expands in all directions creating a sphere of gravity around the object." is exactly correct.

    Bobbywhy
     
  4. Mar 23, 2013 #3
    Thanks
     
  5. Mar 23, 2013 #4
    What bobby said is correcting. Just adding in, the point of visualizing it as a fabric or trampoline isn't that it is supposed to look like that. That is more of a cross-section view showing one half of the gravitational field/influence the object has on it. It's more difficult and confusing for a viewer if they try to draw a full sphere of grid-lines encircling a solid object to illustrate how that object warps those lines due to the overlap.

    There is also the option with a cross-section then to use instead of grid lines a solid object such as, like you said a trampoline. but if you tried to have the same influence on all angles of an object using a solid fabric you wouldn't be able to see the object inside it for the visualization.
     
  6. Mar 25, 2013 #5
    I'll try in helping you visualise gravity. :)
    First, the basics. Gravity is a weak force, but has a long range. An electron, being such a small particle, still can exert its gravitational influence (albeit very weak) to the very end of the observable universe (if we had a sensitive enough instrument to measure it, we can!).
    Now to the visualizing part. I assume you ask this question from the perspective of an observer on earth. From this perspective, "gravity" "reduces in its intensity" as we go skywards. Since you talk about "fluids", I'll try to help you visualise this on the basis that, the stronger the gravity is, the "darker" it is to see around. If you had the sense to visualize gravity in this sense, what you would see would be similar to what a fish would see in a murky pond. the deeper you are, the murkier and darker it gets. So on the surface of the earth, you wouldn't be able to see a thing, but, as you go higher, things start clearing up and when you reach "space", you start seeing things. In this case, the level of "darkness" corresponds to the strength of gravity.
    What it means actually is that, from the perspective of a person on the surface of the earth, gravity reduces gradually from the surface as you move skywards.
     
  7. Apr 3, 2013 #6
    For Newtonian 1/r^2 gravity it will work just fine. With the weird effects of general relativity like gravity waves you won't have much luck. I don't know any simple model that works for that.
     
  8. Mar 9, 2016 #7
    Please don't misconstrue what I'm about to say, but, this has bothered me for decades.When I visualize a spinning sphere, in a space/ time fluid like matrix, that supposedly causes gravity, I see a vortex develop, at the top and bottom of the sphere, due to differentials in the speed of rotation at higher and lower latitudes, that's just how fluid dynamics works. Even considering the helical path of the object through this matrix, I see a vortex behind it. If "frame dragging" is the cause, what am I missing? Is the frame dragging in all possible directions all at once? Thanks in advance.

    Bob
     
  9. Mar 9, 2016 #8

    Drakkith

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    I'm not familiar with such a concept. Are you referring to spacetime as described by General Relativity?
     
  10. Mar 9, 2016 #9
    Thank you, yes That was the idea as explained by a Prof. @ Cornell ,I met @ Watkins Glen, few years back.. Or he didn't describe it properly/ I misconstrued his explanation ? Thanks in advance.
     
  11. Mar 9, 2016 #10

    Drakkith

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    GR doesn't describe spacetime as a fluid, so I don't know what happened. :olduhh:
     
  12. Mar 9, 2016 #11
    You could also imagine gravity waves as sound waves emanating from a point source in a medium of air (ignoring the inertia of air molecules).
     
  13. Mar 9, 2016 #12
    My bad, I believe the term he used, was a friction-less super fluid, if that's any different, a description.
     
  14. Mar 9, 2016 #13

    Drakkith

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    I believe certain aspects of General Relativity are analogous to a super fluid, but as far as I know it's just an analogy, not a real description.
     
  15. Mar 10, 2016 #14
    Many thanks Drakkith... So the mental semantics, was in my interpretation, of his analogy..
     
  16. Mar 10, 2016 #15

    Drakkith

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    If you're interested, you can see the following link for more analogies: http://arxiv.org/abs/gr-qc/0005091
     
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