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

#### jt3213

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?

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#### Bobbywhy

Gold Member
jt3213,

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

Bobbywhy

Thanks

#### TheTechNoir

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.

#### surajt88

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.

#### ImaLooser

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?
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.

#### Quickbobo

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

#### Drakkith

Staff Emeritus
Science Advisor
2018 Award
.When I visualize a spinning sphere, in a space/ time fluid like matrix, that supposedly causes gravity
I'm not familiar with such a concept. Are you referring to spacetime as described by General Relativity?

#### Quickbobo

I'm not familiar with such a concept. Are you referring to spacetime as described by General Relativity?
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.

#### Drakkith

Staff Emeritus
Science Advisor
2018 Award
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.
GR doesn't describe spacetime as a fluid, so I don't know what happened.

#### Loren

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).

#### Quickbobo

GR doesn't describe spacetime as a fluid, so I don't know what happened
My bad, I believe the term he used, was a friction-less super fluid, if that's any different, a description.

#### Drakkith

Staff Emeritus
Science Advisor
2018 Award
My bad, I believe the term he used, was a friction-less super fluid, if that's any different, a description.
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.

#### Quickbobo

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.
Many thanks Drakkith... So the mental semantics, was in my interpretation, of his analogy..

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#### AZFIREBALL

Re: “If you could see gravity what do you think it would it look like?”

From here on earth, I think it would look like the Aurora Borealis everywhere; dynamic and fluctuating wave forms with its luminosity varying in direct proportion to its intensity. Much like the lines of magnetic flux as seen using iron filings but, ever moving and changing.

#### Klystron

Gold Member
I developed a method to visualize electromagnetic (EM) fields from studying books by Feynman and Weinberg, and papers by Dicke, among others, while working with different types of antennae at different frequencies.

First I visualize a small section with splines in multiple dimensions shaped somewhat like a shepherds crook or a stretched integral sign. The 'curl' at the 'top' varies by signal strength (intensity) and 'curls away' from the radiation spheroid. E and H are perpendicular to each other and normal to the direction of propagation of the field. Sheaves of splines form lobes.

Expand or shrink this section as the problem dictates in as many dimensions as required. I used to keep all the dimensions perpendicular until I learned more differential geometry. Also, I now replace splines with manifolds visualizing manifold 'surfaces' to represent fields in my mind.

I use various modifications of this technique to visualize other fields. It is very helpful when introducing an object -- target in military jargon -- such as an aircraft intercepting radar lobes, a meteor entering the Earth's gravity field, atmosphere, magnetosphere; and solar storms and sunspots.

[Edit: Describing my personal method to visualize fields. I do NOT imply that gravity and EM fields are the same. Thanks.]

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