Unraveling the Mystery of Gravity: The Role of Mass in Space-Time Distortion

[Naty1]

Nobody knows why matter causes gravity...nor why energy and pressure also "causes" gravity...nor forces,energy,mass,time nor space for that matter. The best can do (so0 far) is assign some mathematics that seems to capture most conditions we observe, some we don't, so we can predict SOME things...and test them experimentally...If you ask what is gravity in the quantum mechanics forum, you'll get an almost entirely different set of reasoning, logic and mathematics...

 

[Altabeh]

It's similar to the discussion which arises in classical mechanics when only potentials, not forces, enter into the fundamental equations. In this sense, the potential really is what's fundamental, not the force. In my mind, this situation is completely analogous.

In fact, say, the gravitational potential and the gravitational force entering in Newton's gravitation law are not two separate things and indeed one implies the existence of another in the form required. Talking about which one of them is more fundamental than the other is a matter of realization and does not necessarily pertain to one and all though I think forces are more fundamental not only because they were the first "objects" to be found having a role in the conduction of all efforts made to describe the most simple kind of motion, but because the potential energy only exists when there is a force that tends to pull an object back towards some lower energy position so force foregoes potential.

AB

 

[Frame Dragger]

I SAID that "why" questions never end well when people expect a science to produce "TRUTH". Physics produces amazing lenses and tools to look at and deal with the world. The ultimate "why" questions MIGHT be answerable by physics, but no sane physicist claims to HAVE that knowledge or be anywhere near it.

What is spacetime made of? Why does it bend?

No, for physics the question can begin with "why", but the GOAL is "HOW", as I said earlier in this thread. Really, sometimes these threads are positively deterministic except for specific kinks (say, Ich handing my *** to me for instance )

 

[Hoku]

Nothing anyone has stated on the subject here has given you the least reason to call it "mystical"...So I would encourage you to pursue this line of questioning, but just without the inflammatory language.

If I may direct your attention to post #11 on this thread by Nabeshin. His first paragraph uses the word "mystical", which is what I was addressing. I'm just as happy to call it, "mysterious", "unknown", "initial condition" or whatever. If Nabeshin wants to use the word "mystical" I don't have a problem using his semantics. That's what I did when I initially addressed this in post #14.

@ Nabeshin: You said, "I was trying to illustrate that neither picture is more correct, better, or any more real. Your original post seemed to be implying the force description was indeed the "real" description of gravity, which is hogwash."

You said it yourself, "neither picture is more correct", which is just as much saying, "both pictures are equally correct". Therefore, it is NOT hogwash for me to suggest that the "force" description is "real". Let's not forget that we are dealing with a "law" of gravity, which came from Newton, and a "theory" of relativity.

My point in this thread was to demonstrate that there is a lot of conflicting information about gravity. Yet, many people are not hearing both sides of the story, so they don't realize there IS another side! I think this is a problem.

What I would like to see is a reconciliation of these two views such that both views are understood, integrated and accepted across the board. I think this is a reasonable and worthy desire.

However, this topic, IMO, is really the key issue for you at this time, much more important than the discussion about forces.

This is important. I will begin a new thread soon where we can continue exploring it.

 

[Dale]

If I may direct your attention to post #11 on this thread by Nabeshin. His first paragraph uses the word "mystical", which is what I was addressing. I'm just as happy to call it, "mysterious", "unknown", "initial condition" or whatever. If Nabeshin wants to use the word "mystical" I don't have a problem using his semantics. That's what I did when I initially addressed this in post #14.

Ahh, my apologies, I completely missed that.

This is important. I will begin a new thread soon where we can continue exploring it.

Excellent. I look forward to it.

Btw, once you understand the geometric view I think that it will not be very difficult for you to understand the connection between it and the forces view.

 

[Frame Dragger]

Ahh, my apologies, I completely missed that.

Excellent. I look forward to it.

Btw, once you understand the geometric view I think that it will not be very difficult for you to understand the connection between it and the forces view.

To be clear: The graviton would quantize the curvature that GR describes, not some kind of gravitational energy in the manner of a usual force field?

 

[Dale]

I simply don't feel comfortable talking about the properties of gravitons in any fashion without a workable theory of quantum gravity. I was referring to the well-known Newtonian limit of GR, not the rather unknown quantum limit.

 

[Frame Dragger]

I simply don't feel comfortable talking about the properties of gravitons in any fashion without a workable theory of quantum gravity. I was referring to the well-known Newtonian limit of GR, not the rather unknown quantum limit.

Understood, and understandable.

 

[DaveC426913]

I SAID that "why" questions never end well when people expect a science to produce "TRUTH".

Simply rephrase the question as how does mass cause gravity?

Exact same question, without the annoying philosophical implications.

 

[Frame Dragger]

Simply rephrase the question as how does mass cause gravity?

Exact same question, without the annoying philosophical implications.

This is true, and the answer is: the SET describes how that occurs, but not how mass arises. There is no "Why", only a "How". It's not quite the same question however, because if the person then says, "Well, how does the SET work?", that is a clear question. If they ask what mass really is, then you instnatly recognize a dead-end.

 

[Nickelodeon]

This is true, and the answer is: the SET describes how that occurs, but not how mass arises. There is no "Why", only a "How". It's not quite the same question however, because if the person then says, "Well, how does the SET work?", that is a clear question. If they ask what mass really is, then you instantly recognize a dead-end.

I'm lost on the first part of your post but the last sentence seems not quite right. Mass represents the energy equivalence of matter. I could understand more if you recognised a dead end if they asked what matter really is. Is that what you meant?

 

[Frame Dragger]

I'm lost on the first part of your post but the last sentence seems not quite right. Mass represents the energy equivalence of matter. I could understand more if you recognised a dead end if they asked what matter really is. Is that what you meant?

No... In fact, that would be the bassackwards way of putting it.

mass and energy are equivalent, which really just means the question is: "What is mass/energy and what is inertia/momentum?"

 

[Altabeh]

I was trying to illustrate that neither picture is more correct, better, or any more real.

This is hogwash. You seem to have forgotten the cornerstone of Einstein's field equations is built on the analogy between the weak gravitational field and the Newtonian gravitational law. Solving the geodesic equations of a spherically symmetric time-independent "perturbed metric" and using the EP, where the inertial and gravitational forces along r implied on a free falling particle are put in an equality, we lead to the fact that the "perturbed tensor" is actually made of Newtonian gravitational potential. So we are introducing in GR the potential stemming from Newton's law of gravitation which explicitly involves forces. Furthermore using the field equation for an empty space and assuming a non-relativistic radial velocity in a Schwartzschild metric, you can lead to the Newtonian gravitational force law. So it seems we have reached a middle ground between two ways of looking at gravity in the context of GR and your claim doesn't sound right at all.

AB

 

[Ich]

What exactly are you trying to say, Altabeh? How does the existence of a Newtonian limit prove that "Your original post seemed to be implying the force description was indeed the "real" description of gravity, which is hogwash." is hogwash? Nabeshin is quite right here.

 

[Altabeh]

What exactly are you trying to say, Altabeh? How does the existence of a Newtonian limit prove that "Your original post seemed to be implying the force description was indeed the "real" description of gravity, which is hogwash." is hogwash? Nabeshin is quite right here.

Imo, Nabeshin's claim that neither picture is more real is hogwash because definitely gravity is a force but is looked at another way in GR. After all, we say that gravity is one of the fundamental forces of nature but a theoretical framework that GR seems to construct deos also provide a mechanism by which we can get an equivalence between an "interacting force" and "curvature" and the first being more realistic doesn't deny the curvature approach is correct! From a philosophical point of view, as I earlier said, this is a matter of realization to say which one of them is more realistic. Maybe Nabeshin sees the problem from another angle but I do like to stick to the fact that I can feel the force of gravity every day by looking at things around falling down to the ground due to this force!

B.t.w. "Your original post seemed to be implying the force description was indeed the "real" description of gravity, which is hogwash." seems to have entered in my quote accidently, just a mistake, and it has definitely nothing to do with my post and I'm going to edit it!

AB

 

[Ich]

Imo, Nabeshin's claim that neither picture is more real is hogwash because definitely gravity is a force [...]

You're using strong words to attack a strong position with weak arguments.
Especially as you concede that:

From a philosophical point of view, as I earlier said, this is a matter of realization to say which one of them is more realistic.

Maybe Nabeshin sees the problem from another angle

Well, maybe I see the problem from yet another angle. Becuse I'd say that viewing gravity as a force is level with postulating an ether. Hogwash, except for practical reasons, to simplify calculations or facilitate reasoning in certain circumstances.

but I do like to stick to the fact that I can feel the force of gravity every day by looking at things around falling down to the ground due to this force!

That's natural philosophy, not physics.
Gravitational force is fictitious.

 

[Altabeh]

Well, maybe I see the problem from yet another angle. Becuse I'd say that viewing gravity as a force is level with postulating an ether.

This is hogwash. Neither in GR nor in the Newton's picture there is a theoretical "cause" for
gravity and such a postulation is not even true as is thinking that there is a reason for why spacetime is curved by mass in GR. All comes to whom which theory sounds more realistic and we all just attack each other's views on the subject by our own thoughts\understandings.

Hogwash, except for practical reasons, to simplify calculations or facilitate reasoning in certain circumstances.

And you see that there's been a bunch of "hogwashs" in this thread just because everyone sees the problem from his own angle. Since this could be by itself just an idea, I don't see a problem in it!

That's natural philosophy, not physics.

So how could physics possibly prove what picture is realistic in case both can be considered as being more real by different people with different viewpoints? This issue is more of philosophy than physics.

Gravitational force is fictitious.

Only GR interprets gravity as a fictitious force under some strict circumstances (the non-relativistic velocity, weak gravitational field and etc. will lead to gravity appearing as a real force as in the Newton's theory), so in the classical viewpoint it's still a highly credited force!

AB

 

[daisey]

I've read comments here that refer to Gravity both as a force as warped space-time. Can it be both? A force has a force-carrying particle, and as stated above is the not-yet-observed graviton for Gravity. Does the graviton actually perform the warping of space-time?

 

[Frame Dragger]

I've read comments here that refer to Gravity both as a force as warped space-time. Can it be both? A force has a force-carrying particle, and as stated above is the not-yet-observed graviton for Gravity. Does the graviton actually perform the warping of space-time?

According to GR, it is geometry, and a pseudo-force. As for the graviton, there was a recent thread about that... a search for active threads in the last 2 weeks should turn it up. One way or the other, gravity is not a force, but what the graviton is... IF it is... well... hypothetical, and unknown.

 

[petm1]

Gravity, and I know this is only in my mind, is the center connection to my past which I feel as mass. This last week I joined my center connection with my Road Glides center connection for a 1500 mile trip around the center connection of this sweet planet we call Earth. :!) I don't know why mass causes gravity but I like thinking of it the other way, why does gravity cause mass.

 

[DaveC426913]

...I like thinking of it the other way, why does gravity cause mass.

Gravity does not cause mass.

 

[petm1]

"The point is that the raw material doesn't really have to come from anywhere. When you have strong gravitational fields, they can create matter." Stephen Hawking
I Found this quote in Cosmology forum today?

 

[Frame Dragger]

"The point is that the raw material doesn't really have to come from anywhere. When you have strong gravitational fields, they can create matter." Stephen Hawking
I Found this quote in Cosmology forum today?

Matter, not new mass.

 

[petm1]

Exactly.

 

[Frame Dragger]

Exactly.

OK then we're on the same page.

 

[petm1]

I'm still a little confused. In the time line of big bang mass does not come into play until the quark epoch with matter in the form of particles following and all formed from a gravitational singularity. But of course this is looking back through time.

 

[Frame Dragger]

I'm still a little confused. In the time line of big bang mass does not come into play until the quark epoch with matter in the form of particles following and all formed from a gravitational singularity. But of course this is looking back through time.

Energy and momentum existed, but not matter. I suppose there is also the issue of GUT theories and no SSB...

 

[petm1]

Gravity describes the geometry of space/time. The way that matter formed from this dilating gravitational singularity we call big bang into our visible universe, in my mind, makes gravity the cause and mass, the trail through the past to that dilating motion, the effect. Is this equivalent to mass causes gravity?

 

[stevmg]

How about this approach...

Imagine a laticework of an "infinite" (so-to-speak as we do not know if the universe is infinite) of points arranged in a zillion little cubelets. I cannot draw this. I wish I could.

Then imagine objects with mass in the latticework and displacing it outward creating compression towards the center of the mass. Hence, space is displaced outward and the tendency is to push obects in. This would be the gravity. The volume of the object is not relavant, only the mass. Ithink someone above talked about a "dent" in space time causing distortion. That's as good as anything else.