Pushing Gravity

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22 years 3 months ago #2690 by tvanflandern
> [Neil]: 1- The electric force and the magnetic force are attractive (or repulsive). Is there a theory for "pushing magnetism," or "pushing electrical force" to account for the attraction, which is analogous to the theory of "pushing gravity?"

No, the counterpart of the LeSage model for gravity does not yet exist as a coherent, testable theory. However, it is easy to see that these forces could be produced in much the same way. (I give an example in "Dark Matter..." of how to get both attractive and repulsive forces from such models.) Speaking for myself, I've assembled a slew of notes about how such a theory might be constructed, but don't know all the relevant experiments well enough to put it all together yet.

> [N]: 2- On the question of gravitational shielding, there has been a technical discussion going on for some time on this message board as to whether shielding can be demonstrated experimentally. Here's a simple question: Imagine a roof of one mile (100 miles, 1000 miles), of solid rock over a room containing a one pound steel ball. Is the weight of the ball less than it would be without the shielding?

No. The roof has its own normal gravitational force, and that pulls upward, decreasing the weight of the ball. Shielding is an extra effect that prevents the body doing the shielding (or one behind it) from having as much gravitational attraction as it would otherwise have because of a density so great that gravitons cannot fully penetrate it. So if the roof has less real gravity than it should for its mass, the ball will end up weighing more.

Your example is conceptually the same as the example of the Moon eclipsing the Sun and shielding the Earth from some of the Sun's gravity. The result of such shielding, if it exists, would be to increase the downward push on objects on Earth, increasing their weight.

> [N]: 3- If an object, (say a comet), falls toward the sun from far outside the solar system, and if the force impelling the object comes from gravitons pushing it toward the sun, would not the object eventually accelerate to the speed of the gravitons pushing it—that is to say, many times the speed of light? [best regards, Neil]

No. First, if a body falls from infinity, gravity from a source mass (so to speak) accelerates the body so that its speed is always exactly equal to escape velocity. Escape velocity remains finite and sub-lightspeed at the surfaces of all real astrophysical bodies. If it were possible for a mass to collapse to a point, then the speed of an infalling body could in principle approach the speed of gravity, as you suggest. But that cannot happen in practice for the following reason.

All matter consists partly of constituents with a wave-like character (called DeBroglie waves), which is what prevents them from exceeding the speed of light. Of course, every wave is limited to the propagation speed of its own medium.

This resistance of bodies to further acceleration when traveling very fast is what produces effects such as the perihelion advance of Mercury. Mercury's orbit is an ellipse. It travels faster on the inner part of that ellipse, but also experiences more resistance to acceleration. When an elliptical orbit feels more resistance on its inner portion than on its outer portion, it is forced to precess.

Good questions. Sorry if the answers are not grandmotherly, but I can try again if you indicate what in the above is least clear. -|Tom|-

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22 years 3 months ago #2608 by nderosa
Replied by nderosa on topic Reply from Neil DeRosa
As you might have imagined, I'm having a big problem conceptualizing gravity that "pushes" instead of "pulls," (I understand that I am in good company). Could you please reconcile "pushing gravity" with two comments you just made in connection with tides. I'm particularly interested in your use of words like "lifts," "raised," and "pulling." (I might also add your statement above where you say, "The roof has its own normal gravitational force, and that pulls upward, decreasing the weight of the ball"). Also, it seems to me that the Moon's tidal bulge is more consistent with a pulling force, (which would have the tendency to stretch the object in the direction of the pull), than a pushing force (which would have the tendency of flattening out the pushed object). Or am I thinking too one dimensionally here?

[TVF] I'm not sure what you mean by "tide". The average solid-body tide raised by the Moon on the Earth is about 3 feet. That raised by the Earth on the Moon is much larger. But because the Moon keeps the same face toward the Earth, the "tide" there is a permanent bulge toward the Earth. So nothing much changes on the Moon day-by-day because of the tide raised by Earth.

[TVF] Ocean tides are a rather different phenomenon. Those are unique to Earth (having the only oceans so far discovered), and are due to the horizontal flow of water relative to land, not to any lifting force. That is why ocean tides can get magnified in special places. Each day, when the Moon is pulling the whole Atlantic Ocean westward, a wide-mouth river that empties into the Bay of Fundy in Nova Scotia gets an excess portion of that Atlantic tide stuffed into its mouth. All that water flows upstream where the river narrows, making the tide higher and higher. Under optimal conditions, the ocean tides upstream can be as high as 50 feet.


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22 years 3 months ago #3026 by AgoraBasta
Replied by AgoraBasta on topic Reply from
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>
As you might have imagined, I'm having a big problem conceptualizing gravity that "pushes" instead of "pulls," (I understand that I am in good company).
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>

Pardon me for interrupting your chat, but I always had an opposite problem.
I will try to explain it at the simplest possible level:
I can understand why would two electric charges of different polarity pull each other - this way they cancel each other somewhat and "restore the neutrality" which is the obvious property of the medium we inhabit. If now gravity also has a charge, then concentration of that charge in one place only further destroys the "neutrality". Consider another "analogy" - there are two half-full bottles of milk; if you put all the milk into one of them, the "system" becomes simpler; thus some "attraction" could've developed. But it's not the property of milk to come together, it's rather the extraneous consideration of "order" that puts it together. So the pushing gravity from some extraneous agent really appears much more intuitive to me...

Now seriously - gravity seems to be the only truly charge-neutral interaction of our reality. This charge-neutrality simply must be the most important its feature. If those ungodly mathematicians push the idea of the Higgs bosons as carriers of the "mass charge" into the mainstream, we risk to lose yet another coupla' centuries in our current ignorance of the nature of gravity and inertia...
Curiouser and curiouser it really gets.

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22 years 3 months ago #3027 by tvanflandern
> [Neil]: As you might have imagined, I'm having a big problem conceptualizing gravity that "pushes" instead of "pulls," (I understand that I am in good company). Could you please reconcile "pushing gravity" with two comments you just made in connection with tides. I'm particularly interested in your use of words like "lifts," "raised," and "pulling."

Those of us used to thinking in terms of "pushing gravity" often use the word "pulling" because it conveys the same picture in more familiar terms, because all of us were trained first to think of gravity as a pulling force.

Suppose we have an isolated mass in space. It is bathed in gravitons uniformly from all directions. Most fly right through the body, but some do not and are absorbed. The result is that an object sitting on the surface of this body feels a downward graviton wind because more gravitons arrive from above than below because the body itself blocks some gravitons from getting through to the object from below. The downward-pushing graviton wind is what makes objects on or near a mass feel a downward force.

That is the basic "pushing gravity" picture. Let's look at the single-graviton level instead of the statistical ensemble. The surface object feels the downward push from an impact by a single graviton arriving from above that would have been balanced by the upward push from the impact of a single graviton arriving from below if the body had not absorbed that graviton before it could hit the surface object from below.
<img src=" metaresearch.org/msgboard/graviton-pic.jpg " border=0>

So now we can see an "equivalency" on a graviton-by-graviton basis: Every unbalanced graviton hit that produces a push on an object is the physical and mathematical equivalent of a "negative (missing) graviton" coming from the opposite direction and producing a pull on the object. Hence, we can speak of gravity interchangeably as either a push from above or a pull from below, whichever is more convenient.

> [Neil]: Also, it seems to me that the Moon's tidal bulge is more consistent with a pulling force, (which would have the tendency to stretch the object in the direction of the pull), than a pushing force (which would have the tendency of flattening out the pushed object). Or am I thinking too one dimensionally here?

You just need to get used to the idea that, when properly viewed, the push from one direction and the pull from the opposite direction do exactly the same thing. Therefore, LeSage "pushing gravity" is identical to Newton's pulling gravity in every respect, until Einstein's small relativistic effects are considered.

So to describe the Moon's tidal bulge toward the Earth, we can say either that the Earth pulls more strongly on the near face of the Moon than on the far face; or we can say that the Earth blocks more gravitons from hitting the Moon's near face than from hitting its far face, so that the near face gets pushed toward the Earth by the universal flux more than the far face, resulting in a bulge of the Moon toward the Earth.

The key is the equivalency between push and pull in the single graviton picture. If that is true for each potential graviton pair, then it is true for them all. One could generalize this by saying that fluxes produce push forces and blocked fluxes produce apparent pull forces. (That is a hint about how this concept can be generalized to work for electrodynamic forces too.) -|Tom|-

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22 years 3 months ago #2609 by nderosa
Replied by nderosa on topic Reply from Neil DeRosa
[Tom} Those of us used to thinking in terms of "pushing gravity" often use the word "pulling" because it conveys the same picture in more familiar terms, because all of us were trained first to think of gravity as a pulling force.

This gives me enough to go on for awhile till I read more, thanks. That's a good qualitative decription. AB thanks also.

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22 years 3 months ago #2610 by dholeman
Replied by dholeman on topic Reply from Don Holeman
In the fascinating book <u>Pushing Gravity</u> Martin Kokas discussions ocean tidal loading as a possible mechanism for inducing earthquakes. I am confused by the idea that high ocean tides would exert a greater static load - weight - than low ocean tides. It seems to me that the weights in both cases would necessarily be identical because of the nature and origin of tides: gravitational shielding. I am neglecting the dynamic forces which are mostly tangential, or lateral for all practical purposes, which I can see could indeed contribute to earthquake inducing shakes rattles and rolls having been tossed by a wave or two myself. Wouldn't the density of a water column change with the shielding of the moon?

I realize this is conceptually the same as placing a 'roof' over the ocean, as in the above discussion, but I'm still confused by it. In the Meta Model, aren't the phenomena of gravity and gravitational shielding the same animal?

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