# Where is most "gravity", inside or out?

Discussion in 'Astronomy, Exobiology, & Cosmology' started by nebel, Feb 29, 2016.

1. ### nebelValued Senior Member

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So, if this correct, any object, including the universe ( or any object in it) would have gravity reaching into infinity, never to come to zero gain. Mass, a form of energy, having a massive effect.
Energy in Time must therefore be infinite, because from here it reaches there.
Perhaps it came from there in the first place.

3. ### nebelValued Senior Member

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Case of a disk, spiral galaxy: with equal distribution of matter, (which will not be the case, what with thousands of black holes holed up near the center), a gravity detector flying at 2 R, well into the outer halo, would detect 8 times more "total gravity "*,- than when measuring around the inner, 1/4 R circumference. Still at any given point the strength would be equal.
* strength of the field X distance (circumference) through which g acts.
thanks to origin for the original image.

5. ### nebelValued Senior Member

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using the above original graph, if the object in question is not a disk as in post 162, but a globe of even mass, the "total gravity" at 2R outside "sphere " would be 64 times that of the equal strength gravity at the inside sphere of 1/4 R, because it is acting over a much greater surface.
The same strength at any given point, at 1/4R or 2R, but at distance 2R much more pervasive.

7. ### nebelValued Senior Member

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Since outside any entity gravity falls off from the surface in all directions with the inverse square from the zero gravity centre, it should never come to zero, or only at infinity. Since gravity is a manifestation of energy /mass, they must have an infinite reach.

8. ### nebelValued Senior Member

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Perhaps we can all agree that there is nothing outside the universe. There was not a thing before the universe either. Energy converted into matter, (things) at the Big Beginning, but
does that mean the effects of mass, matter can not reach beyond it's location? Do the effects of gravity reach into infinity? even if matter does not?

9. ### CyperiumI'm always meValued Senior Member

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It's not gravity as a entity of itself that reaches infinitly far, it's the bending of the curvature of spacetime that was caused by residing a body of mass.

Gravity is not a push or pull force, it requires no energy and the apparent effect of things falling is simply objects following a straight line through curved spacetime. Even a object stationary in space moves through time at the speed of light and a object always moves straight without any force acting on it.

10. ### CyperiumI'm always meValued Senior Member

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I should also mention that the curvature doesn't happen instantly but must as everything else move at most at the speed of light (hence creating ripples of spacetime curvature as a object moves, if it was instant there would be no ripples). As it isn't instant the curvature doesn't actually extend infinitly but rather extends forever.

11. ### nebelValued Senior Member

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thank you, point well taken. so: is not the idea of a force Newtonian, and warping of spacetime relativistic, but describing the same phenomenon? and how did a body of mass get to exist? if not through conversion from Energy? and is not energy too affecting spacetime?

Since energy can not be destroyed or created, it, with time to exist in*, must be fundamental, have existed in the infinity past ( hate that word forever, heard it in too many sermons). so: There should not have been a wave front of gravity rushing out with velocity "c" into the future at the conversion of energy into to matter at the BB. --or?
Point of this thread was, that there must be more gravity outside an entity than inside, one reason being, that there is so much more spacetime outside than in the interior, and the Shell Theorem. Then there is energytime* and timespace and mattertime to consider, as discussed in the "ALMA" thread in the fringe, Alternative Theories section.

12. ### CyperiumI'm always meValued Senior Member

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Yes, energy and mass both create spacetime curvature by residing in it. Yes again that mass is a conversion of energy. The idea of gravity being a force is indeed newtonian and as such incomplete when deriving conclusions from it, your ideas require a relativistic explanation to make sense.

The curvature quickly dissipates and becomes almost flat, a intuitive guess would be that it approaches more curvature but never quite get there, I guess that the limit is set because the curvature doesn't move at infinite speed and as such the cumulative curvature never becomes "more", I'm not sure what the implication would be if there were indeed more curvature outside than inside an object, perhaps this thread isn't actually about there being more gravity outside than inside an object but rather the implications thereof? If so, what do you think those implications would be?

13. ### CyperiumI'm always meValued Senior Member

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Also, yes there would be a "wavefront" but as the universe during inflation stretched many times faster than the speed light it became very flat and also not residing at the edge of the universe.

14. ### nebelValued Senior Member

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Last edited: Jun 6, 2018
15. ### nebelValued Senior Member

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IMHO The curvature is not more pronounced outside an entity, but there is vastly more of it. My threads are started innocently, and then take on a life of their own. One iteration shows that
In an empty shell, of whatever dimension, -- let's say the spherical universe model in " ALMA", --or posts # 153,154, there is no gravity inside at all, all must be in the outside.

16. ### nebelValued Senior Member

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sorry my ideas remain expressed in Keplerian terms, which still work when sorting our asteroids. Gravity of course affects the rate at which matter moves through time, and that is addressed, by declaring black holes stuck on their radius, travel through time, but really, I leave relativity, quantum mechanics, vibrating strings, to the experts.
We can launch a satellite, using Newton, Einstein is only required once the Satellite position system is activated.

17. ### CyperiumI'm always meValued Senior Member

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If you don't take into account the relativistic perspective then you run the risk of misinterpreting an coming to false conclusions, like there being no gravity inside at all, gravity is curvature and of course exists within a body.

18. ### nebelValued Senior Member

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It all depends on the body of course. If you scan through the previous posts, you will see that we are talking about ideal bodies, ideal empty shells (of zero thickness even), constant densities. In such bodies, the evenly distributed outside mass does not contribute to the surface gravity of the enclosed sphere. An empty shell of the right material will not only have no interior gravity, but no electromagnetic forces either. Consider a Gauss cage.
If you think that relativistic considerations change that, supply the proofs of that please.

Last edited: Jun 7, 2018
19. ### CyperiumI'm always meValued Senior Member

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As long as there is mass it effects the curvature of space, however, mass could be configured in such a way that an object will not feel any gravity and behave as if there were none, if there is equal gravity in all directions. Gravity is still there though and any relativistic effects of gravity would still apply (such as time moving slower), if you pull something in all directions with equal force you can't say that there is no pull even though the object isn't moving.

Relativistically time remains curved even though space hasn't curved (or rather space has curved in a way that resembles a straight line) due to mass being placed in such positions in space.

20. ### nebelValued Senior Member

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That is a scary thought being pulled in all directions at once. When I mentioned "gravity" I guess it meant gravitational force, which has to be experienced, or potential that is there whether a body experiences it or not.
So: please elaborate on this: If
You are inside a spherical cavity, where there is no gravitational force because of the surrounding mass cancelling out, tugging each other to zero, are there two gravitational forces impeding your travel through time, slowing you down, whereas on the outside at the surface with only one tug, or warp, there would be freer travel through time?
In other words is there double the relativistic effect even though there is no gravitational force? interesting! but my question was not about about the effects of specific or general relativity , but simply concerning gravity, the force, the potential. An that is huge on the outside, and far reaching.

Last edited: Jun 7, 2018
21. ### nebelValued Senior Member

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Even in any body, full of stuff, to look at origin's appreciated diagram, there is zero gravitational force at the centre, like everywhere in the empty sphere cavity. No gravity detectable, but you will be forever young? if the sphere is heavy, or small enough, or both? Has this ever been tested or detected in reality?
Minimum gravity accompanied by max time dilation?

22. ### CyperiumI'm always meValued Senior Member

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That would be correct, but forever young means stopping time completely which would require infinite mass. But you could make it go much slower, though you would only notice the surrounding worlds time move faster to you, we always experience normal time in our own frame.

23. ### CyperiumI'm always meValued Senior Member

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the gravity is still there, you just don't notice it, the net effect is cancelled but gravity is still there.