Write4U: Static means that the field configuration is not changing over time. Obviously, the gravitational field will vary if sources masses move around, but there's no problem with considering static situations. When we're talking about the shell theorem, we're interested in the field of a symmetrical, stationary shell of matter, which is a static field. The concept of the flux of a vector field through an area does not mean the field is not static. Calculating the flux is like counting how many field lines are passing through a given area. There is no actual movement of anything. Some people get confused by the term "flux", which sort of implies change and movement, but the use of that term in physics is broader than that. In fluid flow, a flux usually represents an actual flow rate of fluid through an area, but the flux of an electric or gravitational field doesn't involve an actual flow of matter.
If I understand it, this phenomenon also is peculiar of the wave function which moves horizontal but the water molecules themselves remain virtually stationary.
Thank you for putting that up. I selectively saw there, that there is indeed no gravity inside a shell, and that applies even to the case of general ellipsoidal bodies. There is no gravity at the center of a body either, and of course no inside gravity on a small enough entity. Your link showed how gravity can span, or is calculated to act across the gravity-free zone of an empty shell to the opposite side!, but my query was, how does that happen? does gravity have to traverse from the mass to the outside? or is the field static, all pervasive, and the addition and subtracting, cancelling of vectors is just a local condition in the interior?
I just brought this up, to introduce the idea of a simple interior. which according to you good earlier suggestion, is permeated by the outside gravity fields of many distinct bodies. Some of the directions of that gravity cancel, other add well, I wanted to keep these questions open, because are there not hypothesis that imply movement inside gravitational fields? This now being in the pseudo section, imagine somebody suggesting a wave theory of gravity, and the gravity-dead zone inside an ellipsoid cavity being seen as an interference area.. .
The answers is that the field is all pervasive. Nothing "blocks" gravity. If you have mass A on one side of a wall and mass B on the other side, then mass A will feel the force of gravity from mass B despite there being a wall "in the way". Even if the wall completely encloses mass B, the gravity still "gets through".
well, of course, imagine if we could, some of the proposed freaky free energy devices would actually work. I was curious whether a mechanism had been proposed that models the cancelling of gravity in the interior. It can not just be book keeping. If time dilation happens despite no measurable gravity, two gravity fields with opposing directions both exist through each other in the interior. or?
Question; Why is gravity a priori associated with mass? There is no a priori attraction such as magnetism. There is a warping of spacetime, created by the massive object, causing an acceleration toward the spacetime "well" along the stretched st-coordinates . Is gravity not a secondary spacetime effect caused by a massive object on the fabric of spacetime itself? From what I visualize, spacetime itself becomes stretched in vicinity of a massive object. This causes an acceleration toward the deepest part of the spacetime distortion. If that is the case, can we say that gravity of an object begins at the "deepest" point of the gravitational spacetime well?
It's not a priori. It is an experimental observation that the more mass there is, the more gravity there is. As for magnetism, it is experimentally observed to be an effect of moving electrical charge. Again, nothing a priori about it. In the general relativistic picture, falling objects follow the shortest paths in a curved spacetime. A falling object is only observed to accelerate due to gravity if you're viewing it in a non-inertial frame of reference. Don't know what you mean by "secondary". What would be "primary" in that case? Well, curved. Only if you're an observer trying to stay at rest in the curved spacetime, in which case you're accelerating and non-inertial. You seem a little fixated on this idea of gravity having a source that propagates outwards from masses. It doesn't work like that. Gravity is a field - it exists at all points in space, regardless of whether there is mass there. Mass causes the field to curve in a particular way, roughly speaking.
And if that curvature comes from the "effect" of mass, gravity is the "effect" of curvature, not from the mass directly. A secondary effect, no?
Even if you did not have a probe sensing gravity on that" interior" line, the fields would cancel in the neutral center point, zero gravity, flouting, like inside the space station, where the acceleration of earth's gravity and acceleration from centrifugal "force" of orbit velocity balance. Between the two point masses the opposing gravity accelerations are balanced, cancelled. but should exist, just as the Earth, and the orbit exist and exert their force. but When it comes down to the smallest masses, , gravity or acceleration is all outside.
Gravity is not the effect of curvature, gravity is the curvature. It can't be a secondary effect because there is no primary effect. Spacetime is not a thing. We can't measure it. All we can do is measure how masses move. There's no middleman here.
I like the expression stretched, or tensioned you use, for if light passes near a heavy object, its pass is pulled inward during the passage Here are 2 attempts from page 16 to visualize that, origin and exchemist the sourcesPlease Register or Log in to view the hidden image! Here the the zero value for gravity (center and infinity) would be on the horizontal axis Please Register or Log in to view the hidden image! In this illustration, The zero value is indicated by the horizontal slope at the bottom and far rim, greatest strength of gravity by the steep gradient of the slope (greatest at the surface ) Both are different illustrations of the strength of gravity, no slopes exist in nature it is a tensioning, of space a readiness to pull in directly toward the center from all directions. There is near zero gravity near the center in both cases. One way or another, despite the great mass near the center, gravity is cancelled out there , in case of a shell, totally cancelled in the whole interior. . All gravity appearing only outside the surface.
These quotes seem to contradict what you just said. and https://en.wikipedia.org/wiki/Gravity Hence my question for clarification. Nowhere is there mention of spacetime curvature or stretching of spacetime being the "cause" for gravitational phenomena. The definition clearly states gravity is a "dynamic" force between massive objects (somewhat similar to magnetism) rather than a "passive" effect of warped space around the massive objects. You visualize space curvature as a result of gravity, I see the curvature being causal to the phenomenon of gravity. It is the mass which causes the space curvature and is causal to a mutual "falling inward toward each other", not some mysterious direct attractive force between two massive objects.
is there not this sequence: primary and further causes, matter receives mass through the Higgs Boson, Mass than bends, warps or "tensions" spacetime, which causes the deflection of matter, light, dilation of time?
Higgs Boson does not go deep enough into the understanding of energy and matter . In our Universe . Nor does the quantum world
Um. OK. This should have gone without saying, but apparently it needs to be said. The passages you quoted describe Newtonian gravity - a force. In Newtonian gravity there is no such thing as spacetime, let alone curved spacetime. In Einsteinian gravity, it is not a force at all. Gravity is the curvature of spacetime. These two are completely different animals.
Disagree Gravity has so little affect on anything as to be irrelevant to any physical movement of anything .
true only at very small scales, the point mass of post #457, even then those truly small effects add up require serious muscles to lift against even 1 G.
I agree. That's why I cited the dictionary definition of the word "gravity", which gives only the Newtonian interpretation. Actually, I am proud to have caught that distinction myself. I may have had it buried in my memory. Therefore, the attractive gravitational effect of a body on a second body is not a first direct causality but a secondary causality, and vice versa, no? That is what Einstein "added" to the Newtonian equation, no?