studiot

You can't seriously be denying that surveyors on Earth have a different correction for spherical excess than hypothetical surveyors on Jupiter? So are you saying that if the Earth expanded to the size of Jupiter, surveyors would notice no difference?

But we are talking about dilation. Indeed so, but as noted, we are talking about dilation, which is a dynamic thing, not the static one both you and Strange are describing. Is it not true that the intrinsic indicators of curvature will change with expansion? For instance spherical excess on the balloon will increase as the balloon expands. Further you are both ignoring my earlier comments about the subject.

Ok smartypants, how would the analogy be possible if the surface of the balloon was not curved in the third dimension?

Why would it change? Would that not imply this additional space is different from the previous space. So what is your proposal for phenomena that cross the boundary between the old space and the new space? Well I think it good enough to give +1 to. SJ has effectively put forward the Physics definition of a Field. Far better than the sort of Field the OP seems to envisage as some sort of web spun out by spiderman. Please, please get hold of a copy of "The Lighness of Being" by Nobel physicist Frank Wilczek. He dedicates this book to developing this sort of Field and the idea that 'particles' are disturbances of it. Please tell me how the balloon could exist or expand without the third dimension? Perhaps not time itself, but Minkowski ct, which would be a length and therefore accaptable as a measure of radius. Do you have a reference, If so I would be very interested. The diagram of this is what I was considering for geordie. Still thinking about this, my trip up Crook Peak offered wonderful clarity.

But charge may 'bend' a field, but it can't bend space. Mass, by way of gravity 'bends' space. Do you consider space to be finite or infinite? The answer makes a very big difference since infinity plus 20% is still just infinity. As to which type of field, your answers elad me to believe that you are referring to what is known as the common background radiation along with the general distribution of light (EM radiation) we observe, which varies from direction to direction. Such 'fields' are indeed one use of the word but they are neither the formal definition of a Field as used in Physics or in Mathematics (The one in Mathematics is different). I am just going out onto the Mendips, so you will have to educate me another time as to how you find these past trheads so readily and quickly. I can never find them when I want them.

I suppose it depends upon your background. I have done so much surveying in my time that the idea comes naturally to me. Do you remember I once tried to explain the surveyor's concept 'through chainage' to (I think) you. This is an elementary example of it in everyday practice.

No, geordie, I know that. But then nobody else has either. Everybody glibly says words to the effect "There is no centre of dilation" for this expansion and the balloon analogy is offered with the statement There is no centre of expansion for the balloon. This statement is untrue and hides the fact that There is no centre of expansion in the manifold that forms the surface of the balloon. However the centre of the balloon is also the centre of dilation, but it is not in the surface manifold. In fact it is not in the same dimension as the manifold. The connection between this statement and curvature and dimension is fundamental and usually glossed over. I am trying to work out a way to draw this for you, but would welcome anybody else who has a good answer.

I'm not sure what you mean by this. Can you elaborate? I agree it's unfinished or something, I don't know what. I asked you before and you didn't answer You need to distinguish what sort of field you are talking about please? I would suggest that you also need to distinguish between energy and mass as they are somewhat different. Energy is not a sort of liquid form of mass that can be transferred from one body to another. But you can coalesce two masses to form one.

Well that's wrong. You can have space with no field at all. So how is this different from space where there is a field? You might say that a field is the influence or effect of a source (or sink) on a region of space.

Good stuff. You can write powers directly using superscript on this forum. Having superscript and subscript is a great boon. Look for the X2 and X2 symbols on the toolbar at the top of the text entry editor.

Hello and welcome to St. Please explain what you mean by the above statement. Strain is a dimensionless quantity, not measured in metres.

That is what I asked you. (except that the edges of the block are not outer walls) This apparantly innocuous question seems to be causing a deal of difficulty. Perhaps that is because expansion and contraction is more complicated than at first meets the eye. Let me ask again. Suppose you were to printout my sketch and then photocopy it on the 100% enlargement setting. Would the hole get bigger or smaller? Would every point in the solid part of the block be further from its neighbours than before? To save time: Yes, of course the hole would get bigger. Yes every point would be further from its neighbours. Now there is a point to all this because the expansion of the universe is not like my example (with or without the hole) The expansion of the Universe is an entirely different sort of expansion. And you need to understand this difference before trying to discuss the expansion of the Universe. Interestingly this difference has to do with curvature and another dimension, which everyone seems anxious to discuss.

Realistic of what? Your choice of scenario, so long as it is clearly stated.

Expansion (and contraction) are actually peculiar processes. Here is a simple block that expands (equally) in all directions, as shown by the arrows. But it has a hole in the middle. Can you tell which way the sides of the hole move? That is does the hole get larger or smaller?

No you are missing my (our) point. This is not Star Wars; Jedi knights and 'The Force' is a work of fiction. There is no such thing as 'an all-universal permeating field'. So decide what you want to discuss, picking only from that we can observe.

No there is no contradiction. Strange touched on the why of it but only briefly. It is space that expands, not matter. Matter is not space. Now consider our solar system. The disposition of the planets is governed by the balance of the gravitational forces within the solar system. In turn these are governed by the amount of the matter in the system. But matter does not change. So the balance of forces will not change. So the disposition of matter will not change. That is the solar system will remain the same size. However the distance between our solar system and the next will increase. In the 'empty' space between solar systems there field strength is low. The % of 'empty' space will increase in a given portion of the universe. So the average field strength will go down. You can make the same case for galaxy sized agglomerates and atomic scale assemblies (molecules), although at the atomic scale the fields and forces have a different origin. Note I emphasised the phrase 'in a given portion of the universe'. This is because of the peculair behaviour of infinity. We have to discuss a limited volume, because the introduction of additional volume in an already infinite volume presents mathematical and philosophical difficulties. We do not know if the universe is actually infinite or is finite.

With respect you have spent too much effort on clever drawing/animation and not enough on laying out the maths properly. A much simpler drawing would be adequate, accompanied by better presented maths.

Sort of. We live in a three dimensional (of space) universe so I think the fruit cake analogy is better than the balloon one. Gauss's Law applies in all cases not just spheres and surfaces. The point of the fruit cake is that as the dough rises the cake expands in 3D. As it does so all the sultanas etc move further away from each other. So any interaction will take place of an increased distance.

As I understand what you are asking and rephrasing it The total energy in a given field, say electrostatic or magnetic, is being spread out over an increasing volume as the Universe expands. Does that not mean that the measures of field strength diminishes? The answer to this is yes it does. This is known as Gauss's Law. But matters are complicated because you have misunderstood some terminology. There is no such thing as 'potential force' There are various measures of field strength, appropriate to the particular type of field. These measure are also called flux density or field intensity. But you should not confuse this type of field with a quantum field, which is a different thing entirely. Also I think you should be careful not to confuse force and energy. These are different things that may exist independently. Finally potential is yet another different thing that I recommend you leave out until you have a proper handle on the others. So the first question is Which type of field do you wish to discuss?

I am having considerable trouble following what you think is happening and what you are taking into account. You say there is more water at the end in a vessel of constant volume? Where does this water come from? Clearly if there is more water, there is less polystyrene and you say you shorten the polystyrene strips. How? You say the volume remains constant. You also say the width and height remain constant. But you have marked none of these on your diagram so it is not clear what these dimensions refer to. Obviously to maintain these values constant the third dimension must change, can you indicate that as well? I don't see how you have calculated your energy values. Have you taken bouyancy into account?

Yes please I would like an answer to my polite straightforward question. Thank you moderator +1

Sorry, that won't wash as an explanation. Yes this bit is correct But There are several Zeno paradoxes. One of them is about an arrow. An arrow will never reach its target because Before it can cover the whole distance it must cover half that distance, leaving half the distance uncovered. No matter what speed it travels it there will always be half the distance remaining, however small. So it will never reach the target.

How does your hypothesis work with double blind testing, and why is double blind testing necessary if what you say is true?

Here is a picture that illustrates what I mean about the water movement and the wave. And here is a report on trials of a mechanical system alongside a harbour wall. It has many facts and figures about the size and frequency of waves and the power that can be extracted. https://www.sciencedirect.com/science/article/pii/S2092678215300480 And here are the salter ducks

There have been trials of arrays of distributed bobbing or nodding extractors, using wave action. But sea wave particles do not go up an down they go round and round. So a weighted shape, like a duck that bobs side to side is used. As swansont noted the frequency is low, perhaps 100 to 25 times lower than that of the ordianry mains. Also synchronisation of the array is not practicable both because the ducks drift about and because the wave itself passes irregularly. So for both these and storage reasons, the energy has to be converted perhps several times before final delivery. I will try to find some references when I have time