Strange Posted June 27, 2016 Posted June 27, 2016 We have no idea what dark matter is, nor does it have a physical basis, Strange. The physical basis is matter (something which is known to physics) which does not interact via electromagnetism (also something which is known to physics) but does via gravity (also, known to physics). The amount, distribution, density and velocities of this matter is fairly tightly constrained. All of this can be modelled using existing physics That is what I mean by having a "physical basis". Even MOND (which seems closer to the OP) is physically based in that it provides a specific modification to Newtonian gravity in order to produce the observed rotation curves. Admittedly, that is slightly ad-hoc because there is no underlying reason known for the modification, other than it works. Unfortunately, it has to be tuned for each specific case. And doesn't help with large structure formation and the other evidence for dark matter. But at least it has its basis in physics. Unlike the OP. Could you answer questions about the mass of particles comprising it ? There are constraints on that. There are also a number of hypotheses about the nature of the particles which are testable and, in some cases, being tested. Just saying "black holes ... magic ... equations ... fits the curve" is less than useful. The best scientific tool is an open a critical mind. FIFY (I don't really agree with that version either.)
MigL Posted June 27, 2016 Posted June 27, 2016 It seems that Declan's intent is neither the modification of Newtonian gravity, nor 'unseen' additional matter. He is looking for a third way out of the dilemma. I think that's commendable, albeit speculative. But the again, both MOND and DM are speculative.
Strange Posted June 27, 2016 Posted June 27, 2016 It would be interesting if you could explain what his "third way" is and what physics it is based on.
swansont Posted June 27, 2016 Posted June 27, 2016 As I said earlier the equation for the velocity would be in the form of v = sqrt(a*r) where 'a' would be constant with distance. Up to this point there is no new science. This is just centripetal acceleration, a very basic and well-known phenomenon. Dark matter uses additional mass to modify the acceleration using Newtonian gravity. You can calculate the mass distribution by knowing the rotational speed data. What you need to do is the equivalent: you need to say how big the effect is as a function of distance, and how the "flow of spacetime" must then vary with distance to give rise to this, which means you have to have some relationship between "flow of spacetime" and the acceleration. That's the meat of your proposal, and you have basically nothing except hand-waving. From your description, the "flow of spacetime" has to increase as you get closer to the center, based on continuity and geometry. But the details will depend on how this flow is affected by the black hole. Is it a 1/r^2 effect, or something else? How much does the mundane mass in the galaxy (stars, and dust) affect this flow? (Once you've done that, you can explain where the spacetime comes from if it's being sucked into a galactic black hole. But that's for after.)
ajb Posted June 27, 2016 Posted June 27, 2016 He is looking for a third way out of the dilemma. I think that's commendable, albeit speculative. People have thought of other solutions, like extensions of general relativity, again with not great success. But the key difference is that they actually built models.
MigL Posted June 27, 2016 Posted June 27, 2016 Swansont's post above is a great example of constructive criticism. It doesn't say you have nothing, or you're embarrassing yourself. It points to a way forward, which will either allow Declan to discard his idea or modify it accordingly. Like I said, I don't think his idea will fly either, mostly because I can't think of a way space-time would flow ( and sink ). You guys are the experts, you provide guidance, in the way of knowledge and critical thinking; Should you be a little more forgiving of new members and not scare them away ? ( luckily, I'm either thick-skinned or too dense to get the hint, and stuck around after I first joined )
Strange Posted June 27, 2016 Posted June 27, 2016 (edited) Like I said, I don't think his idea will fly either, mostly because I can't think of a way space-time would flow ( and sink ). Well, there are coordinate systems (e.g. Gullstrand–Painlevé) which can be viewed as space falling into a black hole, rather than just the curvature of space-time. Edit: https://en.wikipedia.org/wiki/Gullstrand%E2%80%93Painlev%C3%A9_coordinates But there is no suggestion that this is what the OP is thinking of. Or how the (relatively) tiny mass of black holes could affect all the stars in the galaxy. Or ... I try to constructive but apparently it never comes across that way. Edited June 27, 2016 by Strange
Declan Posted June 27, 2016 Author Posted June 27, 2016 Thank you MigL, at least someone is prepared to consider the idea without cutting me down before they even understand what I am saying... To the others: If you bothered to read my other papers first before criticizing you would see I *have* constructed a model that explains all the effects of Relativity from a Classical perspective and the notion of an energy field that fills space, and have worked out wave-functions for the Electron & Positron that have all the right properties, based on modeling them as 3D standing waves made from energy waves. The latest paper on rotation rates is the least developed and I was hoping to come to this Forum to have a discussion to help develop it further. Incidentally the current model of an Expanding Universe already accepts that space-time is flowing. The often used analogy of dots on an inflating balloon representing the expanding Universe - representing space-time expanding & carrying the stars further apart as it expands (i.e. expanding = flowing).
Mordred Posted June 27, 2016 Posted June 27, 2016 (edited) Ive looked over your papers. Truthfull the questions being asked are valid ones. Particularly since your attributing properties to spacetime that dont exist under GR. At least not under SO(1.3) Lorentz group. The equations thus far presented don't properly define how your value a comes about. Either way It still apears to be Keplarian still. As added energy in GR adds to mass curvature. This is different in the NFW profile and I don't see a comparison to the 21cm line. As I don't see those details within the paper... Edited June 27, 2016 by Mordred
Declan Posted June 27, 2016 Author Posted June 27, 2016 Sure, GR doesn't talk about space-time flowing, but originally the Universe was not known to be expanding either. As the current understanding cannot explain the observations then some new ideas may need to be considered. As I said earlier I don't currently have an equation to determine the value of 'a' given a black hole of a known size/mass, however the point is that space-time flowing into a black hole would result in some value for 'a' and that the orbital velocity profile that would result from this would match the observed profile's characteristics, so the idea is worth exploring. To MigL/Swansont: Yes that is good constructive criticism thank you Swansont: I will attempt to address your comments: Centripetal acceleration is not new, it a safe equation to use as it is well-known, however the new part is the inward flow that causes the orbiting star's velocity to be curved inwards as it orbits - behaving just like a conventional gravitational acceleration. The exact details of the flow rates etc. are still to be worked out - the idea is in conceptual stage at the moment, but here are my current thoughts on this: As the space-time field would be flowing inwards from all directions, then either its density would increase in accordance with inverse-square law towards the center of the Galaxy - in the same way that Dark Matter density does - or its density would remain constant and it flow rate would increase near the center. Conservation of energy is maintained in both these possible scenarios. At quite large distances from the Galactic center, the density/flow rate would not change with distance so much and would appear to be more of a constant flow towards the Galaxy center. Other gas/dust would not affect the flow at all, because the space-time field is the medium in which all other matter is embedded. The waves that comprise other matter are propagating through the space-time medium. An analogy for this is having a wave tank with water waves travelling across it, and then you move the whole wave tank along: the water waves keep flowing through the water even though the whole wave tank is also in motion. As for where space-time comes from: this is the same as asking where did the Universe come from? The space-time field is a field of energy, just like condensed matter is whole lot of energy standing-waves. Currently, both are understood to have been created in the Big Bang, and thus both get consumed within a black hole.
swansont Posted June 28, 2016 Posted June 28, 2016 The exact details of the flow rates etc. are still to be worked out - the idea is in conceptual stage at the moment, but here are my current thoughts on this: As the space-time field would be flowing inwards from all directions, then either its density would increase in accordance with inverse-square law towards the center of the Galaxy - in the same way that Dark Matter density does - or its density would remain constant and it flow rate would increase near the center. Conservation of energy is maintained in both these possible scenarios. So it should cause a larger acceleration as r decreases. Which is not what you need to explain galactic rotation curves.
Mordred Posted June 28, 2016 Posted June 28, 2016 (edited) Sure, GR doesn't talk about space-time flowing, but originally the Universe was not known to be expanding either. As the current understanding cannot explain the observations then some new ideas may need to be considered. As I said earlier I don't currently have an equation to determine the value of 'a' given a black hole of a known size/mass, however the point is that space-time flowing into a black hole would result in some value for 'a' and that the orbital velocity profile that would result from this would match the observed profile's characteristics, so the idea is worth exploring. First point, you need to match the 21cm hydrogen line curve. Otherwise you shouldn't claim your model matches the rotation curve. A comparison on other galaxies with known rotation curves to luminosity data is also recommended. Secondly If you wish to model spacetime itself as moving. Then your going to need to show those metric changes in the [latex]G_{\mu\nu}[/latex] tensors. Naturally your going to need to look at the Ricci tensor and stress momentum tensor. We do have a profile that does an excellent job of matching galaxy rotations curves. It is the Navarro Frenk white profile. Yes it uses dark matter but the important part is the how the formula handles the mass distribution. Edited June 28, 2016 by Mordred
Declan Posted June 28, 2016 Author Posted June 28, 2016 In reply to Swansont: Not if the quantity that determines the inward acceleration is the amount of space-time energy flowing rather than just its density or speed. The amount would be constant with distance as you move inwards. I have shown in my Energy Field Theory paper that light/matter waves propagate through a fixed amount of space-time per second, thus the speed decreases as the density increases (this is the cause of Gravitational time dilation). In reply to Mordred: Yes, I guess it would need to be defined in terms of GR in order to convince people - I haven't thought about how to do that as yet. I had a think about how the metric Tensor could incorporate the flowing of space-time into a black hole. It seems to me that the Schwarzchild Metric could be modified by altering only the dr^2 term such that the multiplier of this term could be altered from its current form: 1/(1 - 2GM/rc^2) To become: (1/(1 - 2GM/rc^2) - f) where 'f' represents the steady inward flow rate of the space-time field. Something like this could represent an extra shift towards the black hole that is independent of distance 'r' from the center.
ajb Posted June 28, 2016 Posted June 28, 2016 (edited) Sure, GR doesn't talk about space-time flowing, but originally the Universe was not known to be expanding either. But we all know what expanding means. I am still totally lost by your term 'space-time flowing'. What does this mean? Edited June 28, 2016 by ajb
MigL Posted June 28, 2016 Posted June 28, 2016 I'm not understanding the concept of space-time 'flowing' either. Especially with the notion of a BH sink and, therefore, a source. I don't think it can simply be explained away as similar to expanding space-time, since that simply implies distances between co-ordinates ( events ) becoming larger. There is no actual 'flow'. What would it be flowing relative to ? And if there are sinks in BHs, where are the sources ? And what process is 'creating' space-time at these sources ?
Declan Posted June 28, 2016 Author Posted June 28, 2016 space-time is a field of energy waves that fills space (synonymous to the gravitational potential field) and whose density determines the rate of gravitational time dilation at every point in space. It is comprised of the sum of all the wave functions of all the particles (near and far) in the causally connected Universe. When everything is normal (i.e. no black holes) there is just as must of this wave energy leaving a volume of space as there is entering it (i.e. zero divergence). But when a black hole forms, even this form of energy wave cannot escape the black hole's gravity and so starts to flow into the hole and become part of the black hole. Thus the divergence is now non-zero and the energy field starts to flow into the black hole. So the volume of space in which the black hole exists has a negative divergence and there is more of the space-time energy field waves flowing into it than out of it. This is what I mean by space flowing. The effect this flow has on objects surrounding the black hole is to make them move towards the black hole with the flow. In the case of circular motion (i.e. stars in orbit) this causes the orbiting stars velocity to be constantly bent towards the black hole (just like a conventional acceleration does). Thus the star's orbital velocity must be higher to remain in the same orbit. The quantity of space-time energy field would be essentially fixed for a given black hole size/mass, and the field would remain denser near the black hole than further away (as is the case for a star/planet - but in this case the gravity is not sufficient to consume the field - so it doesn't flow).
ajb Posted June 28, 2016 Posted June 28, 2016 What would it be flowing relative to ? Not that I have any idea if is this anything to do with the OP, but... A flow is understood as a one parameter family of local diffeomorphisms of space-time (or really any smooth manifold). Thinking of the active picture you can imagine a small region of space-time getting mapped to itself. Thus the space-time locally changes, but with respect to some external parameter - informally I often call this parameter 'time', but this is not the coordinate time, but it could be the proper time of some observer. Anyway, in general this notion has nothing in particular to do with GR. So it is up to Declan to really explain his notion of flow carefully. Only then can we start to see if has any meaning. Until then the phrase 'not even wrong' still applies. space-time is a field of energy waves that fills space (synonymous to the gravitational potential field) and whose density determines the rate of gravitational time dilation at every point in space. Fields as we understand them require a space-time in the first place. Classically, fields are sections of some bundle over the space-time. You will have to explain very carefully how you get fields without an underlying space-time. Also, I am confused about your use of gravitational time dilation. It is not really an intrinsic thing in GR, it comes from comparing clocks when it is possible to do so. It is comprised of the sum of all the wave functions of all the particles (near and far) in the causally connected Universe. Wave functions we usually understand in terms of sections of a complex line bundle. Again in the usual understanding the space-time needs to be given.
swansont Posted June 28, 2016 Posted June 28, 2016 In reply to Swansont: Not if the quantity that determines the inward acceleration is the amount of space-time energy flowing rather than just its density or speed. The amount would be constant with distance as you move inwards. The amount stays the same (continuity demands it), so the flux must increase as r decreases, because it depends on surface area. The flow cannot be the same. I have shown in my Energy Field Theory paper that light/matter waves propagate through a fixed amount of space-time per second, thus the speed decreases as the density increases (this is the cause of Gravitational time dilation). Well perhaps we should be discussing that speculation first, if this one is based on it, rather than assuming that it's true. 1
Declan Posted June 28, 2016 Author Posted June 28, 2016 In reply to ajb: Gravitational time dilation is a real effect and has been measured in mine shafts, satellites & spectra from the Sun. I mentioned it as the density of the space-time energy field determines the rate of time at a point in space. All of Physics has the problem of wave activity without some underlying field at some point. The energy field I refer to is the sum of the wave functions of all the particles in the Universe & its effects on condensed matter. In reply to Swansont: The rate of flow can remain the same as the shell far away from the center has lower density but larger surface area and the shell near the center has higher density but lower surface area - the two quantities of space-time that flow inwards are the same.
swansont Posted June 28, 2016 Posted June 28, 2016 In reply to Swansont: The rate of flow can remain the same as the shell far away from the center has lower density but larger surface area and the shell near the center has higher density but lower surface area - the two quantities of space-time that flow inwards are the same. Higher density and lower surface area both increase the flow. Those effects don't cancel. You divide by the area.
ajb Posted June 28, 2016 Posted June 28, 2016 (edited) Gravitational time dilation is a real effect and has been measured in mine shafts, satellites & spectra from the Sun. In the specific situations you describe yes. This is because to a good approximation we can use the Schwarzschild solution - this describes the space-time round a non-rotating spherically symmetric massive object. In general you need a notion of comparing clocks, I think you will need at least stationary space-times for that (but don't quote me). Anyway, you don't have a notion of gravitational time dilation in general. It is a feature that makes sense for some and not all space-times - you will want the coordinate time to be related easily to the proper time on the clocks. I mentioned it as the density of the space-time energy field determines the rate of time at a point in space. Rate of time? You mean when comparing clocks? If so see above. All of Physics has the problem of wave activity without some underlying field at some point. You mean waves must be waves in something? Sure. The energy field I refer to is the sum of the wave functions of all the particles in the Universe & its effects on condensed matter. Okay... so you have space-time as a pseudo-Riemannian manifold. You then place on top of this a (complex) line bundle (or really some huge tensor product of such things). A section of which is this 'energy field'. Great we are getting somewhere... or have I misunderstood? If I am on the right lines, now say something about 'space-time flow'. Edited June 28, 2016 by ajb
Declan Posted June 28, 2016 Author Posted June 28, 2016 Reply to ajb: I am a bit confused by your terminology as you are with mine - but yes I think you are in the right track... I described the space-time flow a bit earlier - I'm not sure how else to describe it - please re-read my earlier post... Reply to Swansont: No, the actual speed of the flowing energy and the amount of energy passing through each shell (at every level) remain constant - its just that as the energy converges towards the center its density increases, but the shell it fills get smaller by the same proportion. I guess you could think of it as a compressible gas?
swansont Posted June 28, 2016 Posted June 28, 2016 Reply to ajb: I am a bit confused by your terminology as you are with mine - but yes I think you are in the right track... I described the space-time flow a bit earlier - I'm not sure how else to describe it - please re-read my earlier post... Reply to Swansont: No, the actual speed of the flowing energy and the amount of energy passing through each shell (at every level) remain constant - its just that as the energy converges towards the center its density increases, but the shell it fills get smaller by the same proportion. I guess you could think of it as a compressible gas? Yes, the total is the same. The flux must increase. One reason why you need a formulation of what's going on, rather than a qualitative description. Why would an acceleration at one point or in one region depend on the total amount passing through the shell, rather than on the amount passing through the object, or in its vicinity?
Declan Posted June 28, 2016 Author Posted June 28, 2016 It is the rate of flow of the energy, not the flux, that determines the acceleration on the orbiting stars. The stars' orbits are shifted towards the galaxy center at the rate of the flow. The density of the energy field determines the amount of gravitational time dilation experienced by observers at any point in the energy field.
ajb Posted June 28, 2016 Posted June 28, 2016 I described the space-time flow a bit earlier - I'm not sure how else to describe it - please re-read my earlier post... What is 'flowing' exactly (the points on the space-time or something else?) and what is the 'parameter' of this flow?
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