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#1700 by ThereIWas3 on 18 Sep, 2017 16:49
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The most important factor is doing so is finding the correct period of oscillation.
This is an interesting idea. I wonder if the 'resonant frequency of spacetime' for the purposes of emdrive can be determined along the same lines as is used for electromagnetic waves. Back in school we had it drummed into our heads that the 'characteristic impedance' of space was 377 ohms, and that was purely resistive. But that is specifically for electromagnetic fields and here we are talking about gravitational forces. The relevant formula might be different than just "the product of the vacuum permeability and the speed of light in vacuum." -
#1701 by Mulletron on 18 Sep, 2017 16:57
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The way I see it is that every mass in the universe is causally connected to every other mass in the universe via mutual gravitational interaction. Is that instantaneous? No. Information can never travel faster than c.
Now if I stand with my arms down by my side, and I begin rotating and my arms fly out, as I view the apparent rotation of the distant stars, do the distant stars have any knowledge that I'm rotating? No, of course not. There hasn't been enough time for that information to be communicated to and from the distant stars. Is there a constant causal chain linking me to the distant stars? Yes but it isn't instantaneous.
Now if I push on something, and it pushes back on me, is that happening instantaneously? No of course not. It takes time for this information to travel through my molecules and through the electric charges which interact with the other object, and then it takes time to propagate through the parts of both me and the object I'm pushing for the whole parts of both to even know that it got pushed.
Nothing is instantaneous besides weird quantum tunneling stuff and the like and even then constraints have been put on that by experiment.
So if I take the center of mass of all those distant stars and everything else out there, and some observer located at one of those distant stars does the same thing, and this is repeated ad infinitum, knowing that the universe does not have a center, where is the center of mass of all this stuff? It's everywhere.
Edit: added ad infinitum -
#1702 by JasonAW3 on 18 Sep, 2017 17:09
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Nothing is instantaneous besides weird quantum tunneling stuff and the like and even then constraints have been put on that by experiment.
Dumb question; Could gravity itself be a quantum tunneling phenomena? -
#1703 by M.LeBel on 18 Sep, 2017 18:38
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...In (1) Sakharov disproved Hawking, who previously claimed (before they met in 1987) that maximal entropy alone would reverse the arrow of time. Sakharov showed him he was wrong, as entropy grows with the arrow of time (both are related) and the time arrow can reverse only if entropy reaches a minimal state, i.e. zero value. ...
This is interesting
Thanks for pointing this out.
While on the subject of gravity and entropy ...
Well, gravity and entropy are the same. Time runs slower as we get closer to the ground, yes? And an object moves spontaneously (fall) toward the ground, right? We could say that slower time pulls the object down ... ??
There is another way to approach this. The speed of light is constant everywhere, any frame of reference. As we get closer to the ground, the speed of light must remain constant. Let’s see. As time slows down the units seconds must be relatively longer. So, “space” must also get longer in order for the ratio meter/second to be constant. In other words, an object falling toward the ground is actually falling into larger space. Reminds you of something? Entropy is the spontaneous dispersal into a larger volume. And, because of the constancy of c, we can say as well “dispersion in time”.
Is this wrong, and why?
Marcel,
"It is the contracted ruler that makes it appear space has stretched."
There is no “ruler” in my argument. There no “appears” either. Even without a falling object, the argument says that space is larger down here than above in order for c to remain constant.
" It is the slow clock that results in time dilation."
The clock is a measuring instrument. It doesn’t affect or change time. The clock measures local time because local time makes the clock work at a certain rate, faster or slower.
Warptek, I don't see here any "wrong" demonstrated.
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#1704 by WarpTech on 18 Sep, 2017 19:13
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...In (1) Sakharov disproved Hawking, who previously claimed (before they met in 1987) that maximal entropy alone would reverse the arrow of time. Sakharov showed him he was wrong, as entropy grows with the arrow of time (both are related) and the time arrow can reverse only if entropy reaches a minimal state, i.e. zero value. ...
This is interesting Thanks for pointing this out.
While on the subject of gravity and entropy ...
Well, gravity and entropy are the same. Time runs slower as we get closer to the ground, yes? And an object moves spontaneously (fall) toward the ground, right? We could say that slower time pulls the object down ... ??
There is another way to approach this. The speed of light is constant everywhere, any frame of reference. As we get closer to the ground, the speed of light must remain constant. Let’s see. As time slows down the units seconds must be relatively longer. So, “space” must also get longer in order for the ratio meter/second to be constant. In other words, an object falling toward the ground is actually falling into larger space. Reminds you of something? Entropy is the spontaneous dispersal into a larger volume. And, because of the constancy of c, we can say as well “dispersion in time”.
Is this wrong, and why?
Marcel,
"It is the contracted ruler that makes it appear space has stretched."
There is no “ruler” in my argument. There no “appears” either. Even without a falling object, the argument says that space is larger down here than above in order for c to remain constant." It is the slow clock that results in time dilation."
The clock is a measuring instrument. It doesn’t affect or change time. The clock measures local time because local time makes the clock work at a certain rate, faster or slower.
Warptek, I don't see here any "wrong" demonstrated.
There was less "wrong" in your original post. As an engineer, there is no measure of spacetime unless you have "physical, material" instruments with which to measure space & time. I.e., rulers and clocks. If you don't have them, you don't have any data, just unknowns and assumptions. IMO, there is no time except that which is measured by a clock. You seem to think there is something "absolute" about time, that is independent of the instruments we use to measure it. I disagree 100%.
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#1705 by meberbs on 18 Sep, 2017 19:28
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The issue is less whether your post is wrong than whether or not it means anything. you are postulating a relationship between time, gravity, and entropy. You have not given any relation between these other than a general correlation. Entropy just says that dS/dt >= 0. Something falling under gravity is generally a thermodynamically irreversible process, so dS/dt > 0. Time runs slower deep in a gravity well, but this just means different observers will measure different values for dS/dt, but will agree on the physical result.
There is no “ruler” in my argument. There no “appears” either. Even without a falling object, the argument says that space is larger down here than above in order for c to remain constant....In (1) Sakharov disproved Hawking, who previously claimed (before they met in 1987) that maximal entropy alone would reverse the arrow of time. Sakharov showed him he was wrong, as entropy grows with the arrow of time (both are related) and the time arrow can reverse only if entropy reaches a minimal state, i.e. zero value. ...
This is interesting Thanks for pointing this out.
While on the subject of gravity and entropy ...
Well, gravity and entropy are the same. Time runs slower as we get closer to the ground, yes? And an object moves spontaneously (fall) toward the ground, right? We could say that slower time pulls the object down ... ??
There is another way to approach this. The speed of light is constant everywhere, any frame of reference. As we get closer to the ground, the speed of light must remain constant. Let’s see. As time slows down the units seconds must be relatively longer. So, “space” must also get longer in order for the ratio meter/second to be constant. In other words, an object falling toward the ground is actually falling into larger space. Reminds you of something? Entropy is the spontaneous dispersal into a larger volume. And, because of the constancy of c, we can say as well “dispersion in time”.
Is this wrong, and why?
Marcel,
"It is the contracted ruler that makes it appear space has stretched."" It is the slow clock that results in time dilation."
The clock is a measuring instrument. It doesn’t affect or change time. The clock measures local time because local time makes the clock work at a certain rate, faster or slower.
Warptek, I don't see here any "wrong" demonstrated.
It is not clear how you intend to take these concepts and relate them together, and it seems like an impossible task, because entropy clearly depends on things other than gravity. If you do propose a specific relationship between these things, then it could be determined what your proposal predicts in different situations and this could be compared to reality. Without a specific relationship (using math, because math is the best tool to define physical relationships) this cannot be done, and it can't be determined whether your model matches reality when you haven't actually proposed a model that is capable of making predictions. -
#1706 by ThinkerX on 18 Sep, 2017 20:10
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Nothing is instantaneous besides weird quantum tunneling stuff and the like and even then constraints have been put on that by experiment.
Dumb question; Could gravity itself be a quantum tunneling phenomena?
This reminds me of something I looked into ages ago in connection with another project: Galactic Orbits of stars. That the combined mass of stars, dark matter, and other objects is sufficient to force stars into galaxies in the first place testifies to the strength of gravity across literally interstellar distances. It is also a point in favor of some variant or another of Woodward Mach theory.
So, if the gravity of distant objects - be it stars, black holes, or DM - is powerful enough to influence stellar trajectories across interstellar distances, then perhaps, just perhaps it can be tapped into to propel interstellar spacecraft to near relativistic speeds. Please note the 'perhaps' part.
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#1707 by flux_capacitor on 18 Sep, 2017 20:42
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I will cite several passages of Jim Woodward talking of the instantaneity of inertial reaction forces in his book Making Starships and Stargates – The Science of Interstellar Transport and Absurdly Benign Wormholes (Springer 2013). Emphasis mine:Quote from: Jim Woodward, MSAS, Acknowledgments – xxiv
[John Cramer] had applied the ideas of John Wheeler and Richard Feynman – so-called “action-at-a-distance” or “absorber” electrodynamics – to quantum theory to reconcile seemingly instantaneous actions with the principle of relativity that demands that nothing travel faster than the speed of light. Instantaneous action is a feature of inertial reaction effects; so I included mention of his work in the first paper on Mach effects where almost everything was pulled together. Squaring instantaneous action with relativity is required if your physics is to be plausible. John returned the favor by mentioning Mach effects in one of his Alternate View columns for Analog. That was the event that lifted Mach effects from obscurity and triggered much of what you will find in the following pages.
Quote from: Jim Woodward, MSAS, page 36The inverse first power of the distance dependence of the term from the vector potential that causes inertial forces also signals that the interaction is “radiative.” That is, the interactions that arise from this term involve propagating disturbances in the gravity field. They do not arise from instantaneously communicated effects or the passive action of a pre-existing field. So inertial forces would seem to be gravity “radiation reaction” effects. This poses a problem, for an inertial reaction force appears at the instant an accelerating force is applied to an object. How can that be true if the inertial reaction force involves an active communication with chiefly the most distant matter in the universe, and communication with the stuff out there takes place at the speed of light?
If reaction forces were produced by the interaction with a passive, locally present pre-existing field, this would not be a problem. But that is not what is calculated in Sciama’s treatment. The trick of using the instantaneous frame of rest where the universe very obviously appears to be moving rigidly past the accelerating object not only sidesteps a messy calculation involving Green’s functions; it blurs the issue of instantaneity of reaction forces. This is arguably the most difficult aspect of coming to grips with the origin of inertia.Quote from: Jim Woodward, MSAS, page 46The immediate fact of inertial reaction forces is that they respond to applied forces instantaneously. Why? Well, if you believe, as Newton and legions after him have, that inertia is an inherent property of material objects needing no further explanation, then this question needs no answer. The problem with this view, of course, is the fact noted famously by Mach that inertial frames of reference seem to be those in inertial motion with respect to the “fixed stars.” Today we would say inertial motion with respect to the local cosmic frame of rest, and that, remarkably, isn’t rotating. This suggests that the stuff out there has something to do with inertia. But it is so far away, typically billions of light-years distant. How can that produce instantaneous effects?
Quote from: Jim Woodward, MSAS, page 49What we do see, moving forward in time, when and advanced wave comes back from the future is a wave that appears to be propagating away from the impact of the rock toward the shoreline of the pond. That is, the advanced wave looks exactly like a retarded wave. As long as the advanced wave coming back from the future didn’t propagate farther into the past than the rock hitting the water that initiated all of the waves, neither you nor I could tell whether the waves in the pond had any advanced component. So, using retarded and advanced waves to get distant objects to “instantaneously” affect local objects becomes finding a solution for wave action that cancels the advanced waves at the source (the rock hitting the water) to keep them from traveling farther into the past.
What Wheeler and Feynman noted was that if a forward in time propagating wave in the electromagnetic field was eventually absorbed by enough material out there in the distant universe, and as it was absorbed it produced an “advanced” wave propagating backward in time, all of the contributions from all of the parts of the absorber would just get back to the source at exactly the right time to produce the apparent force of radiative reaction. And as they passed the origin of the waves into the past, if the waves were half advanced and half retarded, they would cancel out the “advanced” wave propagating from the source into the past. So future events would not indiscriminately screw up the past (and our present). But the half-advanced waves coming back from the future provide a way for arbitrarily distant objects to affect events in the present seemingly instantaneously. In the case of gravity, this allows the whole universe to act on any object that’s accelerated by an external (non-gravitational) force with an equal and opposite force. This solution to the problems of radiation reaction is so neat it almost has the appearance of a cheap tourist trick, too good to be true. But it actually works.Quote from: Jim Woodward, MSAS, page 52Wheeler and Feynman’s elegant solution to the problem of radiation reaction is the only apparent way to get seemingly instantaneous reaction forces that depend on distant matter without screwing up the dictum of the principle of relativity that limits signal propagation velocities to the speed of light. Feynman may have harbored similar views, for he devoted the first part of his Nobel address to absorber electrodynamics.
Quote from: Jim Woodward, MSAS, page 72if the coupling between the test object and the distant matter in the universe is carried by the kink in the field propagating at the speed of light, it will take billions of years for the kink to reach the distant matter, and billions of years for a return signal to get back to the accelerating object. Inertial reaction forces, however, are instantaneous. Push something and it pushes back immediately. How can the distant matter in the universe act instantly on an object when it is accelerated by an external force without violating the speed limit, c, of SRT?
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#1708 by M.LeBel on 18 Sep, 2017 21:43
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The issue is less whether your post is wrong than whether or not it means anything. you are postulating a relationship between time, gravity, and entropy. You have not given any relation between these other than a general correlation. Entropy just says that dS/dt >= 0. Something falling under gravity is generally a thermodynamically irreversible process, so dS/dt > 0. Time runs slower deep in a gravity well, but this just means different observers will measure different values for dS/dt, but will agree on the physical result.
There is no “ruler” in my argument. There no “appears” either. Even without a falling object, the argument says that space is larger down here than above in order for c to remain constant....In (1) Sakharov disproved Hawking, who previously claimed (before they met in 1987) that maximal entropy alone would reverse the arrow of time. Sakharov showed him he was wrong, as entropy grows with the arrow of time (both are related) and the time arrow can reverse only if entropy reaches a minimal state, i.e. zero value. ...
This is interesting Thanks for pointing this out.
While on the subject of gravity and entropy ...
Well, gravity and entropy are the same. Time runs slower as we get closer to the ground, yes? And an object moves spontaneously (fall) toward the ground, right? We could say that slower time pulls the object down ... ??
There is another way to approach this. The speed of light is constant everywhere, any frame of reference. As we get closer to the ground, the speed of light must remain constant. Let’s see. As time slows down the units seconds must be relatively longer. So, “space” must also get longer in order for the ratio meter/second to be constant. In other words, an object falling toward the ground is actually falling into larger space. Reminds you of something? Entropy is the spontaneous dispersal into a larger volume. And, because of the constancy of c, we can say as well “dispersion in time”.
Is this wrong, and why?
Marcel,
"It is the contracted ruler that makes it appear space has stretched."" It is the slow clock that results in time dilation."
The clock is a measuring instrument. It doesn’t affect or change time. The clock measures local time because local time makes the clock work at a certain rate, faster or slower.
Warptek, I don't see here any "wrong" demonstrated.
It is not clear how you intend to take these concepts and relate them together, and it seems like an impossible task, because entropy clearly depends on things other than gravity. If you do propose a specific relationship between these things, then it could be determined what your proposal predicts in different situations and this could be compared to reality. Without a specific relationship (using math, because math is the best tool to define physical relationships) this cannot be done, and it can't be determined whether your model matches reality when you haven't actually proposed a model that is capable of making predictions.
Well said meberbs. But please consider the following..
“The issue is less whether your post is wrong than whether or not it means anything. You are postulating a relationship between time, gravity, and entropy. You have not given any relation between these other than a general correlation.”
We have excellent descriptions (models, laws, GR) of HOW gravity works as observed. This “general correlation”, like you say, is meant to supply the WHY. It is offered only as such. In that sense, this correlation actually “means” something (explanatory), while GR is but a factual empirical description, and necessarily involving the observer.
(How can you have any hope of understanding the working of the universe if you do not accept to remove yourself from these models and laws. My above correlation is essentially about thinking without us in the picture. Physics is not the end of the road. For “doing” things, maybe it is. But for understanding, we have to go further and deduce from physics what it says about the universe. That’s all I’m asking; deduce and think further.)
“Entropy just says that dS/dt >= 0. Something falling under gravity is generally a thermodynamically irreversible process, so dS/dt > 0. Time runs slower deep in a gravity well, but this just means different observers will measure different values for dS/dt, but will agree on the physical result.”
O.K. dS/dt > 0 is right. Does it stop there? What does it mean? Let’s read it again. The variation of entropy in time is greater than zero i.e. it increases as the inverse of dt, or 1/dt. We have dS x 1/dt >0. What is 1/dt? Let’s assume 1/t is the “rate of time” as “per second”. Works fine since, as expected, a slower time (smaller 1/t) means longer seconds at the denominator t. So, 1/dt is read as a differential in the rate of time. A differential in the rate of time is gravity (quote from Unruh, posted n times already). Then, the product dS x 1/dt >0 is clear. No differential (1/dt =0)* equals no entropy. The “cause” for entropy dS is a differential in the rate of time 1/dt which is what gravity is. I don’t have to write a new equation for you to test and ponder. This one is fine, and no prediction is changed. But now, you may think differently about it and understand what the equation says about the universe. *( here, 1/dt=0 is not the end of time but an absence of variation in the local rate of time.)
Knowing is no substitute for understanding (or trying to) :-)
modified: added a few deltas... -
#1709 by meberbs on 19 Sep, 2017 00:02
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We have excellent descriptions (models, laws, GR) of HOW gravity works as observed. This “general correlation”, like you say, is meant to supply the WHY. It is offered only as such. In that sense, this correlation actually “means” something (explanatory), while GR is but a factual empirical description, and necessarily involving the observer.
GR does have an explanation of why: objects fall in gravity because spacetime is curved. Other interpretations are possible, such as the polarizable vacuum model that WarpTech has been discussing. The trick with any such interpretations is that they have to match all observed data. At the same time, there has to be something testable different about them if they are going to teach us something new. (Although a different mathematical way of writing the same theory if they are truly equivalent has its own uses.That’s all I’m asking; deduce and think further.
This is what you need to do too. The biggest question with your proposal is: so what? What are the consequences of what you are proposing?O.K. dS/dt > 0 is right. Does it stop there? What does it mean? Let’s read it again. The variation of entropy in time is greater than zero i.e. it increases as the inverse of dt, or 1/dt. We have dS x 1/dt >0.
This is simply a misunderstanding of the math. dS/dt is a derivative, the result of the operator d/dt acting on S. If you instead start looking at differentials like you did, you start running into problems, especially when it is a partial derivative, you can't just say the derivative is the ratio of differentials.
Playing directly with differentials is a good way to accidentally lose all rigor and come to incorrect conclusions if you are not careful. For example:No differential (1/dt =0)* equals no entropy.
Saying that 1/dt=0 means that dt = infinity, which is a contradiction, because dt is a differential which by definition is infinitely close to 0.The “cause” for entropy dS is a differential in the rate of time 1/dt which is what gravity is.
Correlation is not causation. In particular time can move forward without entropy increasing, or with entropy increasing slowly, or with entropy increasing quickly. "rate of time 1/dt which is what gravity is" First, you made a jump somewhere from 1/dt representing the inverse of a differential representing the time passed between 2 arbitrarily close states, to this somehow meaning "rate of time" which you seem to be defining somehow as relativistic time dilation. It is completely unclear why you think you can make the statement that this "is what gravity is" when there is so much more to general relativity than just time dilation.I don’t have to write a new equation for you to test and ponder. This one is fine, and no prediction is changed.
You have not provided anything to ponder. You have pointed out correlations that you tried to pass off as causations without providing any mechanism by which one could cause the other.
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#1710 by M.LeBel on 19 Sep, 2017 02:56
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We have excellent descriptions (models, laws, GR) of HOW gravity works as observed. This “general correlation”, like you say, is meant to supply the WHY. It is offered only as such. In that sense, this correlation actually “means” something (explanatory), while GR is but a factual empirical description, and necessarily involving the observer.
GR does have an explanation of why: objects fall in gravity because spacetime is curved. Other interpretations are possible, such as the polarizable vacuum model that WarpTech has been discussing. The trick with any such interpretations is that they have to match all observed data. At the same time, there has to be something testable different about them if they are going to teach us something new. (Although a different mathematical way of writing the same theory if they are truly equivalent has its own uses.
>>> The essence of spacetime is that no two points are at the same moment; there if always some time between them. To speak of a "curve" consists in considering a bunch of points at the same time! The universe has no need for space; you do! That is the difference. So, curvature is no "why".That’s all I’m asking; deduce and think further.
This is what you need to do too. The biggest question with your proposal is: so what? What are the consequences of what you are proposing?
>>> For one thing, forget about curvature. Think as what the universe needs to do what it does, not what you need to describe it.O.K. dS/dt > 0 is right. Does it stop there? What does it mean? Let’s read it again. The variation of entropy in time is greater than zero i.e. it increases as the inverse of dt, or 1/dt. We have dS x 1/dt >0.
This is simply a misunderstanding of the math. dS/dt is a derivative, the result of the operator d/dt acting on S. If you instead start looking at differentials like you did, you start running into problems, especially when it is a partial derivative, you can't just say the derivative is the ratio of differentials.
>>> You are absolutely right! What I meant is a gradient. A variation form close to close of the rate of time.
Playing directly with differentials is a good way to accidentally lose all rigor and come to incorrect conclusions if you are not careful. For example:No differential (1/dt =0)* equals no entropy.
Saying that 1/dt=0 means that dt = infinity, which is a contradiction, because dt is a differential which by definition is infinitely close to 0.
As above. A gradient of the rate of time, not a differential (calculus).The “cause” for entropy dS is a differential in the rate of time 1/dt which is what gravity is.
Correlation is not causation. In particular time can move forward without entropy increasing, or with entropy increasing slowly, or with entropy increasing quickly. "rate of time 1/dt which is what gravity is" First, you made a jump somewhere from 1/dt representing the inverse of a differential representing the time passed between 2 arbitrarily close states, to this somehow meaning "rate of time" which you seem to be defining somehow as relativistic time dilation. It is completely unclear why you think you can make the statement that this "is what gravity is" when there is so much more to general relativity than just time dilation.
>>> I am so sorry, but you are asking for it, again.
‘ .. A more accurate way of summarizing the lessons of General Relativity is
that gravity does not cause time to run differently in different places (e.g., faster far from the earth than near it). Gravity is the unequable flow of time from place to place. It is not that there are two separate phenomena, namely gravity and time and that the one, gravity, affects the other. Rather the theory states that the phenomena we usually ascribe to gravity are actually caused by time’s flowing unequably from place to place... “ arXiv:gr-qc/9312027v2 17 Dec 1993
This time unequably flowing from place to place, is the rate of time, a gradient. For an object placed in the gradient, we may ask; which way is it going? Toward a faster rate of time or, toward a slower rate of time? Simple answer; look at what happens in a gravitational field. An Object move spontaneously (fall) toward a slower rate of time. Can't be any clearer! The causation is spelled out right there.I don’t have to write a new equation for you to test and ponder. This one is fine, and no prediction is changed.
You have not provided anything to ponder. You have pointed out correlations that you tried to pass off as causations without providing any mechanism by which one could cause the other.
The mechanism is simple (to me, at least). In the rate of time 1/t, t is the time of residence, the relative size of the "second".. The slower the rate of time in this gradient, the longer the time of residence. In other words, at any point in the gradient of the rate of time (gravitational field), anything that exists is presented with a higher probability of existence, (to be) where the time of residence is longer, i.e. below. Because "existence" is all that is required, everything that exists will fall the same way.
The actual maths could be difficult. The physics, nearly impossible, simply because "existence" has no meaning for physics. Physics will describe where we will find something, but will not say what logic is involved for this something to BE there, to be found. (QM is in fact the closest (metaphysical) explanation why
a particle will BE where it will be found.) -
#1711 by spupeng7 on 19 Sep, 2017 08:59
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...
If I understand correctly, it is not about the propagation of something, but about a local property, without any notion of distance involved.
What I am not sure to understand is what “resisting to acceleration” means. Maybe spupeng7 meant something like “Inertia law locally applies instantly to any modification due to a force of the trajectory of any material object ”
Spupeng7, please, can you give an explanation of what you meant exactly ? I am not sure of my understanding....
Thank you for the interesting video. Please note:
1) There is nothing discussed in this video about Mach's principle that is not fully contained in Einstein's General Relativity. So if Mach's principle makes one aware of something that is already present in Einstein's General Relativity, great!. However, there is no "extra-Machian" effect discussed in the video that is not already present in Einstein's General Relativity.
(...)
Nothing except that mass resists acceleration instantly. ...
His post was in reference to the video on Mach's principle posted by SeeShell.
The word "instant" or "instantaneous" does not appear once in:
Brans (of Brans-Dicke fame) recent Expert Opinion article on "What is Mach's principle?" in Annalen der Physik http://onlinelibrary.wiley.com/doi/10.1002/andp.201100706/pdf
Wikipedia's article on Mach's principle
https://en.wikipedia.org/wiki/Mach%27s_principle
and most importantly, the vague book of Mach himself:
E. Mach "The Science of Mechanics" OpenCourt, translated by McCormack
https://www.amazon.com/Science-Mechanics-Critical-Historical-Development/dp/0875482023/ref=sr_1_2?ie=UTF8&qid=1505746398&sr=8-2&keywords=Ernst+Mach++Mechanics
where in p. 267 where Mach himself discusses what is now known as his principle...
Stop for a moment. Think about what you are saying above.
The inertial restistance of mass to acceleration is not a property that propagates, even while it involves a change in the velocity of mass....
Stop for a moment. Think about what you are discussing: posts about Mach's Principle that state that inertia is due to "the distant stars". I asked what was discussed in this video about Mach's principle that is not fully contained in Einstein's General Relativity, and this was answered by "Nothing except that mass resists acceleration instantly."
Then explain:
1) how do the "distant stars" in Mach's principle "resist [locally, here] acceleration instantly"
2) how does the explanation in #1 above differ from Einstein's General Relativity. What is needed that is not in Einstein's General Relativity?
3) experiments supporting explanation in #1 and #2 above
Rodal,
how we see the world comes from our perspective. When a soccer ball hits me in the head it is the instantaneous resistance of my head to acceleration which causes uncomfortable pressure between me and the ball, non?
This is the equal and opposite reaction underlying all statics and all dynamics, is it not? We see things differently but the immediate empirical evidence is the same for all of us.
You ask for an explanation of inertia differing from that which you accept. In http://vixra.org/pdf/1405.0252v3.pdf I take some careless baby steps toward forming that alternative explanation. I hope it will be taken in good spirit.
jmn.. -
#1712 by spupeng7 on 19 Sep, 2017 09:02
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...In (1) Sakharov disproved Hawking, who previously claimed (before they met in 1987) that maximal entropy alone would reverse the arrow of time. Sakharov showed him he was wrong, as entropy grows with the arrow of time (both are related) and the time arrow can reverse only if entropy reaches a minimal state, i.e. zero value. ...
This is interesting Thanks for pointing this out.
While on the subject of gravity and entropy ...
Well, gravity and entropy are the same. Time runs slower as we get closer to the ground, yes? And an object moves spontaneously (fall) toward the ground, right? We could say that slower time pulls the object down ... ??
There is another way to approach this. The speed of light is constant everywhere, any frame of reference. As we get closer to the ground, the speed of light must remain constant. Let’s see. As time slows down the units seconds must be relatively longer. So, “space” must also get longer in order for the ratio meter/second to be constant. In other words, an object falling toward the ground is actually falling into larger space. Reminds you of something? Entropy is the spontaneous dispersal into a larger volume. And, because of the constancy of c, we can say as well “dispersion in time”.
Is this wrong, and why?
Marcel,
It is the contracted ruler that makes it appear space has stretched.
It is the slow clock that results in time dilation.
Quantum mechanically, both effects can arise from radiative damping due to stimulated emissions, which affect the length of the ruler and the rate of the clock.
WarpTech,
the clock does not slow due to time dilation, except from a remote perspective.
jmn.. -
#1713 by spupeng7 on 19 Sep, 2017 09:06
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Nothing is instantaneous besides weird quantum tunneling stuff and the like and even then constraints have been put on that by experiment.
Dumb question; Could gravity itself be a quantum tunneling phenomena?
JasonAW3,
NO, it is not a dumb question.
YES it could !!! Please see http://vixra.org/pdf/1405.0252v3.pdf
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#1714 by Propylox on 19 Sep, 2017 10:30
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-snips-
1) Mass, or energy with a mass carrier, can never travel faster than c, but that doesn't limit information to c. In the absence of matter, energy is not confined to time and thus not confined to velocity within space.
1) Information can never travel faster than c. ... Nothing is instantaneous besides weird quantum tunneling stuff and the like and even then constraints have been put on that by experiment.
2) So if I take the center of mass of all those distant stars and everything else out there... knowing that the universe does not have a center, where is the center of mass of all this stuff? It's everywhere.
Previously: Einstein set a speed limit of c and refuted the notion of anything exceeding it, perhaps because he didn't consider pure energy cannot exist in the Universe without a mass-carrier and the smallest mass(less object?) he knew was a photon. Though particle-wave duality, or energy confined to time vs creating a ripple in it, should have clued him in.
2) Why don't you know where the center of the Universe, and associated center of mass is? Time is a dimension in which mass and our reality is confined, traveling between a finite rate and zero (depending on mass density and subsequent distortion of spacetime). Imagine our universe and reality was 2-dimensional; the 3rd dimension of time would be the radius of a constantly expanding sphere with a surface containing valleys and pits of matter, locally retarding t and space's expansion. The result would be a sinuous formation of mass with large expanses of empty/expanding space - exactly what our universe looks like.
So where's the center of the universe and its mass? At t=0, or the Big Bang, of our 4th dimensional sphere. note: Light loops repeatedly through the universe, so every direction peers back in time to t=0, but due to mass's ability to bend light it's likely impossible to see our galaxy's past on any loop.
-------- Back to the EM drive, or exceedingly inefficient electron gun as I call it. --------
I figured I'd clarify "electron expulsion" from earlier, posted below. Consider a crater's rebound peak wherein forces build, release and matter heads the other way: Same thing with the EM drive, but with electrons. Emissions building on the magnetic pole should follow the field into the resonance cavity, but the emission strength / electric field is great enough for electrons to fire against the magnetic field outward (expulsion) producing thrust. "Impossible", you say? Others claim EM drives are. I'm just saying wave a phosphor screen past it to verify whether it is or isn't an electron gun.With the intense electromagnetic fields being created, I doubt a Faraday cup could distinguish slight electron expulsion... Time to bust out the phosphor screen and see if anything hits it, or strikes that theory.
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#1715 by Rodal on 19 Sep, 2017 12:35
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...You ask for an explanation of inertia differing from that which you accept...
An explanation of inertia that I accept? On the contrary, I asked for experiments confirming the opinions expressed in the last few pages. For all the spilled ink in expressing subjective opinions (unsupported by experimental evidence) nobody has come up with a single experiment confirming any of those opinions. The fact is that there is no experiment showing any "Machian effect" not already present in Einstein's General Relativity. On the contrary, all the experiments (since the 1960's, trying to confirm Brans-Dicke's theory) looking for such Machian effects have failed to find any such evidence of Machian effects not present in Einstein's GR. Coalescence of black holes is calculated nowadays analytically and numerically using General Relativity and the results (gravitational waves including the kick of a binary black hole with accompanying star cluster out of its galaxy) are in excellent agreement with General Relativity.
If anybody thinks that Mach's principle has anything to add to General Relativity that is lacking in General Relativity, please cite experiments supporting such opinion, and explain what is missing in General Relativity that is present in Mach's principle and cite experimental support for any such claim.
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#1716 by meberbs on 19 Sep, 2017 14:21
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Utterly and completely wrong. Any information travelling faster than light would allow for sending messages to the past. See the FTL paradox thread for details.-snips-
1) Mass, or energy with a mass carrier, can never travel faster than c, but that doesn't limit information to c. In the absence of matter, energy is not confined to time and thus not confined to velocity within space.
1) Information can never travel faster than c. ... Nothing is instantaneous besides weird quantum tunneling stuff and the like and even then constraints have been put on that by experiment.
2) So if I take the center of mass of all those distant stars and everything else out there... knowing that the universe does not have a center, where is the center of mass of all this stuff? It's everywhere.Previously: Einstein set a speed limit of c and refuted the notion of anything exceeding it, perhaps because he didn't consider pure energy cannot exist in the Universe without a mass-carrier and the smallest mass(less object?) he knew was a photon. Though particle-wave duality, or energy confined to time vs creating a ripple in it, should have clued him in.
Photons are pure energy. They have 0 rest mass, and Einstein explicitly showed how this works. Saying that Einstein didn't consider something he explicitly did only shows that you haven't actually studied the things you are talking about in any real depth.
You do know that Einstein is the one who got wave particle duality generally accepted by his explanation of the photoelectric effect right? It doesn't have anything to do with "energy confined to time vs creating a ripple in it" mostly because that doesn't mean anything. "Confined to time" does not have any meaning. "Ripple in time" almost has meaning, but you have to match reality consider the ripple to be in spacetime, not just time, and again this is something Einstein explicitly dealt with in GR. He showed that gravitational waves travel at the speed of light, and he did not propose any kind of "mass carrier" for them. We still don't know if there is a graviton particle associated with these or not."Impossible", you say? Others claim EM drives are. I'm just saying wave a phosphor screen past it to verify whether it is or isn't an electron gun.
That in and of itself is fine, but what you posted before that isn't "impossible" it is just nonsensical:Emissions building on the magnetic pole should follow the field into the resonance cavity,
Emissions from what magnetic pole? Saying "the" implies just one, but magnetic monopoles don't exist as far as we can tell. The drive doesn't have any defined magnetic poles. Depending on the antenna type, the antenna might be roughly a magnetic dipole, but even then your sentence doesn't make sense because the only thing emitted from the antenna is the electromagnetic fields, but then you would be saying "the fields follow the fields" which is just circular and nonsensical. -
#1717 by RERT on 19 Sep, 2017 14:27
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There has been recently a discussion of the relation between time dilation and acceleration. I think this reprises a discussion many posts back, at which time I looked into this model metric to explore the effect of spatial variation in the rate of flow of time:
ds˛=-(1-f(x))c˛dt˛+dx˛+dy˛+dz˛
In this metric, the interesting geodesic equation is:
d˛x/dt˛=˝c˛(∂f/∂x)(dt/dτ)˛
In other words, even when t~τ, i.e. dt/dτ ~1, tiny variations in the time flow rate lead to large accelerations, because of the factor of c˛. Whether this means that variations in the rate of time 'cause' forces on particles is more of a philosophical question, but it does look as if engineering a spatial variation in the rate of flow of time is likely to cause particles to move. -
#1718 by aero on 19 Sep, 2017 16:15
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Not quite on the current topic, but I found this interesting link over on talkpolywell. There probably is or should be a similar link in advanced concepts.
http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5341&p=129833#p129833
It relates because the PFRC engine is to provide one MW of power or 5 N of thrust, long-term in a space vehicle.
How does the EM drive stack up to those numbers, which I translate to 5 micro-newtons per Watt? -
#1719 by Rodal on 19 Sep, 2017 16:23
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Not quite on the current topic, but I found this interesting link over on talkpolywell. There probably is or should be a similar link in advanced concepts.
I don't understand why compare this to the EM Drive based on thrust per input energy.
http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5341&p=129833#p129833
It relates because the PFRC engine is to provide one MW of power or 5 N of thrust, long-term in a space vehicle.
How does the EM drive stack up to those numbers, which I translate to 5 micro-newtons per Watt?
The direct fusion drive http://www.psatellite.com/fusion/ is a conventional rocket expelling propellant, it just uses fusion instead.
Any comparison of thrust between a rocket expelling propellants and a propellantless concept like the EM Drive is not a fair comparison, because it misses the fact that propellant is a large ratio of the total mass of the vehicle and thus the payload (which is what matters) , duration of flight are not entering in the comparison as they should.
The comparison depends on how far you are attempting to go:QuoteReaching Alpha Centauri in anything close to a human lifetime remains a significant challenge, but PFRC could be part of an architecture to reach the star in 300 to 500 years, and slow down enough to go into orbit around the potentially Earth-like planets there!
http://www.psatellite.com/tag/dfd/
Thanks for pointing this out.