The speed of gravity [Archive]

Aloysius

05-30-99, 08:47 AM

Well, I am informed otherwise, to my consternation, by the physicist Tom van Flandern.

On http://www.vigier.yorku.ca/VigierII/VANFLAND.html
he writes:

THE SPEED OF GRAVITY -- WHAT THE EXPERIMENTS SAY

T. Van Flandern
University of Maryland, USA.

If gravity from the Sun propagated outward at the speed of light, the transmission delay would progressively increase the angular momentum of bodies orbiting the Sun at so great a rate that orbital radii would
double in about 1000 revolutions. Direct measurements of the directions of bodies and their accelerations (using, e.g., planetary radar ranging) show that, while light of any wavelength undergoes aberration as
an immediate consequence of its finite speed, gravity has no such aberration at a detectable level. Dynamical studies of binary pulsars show that not only the position and velocity of a source of gravity are
anticipated without light-time delay but accelerations of the source are anticipated as well, in contrast with the behavior of electromagnetic forces. Indeed, Newton's universal law of gravity, to which general
relativity is supposed to reduce in the low-velocity, weak-field limit, unconditionally requires infinite propagation speed for gravity. These paradoxes are supposed to be explained by general relativity's curved
spacetime interpretation of gravity. Yet that interpretation leads to new, equally unresolvable paradoxes, especially acute in the case of binary black holes. Moreover, that interpretation is in conflict with
results from neutron interferometer experiments (D.M. Greenberger and A.W. Overhauser, Sci.Amer. 242, May, pp. 66-76, 1980). One resolution of the paradoxes is to interpret the experiments literally,
and from them deduce that the speed of propagation of gravitational force is no less than 1010 c. Although this is inconsistent with the Einstein interpretation of special relativity, it is perfectly consistent with
Lorentzian relativity, a variant espoused by Lorentz until late in his career, which behaves like Einstein relativity in most particulars, but permits faster-than-light propagation in forward time. This subtle
alteration in our thinking about what is allowed under the laws of physics has several immediate consequences, all beneficial, occurring in areas that are also facing paradoxes or internal contradictions, such as
the locality dilemma of quantum mechanics or the existence of singularities in nature ("black holes"). The "speed of gravity" issue may be pointing us to the "wrong turn" physics made to get into these
difficulties.

His home page, with a much fuller account of this assertion, can be found at:

http://www.ldolphin.org/vanFlandern/gravityspeed.html

Boris

05-31-99, 04:55 AM

This is amazing! Basically, I've been trying to contemplate a 'refracting medium' interpretation all on my own; I never knew there was so much activity already around the issue. Many thanks for bringing this to my (our :)) attention!

Plato and others who have read my posts in "With regard to space access" thread, will probably see that I've been having very similar problems with the standard formulations of QED and relativity. I've been looking for an 'underlying medium', or in a way, a preferred frame of reference, and it seems I'm not alone! (nor the first :)!)

Anyway, a lot of what Dr. Van Flandern says makes perfect sense to me. Although some of his statements concerning acceleration within the geometrical framework of GR are a bit off, I also see how an underlying medium with varying density can be equivalent to warped geometry -- heck, lately I've been thinking along some very similar lines... The aberration argument also seems to be pretty solid; at least I can't find a flaw in it. Though of course I'm not neccessarily saying that the theory is sound. After all, I'm not a world-renown authority in cosmology (or math for that matter) -- so at this point I'm very cautious of what my intuition is trying to tell me.

The few points in the paper I'm not sure are correct:

1) There is a reference to stretching a taut line between two bodies on the same orbit, and claiming that this is a straight line in local spacetime. Well, in fact it's not a straight line (geodesic) as far as GR is concerned; although the line may achieve the shortest distance, it does not represent the shortest Minkowsky interval between the orbiters.

2) A claim is made that gravitational fields somehow transfer momentum, and therefore cannot be static (as in non-regenerating). Well, this can still be accomplished if we remember that it's not just the 'source' that emanates a field, but that the target does so as well; so whereas the source's field affects the target, the target's field affects the source. So, there is really no communication necessary between the two in order for momentum transfer to occur.

Hey Plato, do you think it couldn't be just gravity that goes faster than light, but also electroweak and strong forces? (basically, anything except EM?) Could be a neat explanation for the EPR effects, and why universe-wide wave functions are a good approximation to experiment!

But anyway, it's pretty promising stuff (I think). I look forward to what may develop henceforth.

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I am; therefore I think.

Plato

05-31-99, 12:29 PM

I hate to break the expectations but I would ask for some caution in this matter. For one thing, I did a little search on other things this Van Flandern guy (this is stange because I am actually of Flanders) published and he is kind of notorious of putting forward controversial ideas. Like claiming that Mercury is a former moon of Venus or discediting the Big Bang theory.
I'm not saying there is anything wrong with that because science needs people like him to pour out new ideas but what I am saying is that his theories might leap ahead on experimental evidence.
He claims that there is experimental evidence that gravity travels at 10^10 c. On the other hand under "Does gravity travel at the speed of light? [98-05-06]" at http://src.doc.ic.ac.uk/usenet/news-faqs/sci.astro/%5bsci.astro%5d_Astrophysics_(Astronomy_Frequently _Asked_Questions)_(4_8).
There they talk about the observations of binary neutron stars where the orbit is gradually decaying. This can only be because of gravitational radiation, just like in electromagnatic theory. This automatically implicates that gravitation has a finite speed. If one agrees with the general relativity theory, the dampening effect leads to a speed of gravity as being the same as the speed of light, with an error of 1%.
There are other experiments on the way to further refine these findings but a speed of 10^10 c is a bit more than 1% deviation I would think...

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greetings,
Plato

Aloysius

05-31-99, 01:02 PM

Plato, you mention gravity waves travelling at light speed, and I (and Van Flandern) agree with this. It's the speed of assertion of the gravitational potential, not gravity waves (which require acceleration to be produced) that is under discussion here.

To be more concise, "What's the speed of gravity?" refers not to gravity waves, but to the gravitational field. I wonder if that's causing confusion here.

As a footnote, I would have thought an experiment could be quite easily set up to check van Flandern's assertion. After all, gravitational fields are much stronger than waves (for normal events around here, else we'd be dead :)) so one could precalculate the two possible orbits for a given set-up (one for instantaneous and one for lightspeed-delayed interaction) and just go measure the darned thing.

I would have thought that this had already been done. Van Flandern asserts, using as his set-up the earth-sun system, that he has an open-and-shut case. I'd like to take a closer look at that I think, because that's the lynchpin of his assertion right there - and checkable against hard experimental evidence with some not-too-hard maths.

Plato

05-31-99, 01:42 PM

Aloysius,

I might have been on the wrong subject there but have you read the URL link ? It also talks about the field itself. If one does calculations of the retarded field (in electromagnetics as in GR) there it seems as if the force still works instantanious while the speed limit of the virtual gravitons is still limited to the lightspeed, as is the speed of the virtual photons who give way to the electromagnetic force.
Now I do know that regarding GR I shouln't mention the gravitons because they arise in quantum gravitational theories but I was merely using them to get the analogy with photons right.
You see, gravitation waves consist of real gravitons, these are the same physical particles as their virtual counterparts who give rise to the gravitational field.

------------------
greetings,
Plato

Boris

05-31-99, 06:46 PM

Plato:

As I said, I'm not all that sure that Dr. Van Flandern (VF) has found a true problem with GR. However, even after reading the posts you referenced, I still think there might be something to it.

a) to be calculating retarded potentials, and in general to be treating geometry as if it was a field, you need some kind of a restoring force that will 'untwist' the geometry after a massive object has passed. There's nothing like that inherent in GR, as far as I am aware. Also, I find it amazing that the restoring force, even if it exists, is perfectly dampened (i.e. it doesn't oscillate the geometry back and forth, but simply restores it directly to the most relaxed state.)

b) VF has a point about reference frames. (Did you read the paper on his website?) In fact, I have a thought experiment to practically demonstrate that a universal preferred reference frame exists and is measurable. (Although I might be missing something, and may be totally wrong...) The preferred reference frame would be the same one in which gravity wells exist and light propagates. Here's my thought experiment:

Assume for now that nothing exists in the entire universe except for the following setup:
Imagine you have a really massive object (e.g. a neutron star) being orbited by two very light objects (the weight of ping-pong balls). The two orbiters are actually on the same orbit, but separated from each other. Now, in this system the neutron star is stationary to astonishing accuracy, so I'll treat it as stationary (and call it N). Also assume that the two orbiters (call them A and B, and assume that A is ahead of B in direction of orbit) are on a perfectly circular orbit. Now, imagine N emits a flash of light. The spherical wavefront propagates out and strikes A and B simultaneously. At this point, each orbiter emits its own flash of light (of a different frequency maybe). Keep in mind that throughout this, both A and B are continuing forward on their orbits. The wavefront from A propagates out and strikes B, and likewise B's wavefront will eventually reach A. However, A's wavefront will strike B first because B will in effect 'run into' it. A, on the other hand, is 'running away' from B's wavefront, and will receive B's flash later. Now, as soon as B receives A's flash, it sends a signal back to N; likewise A sends a signal to N as soon as it receives B's flash. The two signals take exactly the same time to propagate back to N since the orbit is perfectly circular. Therefore, N will receive a signal from B first, and only later will it receive a signal from A. From N's point of view, this looks like the only plausible sequence of events. At least I can think of no other way this system could work.

However, what I just showed is that light propagates within N's reference frame! That includes light from both A and B. However, A and B are both in freefall, and N's reference frame should not be preferred over theirs! In fact, this way A and B can use N as an intermediary to measure their velocities with respect to this absolute reference frame -- using none other than light itself!! Notice, however, that in my perfectly empty universe (and assuming N doesn't have any distinguishing marks on its surface), A and B originally have no way of telling in which direction they are moving (i.e. which is ahead, A or B?) However, simply by sending and receiving a few light signals, they are able to make just such a determination, which goes against the principle of equivalence!

Now, imagine that this three-body system is orbiting yet another object, still far more massive. Now, by similar arguments, we will see that the velocity of the three-body system (essentially of N) will also influence its reception of signals from A and B. However, this influence will manifest itself differently when A and B are moving in N's direction of motion rather than opposite to N's direction of motion. Suppose that the super-massive object around which N orbits is a black hole, H. Then, using its two orbiters, N can measure its velocity around H! Also, even if N can't see H, it should be able to deduce in which direction H (i.e. the center of mass) is located! And not only that, A and B can measure their absolute velocities now as well...

By extension, we can now add the rest of the universe -- and see that even with all the complex gravitational contributions to the orbit of N, A and B can still measure their absolute velocity with respect to the underlying medium -- that medium which contains the gravity gradient as well as propagates light. In fact, if we now take the existence of such a medium for granted, and return to the three-body system, we will see that even if the system simply flies along a straight line in Eucledian space, it will be able to determine in which direction, and at what speed, it's flying -- by using nothing else other than light signals.

So, it seems to me that although without gravity special relativity makes sense, once gravity can be used in an experimental setup, special relativity breaks down.

In fact, with non-Euclidean spacetime you don't even need any orbiters to determine your absolute velocity with respect to the gravity gradient. All you need is a gyroscope to define a fixed orientation in space, and a meter stick. Then, you can orient the meter stick in a fixed direction, and measure tidal distortion on the stick as you move along on your orbit. Granted, in most cases the tidal force is miniscule, and your measurement would have to be really accurate. However, it would enable you to directly detect gravity gradient, as well as direction of the center of mass.

Then I also have this quantum idea. Since we are supposed to have particle pairs popping up and disappearing all over the place throughout the vacuum, then what if we somehow found a way to make them interact with a laboratory setup? And if so, would they not provide an absolute velocity measurement, by simply being blue-shifted in one direction and red-shifted in the opposite direction? (Though I'm not so sure about this particular idea, since I'm not exactly a QED guru).

The whole point is: there seem to be ways of detecting a preferred inertial reference frame. Which is what I've been talking about all along. Existence of any such frame comes into direct contradiction with any relativistic theory.

Now, I may be totally wrong on all counts, and may simply be an ignorant ass professing my misunderstanding of the theory. So, if there are any other relativists out there, how about taking a shot at my 'thought experiments'?

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I am; therefore I think.

Aloysius

06-01-99, 06:55 AM

Boris, that's a delicious thought experiment. I don't have the time right now to say anything deep about it, except two immediate hunches which might gainsay it:

1. You'll get a null result if the orbiters lie precisely 180 degrees apart. Because then they are indistinguishable, of course.

2. Mossbauer effect plays a role, rendering to Caesar all that is Caesar's? (erm I mean Albert :))

Plato

06-01-99, 08:22 AM

Boris,

First of all, I will take a look at your thought experiment a little closer this evening but for the moment I have one comment that kind of is in the line of Aloysius. I don't know if you have any experiance with the three body problem ? It is a very tricky thing which has real solutions only in certain cases (I'll tell you later which since I don't have the formula's with me here at work). One of the cases was indeed if one of the three is a very massive object but I think it was shown that the only solution of stable orbits in that case was that the two objects would be on opposite sides of the heavy one.
I promise I'll get back to this later...

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greetings,
Plato

Aloysius

06-01-99, 11:41 AM

Plato, I read the Alcubierre Mark II paper with interest. Unless I'm mistaken, the author has actually proposed the Tardis! For non-cognoscenti of Doctor Who, this is a fictional time machine which is larger inside than it is outside.

Funky.

Boris

06-01-99, 02:29 PM

Plato, Aloysius:

I see where you guys are coming from -- trying to ruin the perfect setup with technical difficulties :) But no matter; it is only important that the system be semi-stable for a short time so that the measurements can be made. That's why I made the central body so massive and the orbiters so puny. Also, Plato: although the particular three-body system will not be stable as I described it, the problem is easily fixable by making the three-body system into a symmetric n-body system, where now we have n bodies orbiting the neutron star, all of them separated by exactly the same distance. E.g. a simple construct would be three bodies orbiting in an equilateral triangle configuration (with 60 degrees between any pair). Though the equilibrium in such a system would still be precarious. But no matter -- it's the *principle* that's important :)

Aloysius: what does Mossbauer effect have to do with anything? Is there humor in there too subtle for my thick skull? (It's been a looong day...)

----------------------------
I'm too tired to think...

Plato

06-01-99, 04:02 PM

Ok Boris, I think I got it know.
De way to make you see that it only 'seems' that N is your preferential reference frame is to do your same argument in the reference frame of A and B.

First, you will agree that A and B have the same reference frame as they completely are at rest to each other. Let's take our origan of this frame also on their orbit and as far from A as from B. Thus AOB is in effect a two legged triangle with | |AO| | = | | OB | |.
In this reference frame N is seen to revolve around O in the opposite direction as in the N-frame.
Let's say N starts his flash when he crosses the vertical axe (time t). Since the veritical axe is the set of all points at equal distance of A and B, the lightsignal will indead arrive at the same time (t_0) in A as in B.
Then A signals to B and vice versa. Since they are at rest to each other, they to will get each others signal at exactly the same time (t_1). So at t_1 A and B send their signal to N, this however has moved further along his orbit, since a time t_1 - t has passed. So now N is actually closer to B then to A, this is why B's flash reaches N before A's.

You see that the result is completly the same but in a totally different referential system. So I have to conclude that there is no preference for one frame above the other to explain the same effect.

------------------
we are midgets standing on the backs of giants,
Plato

Boris

06-01-99, 10:44 PM

Plato:

Nice try, but I'm afraid it's more complex than that... One very simple thing you're missing: N never gets any closer to B than it is to A -- in fact it remains at the center as A and B orbit it -- and they can verify that using radar ranging (i.e. verify that the distance to N is not changing). Also, A and B are not exactly at rest with respect to each other. For example, if they both start out facing in the same direction, so that B stares at A's back, then half a revolution later it'll be A staring at B's back! So indeed A and B have reasonable means to deduce that it is they who are orbiting, and not N. In fact, due to this same rotational effect, if you put an 'origin' between A and B, then to this origin it will appear that all 3 bodies orbit it, not just N. And from those orbits, it will be clear that the distances of NA and NB remain constant. Finally, it is clear who orbits whom simply from taking a look at the surrounding gravitational gradient. And logically, it is nonsensical for a neutron star to orbit a ping-pong ball. So I'm afraid the 'absolute reference frame' is quite a tenacious little beast in this scenario...

Rotation is tricky. In fact, it is the one thing that doesn't seem to be relative, but indeed absolute. For example, you can't argue that it's the rest of the universe rotating around you instead of you rotating on your own -- simply because it is you who feels the centrifugal force. That's why gyroscopes can act as beacons of direction -- yet another indication of an ultimate underlying reference frame.

Well, ok, maybe I don't have the justification for pushing the line _that_ strongly... But there's something out there... somewhere.

Plato

06-02-99, 09:47 AM

I admit that I was a little hasty in my previous mail. It appears I applied two different transformations for A,B and N.

I have put in more thought about it now and have the following claim.
There will be no difference in time what so ever between the two signals because there is no relative velocity between A, B or N if there are no fixed points in the universe to orient your 'fixed' frame in. You can argue that they have to turn around N because that is the massive one and in order not to fall to N they have to be in orbit. But that is only when you can proof there is something as gravity. In the system that you described there is no way these three object can proof that, the way they are orbiting. Only if A is on a different distance from N then B there is going to be relative velocity between them and one can deduce the fact of turning around N but then your little scheme won't work anymore.

I guess what you have done is assume there is a fixed reference frame in which A and B are turning around N and then after some elaboration you proved that there is indeed a fixed reference frame in which A and B are turning around N. This is a trivial proof but not a valid one because it is as meaningless as saying statement A equals statement A.

------------------
we are midgets standing on the backs of giants,
Plato

Aloysius

06-02-99, 10:43 AM

Boris, you're a bright young sonofabitch.

RE. Mossbauer effect, I originally meant it as serious (so there! :)) but there is a humorous side in my case.

In my _viva voce_ at Oxford for my physics degree, I was quizzed by Nobel Laureate Sir Rudolph Peierls. It appears that the question on the Mossbauer effect had run afoul, in the fear and loathing of my tortured adolescent brain, of a certain paregoric (this was 1969) which I had simply transferred from one piece of silver paper to another. Unfortunately, I licked my finger...can you spell Sunshine?... and this was to be my undoing in the finals paper on the morrow in Nuclear Physics. I calculated, in my euphoria that next day that the increase in weight of a cosmic meson hitting the earth would result in an effective mass of ten TONS when striking the surface of the planet. It seemed to make sense at the time.

Fortunately, at the viva I got it right, and maintained my honours degree status.

So, I always giggle when I say Mossbauer.

You were not to know.
I apologise for the wealth of personal information, rather akin to Lori's confession of the hicks that beat up their spouses and rev their engines.

It will all end in tears, I'm telling you.

:)

Aloysius

06-02-99, 10:50 AM

OK, since I started this, and since Boris is homing in on where I'd hoped someone would home in - i.e. Machian philosophical quandaries about the nature of absolute versus relative rotation - I'd like to throw a second link into the soup. God I'm so manipulative.

Actually, you guys are great.

http://chaos.fullerton.edu/Woodward.html

Plato

06-02-99, 01:14 PM

Aloysius,

First of all I remember the Mossbauer effect as being one of the most boring experiments we did in my student time. We had the choise between electron-positron annihilation experiments or Mossbauer and since everyone wanted to do the first one I thought it was cool to take Mossbauer... not !

Anyway I kind of suspected you were manipulating us, this question in the beginning was far to innocently put as if it was to lure us into some tricky discussion about absolutism >< relativism.

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we are midgets standing on the backs of giants,
Plato

Double Overdrive

06-02-99, 02:38 PM

Why is the format of this topic so wierd. How do we center it so we don't have to go back and forth?

-DO

Double Overdrive

06-02-99, 05:23 PM

How do we fix this?

Double Overdrive

06-02-99, 05:23 PM

...

[This message has been edited by Double Overdrive (edited June 02, 1999).]

Plato

06-03-99, 08:59 AM

Aloysius,

Silly me thinking that inertia was simply a matter of conservation of impulse.
Maaaaannnn !
I must admid I heard something about a theory accrediting inertia to interaction with distant matter but I thought that was just an other crackpot theory. Now I read that serious scientist like Wheeler and Feynmann actually concocted a theory to make this possible while preserving the finite velocity of interactions, just makes my hair stand on the back of my head.

Do you actually buy this stuff ? I mean if they claim that me moving my chair here has something to do with a wiggle that will happen a billion years in the future on a distant quasar then I have just proven that the quasar will still exist then or rather that the universe will will be in existence. How far can this get ?
Suppose there is going to be a big crunch after all and things will end, will this mean that as we approche the time of crunch things will begin to lose their inertia because there isn't matter in the future any more tho wiggle ?
Sounds pretty far fedged to me.
Any why about the quantum vacuum, are they claiming that there are no fluctuations at all or just that there aren't that many ? Because how else are you going to explain things like Lambshift and Casimir effect if there isn't a vacuum that is boiling with particles coming in and out of existence ?

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we are midgets standing on the backs of giants,
Plato

Boris

06-03-99, 09:49 AM

Plato, with respect to my thought experiment:

Again, nice try. You made me think even longer this time :)

But, in fact N is the one that can tell that A and B are orbiting. How? By simply tossing something up and watching it come back down! The fact is, N can measure its own gravity that way. Then, it can determine the distances to A and B via radar, and calculate the orbital velocities needed to keep them in orbit. (The velocities are conveniently independent of A and B's masses). Given the range and velocity data, N can determine precisely how long it should take A, for example, to cross its 'sky' from horizon to horizon. Not only that, but by subtracting the actual time from predicted time, N can learn about its own rotation, if any! Again, seems like rotation is absolute!

Wait... Did I just disprove the Machian principle?!! Somebody tell me where I went wrong, please!!

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I am; therefore I think.

[This message has been edited by Boris (edited June 03, 1999).]

Boris

06-03-99, 10:02 AM

Plato, you just learned about Mach's principle? It is the foundation of relativity; it's where Einstein got some of his main ideas!

But, as I've been kind of showing, the principle makes no sense! And you are right about the future-oriented, time-travel effects. I, for one, think that time is not even a dimension at all, so you can no more travel back in time than you can travel back in temperature! And you've got a point about quantum vacuum. In general, this whole thing makes about as much sense to me as the multiple-universe interpretation of QM. It's may be nice mathematically in some areas, but conceptually it's total bs.

Frankly, I've always felt that this whole relativity interpretation, going back to Mach, smells to high heaven. That's why I've been trying to advance the 'cosmic matrix', or 'underlying/refracting medium' idea. And the more I think about that (and you guys are helping big-time), the more I'm convinced that I am right...

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I am; therefore I think.

Boris

06-03-99, 10:15 AM

With regard to GR & absolute reference frames:

I've been forgetting one of the fundamental constructs in GR. I am referring to the fact that the 'inertial reference frames', as defined in SR, no longer function on any scale in GR (i.e. when gravity is introduced). Because of the gravity gradients, and therefore tidal forces, throughout the universe, any 'inertial' lab of any extent cannot be equal to any other inertial lab. So, GR 'cheats' by making the relativistic inertial observers into mathematical points!! Now, since the entire 'laboratory' is infinitely compressed, the inertial frames are equivalent again. To see how macroscopic objects hang together in this framework, one actually defines 'connections' between the discrete points, which basically consist of a mathematical interpolation of spacetime properties. This is what originally got me worried, and looking into the 'underlying medium' hypotheses. After all, if things are relative only on vanishing scales, then the whole theory is ultimately only a mathematical approximation since even the smallest elementary particles are of finite size! That means GR absolutely cannot be the picture of what's *really* going on. Or am I wrong?!

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I am; therefore I think.

Plato

06-03-99, 10:45 AM

Boris,

You really are a though guy aren't you ?
It seems that I won't be able to convince you with some simple argument alone but I'm afraid I kind of forgot to actually calculate the geodisics that light travels along in your thought experiment. That will eventually convince you that the signals indead will be without any delay.

May be one thing. You set that one will be able to view when A and B set's on N but this implicates N turns with a different angular velocity then A and B around itself. An observer could still argue that the setting and rising of A and B are solely due to the fact that N is turning around it's axe and A and B are not in an orbit but stationary points in reference to N.

I feel somewhat ashamed that I didn't know relativity was build on Mach's principle :o . I thought Einstein was reconciling Maxwell's theory of electromagnetism with Newtonian mechanics but this is the special relativity.
Then again when we got the concept of general relativity served it was kind of forced upon us. We first had this treaty about Riemann space and tensors. After the introduction of the math one of the first equations we got was that in a universe without mass the Riemann tensor R_{ij}=0.
Up untill now I still don't know why this is, it was simply forced upon me like that.

Do you (Boris or Aloysius) know what the underlying reason is. Does it has anything to do with Mach ?

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we are midgets standing on the backs of giants,
Plato

[This message has been edited by Plato (edited June 03, 1999).]

Plato

06-03-99, 11:00 AM

Boris,

this Woodward guy is really serius about Mach's principle. Seems there are some experiments actually backing up Mach's theory and at
http://chaos.fullerton.edu/~jimw/nasa-pap/
he is proposing an Impuls engine ! This is an engine who accelerates without ejecting anything, how about that for a propulsion drive ?

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we are midgets standing on the backs of giants,
Plato

Aloysius

06-03-99, 01:37 PM

Sorry, but can't, off-hand, comment on the zero Riemann tensor.

Btw, I'm attempting a reproduction of Woodward's experimental results in my own special way. If it works...

WE'RE OUTTA HERE!!
:) :) :)

Plato

06-04-99, 10:58 AM

Boris,

I found the coup the grace, I think ! Could you have a look at :
http://home.ba.net/~sullos/mimoex.htm

You will find striking similarities between your experiment and Michelson and Morley's. There also a velocity v is substracted and added, same as A running away (+v) and B running into (-v) the lightpulses.

Still I think your thought experiment is a very good test for relativity, I certainly never thought of something that devious.

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we are midgets standing on the backs of giants,
Plato

OOM-9

06-04-99, 05:28 PM

Damn, I leave for awhile and everything goes to hell :) I don't know where you dug up this Van Flaccid guy, but he's a complete fucking idiot. His first sentence says that the solar system will gain angular momentum by gravity's propogation at the speed of light. WTF? This not only is unsubstatiated, but also nonsensical and incorrect. WHY would gaining angular momentum occur? He just has you accept it, I guess. Anyway, gravity waves are just changes in a gravitational field, so they in effect ARE the speed of the field, the speed of gravity waves is the speed of gravity itself, by definition. I really haven't read much of the intervening material so I'm probably rehashing stuff ppl have already said. But anyway. :)

Sirius B

06-04-99, 09:37 PM

Boris/Plato

You guys leave my brain in a state of "flux"
:o
Just when I think I agree with one of you, the other one makes a very, valid point!

I would just like to know one thing...What's your occupation? JPL, NASA, what???????

What lead you up to this knowledge? (it's amazing to me :) )

Boris

06-07-99, 01:21 AM

Plato:

On the zero Riemann tensor... Actually, more correctly it's a 'vanishing' tensor. It's necessity comes about due to a certain tensor theorem that states: "a necessary and sufficient condition for a manifold to be affine flat is that the Riemann tensor vanishes." Affine here means that the manifold contains 'integrable' connections between any two points; integrable means that if you transport a vector from point A to point B, the resulting vector will be independent of transport path. Affine flat, on the other hand, means that over the entire manifold the connections vanish. Intuitively speaking, affine flat is just Euclidean -- no matter where you are in the manifold, it looks the same and no special transformation is needed for you to move from one point to another. An affine-flat spacetime manifold in GR can only arise in total absense of any gravity.

Going back to my thought experiment: you're missing the point about N's gravity. Because N knows of its gravity field, it therefore knows that A and B would fall unless they are moving along orbits. They simply can't be fixed points since such a property would defy the laws of physics. From the fact that the distances to A and B are known, and the fact that the gravitational acceleration at N's surface is measurable, it is easy to calculate A and B's orbit velocities. (Btw remember that A and B are in perfectly circular orbits -- that means the distances to them are constant, and that makes their velocities particularly easy to calculate.) As for geodesics -- the only significant contributor to spacetime curvature is N; therefore the geodesics will be basically defined by N's reference frame. Given that, it seems inescapable that A and B's velocities with respect to the absolute reference frame will be rigidly defined by light propagation. Unless, that is, the entire spacetime framework of N is moving within a larger framework, akin to Alcubierre's warp bubble :)

With respect to the impulse engine. I'd love to be wrong on this, but I suspect the only reason he measures propulsion forces is because his experimental setup is tied to planet Earth. I.e. I think his engine is simply pushing against the table, similar to how a car's tires push against the pavement to move the car. Specifically, I find it suspicious that he first postulates a 'magical' mass fluctuation at the 'propulsive' ends, and then proposes that this fluctuation be induced by transfer of electrons from capacitor/inductor arrays -- after that concluding that the power sources will be dragged along by the device. By Newton's second law, I'd think whenever the device moves forward the power sources should move backwards, thus canceling all motion altogether.

Anyway, his paper contains way too many simplifying assumptions and shortcuts; I'd be wary of this kind of easy science. But don't get me wrong; if he is by some miracle correct and the concept ends up working, it'll be just awesome! But even if that happens, I doubt that Mach's principle would ultimately be responsible for the success.

As for the 'eteron' web page :) Well, got to give the guy credit, he certainly showed that speed of light is not constant -- to the consternation of Maxwell, Einstein, and the entire QED world I'd imagine... The only problem is, he did this based on the assumption of relativistic space compression -- which was derived by SR in the first place, based on precisely the premise that speed of light is constant! How's that for a circular argument? But nice try, though. However, this does bring forth a potentially important (in my opinion) point: one doesn't have to start out with constant light speed to derive relativistic effects; other phenomena might just as easily account for the so-far flawless experimental standing of SR.

OOM-9:

my man (woman?), you ought to think more before spewing outrage at other's stupidity. There is absolutely nothing trivial about the aberration argument; go back to it and mull it over a bit more carefully this time. And stop regurgitating GR doctrine as if it was some religious truth; if you are at all serious about science, you should know never to put 100% trust into any theory -- especially one so complex and esoteric!

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I am; therefore I think.

Plato

06-07-99, 09:18 AM

OOM-9,

Van Flandern really has a point in saying that a finite velocity of gravity would make the sun and earth not aligned with their mass centre. This would lead to a force-couple which in turn would make the orbit of earth around the sun bigger and bigger. This, it appears, has been pointed out quite early in the development of general relativity.
Woodward says that the answer lies in gravito-magnetism. It appears in the beginning of the eighties it was shown that GR could be seen te interact the same way as the electromagnetic force, this made these crazy notions of how inertia came to be more plausible.

Now, I had an other look at the proposition of Sciama of how inertia came to be and I must say I'm beginning to like it. I always had the feeling that gravity and electromagnetism where very similar forces so why not have gravito-electro and gravito-magneto forces ? If they can explain why the earth stays in it's orbit and where inertia comes from, that's cool. Still, I will have to have a better look at the experimental evidence that supports it.

Sirius B,

Let's say it's just a hobby of mine... ;)

Boris,

You are right of course that if the laws of Newton are postulated, one could calculate the orbital velocities of A and B. I was more thinking along the lines of how people who lived on N (suppose they wouldn't get crushed by the immense gravity of the neutronstar ;) ) would come up with those Newtonian principles. I mean how would a Kepler go about and propose his three laws of heaven dynamics ? There are no fixed stars to measure the velocities of A and B, all you have is a theory of gravity which can not be veryfied if there is no 4th body who is in a different orbit than A and B. Thus the universal law of gravity will never be found by these neutronstar people.

Anyway about the light pulses. Would you agree that the following is equivalent as in your thought experiment ?
Given two frames of reference who are moving with a constant velocity v relative to each other : O and O'.
In O we have one observer N and in O' there are two observers A and B. A and B have synchronised there watches and are a certain distance d' from each other in the O' frame.
N sends a message to A and B, to tell them to flash their flashlights to each other at a certain time t' and record the time when each receives the flash of the other.
A measures a time t_a and B measures a time t_b, do you think, Boris that (t_a - t') <> (t_b - t') ? In your thought experiment you do.

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we are midgets standing on the backs of giants,
Plato

Boris

06-07-99, 10:50 PM

Plato:

Well, in the scenarios of thought experiments one doesn't usually concern oneself with epistemology :) Let's just assume that the laws of the universe are already known to N -- maybe God himself confessed them. :) :)

On the issue of your suggestion: no, there is no equivalence between what you described and my setup. First of all, the light pulse from N must reach both A and B simultaneously. That means, in your scenario, they are separated along an axis perpendicular to v. That also means that the spacetime trajectories of A and B are the same with respect to the source -- not the case with the orbiters (where A reaches a position <x,y,z> before B does).

In general, let me caution you that this thought experiment was not a haphazard thought off the top of my head; I've been contemplating its variants for a couple of months before writing it down here, and I've been thinking about relativistic paradoxes for at least a couple of years. I'd think that most trivial solutions have already been ruled out... However, if you want to challenge me anyway, feel free; maybe I did miss something after all. But be warned -- I don't think it's likely that the solution to my paradox, if any, would be trivial.

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I am; therefore I think.

Plato

06-08-99, 06:13 AM

Boris,

I don't think you get what I was trying to say. The equivalence of my setup with yours lies only in the fact that two observers (A and B) are flashing light to each other and recording the time it takes to go from A to B and from B to A.
This is the same thing that happens in your setup where planet A flashes to planet B and back. When you say that A 'runs away' and B 'runs into' the light you are wrong ! This would mean that A and B would measure a different lightspeed then N, this is not the case. That is what countless experiments have proven. What you are doing is adding velocities in the Galiliean/Newtonian way, we don't live in such a universe unfortunately.
The correct formula to add velocities you find at http://weber.u.washington.edu /~gdaly/CH28FLDR/Pages/Velocity.htm

If one puts u'=c then u = (c+v)/(1+cv/c^2) = c !! Thus there is no 'running into' what so ever and N will receive it's pulses from A and B simultaneously !

Boris, I don't know what else I can do to convince you. Have you seen the above formula in your GR class ? If not that explains your error.

Now, what I don't understand is why this absolute frame of reference is so important to you. I have read your post to the 'With regard to space access tech ' thread and this just makes me more confused.
You seem to claim, just like me, that all matter essentially comes from the same basic form and that all forces were at the instant of big bang one but then our paths divide.
First of all I don't see how you can accept basically the framework of unifying forces in higher dimensions without looking at time as just another of those dimensions.
Yes, we experience time differently as the other three, yes we can go back and forward and stand still even with respect to the other three but this is because we don't live in a Euclidean universe ! Flat space is a Minkowsky space with g_ii = diag(1,1,1,-1) ! If you want to doubt this then you will have to reconstruct the entire twentieth century physics because just about everything we have now is based upon that notion. Besides how can you explain things as time dilation and space contraction if there are only three dimensions with time as a mere parameter ? Don't give me anything of that Lorentz crap because he just couldn't accept that someone else went away with the credit of his original formula's and was afraid of the ultimate consequences of these formula's.
You know relativity isn't just a mere physical theory, it's a whole philosophy ! What it says in it's basics is that everything has it's own truth and it's own way and that everywhere in the universe the laws of nature are the same. It is no wonder Einstein despised the uniformity of the Nazi's, it was against the very basics of his philosophy ! Relativity is a universe filled with diversity, a multitude of difference, a teeming variaty of life. No control but the most basic that no thing can have more liberty then anything else, in effect we are talking about the practice of the French revolutionary slogan : Liberté, Fraternité et Egalité (freedom, compassion and equality)

How about that for a theory ? :)

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we are midgets standing on the backs of giants,
Plato

[This message has been edited by Plato (edited June 08, 1999).]

Boris

06-08-99, 04:54 PM

Plato:

Now who's getting emotional? :)

The Lorentz transformation of velocities in fact does not apply to light; since it is light that propagates around and does the measurements, it will always travel at the same speed. Please note that I am not saying light will go faster in one direction than another. Also, A and B will not measure different light speeds than N or each other, because 1) they are time-extended, 2) they are space-contracted and 3) the 'forward' edge of these objects is actually ahead of the trailing edge in time (this is easy to see from a space-time diagram).

Now, there's another flaw in your argument. By assuming A and B can unidirectionally send light signals and measure the time of signal travel, you are assuming simultaneity (i.e. that their clocks are exactly synchronized). For spacelike separated objects, such an assumption is not relativistically sound. I achieve simultaneity through my setup only because of the symmetrical spacetime geometry; in my case it is indeed true that A and B send out their light pulses at the same time. Indeed, the particular experiment I described is not even the only variant; I just used this paradigm to avoid using clocks. But the only crucial thing is that N is able to precisely synchronize A and B. In fact, here's another variant: there's only one object orbiting N: call it E. E is large, but still puny compared to N. On E's surface, we have two physics labs, A and B; each keeps an ultra-precise atomic clock. A and B are located on E's equator, and E rotates like the moon does (so it's always facing N.) A and B are arranged so that NAB is an equilateral triangle. Now, to precisely synchronize the clocks at A and B, all we need is that light pulse from N. Once the clocks of A and B are synchronized, they can send unidirectional light pulses and determine exactly how much time it took for light to travel from A to B versus B to A. I am claiming that in such a setup, the times measured will not be the same.

If you are still confused, think of the following picture. Take the classic Einsteinian train traveling merrily on its tracks. Now, somebody on the roof of the train flashes a lantern. The spherical light front immediately propagates backward and forward at equal speed as viewed from the ground. However, within this expanding 'bubble' of light, the train is continuing to move forward -- so it is 'catching up' to one wall of the bubble and 'running away' from the other. Viewed from the train, the bubble is always centered at the point of its emission on the roof; viewed from the ground, the bubble's center is stationary, and not moving with the train.

Now, suppose we've got two trains following each other, and we somehow arrange that they emit their flashes at precisely the same time. Then from the ground, it is obvious that one train will catch the other's flash first. However, without the ground to tell them, the trains have no way of knowing who caught the other's pulse first. Of course, here the ground is not an absolute frame of reference (it is itself moving around its axis, around the sun, around the galaxy, etc.) So the degree of clock synchronization the two trains achieve thanks to the ground is still relative, and not absolute in the true sense. However, in my setup there is only one, singular frame of reference worth consideration -- that of N. Therefore, one can confidently conclude that when A and B synchronize through N they are achieving true synchronization in an absolute sense.

If you will, I am ultimately saying that a preferred frame of reference exists in our universe: the frame of reference centered at the universe's center of mass -- and the one that is truly stationary in an absolute sense. It is within that frame that light's propagation is ultimately defined, as well as the motion of all and any objects.

Come to think about it, this only makes sense. Since all spacetime at some point was supposed to be infinitely compressed into a mathematical point, within that point no motion could be defined at all. That includes the motion of the fields that give rize to EM (and all other) waves. When the universe expanded, the fields therefore remained stationary in an absolute sense, providing an absolute reference point. Since within an expanding universe, all points move except the center -- this center then defines an absolute reference frame.

Though here's a philosophical conundrum for you. Since spacetime is and has always been in its entirety, then how does it make sense to talk about an expanding and contracting spacetime???? What is it that spacetime expands and contracts in reference to??!!! Yet another argument for the 'matrix'. Btw that's what I'm calling it from now on. It's kinda cool (in (r/d)eference to this year's summer blockbuster) -- and succinct at the same time.

As for your personal attachment to Mach's philosophy. Philosophy is nice and entertaining, but with relation to metaphysics (or any natural phenomena) it rarely if ever reflects reality. From Plato's ideal forms, to the somnambulists' dream, to Descartes' all-beneficent God -- we have plenty of examples of metaphysical failure. In my opinion, relativity is only the latest fad in that long string of wild (and in all probability incorrect) guesses. But even given that -- do you know that Mach and others actually proposed relativity on the assumption of 'fixed stars'? They actually _did_ have an absolute frame of reference. Einstein's great leap was to realize that even this frame of reference was not absolute. But what I am saying is that all these guys were looking in the wrong places. That, for such a frame of reference one doesn't even have to look to the distant objects to calculate the universe's center of mass -- all you have to do is perform a simple orbital experiment. In fact we don't even need a neutron star; launching a couple of satellites and adjusting their orbit until it is circular ought to do it; then we could use the Earth as N. Even if I am dead wrong, this would in my opinion be a very worthwhile test of GR.

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I am; therefore I think.

[This message has been edited by Boris (edited June 08, 1999).]

Plato

06-08-99, 08:54 PM

Boris,

first of all I must concratulate you for getting that one back (the score is 1-1 :) )
But, on with the discussion, it's getting better and better. I would like to know where it says that Lorentz transformation doesn't work for light ? If that is true then my textbook on special relativity that I managed to dig up again after all those years must be wrong. There they use this same equation to show that lightspeed is the maximum velocity and that lightspeed is the same in each intertial frame.
But ok, suppose it is wrong and we can't use it then I can still prove you are wrong by your very own words even ! (I hope that didn't sounded to emotional, may be your right, may be relativity is a bad philosophy after all, it obscures rational thinking :( )
Let's get back to observers A and B, first you'll have to agree that they live and observe in the same referential frame in all of your thought experiments because they move at the same speed with respect to N and there are no external accelerations working at them.
Then you must agree that no transformations what so ever are needed to compare measurements of speeds, times and lengths between A and B. A and B have absolutely synchronised watches and I don't really care how they made it that way, if you want to do it by measuring the same sferical wave coming from N that is fine. Until this point we all agree I hope.
OK, A and B send their lightpulse to each other at the same time t. This is possible because they are in perfect synchronisation.
According to you, Boris, A is moving towards the lightpulse of B and is going to measure this lightpulse at a time t_A, while B is moving away from the lightpulse and is going to measure the lightpulse at a time t_B. Your claim is, and correct me if I'm wrong, that t_A < t_B.
Now, it follows then that t_A - t < t_B - t or that 1/(t_A - t) > 1/(t_B - t). Suppose A and B are separated by a distance L, this doesn't change over time because A and B are not moving relative to each other. So multiplying both members with L we get : L/(t_A - t) > L/(t_B - t). What is L/(t_A - t) ? Nothing else but the lightspeed measured by A and L/(t_B - t) is the lightspeed according to B. You explicitly stated that A and B do not measure different lightspeeds so you have and inconsistency in your argument, therefore I must conclude that you are wrong !

In the train we can't do real simultaneous measurements like we do in the three body experiment, an observer in the trainstation can't make simultaneous measures when observers in the trainwagon make theirs.
It is however pointless to argue that the centre of the light bubble travels with the train or is at rest with the trainstation, it is both at the same time. I know this is hard and very counter intuitive but that is just the way it is.

Now, you are very right in saying that your experiment would be a lovely experiment worth doing with some sattelites in the right orbits. Who knows, it might already have been done, I don't know.

About the center of mass of the universe, since the universe is thougth to be a hypersphere, the mass center would be the point of big bang and this is the middle point of this hypersphere, but that is no point of the current universe. If we could climb into a faster then light 'Van Den Broeck' spaceship, we would never arrive to this point. However we could claim that the centre of the universe is everywhere (just like you are always in the centre of the surface of the earth) thus the mass centre is everywhere.

About Plato's ideal forms and the denial of reality al together, I find this also a very unfruitfull philosophical theory. I rather favor towards empirism and I don't think relativity has much to do with idealism, quite the contrary. Plato claimed there was absoluteness while relativists refuse any form of absoluteness.
About Mach, to tell you the truth, I don't know a lot about Mach and his followers what so ever, could you give me a good reference to an introduction to some of his idea's ? First, tell me perhaps when he lived, was he a nineteenth centurier ?

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we are midgets standing on the backs of giants,
Plato

Aloysius

06-08-99, 09:24 PM

Boris and Plato -

I am enjoying your Socratic dialogue immensely. Please keep it up!

Maybe I'll chime in, but nothing for now...

Boris

06-09-99, 06:32 AM

Aloysius: glad you finally made it back here (where've you been?). Chime in any time.

Plato:

In my original setup, I had B trailing A. That is, let's say A and B are orbiting counterclockwise. Then the angle of A minus the angle of B gives a positive number less than 180 degrees.

Everybody:

I've recently had a revelation I'd like to share. Well, actually it's more like a confession:

The reasoning in my little thought experiment was flawed after all. But not in the way Plato thought. I've been trying to come up with a reasonable reply to the last criticism, and then it hit me.

Remember I've mentioned how A and B aren't exactly stationary with respect to each other? In the sense that if we take A as the reference point, then both N and B will seem to orbit it? Well, that's actually the solution!!! The solution is true in general, but I'll present a simplified case.

Assume that A, B, and N are equidistant from each other (this is the simplification). Then, if we take A as the frame of reference, N and B will appear to orbit it along a common circular trajectory in the same direction! Note that N will be trailing B. Now, as before, N emits a flash. Because it is equidistant to A and B, A will receive the flash first (since B is running away from N). The communication from A to B vs. from B to A takes the same amount of time, so B will receive A's flash before A receives B's (since A received N's flash first and emitted its own signal first). Then, B will flash back to N, and since N is running into the wavefront, the communication from B to N is again faster than from A to N. So there we go: two positive boosts insure that N sees B's response first.

In fact, no Lorentz boosts are needed at all to see that this system is perfectly symmetric. I just used Newtonian space and radially propagating circular wavefronts in the orbital plane, traveling all at the same velocity (c).

So, neither N, A, or B is a preferred frame of reference. Until, of course, we take a look at the gravitational gradient...

So, no need to waste money on space missions after all! :)

However, even though the hopes of directly detecting an absolute framework have been dashed for the moment, I'm not giving up yet...

--------------------------------------------

Plato:

With respect to the other points in your last message:

Here's my (of course, biased :)) view of Lorentz transformations. They do not apply to light since it travels within an absolute framework at constant speed. So, when you pop in c, c pops back out -- no surprise there. What the Lorentz transforms are needed for is to make any inertial observer's measurement of c consistent with any other's. The inertial observers travel within the absolute framework. But, they have no way of detecting the framework (especially since my thought experiment died, God rest its soul :)) -- because they are themselves governed by fields that propagate at c, and must utilize those fields whenever they make measurements. (Actually, I think this is just the context in which Lorentz derived his transformations to begin with.)

Who said the universe is a hypersphere? I thought the geometry was still a point of debate... Actually, of late it seems the universe is likely to rather be a hyperhyperbolicparaboloid. (Cool word, eh? :))

Well, anyway. Your point about the simultaneous and distinct realities for each observer (as you seemed to imply in the train/station reference) is just astonishing. Do you really think that for the train the lightfront exists in one place, and for the ground it simultaneously exists in another place?! This smells like multiple universes all over again, only this time you've got them all crammed into one. Of course I have no way of knowing you are not actually right, but I think it's more proper to interpret the lightfront as being the only copy of itself. Though of course this *would* lead to the conclusion that as far as the light is concerned there's only one true frame of reference -- the same one in which the light is traveling. So, the transforms are applied to the *observers* to make their measurements equivalent to each other in accordance with this absolute frame of reference hypothesis. You don't apply the transforms to light -- since it's the benchmark against which motion is measured for the transforms in the first place.

So, actually my position with respect to the absolute framework still stands for the multiple reasons mentioned before. It is my opinion that all the relativistic effects are only a result of this underlying framework -- and do not exist in defiance of it but rather in support of it. Though, again, I may be wrong (though all the indirect evidence for unification and common source is just too compelling...)

--------------------------------------------

And now, for the 'here we go again' section. You didn't think you'd be off that easy, did you :) :)

I think I just came up with yet another devious plan to obtain the absolute reference frame -- the cosmic microwave background. Since the temperature is supposed to be roughly uniform from all directions, would it not mean that for an object perfectly stationary in an absolute sense the background photons from any direction will have the same frequency? But then if so, as soon as you start moving in any direction, the microwave background will Doppler-shift to blue at your front and red at your rear. Is that not so? Now, I know COBE mapped the background -- does anybody know if COBE actually looked at a range of microwave frequencies, and if so whether there was more blue, say, in one hemisphere, and more red on the other?

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I am; therefore I think.

Plato

06-10-99, 07:34 AM

Boris,

you must think I'm crazy but I'm actually going to save your first experiment ! :)
If light would behave the way you describe it, namely travel in an absolute frame then it still stands because N, who is making the actual mesuring of the times between A-pulse and B-pulse, still get's B first. It makes no difference if you are looking at the experiment from A or B, the end result stays the same so light travels at a speed c in the N frame and not in the A or B frame !

Unfortunately similar experiments, and I have only mentioned Michelson and Morley but there are several others, seem to show light doesn't prefer any frame of reference. Besides, do you realise that there won't even be any doppler shift being measured by A or B or N in the lightpulse ! That is because there is no relative motion between those to. All that you are doing is looking at the events in rotating frames but you might as well fix your axes on the three bodies and then everything stands still. Face it, there is no absolute frame of reference. You can't accept Lorentz formula's and try to expain everyting according to the absolute frame, that is pure nonsense I'm afraid.
Just listen to what you are saying when you state that the lorentz equations don't hold for light, as if it's no part of our universe, as if it is something magical that obeys it own Newtonian laws, that simply doesn't make sense !

Look, if there is an absolute frame of reference timedelation and length contraction is simply not possible ! Because everyting would have it's 'true' length according to this absolute frame and everything would have it's 'true' duration. Do you realise that something like electron-spin would even be impossible because an electron would have only spin in regard to this absolute frame, if we would be spinning at the same angular velocity as the electron than we would mesure no spin at all and the electron would in effect become a boson ! Also it would be meaningless to say the rotational impluse of the electron is 1/2h because that is only in respect to this absolute frame, any other frame would give me a different value of the rotational impulse moment.
The reson why classical (non-relativistic) quantum mechanics doesn't incorporate a spin is precisely because of the above reasons. Once Dirac made the equations consitent with special relativity, electron spin poped into the picture as a fundamental property of matter. An other thing he predicted in doing that was the existence of antimatter, that is just an other thing that can't exist in a Newtonian universe !

About the doppler shift of the cosmic background, I don't really see how that is going to prove your point. You are trying to slow light down in one direction and speed it up at another but that is not what doppler shift is about. Dopplershift only happens if a light SOURCE has a relative velocity in respect to an observer, it makes no statements about the speed of light.

Aloysius,
what do you have to say about this ? Didn't you say you were a physicist as well ?

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we are midgets standing on the backs of giants,
Plato

Aloysius

06-10-99, 08:09 AM

I graduated in physics some thirty years ago, and have been an engineer ever since. So I'm impure and unclean, I'm afraid. But probably a likely guy to build a Woodward Drive :)

Re. spin, and an epistemological note: I never bought the fact that spin was in fact "spin" - as in twirling around. It's just a "characteristic parameter" in my book - much the same as strangeness, charm, beauty and all that good stuff. I leave what it actually means to others.

Therefore, to state that spinning around an electron would change the measured value of its spin has a couple of problems, as I see it:

1. I don't think it's spinning!
2. The spin is (as you point out) quantised. It's a "thou shalt not alter" kind of value - um, elementary, yeah, that's the ticket :).
Sooooo...that's a bit like lightspeed, isn't it? So even if Mach Rules, I doubt that the measured spin would alter.

Speaking of dear Dr. Mach (yes, 19th century, to answer an earlier query), I believe you mentioned that you found Woodward's mathematics "simple" and "cheap science".
Well, that may well be. But what in particular causes your nose to wrinkle about it, I'm curious to know?

Plato

06-10-99, 12:00 PM

Aloysius,

Trust me ;) spin does mean to spin around, you can calculate it gives way to the magnetic dipole moment of the electron, if it wouldn't spin, there would be no dipole moment. The reason why we can't alter this spin by spinning ourselves is because for one quantum uncertainty always leaves a residue spin left and the reason why every observer finds 1/2h as spinmoment is because there is no preferential frame as to which it would be calculated, any frame is good enough.

As to Woodward's math, I'm afraid I gave the wrong impression. I have been searching the net for other peoples comments on his views and it seems he really is up to something. I guess my first reaction was one of misinterpretation because I couldn't figure out where the initial mass fluctuation came from. For the moment I believe he said that it was due to an oscillating internal energy, right ?

This was the first time I really got a through explanation of how inertial forces suddenly appear. I never realized they were so exotic. But then again, the universe never seems to run out of surprises for us, keeps things interesting.

Besides Aloysius, I'm not pure anymore either, I'm a darn computer programmer for christ sake ! I mean, how low can you fall ? At least you are still indirectly involved with physics ! (ssssiiiigh)

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we are midgets standing on the backs of giants,
Plato

[This message has been edited by Plato (edited June 10, 1999).]

Plato

06-10-99, 12:13 PM

Now, I do have some critique about the way he (Woodward) discards the quantum vacuum energy as being insignificant. There are a bit to many experimental evidences like Lambshift and Casimir forces who can only be explained if one assumes the vacuum does as an infinite amount of energy available.

Aloysius, are you having plans to build such a Woodward Drive ? Did you know Woodward was also trying to make negative mass with his device ? This would, combined with the modified Alcubierre engine of Van Den Broeck, put the stars in our reach...

It seems, by the way, that our webmaster David Watanabe has also stumbled on this new warpdrive... Right on Dave !

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we are midgets standing on the backs of giants,
Plato

[This message has been edited by Plato (edited June 10, 1999).]

Aloysius

06-11-99, 06:55 AM

Plato:

I'm relieved that you haven't - immediately at least - poked a hole in Woodward's maths :)

Yup, I'm almost done building my device, but having just changed jobs - I too do only programming these days - I've had no time to begin testing. Perhaps after the NCTA show...

Woodward doesn't actually want to generate negative mass. We've discussed this quite a bit. Even if it were possible, I don't think it's the kind of experiment you'd want to do on the planet. I'm not joking actually - even if there's a vanishingly small chance of creating some wormhole, doing it in the atmosphere of the planet you live in is like shitting on your own doorstep. As he says in one of his papers "watch out for the sucking sound" :) If such an orifice were to be created - with no guarantee that it could be closed again, this being a somewhat new experience! - then the other end has a probability close to certainty of lying in a vacuum. Good bye atmosphere!

However, negative mass is cool stuff for van den Broek devices, and in general engineering the shape of spacetime - including pinning open the throats of wormholes.

It turns out that very substantial translational forces can theoretically be evinced from a Woodward Drive without ever having mass excursions anywhere near to negative, even momentarily. And that's the case with all the experiments aimed to reproduce the effect that I know of currently being in progress.

Of course, this could all turn out to be Hooey. There are no True Believers here; just curious and skilled people who have some idea what they're doing. Oh, and some significant government-funded work too.

As regards spin; the creation of a magnetic dipole moment could just be another elementary property. It may lie beyond Maxwell, although I guess you'll counter with Sir William of Occam's sharp thingie. Hey Ho!

Plato

06-11-99, 10:19 AM

Aloysius,

well if Woodward really is proven to be right then we are living in exiting times indeed ! I always thought that the stars where going to stay unreachable certainly in my lifetime and a long time after that but here we are actually talking about an experimental way of creating momentarely negative mass ! It's just to good to be true, there will perhaps lie a whole lot of difficulties on the way to actually create a wormhole or a van den Broek device...

Anyway I wish you all the luck with your experiment and do let us know how it turned out. Could you perhaps tell us how your setup is going to be ?

About spinning, if you think that magnetic dipole moment is just a mysterious property of an electron than you must think that the same thing goes for the entire atom because why should it fly around the nucleus ? You are very right to mention dear old William there, he usually makes life a whole lot simpler and less mysterious. ;)

------------------
we are midgets standing on the backs of giants,
Plato

Boris

06-12-99, 11:27 AM

Whoa, I'm gone a couple of days and all hell breaks loose! :) All right, I'm gonna try and catch up here...

----------------------------------------
Concerning my 'thought experiment'
----------------------------------------
Yes, indeed I'm claiming that N will get the signal from B before A. And it's not inconsistent with relativity, un contraire. The entire discipline is founded on the assumption that light travels at constant speed and therefore is the only reliable measuring stick that doesn't change its properties across frames of reference. Everything else changes: time flow, length, inertial mass -- but light speed is allways the same. Redshift indeed occurs for moving bodies upon emission, but gets exactly cancelled out upon reception in co-moving frames. For example, if B trails A (in an absolute sense, for simplicity) and emits a pulse, then the pulse will be Doppler-compressed at the emitter, and Doppler-expanded at the receiver. Thus, no overall frequency change is observed. And in my case, the bodies _are_ rotating. There's no way to view them as static. Contraction can still occur despite absolute reference frame -- because length is measured by radar ranging (pick up an SR book to see this). Light does all the work of establishing the Lorentz transforms; the only necessary assumptions are that lightspeed is constant within the absolute reference frame -- and that all experimental setups are also subject to lightspeed at the fundamental level.

------------------------------------------
Concerning quantum mechanics
------------------------------------------
I don't believe in 'spin' either. In fact, electrons aren't even orbiting the atoms: they are standing waves! Plato, I'm surprised you take this more primitive orbital interpretation over the more modern statistical one. In fact, 'spin' does not make sense (as defined in our intuitive 3D terms) because then there's no way you can have a 'counterspin'. Obviously, you'd have to use more dimensions than just 3 -- at which point talking about 'spin' is tantamount to assigning a specific conceptual meaning to an arbitrary mathematical construct. Plato, you yourself have gone over the dangers of assigning meaning to math -- especially since there are ample reasons to suspect that our theories are incomplete.

-------------------------------------------
Woodward's impulse engine
-------------------------------------------
My big-time problem with the whole thing is that it was derived from Mach's principle. I.e.: physical effects propagating _backward in time_????????? I don't care how it makes the math work, it's just nonsensical. There's *got* to be a better formulation for inertia. Then, as Plato rightly noticed, Woodward does slight quantum vacuum. Then, I don't know how robust is his 'specialization' to the particle's reference frame. I.e. he discards the Lorentz factor, for the moving object, but doesn't add that factor to the 'force field' that is supposed to generate inertia. Then, I'm not sure about 'instantaneous' compliance with Lorentz invariance for accelerating objects; as far as I'm aware relativity doesn't deal with accelerating objects, period -- instantaneously or not (at least as far as transformation-invariance is concerned). But then, what do I know :) So, Aloysius, I join Plato in wishing you luck -- whatever the final outcome.

-------------------------------------------
More plugs for absolute framework :)
-------------------------------------------
The doppler shift of cosmic background: I'm not speeding up or slowing down light. Think of it as moving through a room filled with white noise. If you stand still, the noise is the same in all directions. However, if you move rapidly, the noise will be more high-pitched in the forward direction and lower-pitched in retrograde direction. Note that the speed of sound in the air does not change as you move. Now, substitute the 'air' with 'ether' and the speed of sound with lightspeed...

Plato: if there's no absolute framework, then you could perhaps explain how a 'spinning' electron could generate a dipole moment?! I.e., what is it spinning in relation to, exactly? Would it be true that in a perfectly empty universe (except for one electron present), an electron would never possess a dipole moment?!! Ever paused to think about what _you_ are saying?

------------------
I am; therefore I think.

[This message has been edited by Boris (edited June 13, 1999).]

Plato

06-15-99, 01:48 PM

------------------------------------------
Concerning quantum mechanics
------------------------------------------

Guilty as charged !
I shoudn't have used these 'classical' terms as orbit and rotating around an axis. What I wanted to do is make the 'spin' concept just a little bit more familiar by relating it on just classical turning. But ok lets look at the wavefunction that represents the electron, we have a standing wave. To have that there must be some statistical moving around of a chargedensity. Twist it any way you want there HAS to be a moving charge in order to have a magnetic dipole moment.
Now counterspin is only a meaningfull properties of a bound electron, this means that it always has a spin orientation in relation to a nucleus or an other electron in it's 'orbital'.

-------------------------------------------
More plugs for absolute framework
-------------------------------------------

An electron is always spinning in relation to any observer, doesn't this sound familiar to you ? Like in light always has velocity c in relation to any observer ?

Tell me, what does it take to convince you that it is impossible to merge lorentz equations with the notion of an absolute framework ?

What a second, let's swich roles here. Give me a good reason why I should believe there is an absolute framework. I don't want an other example or experiment, I want your deepest motivations...

------------------
we are midgets standing on the backs of giants,
Plato

Boris

06-24-99, 06:35 AM

Sorry I've been out of touch for a while. But guess what... I'm baaa-aack! (insert evil laughter here)

<hr>

Plato:

The only thing that would convince me that Lorentz transforms are impossible within an absolute framework is a mathematical proof. I fact, I am willing to bet a lot of money that such a proof had never existed, nor will ever exist. It's rather like trying to prove the (in)existence of God.

I've been over my motivations for this a number of times. Here we go again.

Basically, it's the grand synthesis and the ultimate reduction that catch my imagination. If everything -- including space, time, fields, quanta, and even the speed of light -- could be reduced to just a single entity, that would be the ultimate scientific achievement of our time. You might say string theory does that, but then I'd ask what gives rise to the strings and all the dimensions within which they vibrate. You see, as long as space just is assumed to be there, I'm not satisfied. I want to explain space itself, and time itself -- not just the matter/energy that inhabits them.

I want to know what gives rise to the physical constants, like permittivity, or G, or h_bar. I want to know what gives rise to the three dimensions. I want to know wherefore lightspeed -- and why precisely the speed we measure. I want to know _why_ a moving charge creates a magnetic field, not just how.

The fundamental constants, and the physical laws, are the same regardless of inertial observer. I want to know why. I want to know what makes sure that relativity stands.

I want the ultimate coordinate system and the ultimate math that will apply to absolutely all areas of science at the most fundamental level, and will never have a singularity, or a discontinuity, or asymptotic behavior anywhere within its framework. I want to know exactly what happens inside a quark, and what happens inside a singularity, and what happens inside a photon, and what makes them all ultimately one and the same thing. I want to be able to calculate with arbitrary precision the behavior of physical systems over any spacial or time scales. Ultimately, I want to know what gave rise to the Big Bang.

Are these questions enough to make you wonder, Plato? They certainly are for me...

<hr>

Concerning the electron-spin...
Imagine an electron moving inertially in a perfectly empty universe. Now imagine a co-moving observer. The electron is perfectly stationary with respect to the observer -- and therefore cannot have a magnetic dipole! Hence, it's not spinning. Quantum-mechanically, this is, of course, not allowed -- for if we know exactly how the electron is moving, it becomes uniformly spread over the entire universe and therefore basically ceases to exist! So the only reason the electrons are always spinning is because they are always moving with respect to us -- otherwise, we simply don't see them. (Though, unlike Heisenberg, I think that they exist even though we can't observe them. Could be the source of 'virtual particles'...) But then here's the question: if we know an electron's trajectory 100%, and its position is 100% undefined, then if we introduce a positive charge along a different trajectory into the empty universe, the charge will not accelerate at all!! (since the negative charge is equally spread throughout the universe). Does that now mean that charge, as well as magnetism, is a property of bodies whose momentum is not known 100%? But now we are faced with this conundrum of knowledge: how does 'knowing something' alter the nature of reality -- like making charge disappear?!

------------------
I am; therefore I think.

[This message has been edited by Boris (edited June 24, 1999).]

Aloysius

06-24-99, 08:27 AM

As far as I know, and which makes sense to me, is that a particle in a completely empty universe becomes very peculiar when asked to spin. Because there's nothing to spin relative to. I think this central insight is what got Mach started off down his road.

So if "spinning" and "not spinning" become identical for such a situation, what does this say about inertia? It appears to point to the requirement that "The Fixed Stars" be present, in order for inertia to exist at all!

Plato

06-24-99, 11:52 AM

I think along the same lines here. First of all is it possible to have a 'universe' with a single electron.
May be I should give a definition here of universe : the timespace continuum where everything happens in so I'm only looking at a finite set of dimensions be it four, be it ten or eleven. In order to have an electron there must be a Dirac field present with one quantum (the electron) but if it appears that this field would have to be connected with all other fields and ultimatly of the amount of dimensions of space itself thus giving rise to the universe as we know it like a nescessety.

About all the questions that you rise, Boris as far as I have read about string theory (and that is not that much I'm afraid) they do show that the fundamentel constants like h, e and c are ultimatly connected or do I have this wrong ?
Well anyway any good theory of everything should do just such a thing let it all boil down to just one constant.
Now imagine a Hilbert space (this means a space with infinite dimensions) with a scalar field (of course) that fills the space. This field gives rise to universes (see above definition), each with a different fundamental constant. Now I imagine that only a specific set of choises who will give rise to universes with life and conscience in it. Thus comes in the weak antropological principle : our universe is the way it is because we are here to ask the question. I know, I know, I'm going against my own words that we have to stick to observables but maybe there will be a way to verify the existence of other universes. Jesus, I almost feel like those guys who thought there were other worlds around the pinholes in the sky.

Ok, back to the real world.
Boris,

you would like a mathematical treatment that an absolute frame is incompatible with lorentz' equations. Ok, we can set some requirements that will have to be in it.
First you will have to define the space you are going to use. Second you need to define a frame of reference which one could call absolute. This could be the start of a proof ad absurdum.
To tell you the truth I don't know if such a proof has already been made but I imagine it would. I'll poke around a bit, maybe I find something.

------------------
we are midgets standing on the backs of giants,
Plato

Aloysius

06-27-99, 03:38 AM

Back to the Topic!!! -

You'll find here
http://math.ucr.edu/home/baez/physics/grav_speed.html

that Steve Carlip disagrees with Tom van Flandern. Tom indicated this to me in email recently, and although he maintains a healthy respect for Carlip, still disagrees - as you've already read.

Sounds like Tom's wrong. Anyone agree?

Boris

06-27-99, 01:55 PM

Ok, I guess we can call him Tom from now on (I did feel V.F. was a bit strange)...

But didn't Tom mention on his website that the only reason the GR formulas work out is because a 'retarted' fix was applied to them behind the curtains? Though the pulsar evidence seems formidable. However, couldn't something other than gravity cause an orbit to decay? E.g. tidal energy transfer?

------------------
I am; therefore I think.

Aloysius

06-27-99, 07:47 PM

Man, my SR is rusty. I tried to derive the traveller time for an accelerating spaceship this weekend, and got hopelessly lost in tanh()'s, gamma's and incorrect frames of reference! Never mind my GR (I think I actually understood Christofel-Riemann tensors once, but that isn't the case right now).

Anyway, from my desparate plumbing into SR theory this weekend, I came across something about the Schwarzchild metric that shows that nothing is done "behind the curtains". GR predicts **almost** the same result as Newton I think, and it pops out naturally. I think Carlip mentions a "linear extrapolation of retarded position". Sadly, I have no link to give you.

vliegschotel

06-28-99, 02:20 AM

Just new to the net, I surfed and found your web site. How fast does gravity go? Well, we will have an answer some time in the future. I discovered in 1967, the monopole high-voltage generator as used by these UFO's for propulsion and gravity control. Some time in the future we will be using them for propulsion, rather than rockets, in our space ships,although the Nasa rocket-propulsion specialists told me that they were "Not interested, thank you!" and
hate it. I myself think that gravity goes faster than light. Reason? If you send a radio-signal to a metal container, with a receiver in it, it does not pick up the signal. The light speed does not penetrate metal. But gravity does! I am assembling a monopole shortly, and will try it out on a completely shielded receiver. There is also a puzzle. In the big Pyramid, the "Queens grave" contained a battery to contact other planets. Maybe there is a secondary speed to a light or radio signals. And it could quite well be 10 tot the 10th power in km/sec.

Plato

06-28-99, 06:15 AM

Isn't this ajustment of retarded force just what Woodward claimed to be the effect of gravit-magnetism ?
Steve Carlip doesn't use the term but the whole electromagnetic gravitation treatment is just a reinterpretation of the same equations of GR. This strongly suggests that the three possible origens for inertial forces are down to two, leaving quantum fluctuations and the invert-time gravity waves theorie of Feynmann and Wheeler...

To mister Vliegendeschotel : I think you missed from topic, the 'vliegende schotels' are discussed in the ufo-thread. By the way, I take it you never heard of the cage of Faraday ?

------------------
we are midgets standing on the backs of giants,
Plato

Aloysius

06-28-99, 07:04 AM

Herr Fliegende DinksBumps:
Wonderful that you discovered a monopole high voltage generator in 1967. I hope that you and the generator are very happy together. If you feel like it, post the engineering plans here and we can discuss them. There are enough qualified people here to help you. You probably do need help.

Plato:
Yes, I think it is right...it's down to two.
I don't know if you realise it, but the waves can be advanced or retarded. Theory doesn't differentiate between the two possibilities. I think, aesthetically - and otherwise - coming and going from the future is better than emitting to the past and interfering with a normal wave back from the past. You agree?

Boris

06-28-99, 10:36 AM

Time travel! Nnnnoooooooooo..........

I hate time travel. I know it's irrational, but I hate it, I hate it, I hate it.

Just thought I'd throw a tantrum this once; takes all that stress off, you know.

------------------
I am; therefore I think.

Plato

06-28-99, 12:20 PM

Relax Boris,

Let them stupid waves travel back and forward in time, that doesn't mean actual particles can do the same. Maybe timetravel is only allowed for bosons while the fermions have to follow the normal laws of causality. I don't know, I'm just mumbling.

Anyway I must agree with Aloysius on this, symmetrical emission of waves in time is much more aesthetical then those chaotic vacuum fluctuations...

------------------
we are midgets standing on the backs of giants,
Plato

[This message has been edited by Plato (edited June 28, 1999).]

Aloysius

06-29-99, 05:47 AM

Boris,

I empathise, I empathise....

I keep a piece of solid rubber hose to hand, so that whenever I run into the phrase "over-unity device engineering" and the like (and there are so MANY relatives!), I have something to bite down hard on as I go into spontaneous screaming convulsions.

It makes the screaming less jarring to my family, and they don't have to keep the door locked for so long.
Available at all good hardware stores.

gentle

09-18-04, 08:33 PM

"Framework to the theory of everything!"

Spacetime may not be the true way to understand the relationship between the concepts of matter, energy, time, space and speed. Relativity is the point of origin mass to energy transfer between bound matter (potential energy) and unbound matter (kenetic energy) the Gravity wave ( space). That is to say that matter evaporates, decays, into the gravitational wave creating the resulting continious actions of space, time and gravitational wave sychronization. Space is the gravitational wave being freed to its lowest form of matter. Time is the cosmological constant -the evaporation rate of matter. There is no real curved spacetime. It is gravitational wave sychronization, gravitational waves aligning through the path of least resistance that brings matter together, that is responsible time and space distortion as the waves elongate just as the dopler effect works in sounds. Instead of the sound wave being shortened or elongated when compared to moving objects the gravity wave is shortened or lengthened, red-blue shift which affects not the action of sound but the actions of time and space. Gravitational wave sychronization of bodies in motion change the relationship of the gravitational waves with respect to each other and the resulting actions of time and space change.Time and space are actions created by each discrete piece of matter as the matter evaporates into the gravitational wave. Space is the unfolding of matter. Time is the resulting action of the rate of evaporation of the gravitational wave. Relativity- Point of origin mass to energy transfer in wave form of bodies in motion Newton- Einstein- How it all works!
Part of a paper-Copyright @ 2003, All Rights reserved.

Here is my example of gravitational sychronization-

THE BOBBER- RIPPLE (wave) EXPERIMENT

The experiment ………….

A 1000 kg. Bobber automatically bobbing once every 10 seconds in water, and a 1 kg. Bobber automatically bobbing once every 10 seconds in the same water 10 meters apart. They both have the same pounds per square meter bobbing force.

The prediction…………….

Both bobbers would come together and touch to form a uniform distribution of the ripples. The ripples represent the gravitation e- wave emitted from each object.

The discussion…………..

Evaporative gravitation predicts that the path of least resistance would be for both bobbers to have equal centers of e-wave distribution. Since both condensation masses attempt to take up the space to synchronize to the path of least resistance, they touch and remain that way. If the masses could, they would pass through each other until the centers of each mass overlap perfectly, as in the big bang and almost in black holes. This represents the path of least resistance of each set of gravitational e- waves.

THE EVIDENCE

1).Absolute Zero- evaporation (decay) stops.

2). Time - cannot come in Quantum units.

3). Black holes- evaporate over time.

4). All galaxies are increasingly accelerating away from the big bang.

5). Gravity and acceleration working together distort time. (Relatively speaking). Matter generates space and time, which are actions of the evaporative gravitational wave being generated.

Guided Mode Enhanced Mode
gravitation@cfl.rr.com

"Framework to the theory of everything!"

Spacetime may not be the true way to understand the relationship between the concepts of matter, energy, time, space and speed. Relativity is the point of origin mass to energy transfer between bound matter (potential energy) and unbound matter (kenetic energy) the Gravity wave ( space). That is to say that matter evaporates, decays, into the gravitational wave creating the resulting continious actions of space, time and gravitational wave sychronization. Space is the gravitational wave being freed to its lowest form of matter. Time is the cosmological constant -the evaporation rate of matter. There is no real curved spacetime. It is gravitational wave sychronization, gravitational waves aligning through the path of least resistance that brings matter together, that is responsible time and space distortion as the waves elongate just as the dopler effect works in sounds. Instead of the sound wave being shortened or elongated when compared to moving objects the gravity wave is shortened or lengthened, red-blue shift which affects not the action of sound but the actions of time and space. Gravitational wave sychronization of bodies in motion change the relationship of the gravitational waves with respect to each other and the resulting actions of time and space change.Time and space are actions created by each discrete piece of matter as the matter evaporates into the gravitational wave. Space is the unfolding of matter. Time is the resulting action of the rate of evaporation of the gravitational wave. Relativity- Point of origin mass to energy transfer in wave form of bodies in motion Newton- Einstein- How it all works!
Part of a paper-Copyright @ 2003, All Rights reserved.