A FINAL WORD on the thermodynamics of 'Mach Thrusters'.

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chrismb
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Post by chrismb »

kcdodd wrote:First, no thruster can change the total momentum and energy of the universe from an inertial reference frame, right?
From a conceptual point of view, that would seem true. From a purely Newtonian perspective in which the Universe has 'an inertia', where some of which can transfer to a remote object considered as a separate object to ROTU, then this can only make sense as if looking at the momentum of the universe from a unique POV that is not influenced by being, and is not, part of the ROTU frame.
Hopfully that is agreed.
Ambiguous. Of course, one ends up with a logical fallacy that if the ROTU is what an object thrusts against yet it is part of ROTU, then it is thrusting against itself, in which case one would expect it to go nowhere.

A passenger standing inside a stationary bus with all the brakes off (that has zero rolling resistance) can push as hard as they like on the handle-bars inside and they don't go anywhere!
Second, if a thruster acts on the whole universe, then the whole universe is in a non-inertial reference frame, INCLUDING any observers.
As above - either an 'imaginary' POV can be created in which some universal inertia can be transferred to a remote object, or it can't. If the latter, that pretty much puts a permanent strike-through for 'ME thrusters' that claim to be able to do this.
So, the total energy and momentum of the universe will NOT appear to be constant to physical observers, because you are measuring the total energy in different reference frames as the thruster operates. It would only appear to be constant for some observer "outside the universe" where the thruster does not react against anything.
The only meaningful way to imagine this in any form of analogy is to look at the car/earth example. Does the momentum of the earth go up when a car accelerates? As a body treated separately from the car, yes, as a system, no. And if an observer were looking at these two bodies together and he was standing on the earth, what would he say about the momentum of the earth? His problem then would be that he is in an accelerating frame whilst the earth is undergoing a change of momentum.

GIThruster
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Post by GIThruster »

chrismb wrote: The only meaningful way to imagine this in any form of analogy is to look at the car/earth example. Does the momentum of the earth go up when a car accelerates? As a body treated separately from the car, yes, as a system, no.
You don't understand Mach's Principle. I highly suggest a careful read of Pfister and Barbour whom I've recommended several times now, and especially the essay entitled "A Closed Universe Cannot Rotate". You cannot compare the universe to the Earth because unlike the Earth, the universe has no objective reference.

You can't have sensible discussions of things like conservation when you still have no working knowledge of the theory you're criticizing. I will remind you, it was this insight by Mach that enabled Einstien's theories. You can't continue blunding about pretending the universe obeys Newton when we know it does not.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

chrismb
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Post by chrismb »

GIThruster wrote:You don't understand Mach's Principle. ....
You can't have sensible discussions of things like conservation when you still have no working knowledge of the theory you're criticizing.
There is no criticism of any theory in this thread.

There is only the deductive conclusions arising from an initial proposition. This has just been explained to GIT.

GIT's 'non-analytical' means of analysis seems matched only by his means of arguing logic that seems to lack any form of deduction from one step of the argument to the next.

GIThruster wrote: You cannot compare the universe to the Earth because unlike the Earth, the universe has no objective reference.
That's a debate with kcdodd's post, not chrismb's posts in this thread.

kcdodd has raised this point and it begs the question what does a theoretical ME thruster react against? It would have a defined frame of reference, so how can it react against something else that is not in a defined frame of reference? chrismb's analysis does not seek to tackle that logical inconsistency.

GIThruster
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Post by GIThruster »

You're jibbering word-salad, chris. When you write "so how can it react against something else that is not in a defined frame of reference?" you are not even wrong. You can continue on pretending you know enough to do the analysis you're pretending to do, but it is obvious you do not so I'm just reminding, you need to go read Barbour and Pfister.

When you understand the basics, come back and try to raise a salient point. Until then your analysis will remain childish and insipid. Throwing up some algebra to appeal to the local engineers is not a real analysis, especially when we know the proper way to deal with these various frames is with Lorentz transforms you don't know how to manipulate.

If you think writing in third person and the like makes it appear you're not criticizing M-E theory I suggest you see a doctor. Writing in third person makes it seem you have a dissociative disorder. It does not change the fact your posts about M-E are all attempts to play the troll.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

chrismb
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Post by chrismb »

GIThruster wrote:You're jibbering word-salad, chris. When you write "so how can it react against something else that is not in a defined frame of reference?" you are not even wrong.
Is there anyone else in this forum that can explain, in a more readily intelligible way, what GIT's complaint with chrismb's post is?

Is it not obvious that something without a definable inertia cannot change [by] a defined momentum delta, thus cannot be reacted against?

GIThruster
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Post by GIThruster »

chris, this is just jibberish. Go do the required reading so people aren't forced to pander to your self-imposed ignorance.

If you understand the statement "a closed universe cannot rotate", then you know what you're proposing is nonsense.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

chrismb
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Post by chrismb »

So there is no doubt that in GIT's touch-feely 'analysis-without-analytics', he consigns conservation of momentum to the dustbin on the strength of a few equations that he doesn't understand himself, and that few accept and that have yet to be demonstrated to have any practical value?

..compared with 'conservation of momentum' on which it is barely an exaggeration to say it is one of the fundamental enablers of mechanical calculations on which the whole modern world has been built?

ho ho ho ... :lol:

GIThruster
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Post by GIThruster »

No chris, I think what is obvious to everyone is you continue to criticize a theory you openly admit you do not understand, and you resist all attempts to fill the gaps of your ignorance.

The fact you can do high school algebra is not hiding the more salient fact you are ignorant on the subject you keep going on and on about.

Like I said, not worth my time.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

chrismb
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Post by chrismb »

Where, in this thread, is there a criticism of a theory!?!?

GIT keeps saying it, and, one must presume, in his idea of 'reasoned arguing' (a pretty bizarre place to be, it seems!!), if he says it often enough it becomes true!

kcdodd
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Post by kcdodd »

GIT, I have to disagree with you. One can criticize a theory without knowing much, or anything, about it, simply by looking at what it supposedly predicts. One does not have to pour much water into a bucket to find a leak in the very bottom. If the result is violation of conservation of energy or momentum, then its out, sorry.
Carter

CaptainBeowulf
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Post by CaptainBeowulf »

I think this is probably the chapter that GIT is talking about, it's about Mach's Principle in a book edited by Barbour and Pfister:

http://books.google.ca/books?id=fKgQ9Yp ... te&f=false

GIT, I'm not sure that anywhere Chris' analysis requires a rotating universe. Yes, he makes an analogy to a car moving on Earth, but I think the main focus of the analogy is that so long as you have (1) a power source that converts fuel to energy and (2) something else to push against, you can move while conserving momentum without needing to eject propellant (ie. you do not need to carry your own reaction mass).

In the case of this analogy, a tiny bit of momentum is transferred from the car to the Earth, altering the Earth's speed of rotation by a miniscule amount, although when the car brakes momentum will be transferred back to the Earth (after all, deceleration is equivalent to acceleration in reverse... with a conventional rocket you have to expel propellant to slow down as well as to speed up). But, it's just a partial analogy. I don't think the rotation element was intended to carry over.

In all the discussions about this I've been under the impression that most of us think that momentum has to be conserved by being transferred to Far Off Active Mass (FOAM) or, as it's been called in this thread, the Rest Of The Universe (ROTU). People here have repeatedly made the joke that, as a result, it might be the mass use of Mach Effect ships by alien spacecraft across many galaxies that is causing the expansion of the universe to accelerate instead of slowing and then collapsing back into a Big Crunch.

The more general problem we seem to be back at is "how does the M-E device know how fast it's going compared to the rest of the universe?" Some have argued that relativity requires that no frame should be preferred, and that then the M-E thruster should always get the same thrust in each instantaneous rest frame, so that it will produce constant thrust indefinitely. Then we get the rocket on a flywheel argument, and the disagreement between people who say that Newtonian math will come to the conclusion that any rocket can eventually go overunity by producing constant thrust and that you have to do Lorentz transforms to get a non-absurd result, and people who do the Newtonian math and conclude that Newtonian math does not get overunity for any type of rocket.

I can't do the Lorentz transforms and I can't find any obvious errors in either Andrew Palfreyman's or Chris' math regarding rockets - but if there are errors I wouldn't necessarily catch them. So most of us are stumbling around half-blind in this discussion due to lack of math skills. What I am interested in is following detailed discussions in order to try to learn something and see if any criticisms make sense to me.

So, going back to Chris' analogy. Does the universe have a rotational angular momentum? No (at least assuming Mach's Principle is true). Does the universe have a momentum in a certain direction? No. However, mass in the universe does have a momentum - it's expanding outwards because some expansionary force is stronger than gravity. So, you can perhaps in theory exchange momentum with that large amount of far off mass which is going away from you, in the same way that you can exchange momentum with the planet you are standing on (notwithstanding that the rotation element is not analogous).

From this point of view FOAM is probably a better term than ROTU, because it reduces this confusion. Nonetheless, it seems to me a bit of a semantic difference: the thruster and the FOAM it reacts with are all part of the universe, which is a closed system which conserves momentum (if we agree with Woodward, then the FOAM is the vast majority of distant matter in the universe, although I've once seen the argument made that it can only be the far off matter within a certain prescribed light cone (but that's a different argument and doesn't necessarily affect the outcome here, as it might still be possible to treat all parts of the universe within a given light cone as a closed system).

We also get back to the argument we were having involving Chris a few weeks ago about whether the reaction on the FOAM should accelerate it or decelerate it. I tend to think that even though it's already accelerating away from you, you still accelerate it even more by exchanging momentum with it, similarly to how you always push propellant away from you to speed up or slow down. But, I might have a conceptual blind spot here. In fact, I'm even finding it hard to conceive what sort of momentum exchange you have with Earth when you drive your car on it. Would you be slightly accelerating its rotation if you drive east (against the direction of rotation) and slightly slowing its rotation if you drive west (in the direction of rotation), or slightly increasing its polar wobble if you drive north or south?

And yes, "push" might not be the right word/concept either, given the whole gravinertial transistor concept. But still, in Woodward's theory it seems to me that when you take advantage of gravinertial flux you still transfer momentum by doing so to the FOAM. So, for a discussion at the level we're having here, "push" seems to be an acceptable analogy to me.

Overall, though, I would find it interesting if, simply using Newtonian analysis and "high school" level math, we could reach an approximation that it is indeed possible in theory to push against FOAM (assuming there is a mechanism to do so like gravinertial flux/Wheeler-Feynman gravity radiation, or whatever someone else might propose) while conserving momentum (and not get constant thrust but actually need more energy to keep going faster relative to your original reference frame.) Such a Newtonian approximation may not describe the behavior of a propellantless thruster entirely accurately, and the higher the accelerations/speeds and the larger the distances, the more it might go completely off to left field as compared to a model using GR and SR... but, if on smaller scales a Newtonian analysis provides an OK approximation it would seem to me to actually be favorable towards the whole concept of propellantless thrusters.

Perhaps Paul would like to try to comment on or clarify some of the points above?

CaptainBeowulf
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Post by CaptainBeowulf »

So in short we shouldn't be thinking in terms of changing the total momentum and energy of the universe from an inertial reference frame, but in terms of changing the momentum and energy of the FOAM from an inertial reference frame, thereby altering the expansionary properties of the universe, thereby conserving momentum within the entire system. If that makes any sense.

Chris, would such a model invalidate your previous argument in your mind? GIT and KC, do you find such a description wrong?

GIThruster
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Post by GIThruster »

kcdodd wrote:GIT, I have to disagree with you. One can criticize a theory without knowing much, or anything, about it, simply by looking at what it supposedly predicts. One does not have to pour much water into a bucket to find a leak in the very bottom. If the result is violation of conservation of energy or momentum, then its out, sorry.
Yes but you're equivocating. When we look at chris' analysis, we're not here talking about someone who doesn't understand all of M-E theory. We're talking about someone who has for years been criticizing a theory he has made not the slightest attempt to understand. So when he talks about mass-energy conversion, and the universe having no reference frame, he's talking about stuff that makes no sense whatsoever. As result, he has not found a "hole in the bucket" but rather has proved he has serious emotional troubles he needs help with. People who criticize theories they know literally nothing about have serious emotional problems and that disqualifies chris as someone worthy of an answer on almost all occassions.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

GIThruster
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Post by GIThruster »

CaptainBeowulf wrote:So in short we shouldn't be thinking in terms of changing the total momentum and energy of the universe from an inertial reference frame, but in terms of changing the momentum and energy of the FOAM from an inertial reference frame, thereby altering the expansionary properties of the universe, thereby conserving momentum within the entire system.
That sounds right to me, but I would note that I am not a physicist and I can't do any field theory.

While I do appreciate what you're suggesting, I would just go on record that I don't see wisdom in pretending to be what I am not. Almost all of the complaints to date about conservation (maybe all of them!) come from engineers pretending to be physicists. In order to do the proper accounting for what is a field phenomena, you need to use field theory. We could go on and on here trying to understand in engineering terms how the conservation issue works out, and we could all be wrong and have no idea why.

The universe is connected by a single gravitational field. From all that we know, gravity extends its field toward infinity. For what we know about gravity at present, literally EVERYTHING in the universe is connected gravitationally.

Additionally, gravity uses an inverse square rule so the gravity on any portion of the universe is inversely related to the field source's distance. However, when we understand Mach's Principle, suddenly we start to see that inertia, which is the consequence of gravity, is caused primarily from the farthest mass. How can that be so? You need to read the arguments and papers that explain this before you can say you're ready to have a discussion about the field. We haven't done this and I doubt we can have a sensible discussion of conservation until we have these understandings in common. So again, though what Beowulf is writing seems perferctly reasonable to me, I don't think we can get there from here.

About the book: I'm shocked google has the entire thing posted up online. Especially with such an expensive book, this is highly unusual. Anyone interested in this topic, I do suggest reading as much as you can before it's taken down, except the second section on non-relativistic Machian theories which is all a comlplete waste of time. This is one of the very best books I have ever read on the subject and I hope everyone with an interest will indulge themselves, especially chris.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

chrismb
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Post by chrismb »

CaptainBeowulf wrote:I think this is probably the chapter that GIT is talking about, it's about Mach's Principle in a book edited by Barbour and Pfister:
This awful link will shoot pages worth off the side of a typical screen.

Try editing the post, using the following link instead;

http://books.google.ca/books?id=fKgQ9YpAcwMC

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