Mach Effect progress

[chrismb]

So, which is the flawed premise, or are none of the premises flawed, In your opinion?

[happyjack27]

Yes, entropy is... the most ineluctable of natural laws.

It only seems that way because it's depressing. It's actually the least ineluctable physical law there is - it's not a "strong" law like conservation of energy or momentum; it's only a statistical result, and it only holds probabilistically, and then only between states in thermodynamic equilibrium.

If M-E thrusters were demonstrated to work beyond a shadow of a doubt, and a peer-reviewed calculation showed that they violated the entropy condition, I'd believe it.

Of course, absent such a demonstration, it is reasonable to assume that either the thrusters don't work or they don't violate the entropy condition.

actually entropy is a result of statistical mechanics. thermodynamics is just a simplification of that result. and the statistical mechanics result is a result of math. and you can't beat math.

also the entropy result comes from a more fundamental result about information, and you'll see in e.g. maxwells deamon thermodynamic entropy is equal to information entropy. what's really happening with entropy is that as time passes you're losing information about your previous states. and that's just an inevitable mathematical consequence of the instantaneous differential relations.

[djolds1]

actually entropy is a result of statistical mechanics. thermodynamics is just a simplification of that result. and the statistical mechanics result is a result of math. and you can't beat math.

That's a common claim. Rarely substantiated.

[happyjack27]

actually entropy is a result of statistical mechanics. thermodynamics is just a simplification of that result. and the statistical mechanics result is a result of math. and you can't beat math.

That's a common claim. Rarely substantiated.

you can't substantiate math.

if you come up with a different result, that just means you did the math wrong. that or you have a GIGO problem. (garbage in -> garbage out)

[happyjack27]

beating math would by definition be creating a logical contradiction. and if you do that, well then that mean's you're contradicting yourself, so you've just invalidated your own argument. congrats.

[GIThruster]

if you come up with a different result, that just means you did the math wrong. that or you have a GIGO problem. (garbage in -> garbage out)

That's why chris' argument holds no water. It produces an absurd outcome regardless of the type of thruster you put into the calculation. Obviously, it's the wrong calculation.

M-E thrusters are evaluated in thrust efficiency in the same way that all electric thrusters are, in N/W. That is for stationary thrust. Any accelerating thruster is in a non-inertial frame of reference, so in order to do any sort of conservation calculation, you not only need to do a transform, but a transform with a non-inertial frame. The proper tool to do this is found in the GR toolbox. Now it may be this calculation using exhaust velocity is a work around, but until I see it does this properly with the exhaust from a Hall thruster, I would not assume this. I do assume 93143 knows what he's talking about and so I think there is hope for this work-around, but certainly the complaints from chris, goatguy and Andrew do not look at exhaust velocity so they are not using this supposed work around and their examples all thus come to nothing.

[happyjack27]

also, if it's any consolation to entropy being "depressing", since physics constitutes a nonlinear dynamical system with both positive and negative lyapunov exponents - that is, since its capable of exhibiting chaos - there are thus both source and sinks of entropy.

the "heat death" idea was an unjustified extrapolation of an observation of a system in very particular conditions that are not natural throughout the universe, for a very brief time period. and as such it cannot come near to discrediting the math, which clearly shows that information constantly gets created and destroyed.

but is that less or more "depressing"? it still makes us mortals. but the alternative would make us statues.

[chrismb]

That's why chris' argument holds no water. It produces an absurd outcome regardless of the type of thruster you put into the calculation. Obviously, it's the wrong calculation.

This is entirely false. The only absurdity is the misunderstanding you have pervaded.

ANY thruster using propellant will result in a net increase in KE [of craft + propellant] from its starting frame that cannot be in excess of the energy expended during its flight.

The argument you are rather hopelessly attempting to draw a simile with is the situation where you have 1W of power apparently performing 1kW of kinetic energy rate of change. This never happens.

What you might end up with is the craft increasing by 1kW of KE/dt as a result of a 1W engine whilst it is at speed within a datum inertial frame, but what this actually means is that you have a TOTAL KE increase of 1J/s because there is a mass of propellant that has slowed down by 999J/s. If you were to sum the increase of total KE as a result of accelerating propellant by 1W then the sum of KE/dt of the craft and propellant would add up to 1J/s.

The SUM TOTAL INCREASE of KE* of propellant and craft of ANY KNOWN type of craft can never exceed the energy expended. Period. (*in one [any] fixed frame).

[chrismb]

The argument being attempted by its proponents in respect of 'propellant-less' craft (for example using numbers per the 5 premise posit above) is that the additional 460MJ worth of KE that the craft would have at the end of its run would mean the rest-of-the-universe would have 460MJ less than it did, and this is where this 'extra energy' has come from.

The argument is that, somehow, the 1W thruster has acted like a 'tap', rather than the water in the tap, and by running this thruster it has drawn out of the-rest-of-the-universe some of its KE. That is to say, when this thing operates, the gross KE of the craft and the rest-of-universe will be going up by 1W.

The idea is a bit like doing any sort of work in a heat cycle - e.g. a reverse cycle air conditioner can generate 2.5kW heat for a 1kW electrical input. When primary work is done, it can cause energy to shift from one reservoir to another in the 'wrong' thermodynamic way.

The problem with KE is that it is a 'primary' energy, not like 'heat' energy. The 760MJ of KE in posit 5 would be a genuine, 'readily convertible' energy in the original rest-frame, and if some fantastical mechanism were to be created that could really accelerate that craft to 760MJ with 300MJ expended then it would, indeed, be countering the modern understanding of thermodynamics.

If it could be done, then it would, indeed, be a means to create a device that can generate energy from 'nothing' (other than 'slowing down' the rest of the universe).

But this is a relatively trivial stretch of the imagination compared with an earlier dialogue in a thread (maybe this one) somewhere here - Paul has indicated that this system may not simply be a process of 'work' that is taking entropy from somewhere else in the universe, it may also be taking entropy from another time. This is way beyond any current argument that can possibly be made using known physics.

[GIThruster]

I guess it's hoping beyond all hope chris will honor his word and leave. This is the way trolls are.

I'll just note that Jim's book will be out in 12 days, and douchbags like chris will have their full opportunity to work out their misanthropic antics about physics being demonstrated in the lab at that time.

[chrismb]

Just one more thing to note; the first thread on this stuff was posted long before GIT signed up to this forum.

The first account/discussion of it was given in;

viewtopic.php?t=1488

It may be noted that skipjack and chrismb have never 'bad-mouthed' such devices in the way that GIT would like to suggest is directed at them.

There are ways to probe and question such devices using known scientific principles, and this was done in an inquisitive and appropriate manner.

However, GIT's pompous and acrimonious monologues only serve to make the idea look really stupid. This is not the fault of the experiments being done, because those experiments have everything to prove as they run contrary to known science, and the experimenters know that - but so long as there are people who wish to run that path for themselves then they can do as they wish. The trouble with this thread is that GIT has managed to make the idea sound so crackpot that his commentary inevitably leads the reader to consider the question 'why even bother to do the experiment'?? That is unfortunate, because it is good for folks like Paul M. to want to try out experiments that have no apparent hope of working, it's just bad for folks like GIT to be their cheerleaders!

[cuddihy]

So, which is the flawed premise, or are none of the premises flawed, In your opinion?

I believe premise #4 and how it is arrived at is entirely flawed. 1. It assumes a superconducting or non-waste heat-producing system (the experiments Woodward have done do not support this.) 2. It assumes perfect, linear M-E conversion of electrical power to thrust. There is insufficient evidence to support this as well.
Neither of my two points in any way contradict Woodward's claims-- it is your premise that is extending these assumptions beyond the evidence or claims of M-E proponents. The way to invalidate an extraordinary theory backed by experimental evidence is not to demand that theory also satisfy an even more extreme set of circumstances to be valid. That just proves you're not being objective.

Also, your objection at the end of premise #7 is flawed--the insistence that the 'inertial back reaction', or where the rest of the KE unaccounted for by your statements goes, is "into the rest of the universe" in a manner that violates principles of thermodynamics, is again well beyond what Woodward claims or ME experiments to date show. What manner the GI momentum transfers happen are not proposed. Again it is your extension beyond what Woodward claims (and in a manner not required by any known laws of physics) that is a self-refuting objection.

[quixote]

... momentum is indeed being harvested from the rest of the universe, which ultimately causes it to accelerate in its expansion.

The concept quoted has always confused me, and I wonder if someone might be able to explain it to me.

For the sake of argument, say the M-E thruster is taking momentum from the rest of the universe. Doesn't that mean that either the mass or the velocity of the FOAM is decreasing? If so, doesn't that imply that the acceleration of the universe would decrease, rather than increase? Or is the idea that whatever it is that's causing the acceleration would be able to work more effectively if those quantities decreased?

[cuddihy]

But this is a relatively trivial stretch of the imagination compared with an earlier dialogue in a thread (maybe this one) somewhere here - Paul has indicated that this system may not simply be a process of 'work' that is taking entropy from somewhere else in the universe, it may also be taking entropy from another time. This is way beyond any current argument that can possibly be made using known physics.

This statement, on the other hand, makes me think you haven't even read Woodward's original M-E derivation papers. The fundamental objection to Mach Effect is that it REQUIRES "time-travelling" GI forces in order to be consistent with SR. Woodward deals with it extensively in his writing and the fact that you don't appear to have a passing aquaintance with that fact suggests that you're arguing from a place of ignorance.

There is no known SR or GR objection to the space-time "time-travelling" nature of Mach Effect gravinertial forces. Only an instinctual one. I suggest you actually read Woodward's papers, they're actually quite well-written regardless of your conclusions of his math.

[93143]

@happyjack27: When I said "entropy", I meant what the poster I was responding to seemed to mean by it - the principle of nondecrease of entropy, which I also referred to as the "entropy condition". Known in continuum mechanics as the Clausius-Duhem inequality, as I recall.

It's not so much a fundamental law of physics as an emergent result thereof, that doesn't apply in all circumstances (as you noted yourself).