Mach Effect progress

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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93143
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Post by 93143 »

GIThruster wrote:Accelerate at 1 gee half way and decelerate at 1 gee the second half of the trip. Time to the Moon is about 5 hours. To Mars at its furthest approach to Earth is 2 days. Jupiter is 7, Saturn is 9...

At the time when Paul and I did this, just after STAIF '06, Jim warned us that this needs a relativistic correction.
Huh. Half the Saturn run, 4.5 days at 9.80665 m/s², is about 1.3% of lightspeed. Pretty quick for in-system work, but not really relativistic (Lorentz factor of 1.00008). I wonder what he meant - perhaps something to do with the drive's operation?

GIThruster
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Post by GIThruster »

Could be. Point is, to really understand this stuff, you need a relativist.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

93143
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Post by 93143 »

That reminds me - sfuerst is complaining (again) about mass-energy dipoles being impossible in tensor GR; that the lowest-order arrangement possible is a quadrupole, and that this invalidates M-E.

Did that ever get a satisfactory public answer?

GIThruster
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Post by GIThruster »

I'm sure it did. Fuerst is just wrong. I could make a better explanation, but Jim doesn't want me arguing in his defense. He rightly recognizes there's no end to it. The contention is just wrong and any relativist ought to know this.
"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 »

State which line the error of premise occurs:
1) A 1 kg test thruster is subjected to a 1 W, 130 uN of thrust.
2) It accelerates for 10 years (call it 300 Ms) from a given rest frame at which it was at 0 m/s.
3) 300 MJ has been expended.
4) The test thruster is travelling at 39,000m/s (it'll have reached 3.6 bn miles by then ... a trip to Neptune!)
5) Its kinetic energy wrt the given rest frame is then 760 MJ, which is greater than the 300 MJ expended.

93143
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Joined: Fri Oct 19, 2007 7:51 pm

Post by 93143 »

It's (3).

Hint: Define "expended"...

You could in principle be describing a magsail.

chrismb
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Post by chrismb »

State which line the error of premise occurs:
1) A 1 kg test thruster is subjected to a 130 uN of thrust generated by a 'Mach thruster' driven by a nuclear thermal battery that has an output electronically governed to 1 W.
2) It accelerates for 10 years (call it 300 Ms) from a given rest frame at which it was at 0 m/s.
3) 300 MJ of electrical energy has been generated by the nuclear battery during the flight time.
4) The test thruster is travelling at 39,000m/s.
5) Its kinetic energy wrt the given rest frame is then 760 MJ, which is greater than the 300 MJ that the nuclear battery has put out.

tomclarke
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Post by tomclarke »

The issue is that to propel a rocket travelling at speed v+dv1 faster, exhaust is needed which is fired backward and therefore goes slower at speed v-dv2.

The kinetic energy total is therefore not larger than in the rest frame case, because the extra energy used in the rocket velocity Mr[(v+dv1)^2-v^2] is balanced by extra energy retrieved due to Me[(v^2 - (v-dv2)^2)] for the exhaust. The difference is the same as in the rest frame.
GIThruster wrote:Wel I appreciate Tom is lending a hand here. I wish I could understand all that he wrote. The issue with propellant is not however the issue.

Consider the example of a Hall thruster in space with 1 second of propellant aboard and traveling at 100,000 m/s. The thruster fires with the same thrust efficiency as the M-E thruster for one second. You get the same result.

There is obviously something wrong with the math.

Note that irrespective of V, dV is linear and dE is quadratic. This means that at any thrust efficiency, there is some V where anything producing constant thrust will appear to violate conservation, without regard for things like propellant, and since V is relative, using this method you can show any thruster is always in violation of conservation. There is something wrong with the math, and its got nothing to do with propellant.

cuddihy
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Post by cuddihy »

chrismb wrote:State which line the error of premise occurs:
1) A 1 kg test thruster is subjected to a 130 uN of thrust generated by a 'Mach thruster' driven by a nuclear thermal battery that has an output electronically governed to 1 W.
2) It accelerates for 10 years (call it 300 Ms) from a given rest frame at which it was at 0 m/s.
3) 300 MJ of electrical energy has been generated by the nuclear battery during the flight time.
4) The test thruster is travelling at 39,000m/s.
5) Its kinetic energy wrt the given rest frame is then 760 MJ, which is greater than the 300 MJ that the nuclear battery has put out.
How is it possible to assume #4? Wouldn't you need to test the coupling efficiency of an ME thruster? It hasn't been modeled yet.

Nobody knows what the thrust output of an ME thruster would be under continuous power input and various velocities, and besides you've assumed it to be a superconducting one.
Tom.Cuddihy

~~~~~~~~~~~~~~~~~~~~~
Faith is the foundation of reason.

chrismb
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Post by chrismb »

cuddihy wrote:"Faith is the foundation of reason."
That which he creates, so he destroys!!

chrismb wrote:State which line the error of premise occurs:
1) A 1 kg test thruster is subjected to a 130 uN of thrust generated by a 'Mach thruster' driven by a nuclear thermal battery that has an output electronically governed to 1 W.
2) It accelerates for 10 years (call it 300 Ms) from a given rest frame at which it was at 0 m/s.
3) 300 MJ of electrical energy has been generated by the nuclear battery during the flight time.
4) The test thruster is travelling at 39,000m/s.
5) Its kinetic energy wrt the given rest frame is then 760 MJ, which is greater than the 300 MJ that the nuclear battery has put out.
cuddihy wrote:How is it possible to assume #4? Wouldn't you need to test the coupling efficiency of an ME thruster? It hasn't been modeled yet.
If this is a statement to the effect that there is, as yet, no practical evidence to suppose that an ME thruster can cause any thrust on an unbound craft, then that would seem a suitable premise at which to point to a flaw in the logic.

Does Paul March agree this is the flawed premise to highlight, and that this pendant conclusion is a correct reflection on the state-of-art?

CaptainBeowulf
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Post by CaptainBeowulf »

Alright, I think I understand the accounting argument. The last two and a half pages seem to have shown that even when under continuous acceleration the M-E thruster energy books should balance because of the expenditure of power aboard the craft plus the acceleration of far off distant matter/the rest of the universe. In Chris' example 300MJ would have been generated by the on-board power supply and the remaining 420MJ would be the effect on the propellant/far off distant mass.

In the case of the Hall thruster expulsion of the propellant and the fact that said propellant ends up going slower than it was when it was in the propellant tank on the ship is where (for the observer's frame) the ship gets the extra kinetic energy. In the ship's own rest frame Newtonian rules still apply - it's burning energy, transferring that energy to propellant, and therefore being pushed faster.

Maybe I have this muddled still, but it seems to follow.

So, that brings out more clearly the comment about possible entropy issues someone made in passing a couple of pages ago. A naive or superficial look at the topics suggests that if you hooked the thruster up to a flywheel and used it to generate local power, that you would then be extracting power from (at least a large subset of) the distant universe at large to do work locally. It would appear that the energy density/temperature of the universe at large is lower than that of locally generated power from a flywheel used to do work. So, it appears that you can still draw power the "wrong way" along the energy gradient, or violate entropy.

Perhaps this remaining loophole is the closed by calculating instantaneous rest frames. Or, do we have a different explanation to stay in agreement with thermodynamics?

tomclarke
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Post by tomclarke »

Yes, entropy is a bad one - can't see how you get round it. It is also the most ineluctable of natural laws.
CaptainBeowulf wrote:Alright, I think I understand the accounting argument. The last two and a half pages seem to have shown that even when under continuous acceleration the M-E thruster energy books should balance because of the expenditure of power aboard the craft plus the acceleration of far off distant matter/the rest of the universe. In Chris' example 300MJ would have been generated by the on-board power supply and the remaining 420MJ would be the effect on the propellant/far off distant mass.

In the case of the Hall thruster expulsion of the propellant and the fact that said propellant ends up going slower than it was when it was in the propellant tank on the ship is where (for the observer's frame) the ship gets the extra kinetic energy. In the ship's own rest frame Newtonian rules still apply - it's burning energy, transferring that energy to propellant, and therefore being pushed faster.

Maybe I have this muddled still, but it seems to follow.

So, that brings out more clearly the comment about possible entropy issues someone made in passing a couple of pages ago. A naive or superficial look at the topics suggests that if you hooked the thruster up to a flywheel and used it to generate local power, that you would then be extracting power from (at least a large subset of) the distant universe at large to do work locally. It would appear that the energy density/temperature of the universe at large is lower than that of locally generated power from a flywheel used to do work. So, it appears that you can still draw power the "wrong way" along the energy gradient, or violate entropy.

Perhaps this remaining loophole is the closed by calculating instantaneous rest frames. Or, do we have a different explanation to stay in agreement with thermodynamics?

GIThruster
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Post by GIThruster »

CaptainBeowulf wrote:Perhaps this remaining loophole is the closed by calculating instantaneous rest frames. Or, do we have a different explanation to stay in agreement with thermodynamics?
They're different issues. To do the calculation correctly at any thrust efficiency, with M-E or another electric thruster, you need to use the tools of GR. In the case of an M-E thruster driven at or past wormhole condition where dm=>m, momentum is indeed being harvested from the rest of the universe, which ultimately causes it to accelerate in its expansion. For all we know, the observed acceleration of the universe could well be the results of prolific M-E technology in past, present and/or future.

All inertia derives from gravity acting in Wheeler-Feynman Absorber radiation reaction, which includes time symmetry, so causes now can have effects prior. Absorber theory is the only theory I know of that offers any explanation whatsoever of retro-causal effects. You'll find more on this in Jim's book due on shelves Dec. 24th. There's still time to pre-order and save:

http://www.amazon.com/Making-Starships- ... 1461456223
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

93143
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Joined: Fri Oct 19, 2007 7:51 pm

Post by 93143 »

chrismb wrote:State which line the error of premise occurs:
1) A 1 kg test thruster is subjected to a 130 uN of thrust generated by a 'Mach thruster' driven by a nuclear thermal battery that has an output electronically governed to 1 W.
2) It accelerates for 10 years (call it 300 Ms) from a given rest frame at which it was at 0 m/s.
3) 300 MJ of electrical energy has been generated by the nuclear battery during the flight time.
4) The test thruster is travelling at 39,000m/s.
5) Its kinetic energy wrt the given rest frame is then 760 MJ, which is greater than the 300 MJ that the nuclear battery has put out.
There's no error there, unless the assumption of uniform thrust/power ratio is incorrect (I suppose it could be).
CaptainBeowulf wrote:Alright, I think I understand the accounting argument. The last two and a half pages seem to have shown that even when under continuous acceleration the M-E thruster energy books should balance because of the expenditure of power aboard the craft plus the acceleration of far off distant matter/the rest of the universe. In Chris' example 300MJ would have been generated by the on-board power supply and the remaining 420MJ would be the effect on the propellant/far off distant mass.
Bingo! About time somebody got it...
chrismb wrote:
cuddihy wrote:How is it possible to assume #4? Wouldn't you need to test the coupling efficiency of an ME thruster? It hasn't been modeled yet.
If this is a statement to the effect that there is, as yet, no practical evidence to suppose that an ME thruster can cause any thrust on an unbound craft, then that would seem a suitable premise at which to point to a flaw in the logic.

Does Paul March agree this is the flawed premise to highlight, and that this pendant conclusion is a correct reflection on the state-of-art?
I'm pretty sure he doesn't. The evidence reported thus far seems to indicate that the effect is real. It shows the expected behaviour based on the recent high-accuracy thrust prediction derivation, it shows the correct voltage scaling at the correct harmonic in the correct direction in the rotator experiment, and the current relatively poor data quality (in terms of reproducibility of resonance conditions, scaling studies, etc.) is entirely explained by the fact that it's basically a garage experiment, at least in terms of funding level and institutional availability of electrical engineering expertise. But it's a garage experiment that has (by all accounts) been through an extremely rigorous program of elimination and/or ruling out of potential sources of error.

I'm not totally satisfied yet, but what I've heard so far is encouraging, and unless you're using words differently than I am, I believe it easily qualifies as "practical evidence" on which a supposition could be based. Certainly I've seen nothing to indicate that further experimentation isn't the best way to find out for sure whether Woodward is right or not.

[I have, admittedly, been too wrapped up in my research to really dig into this stuff; it's possible there's some obvious flaw that I just don't know about, but Woodward's theory is peer-reviewed, and you'd think the peer review process would have caught something like that by now...]
tomclarke wrote: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.

paulmarch
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Post by paulmarch »

93143 wrote:
chrismb wrote:State which line the error of premise occurs:
1) A 1 kg test thruster is subjected to a 130 uN of thrust generated by a 'Mach thruster' driven by a nuclear thermal battery that has an output electronically governed to 1 W.
2) It accelerates for 10 years (call it 300 Ms) from a given rest frame at which it was at 0 m/s.
3) 300 MJ of electrical energy has been generated by the nuclear battery during the flight time.
4) The test thruster is travelling at 39,000m/s.
5) Its kinetic energy wrt the given rest frame is then 760 MJ, which is greater than the 300 MJ that the nuclear battery has put out.
There's no error there, unless the assumption of uniform thrust/power ratio is incorrect (I suppose it could be).
CaptainBeowulf wrote:Alright, I think I understand the accounting argument. The last two and a half pages seem to have shown that even when under continuous acceleration the M-E thruster energy books should balance because of the expenditure of power aboard the craft plus the acceleration of far off distant matter/the rest of the universe. In Chris' example 300MJ would have been generated by the on-board power supply and the remaining 420MJ would be the effect on the propellant/far off distant mass.
Bingo! About time somebody got it...
chrismb wrote:
cuddihy wrote:How is it possible to assume #4? Wouldn't you need to test the coupling efficiency of an ME thruster? It hasn't been modeled yet.
If this is a statement to the effect that there is, as yet, no practical evidence to suppose that an ME thruster can cause any thrust on an unbound craft, then that would seem a suitable premise at which to point to a flaw in the logic.

Does Paul March agree this is the flawed premise to highlight, and that this pendant conclusion is a correct reflection on the state-of-art?
I'm pretty sure he doesn't. The evidence reported thus far seems to indicate that the effect is real. It shows the expected behaviour based on the recent high-accuracy thrust prediction derivation, it shows the correct voltage scaling at the correct harmonic in the correct direction in the rotator experiment, and the current relatively poor data quality (in terms of reproducibility of resonance conditions, scaling studies, etc.) is entirely explained by the fact that it's basically a garage experiment, at least in terms of funding level and institutional availability of electrical engineering expertise. But it's a garage experiment that has (by all accounts) been through an extremely rigorous program of elimination and/or ruling out of potential sources of error.

I'm not totally satisfied yet, but what I've heard so far is encouraging, and unless you're using words differently than I am, I believe it easily qualifies as "practical evidence" on which a supposition could be based. Certainly I've seen nothing to indicate that further experimentation isn't the best way to find out for sure whether Woodward is right or not.

[I have, admittedly, been too wrapped up in my research to really dig into this stuff; it's possible there's some obvious flaw that I just don't know about, but Woodward's theory is peer-reviewed, and you'd think the peer review process would have caught something like that by now...]
tomclarke wrote: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.
All:

"If this is a statement to the effect that there is, as yet, no practical evidence to suppose that an ME thruster can cause any thrust on an unbound craft, then that would seem a suitable premise at which to point to a flaw in the logic.

Does Paul March agree this is the flawed premise to highlight, and that this pendant conclusion is a correct reflection on the state-of-art?"

No I do not. Woodward's torque pendulum results indicate that his M-E thrusters should work like any rocket in free space. And as 93143 has indicated the solution to the energy and mometum conservation problem for any "propellantless" propulsion device revolves around how you treat the thruster's back-reaction forces on either the rest of the mass of the universe via the cosmological gravity & inertial (G/I) field, or just the G/I field itself in the case of White's Q-Thrusters.

Best,
Paul March
Friendswood, TX

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