Author Topic: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive  (Read 195642 times)

Offline rfmwguy

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #380 on: 05/05/2015 12:10 AM »
I'm starting to believe COM, linear and angular, is no longer the brick wall I once thought, especially in the quantum realm:

http://arxiv.org/abs/0803.2811

...from Cornell, and other sources regarding "Transmutation of Momentum"

Way over my humble head: "Transmutation methods are developed for equations of the form x2 φ“ + x2(k2” - q̃(x)) φ = (v2 - (1/4)) φ, with v as spectral variable, which correspond to problems in quantum scattering theory at fixed energy k2 (here v ˜ l + (1/2) with l complex angular momentum). Spectral formulas for transmutation kernels are constructed and the machinery of transmutation theory developed by the author for spectral variable k is shown to have a version here. General Kontrorovič-Lebedev theorems are also proved."

Transmutation via the momentum plane

R. Carroll andD. S. Jones Communicater
Article first published online: 6 JUN 2011
DOI: 10.1002/mma.1670060129
Copyright © 1984 John Wiley & Sons, Ltd


Offline PushHigher

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #381 on: 05/05/2015 01:13 AM »
Gravity certainly conserves momentum.

When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

PPNL

I think you answered your own question here.  Assuming the EM drive can create a gravity gradient, the created gravity well extends to infinity via inverse square law.  It is essentially tugging at whatever is in front of it.  The reason it tugs harder toward the front rather than the back is due to the front having a larger more shallow gravity well than the one in the back - the larger one wins by virtue of being closer. 

« Last Edit: 05/05/2015 01:39 AM by PushHigher »

Offline ppnl

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #382 on: 05/05/2015 02:21 AM »
Gravity certainly conserves momentum.

When I drop a brick it falls to the earth. But the earth also falls toward it. True, by only a tiny amount but multiplied by the huge mass of the earth and it gains as much momentum as the brick and in the opposite direction.

PPNL

I think you answered your own question here.  Assuming the EM drive can create a gravity gradient, the created gravity well extends to infinity via inverse square law.  It is essentially tugging at whatever is in front of it.  The reason it tugs harder toward the front rather than the back is due to the front having a larger more shallow gravity well than the one in the back - the larger one wins. 



Well understand that I seriously doubt that any gravitational field is being generated here. You want to theorize that it is? I think the theoretical problems with artificial gravity are massive. But fine we can leave it to the experimentalists for now.

If it is tugging at whatever is in front then that thing will move and that will balance momentum. We don't have to talk about unbalanced momentum in the device or worry about GR at all. That whole discussion becomes pointless.

Now if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.

Now I could propose that the amount of power needed to generate a gravitational field depends on the motion of what that field is pulling on. That seems reasonable even in the absence of any mechanism. But the absence of a credible mechanism creates serious doubt.

I said long ago that if you had a mechanism to react against the local gravitational gradient then you could solve both COM violations and COE violations. But there is no reason to suspect there is any mechanism to do that. And it is in stark disagreement with what Shawyer claims is happening - this drive would be far more useful. It really would be kinda like sailing.

You want to claim that the EMdrive is doing this? Fine, but lets end this nonsense of claiming that this or that theory does not violate COM when it obviously does.

And given a choice of owning the patten on the drive and owning next weeks lotto ticket I will choose the lotto ticket. Much much better odds.

Offline PushHigher

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #383 on: 05/05/2015 03:01 AM »
Now if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.

Thanks for your response

No, from what I'm reading - constant input energy does lead to a sub-C speed barrier.  What I visualize is happening is that as drive accelerates the shape of the frustum becomes more cylindrical until it is and there is no gravity gradient and therefore no more acceleration.

I cannot attest to Shawyers statements nor prove that a gravity gradient is being created.  I agree this is all conjecture at this point.


Offline ppnl

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #384 on: 05/05/2015 03:22 AM »
Now if constant power input generates a constant gravity then acceleration will be constant. That leads to a violation of conservation of energy. Oops.

Thanks for your response

No, from what I'm reading - constant input energy does lead to a sub-C speed barrier.  What I visualize is happening is that as drive accelerates the shape of the frustum becomes more cylindrical until it is and there is no gravity gradient and therefore no more acceleration.

I cannot attest to Shawyers statements nor prove that a gravity gradient is being created.  I agree this is all conjecture at this point.

No I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.


Offline whoster69

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #385 on: 05/05/2015 03:42 AM »
I just found you guys.  I can't say this enough, THANK YOU!  I am so excited I don't think I can sleep tonight!  I can't wait to hear more!

Offline sanman

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #386 on: 05/05/2015 04:27 AM »
If EMdrive becomes a sufficiently huge issue in the public eye, then couldn't Mythbusters be called in to spend some money on proving or disproving it? Or are they not professional enough?


Offline tchernik

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #387 on: 05/05/2015 04:36 AM »
If EMdrive becomes a sufficiently huge issue in the public eye, then couldn't Mythbusters be called in to spend some money on proving or disproving it? Or are they not professional enough?


I doubt they will be interested in anything that doesn't explode, breaks or ends up flying away.

And the initial Emdrive tests would hardly have enough force to push a sheet of paper.

Offline PushHigher

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #388 on: 05/05/2015 04:55 AM »
No I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.

I haven't read anything regarding frame reference problems, I'll look into that - thanks for the tip.

« Last Edit: 05/05/2015 04:56 AM by PushHigher »

Offline ppnl

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #389 on: 05/05/2015 06:16 AM »
I'm starting to believe COM, linear and angular, is no longer the brick wall I once thought, especially in the quantum realm:

http://arxiv.org/abs/0803.2811

...from Cornell, and other sources regarding "Transmutation of Momentum"

Way over my humble head: "Transmutation methods are developed for equations of the form x2 φ“ + x2(k2” - q̃(x)) φ = (v2 - (1/4)) φ, with v as spectral variable, which correspond to problems in quantum scattering theory at fixed energy k2 (here v ˜ l + (1/2) with l complex angular momentum). Spectral formulas for transmutation kernels are constructed and the machinery of transmutation theory developed by the author for spectral variable k is shown to have a version here. General Kontrorovič-Lebedev theorems are also proved."

Transmutation via the momentum plane

R. Carroll andD. S. Jones Communicater
Article first published online: 6 JUN 2011
DOI: 10.1002/mma.1670060129
Copyright © 1984 John Wiley & Sons, Ltd

Quantum mechanics can violate conservation of momentum locally but not globally. To see how this works consider the experiments that demonstrated the violation of Bell's inequality. The local measurement of a particle on one end is ruled by probability and can be anything. But when you connect that measurement to the measurement of its entangled twin they must match. That matching is driven exactly by the need to conserve angular momentum. It will do so even if it has to apparently cheat by violating Bell's inequality.

In the matrix mechanics formulation of quantum mechanics that conservation of momentum is built in at the ground level. In fact all the classical conservation laws are built in. In fact all of Newtonian and classical physics is built in on the classical limit. In the wave mechanics formulation it was less clear that conservation of momentum was preserved. It turned out that the two formulations were equivalent.

So if you want quantum mechanics to violate momentum conservation you are out of luck. It is like squaring the circle or trisecting the angle. The math just will not allow it. 

Offline alexterrell

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #390 on: 05/05/2015 06:51 AM »
But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.



You get back to the perfect EM-Drive machine:

Electrical Energy in = Delta Kinetic Energy + Delta Gravitational Energy.

Which means that a chemically powered "Perfect" EM Drive cannot reach orbit* (Required: about 30MJ/kg)  . It can however levitate to 100km altitude (Required: about 1MJ/kg - and atmospheric oxygen can be used for the first 50km), where upon solar panels can accelerate it to where ever.

*Unless it dumps its fuel-product overboard like a normal rocket. So a fuel cell, then dump the water product away. In this case, a rocket-equation can apply, and I'm not sure if the device is that much better than a fully reusable single stage to orbit rocket.
« Last Edit: 05/05/2015 06:52 AM by alexterrell »

Offline CW

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #391 on: 05/05/2015 11:26 AM »
But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.



You get back to the perfect EM-Drive machine:

Electrical Energy in = Delta Kinetic Energy + Delta Gravitational Energy.

Which means that a chemically powered "Perfect" EM Drive cannot reach orbit* (Required: about 30MJ/kg)  . It can however levitate to 100km altitude (Required: about 1MJ/kg - and atmospheric oxygen can be used for the first 50km), where upon solar panels can accelerate it to where ever.

*Unless it dumps its fuel-product overboard like a normal rocket. So a fuel cell, then dump the water product away. In this case, a rocket-equation can apply, and I'm not sure if the device is that much better than a fully reusable single stage to orbit rocket.

And here I thought that the whole purpose of an EM-drive was to do away with anything chemical needed for propulsion..
;)
« Last Edit: 05/05/2015 11:29 AM by CW »
Reality is weirder than fiction

Offline sghill

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #392 on: 05/05/2015 01:37 PM »
From the article: "Mr. Joosten and Dr. White stated that “a one-way, non-decelerating trip to Alpha Centauri under a constant one milli-g acceleration” from an EM drive would result in an arrival speed of 9.4 percent the speed of light and result in a total transit time from Earth to Alpha Centauri of just 92 years."

I just want to point out that if Pioneer 10 had been an EM Drive equipped probe (with appropriate power source) when it was launched in March 1972, it would be just shy of being half-way to Alpha Centauri right now! (about 47%)

There are plenty of readers on this forum who remember when it was launched.

For those who don't know, Pioneer 10 was the first man-made object to achieve solar escape velocity.

Bring the thunder Elon!

Offline LasJayhawk

So rather than delve into any known physics, I decided to look at this with a "clean sheet" approach and see if I could find rhyme or reason in any of this:


2) here are some tests by Eagleworks and the thrust per watt.

A) 1932.6 MHz 5.4 uN/W
 B) 1936.7 MHz 3.0 uN/W
C) 1880.4 MHz 21.3 uN/W
D) 2168 MHz no thrust detected, cause thought to be the lack of the dielectric resonator.

And the China tests at 2.45 (2.457 seemed to be peak) with a dirty source and they got a lot of thrust as well.



1. D and the China test had no dielectric resonator, so it doesn't seem to be an absolute requirement.
2.  The China test used a dirty fat wide harmonically filled signal. Paul M. Also observed that with FM and AM on his signal provided more thrust. That made me wonder if there was a pattern to the harmonics effecting the operation of the drive. It seems there is....

The only test that provided no thrust is the only test that did not have an odd harmonic close to 160.2 GHz, the others did. Between A and B, more thrust per watt was provided by the unit at a lower Q but the harmonic was closer.

I find it somewhat perplexing, but there seems to be some relationship between the drives operation and the peak of the CMBR. But I have a very limited data set to work with. :'( It may be a tenuous connection at best, but it might provide some insight to what is going on.

If there is some connection, tests at 1884.7, 1907.1, and 1930.1 MHz would be useful, as well as 2464 MHz with a dirty magnetron.

Offline RonM

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #394 on: 05/05/2015 04:14 PM »
If EMdrive becomes a sufficiently huge issue in the public eye, then couldn't Mythbusters be called in to spend some money on proving or disproving it? Or are they not professional enough?

I doubt they would do it, but if they did the Mythbusters would go large.

Instead of some puny magnetron out of a microwave oven, the Mythbusters would use one out of a surplus radar system. The bigger the better. Then they would crank it up until molten copper started spewing out of the thing and there's your thrust!  :)

Offline Star One

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #395 on: 05/05/2015 05:27 PM »
There's an article on the Extreme Tech website now about this which is probably the best I've seen on a general tech/science website, not that this is saying much considering the low standard of most of the articles.
« Last Edit: 05/05/2015 05:28 PM by Star One »

Offline Hanelyp

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #396 on: 05/05/2015 05:43 PM »
The Mythbusters, despite being the best regular demonstration of scientific method in popular media, don't generally operate to the necessary precision to properly review EMdrive.

Offline JasonAW3

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #397 on: 05/05/2015 06:24 PM »
No I'm not talking about speed of light problems. I'm simply pointing out that it should take four times as much energy to go twice as fast. But if the power needed to generate the gravity is constant then it only takes twice as much energy to go twice as fast. That would violate conservation of energy. But if the power needed to generate the gravitational field depended on the velocity of what it was pulling on then you can have conservation of momentum, conservation of energy and do away with the frame dependence problem. Perfect hat trick.

I haven't read anything regarding frame reference problems, I'll look into that - thanks for the tip.

That's actually a very good point.  If space is being expanded behind and contracted in front of a craft, the "faster" one would go, likely would require exponentially more power as more space is compressed behind the craft and space is being expanded much further out to achieve the effective velocities.  It would almost seem that something like the "Cube Square Law" when it comes to the volume of space affected, should apply here.

     On the other hand, if it is a constant volume of space being expanded and compressed, but at a higher cyclic rate, then the power requirements would still increase, but likely at a pretty much linear rate.  Or so it would seem.
My God!  It's full of universes!

Offline masonke

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #398 on: 05/05/2015 06:55 PM »
Chris I read that the confirmation of the EM Drive also helps to validate to possibility of a WARP DRIVE from Dr. White.

Is this TRUE?

Offline Mulletron

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Re: FEATURE ARTICLE: Evaluating NASA's Futuristic EM Drive
« Reply #399 on: 05/05/2015 07:14 PM »
No. Vastly different orders of magnitude.
Challenge your preconceptions, or they will challenge you. - Velik

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