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#2520 by Rodal on 03 Feb, 2016 14:41
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If you re-distribute all the furniture inside the space station, to one corner of the space station, you will not produce self-acceleration of the space station.Dr. Rodal,
None of that is discussed. The relativistic equations for conservation of momentum are posed, treating the EM Drive as a lumped mass system, and then seeing what a change in speed implies for the change in mass in order to satisfy conservation of momentum. For conservation of momentum, it doesn't matter how the negative mass was produced, it is assumed that it can be produced somehow, and the consequences are explored. It is shown that the laws of physics are not violated, within the range of variables explored in the note.
I'm not quite sure I'm following this correctly, but, are you basically saying that you are producing a region of reduced mass at one end of the device while increasing the mass at the other end of the device, or are we talking about what could be a region of expanded space behind the device and a compressed area in front?
If this is a negative or educed mass situation, should there not be a pressure change in the immediate area of the actual negative mass? If so, this should be measurable in the pressure of the air column directly beneath the area of negative mass, should it not?
As to how one can have negative mass:
1) there has not been experimental confirmation of negative mass occurring naturally in the Universe and no experiments exist that have conclusively shown that negative mass can be produced artificially, to my knowledge.
2) Negative mass is a consistent theoretical concept that has been discussed by many physicists, most prominently starting with Bondi. Negative mass is allowed by the laws of physics.
3) As pointed out in my note, Minotti states that self-acceleration of the EM Drive if due to General Relativity theory with the scalar coupling field, implies negative mass. Lobo has discussed a number of other reaction-less propulsion that imply negative mass, and McCulloch's theory implies variable mass. Prof. Woodward's Mach Effect theory also discusses how negative mass can be produced. Ditto for Dr. White's theory.
So, I don't discuss how negative mass can be produced, but Minotti's paper gives a consistent theory of how a General Relativity theory with the scalar coupling field can indeed result in effective negative mass for the EM Drive.
Does it have to be negative mass? Could it be asymmetric mass instead (as determined by the frustum shape)? That would produce a falling effect as we feed energy into the system that would look like thrust to an outside observer. i.e. if you did this experiment with a tube, you'd get a spherical or tubular mass effect inside the cavity. With a frustum, you get a cone or teardrop shape.
You can re-distribute the mass inside the space station, or even throw it towards one corner so that it bounces off the walls and that still will not produce self-acceleration.
You can do that something like that in a boat, but not in space.
You can "swim" in space, according to General Relativity, but your stroke would be extremely small, of inter-atomic length. And one can show that such "swimming in space" preserves the location of mass in spacetime (which is not unique in curved spacetime) and respects conservation of momentum.
Under conservation of momentum and conservation of energy, for a mass to self-accelerate without the action of external forces or fields or ejecting mass, its total inertial mass has to decrease. -
#2521 by SeeShells on 03 Feb, 2016 14:47
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If you re-distribute all the furniture inside the space station, to one corner of the space station, you will not produce self-acceleration of the space station.Dr. Rodal,
None of that is discussed. The relativistic equations for conservation of momentum are posed, treating the EM Drive as a lumped mass system, and then seeing what a change in speed implies for the change in mass in order to satisfy conservation of momentum. For conservation of momentum, it doesn't matter how the negative mass was produced, it is assumed that it can be produced somehow, and the consequences are explored. It is shown that the laws of physics are not violated, within the range of variables explored in the note.
I'm not quite sure I'm following this correctly, but, are you basically saying that you are producing a region of reduced mass at one end of the device while increasing the mass at the other end of the device, or are we talking about what could be a region of expanded space behind the device and a compressed area in front?
If this is a negative or educed mass situation, should there not be a pressure change in the immediate area of the actual negative mass? If so, this should be measurable in the pressure of the air column directly beneath the area of negative mass, should it not?
As to how one can have negative mass:
1) there has not been experimental confirmation of negative mass occurring naturally in the Universe and no experiments exist that have conclusively shown that negative mass can be produced artificially, to my knowledge.
2) Negative mass is a consistent theoretical concept that has been discussed by many physicists, most prominently starting with Bondi. Negative mass is allowed by the laws of physics.
3) As pointed out in my note, Minotti states that self-acceleration of the EM Drive if due to General Relativity theory with the scalar coupling field, implies negative mass. Lobo has discussed a number of other reaction-less propulsion that imply negative mass, and McCulloch's theory implies variable mass. Prof. Woodward's Mach Effect theory also discusses how negative mass can be produced. Ditto for Dr. White's theory.
So, I don't discuss how negative mass can be produced, but Minotti's paper gives a consistent theory of how a General Relativity theory with the scalar coupling field can indeed result in effective negative mass for the EM Drive.
Does it have to be negative mass? Could it be asymmetric mass instead (as determined by the frustum shape)? That would produce a falling effect as we feed energy into the system that would look like thrust to an outside observer. i.e. if you did this experiment with a tube, you'd get a spherical or tubular mass effect inside the cavity. With a frustum, you get a cone or teardrop shape.
You can re-distribute the mass inside the space station, or even throw it towards one corner so that it bounces off the walls and that still will not produce self-acceleration.
If I'm an observer inside of the space station with all the junk piled up into one side of the ISS, I'll feel the slight attraction of that mass. If I'm in orbit around another mass the more massive part of the station with the junk pilled into it will want to point in the direction of the mass. Correct?
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#2522 by Rodal on 03 Feb, 2016 14:52
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...If I'm an observer inside of the space station with all the junk piled up into one side of the ISS, I'll feel the slight attraction of that mass. If I'm in orbit around another mass the more massive part of the station with the junk pilled into it will want to point in the direction of the mass. Correct?
An astronaut inside the space station cannot change the center of mass (location in space with respect to external observer locations) of the space station by re-arranging the furniture from one corner to another.
As the astronaut moves the furniture in the space station, the location (in space with respect to external observers) of the center of mass of the space station does not move. The center of mass location changes in relation to the geometry of the space station, but the location of the center of mass of the space station with respect to external observers in space does not change by his actions inside the space station.
Only an external force or field, can change the center of mass (location in space with respect to external observers) of the space station, otherwise one has to eject mass from the space station, to accelerate, effectively decreasing the mass of the spacecraft, as a rocket ejects propellant to move in space.
So, if you don't use an external force or field (like gravitational attraction from another object in space), you have to decrease the mass of the spacecraft to accelerate, whether you decrease the mass by ejecting propellant (the conventional way to accelerate in space) (or by ejecting ejecting photons, thus ejecting momentum and energy) or whether you decrease the mass by producing negative mass
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#2523 by CW on 03 Feb, 2016 15:21
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It's the same with rockets. The center of mass of the system (rocket+propellant) doesn't change, when the rocket speeds in +x and the propellant in -x . The center of mass never moves. Pretty basic, but interesting, when thinking about how a space probe can reach Pluto, by appropriately splitting its mass into two parts that fly in opposite directions. We should appreciate that more
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#2524 by SteveD on 03 Feb, 2016 15:25
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Variable mass, implying the need for negative mass to self-accelerate, addresses both conservation of momentum and it also addresses conservation of energy.
Energy is conserved, and such a propulsion device is not a free-energy machine, because the greater the speed, the lower the mass. More on that later...
(The practical problem of course is that up to now, nobody has found experimental evidence of negative mass )
How about observational evidence? Can you come up with a situation where negative mass must exist or some observed astronomical phenomena would break CoE? Perhaps something relating to light pressure and acceleration in a short lived but highly energetic resonant system? -
#2525 by SeeShells on 03 Feb, 2016 15:27
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...If I'm an observer inside of the space station with all the junk piled up into one side of the ISS, I'll feel the slight attraction of that mass. If I'm in orbit around another mass the more massive part of the station with the junk pilled into it will want to point in the direction of the mass. Correct?
An astronaut inside the space station cannot change the center of mass of the space station by re-arranging the furniture from one corner to another.
Only an external force or field, can change the center of mass of the space station, otherwise one has to eject mass from the space station, effectively decreasing the mass of the spacecraft, as a rocket ejects propellant to move in space.
That's not what I'm saying. Your correct the mass will remain the same.
I'm in the center of a 100M hollow ball floating in space that I have piled up 200 tons of rocks into one area against the wall. Just floating in the center of the sphere I'll feel the attraction of the mass of rocks and be drawn to it It's mass warps spacetime. If another mass comes close to my sphere it will feel the total spacetime distortion of my sphere but also the increased spacetime distortion of the rocks inside my sphere. My sphere with its rocks will rotate so the rocks will align to the other sphere. Spacetime is the one thing that permeates through the closed frames.
If we turn the rocks into captured photons.
http://physics.stackexchange.com/questions/10612/explain-how-or-if-a-box-full-of-photons-would-weigh-more-due-to-massless-photo
(quote)
The statement that photons are massless means that photons do not have rest mass. In particular, this means that, in units where c=1c=1, the magnitude of the photon 3-momentum must be equal to the total energy of the photons, rather than the standard relationship where m2=E2−p2m2=E2−p2.
But, you can create multi-photon systems where the net momentum is zero, since momentum adds as a vector. When you do this, however, since the energy of a non-bound state is always non-negative, the energies just add. So, this system looks just like the rest frame of a massive particle, which has energy associated with its mass and nothing else.
The statement about gravity is a little bit more subtle, but all photon states will interact with the gravitational field, thanks to the positive results of the light-bending observations that have been made over the past century. So you don't even need a construction like this to get photons "falling" in a gravitational field. (end)
I know you have done the calculations at one time Dr. Rodal and the effective mass increase is very minuscule but it has to happen.
added...
I heard the total mass converted to energy of the first atomic bomb was on the order of a dollar bill. The drive doesn't come close.
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#2526 by Rodal on 03 Feb, 2016 15:27
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It's the same with rockets. The center of mass of the system (rocket+propellant) doesn't change, when the rocket speeds in +x and the propellant in -x . The center of mass never moves. Pretty basic, but interesting, when thinking about how a space probe can reach Pluto, by appropriately splitting its mass into two parts that fly in opposite directions. We should appreciate that more
Great observation, which also applies to the "Photonic Laser Thruster". People get confused by the fact that the photonic laser thruster needs another ship to work, and the other ship moves in the opposite direction as the spacecraft as the result of the photonic laser thuster. .
So for a photonic laser thruster to work for interstellar travel one would need a huge infrastructure of other resource ships placed in space ahead of time !! (and the inventor of the photonic laser thruster discusses the need for such infrastructure )
(because the efficiency of the photonic laser thruster decreases with distance between the 2 ships, it needs a multitude of ships to travel interstellar) -
#2527 by rfmwguy on 03 Feb, 2016 15:31
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NSF-1701A 2016 testing update
Friends, supporters and followers, this morning @ 10:29 EST my Kickstarter project (to help offset costs on this year's testing) ended successfully! The amount pledged far exceeded my expectations and to those that helped I give you my sincere thanks!
There is only one thing left to say...this video link sent to me from one of my big supporters, Michael - Cheers!
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#2528 by Rodal on 03 Feb, 2016 15:36
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And I said that in my discussion of conservation of mass and conservation of energy...If I'm an observer inside of the space station with all the junk piled up into one side of the ISS, I'll feel the slight attraction of that mass. If I'm in orbit around another mass the more massive part of the station with the junk pilled into it will want to point in the direction of the mass. Correct?
An astronaut inside the space station cannot change the center of mass of the space station by re-arranging the furniture from one corner to another.
Only an external force or field, can change the center of mass of the space station, otherwise one has to eject mass from the space station, effectively decreasing the mass of the spacecraft, as a rocket ejects propellant to move in space.
That's not what I'm saying. Your correct the mass will remain the same. ...It's mass warps spacetime. ...
ShellI am not considering warping of spacetime
(why is it that I did not consider warping of spacetime? because of
1) the large amount of mass/energy necessary to warp spacetime
2) the much more complicated (nonlinear) equations involved when considering warping of spacetime
3) the conundrum that warping of spacetime may enable time travel to the past and hence produce problems of causality (hence Hawkings' prohibition of closed-loops)
)
I don't like to speculate as to what the consequences of warping spacetime would be without properly going through the mathematics of such speculations.
What I wrote considered relativistic conservation of momentum for a simple lumped mass object that self-accelerates or self-decelerates. -
#2529 by birchoff on 03 Feb, 2016 15:46
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CONSERVATION OF RELATIVISTIC MOMENTUM FOR REACTION-LESS PROPULSION THROUGH VARIABLE INERTIAL MASS
Minotti states that the weak energy condition (the condition that demands that the mass should be positive) is violated for the EM Drive in Minotti's theory.
Lobo and Visser's paper also states that the condition requiring positive mass is also violated in other models of propellant-less (reaction-less) forms of proposed space-propulsion.
McCulloch, also proposes that the EM Drive self-accelerates because radio frequency photons at the larger end have higher inertial mass, and therefore to conserve momentum in its reference frame, the cavity must move towards the narrow end.
This motivated me to analyze conservation of momentum for the EM Drive (or any such resonant cavity proposed for reaction-less propulsion) analyzed as a lumped-mass that is able to change its inertial mass. Thus, conservation of momentum of the EM Drive under these theories, would be satisfied, when duly taking into consideration the change in mass.
In this post in another thread: http://forum.nasaspaceflight.com/index.php?topic=39214.msg1486645#msg1486645, I analyze conservation of momentum for the case of negative mass, and for the case of variable increasing and decreasing mass.
I define momentum, using the relativistic definition of momentum.
The analysis shows that such a mode of space propulsion (reaction-less propulsion by variable mass) is quite limited on the speeds and changes in speed that it would be able to achieve.
No warping of spacetime is considered in the analysis, only a reactionless variable mass is considered.
Anyone know what minotti's theory would predict for the few DIY projects we have data for? -
#2530 by birchoff on 03 Feb, 2016 15:50
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Dr. Rodal,
None of that is discussed. The relativistic equations for conservation of momentum are posed, treating the EM Drive as a lumped mass system, and then seeing what a change in speed implies for the change in mass in order to satisfy conservation of momentum. For conservation of momentum, it doesn't matter how the negative mass was produced, it is assumed that it can be produced somehow, and the consequences are explored. It is shown that the laws of physics are not violated, within the range of variables explored in the note.
I'm not quite sure I'm following this correctly, but, are you basically saying that you are producing a region of reduced mass at one end of the device while increasing the mass at the other end of the device, or are we talking about what could be a region of expanded space behind the device and a compressed area in front?
If this is a negative or educed mass situation, should there not be a pressure change in the immediate area of the actual negative mass? If so, this should be measurable in the pressure of the air column directly beneath the area of negative mass, should it not?
As to how one can have negative mass:
1) there has not been experimental confirmation of negative mass occurring naturally in the Universe and no experiments exist that have conclusively shown that negative mass can be produced artificially, to my knowledge.
2) Negative mass is a consistent theoretical concept that has been discussed by many physicists, most prominently starting with Bondi. Negative mass is allowed by the laws of physics.
3) As pointed out in my note, Minotti states that self-acceleration of the EM Drive if due to General Relativity theory with the scalar coupling field, implies negative mass. Lobo has discussed a number of other reaction-less propulsion that imply negative mass, and McCulloch's theory implies variable mass. Prof. Woodward's Mach Effect theory also discusses how negative mass can be produced. Ditto for Dr. White's theory.
So, I don't discuss how negative mass can be produced, but Minotti's paper gives a consistent theory of how a General Relativity theory with the scalar coupling field can indeed result in effective negative mass for the EM Drive.
Are negative mass and negative energy density the same thing. Because I just skimmed through and did a word search in the referenced paper and no where does minotti say that the frustum generates negative mass. He talk about negative energy densities though. -
#2531 by Rodal on 03 Feb, 2016 15:55
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..
1) As I stated Minotti discusses the violation of the WEC, which is the same thing as non-positive mass !!!
Are negative mass and negative energy density the same thing. Because I just skimmed through and did a word search in the referenced paper and no where does minotti say that the frustum generates negative mass. He talk about negative energy densities though.
2) Minotti deals with General Relativity and in GR mass and energy are equivalent (E=mc^2 and the principle is conservation of momentum/energy). Negative mass -> negative energy -
#2532 by Rodal on 03 Feb, 2016 15:57
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...
Minotti's predicted force is pretty much consistent with Yang's and Shawyer's experiments. One cannot be too precise, and particular for DIY's !!! , because one does not know precisely what was the amount of forward power and Q present during the experiments (and in many how Q was measured was not shown in reports: Yang, etc.) and because Yang and Shawyer did not report all the dimensions of the EM Drive's tested.
Anyone know what minotti's theory would predict for the few DIY projects we have data for? -
#2533 by rfmwguy on 03 Feb, 2016 15:57
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I'd agree with you Doc except for one thing...the reported interferometer results by Dr White. Until that is proven to be a measurement error, it seems that a non-macro/micro stretching of spacetime (elongated laser path) occurred within an EM field. It does not appear to be controversial theory that EM can distort spacetime.
And I said that in my discussion of conservation of mass and conservation of energy I am not considering warping of spacetime...If I'm an observer inside of the space station with all the junk piled up into one side of the ISS, I'll feel the slight attraction of that mass. If I'm in orbit around another mass the more massive part of the station with the junk pilled into it will want to point in the direction of the mass. Correct?
An astronaut inside the space station cannot change the center of mass of the space station by re-arranging the furniture from one corner to another.
Only an external force or field, can change the center of mass of the space station, otherwise one has to eject mass from the space station, effectively decreasing the mass of the spacecraft, as a rocket ejects propellant to move in space.
That's not what I'm saying. Your correct the mass will remain the same. ...It's mass warps spacetime. ...
Shell
(why is it that I did not consider warping of spacetime? because of
1) the large amount of mass/energy necessary to warp spacetime
2) the much more complicated (nonlinear) equations involved when considering warping of spacetime
3) the conundrum that warping of spacetime may enable time travel to the past and hence produce problems of causality (hence Hawkings' prohibition of it)
)
I don't like to speculate as to what the consequences of warping spacetime would be without properly going through the mathematics of such speculations.
What I wrote was not based on speculation but it properly considers relativistic conservation of momentum for a lumped mass object.
What appears to be controversial is the amount of energy necessary to do so. Alcubierre invented negative mass/energy to make his warp drive formulas, but this is only one approach and there appear to be many over the years. What have we stumbled upon is perhaps my point.
Until we falsify the EW interferometer testing, I'm still betting a sixpack on this being the cause of the emdrive effect. I'll even bet Dogfishhead 120 min IPA (sorry 4 pack only)
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#2534 by Rodal on 03 Feb, 2016 15:59
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...
What is there to disagree with?
I'd agree with you Doc except for one thing...the reported interferometer results by Dr White. Until that is proven to be a measurement error, it seems that a non-macro/micro stretching of spacetime (elongated laser path) occurred within an EM field. It does not appear to be controversial theory that EM can distort spacetime.
What appears to be controversial is the amount of energy necessary to do so. Alcubierre invented negative mass/energy to make his warp drive formulas, but this is only one approach and there appear to be many over the years. What have we stumbled upon is perhaps my point.
Until we falsify the EW interferometer testing, I'm still betting a sixpack on this being the cause of the emdrive effect. I'll even bet Dogfishhead 120 min IPA (sorry 4 pack only)
When you stateQuoteIt does not appear to be controversial theory that EM can distort spacetime
where did I ever state that it was controversial?
Again, with moving red text, as you employedI am not considering warping of spacetime
Not mathematically considering warping of spacetime does not mean that one is saying that it is controversial.
Neither you or others in this thread have mathematically considered warping of spacetime either
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#2535 by glennfish on 03 Feb, 2016 16:03
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Well, E=MC2. So, at the absolute simplest, if we are feeding E into the cavity at some specific bandwidth, then M equivalency has to go up for the duration we're feeding energy into the thing [minus losses]. Right?
Well, if you could convert energy into mass, which isn't likely under the EM Drive modes, but assume you could, then if you have total conversion of a 1kw microwave oven output converted into mass, you would have a thrust equivalent if it's totally in one direction (another unlikely assumption) that would be about 1 X 10-9 newton/s, which would be awfully hard to measure... assuming I did the math correctly. -
#2536 by rfmwguy on 03 Feb, 2016 16:05
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Just noting that you haven't considered warped spacetime and hoping that you won't discount it on a scale somewhere between a macro and micro scale using EM fields....
What is there to disagree with?
I'd agree with you Doc except for one thing...the reported interferometer results by Dr White. Until that is proven to be a measurement error, it seems that a non-macro/micro stretching of spacetime (elongated laser path) occurred within an EM field. It does not appear to be controversial theory that EM can distort spacetime.
What appears to be controversial is the amount of energy necessary to do so. Alcubierre invented negative mass/energy to make his warp drive formulas, but this is only one approach and there appear to be many over the years. What have we stumbled upon is perhaps my point.
Until we falsify the EW interferometer testing, I'm still betting a sixpack on this being the cause of the emdrive effect. I'll even bet Dogfishhead 120 min IPA (sorry 4 pack only)
When you stateQuoteIt does not appear to be controversial theory that EM can distort spacetime
where did I ever state that it was controversial?
Not mathematically considering warping of spacetime does not mean that one is saying that it is controversial.
Neither you or others in this thread have mathematically considered warping of spacetime either
As far as me mathematically considering it...I need a new calculator
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#2537 by Rodal on 03 Feb, 2016 16:09
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...
Well, no, what you said is that you did not agree with something I never stated.
Just noting that you haven't considered warped spacetime and hoping that you won't discount it on a scale somewhere between a macro and micro scale using EM fields.
And concerning the fact that I did not consider warping of spacetime, I had previously stated that in multiple posts, even using moving red text to state it, so there is no need for you to note something that I stated multiple times, over and over again.
There is a huge number of things that you rfmwguy have not considered mathematically in your statements either, and I hope you are not discounting them either Geeeeeeeeeeeee
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#2538 by rfmwguy on 03 Feb, 2016 16:10
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I think you're spot on the math, Glenn. So now, we'll have to consider if all EM warping of spacetime involves a mass conversion...THAT is not in my wheelhouse, at least not yet.
Well, E=MC2. So, at the absolute simplest, if we are feeding E into the cavity at some specific bandwidth, then M equivalency has to go up for the duration we're feeding energy into the thing [minus losses]. Right?
Well, if you could convert energy into mass, which isn't likely under the EM Drive modes, but assume you could, then if you have total conversion of a 1kw microwave oven output converted into mass, you would have a thrust equivalent if it's totally in one direction (another unlikely assumption) that would be about 1 X 10-9 newton/s, which would be awfully hard to measure... assuming I did the math correctly. -
#2539 by Rodal on 03 Feb, 2016 16:28
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... Alcubierre invented negative mass/energy to make his warp drive formulas, but this is only one approach and there appear to be many over the years. ..
1) Alcubierre did not invent the concept of negative mass, which existed much prior to Alcubierre's discussion
2) For Alcubierre's warp drive, negative mass (negative energy) is a necessary (but not sufficient) condition.
3) Lobo and Visser have shown that negative mass (negative energy) is a necessary condition also for other reaction-less drives Ditto for Minotti's paper on the EM Drive. Dr. White and Prof. Woodward have also discussed negative mass (negative energy) for reaction-less drives.
4) Concerning the "other approaches" for reaction-less drives (not using external forces or fields and not ejecting mass or energy) please let us know of what other approaches you know of (*) which does not imply change in mass in order to satisfy conservation of momentum and conservation of energy.
_______________________________________
(*) besides Shawyer's "explanation" which is a non-starter , and besides "swimming in space through GR" which involves no change in the location of center of mass. The photonic laser thruster involves another spaceship moving in the opposite direction, so it does not qualify because it involves and external field. Ditto for solar propulsion, thethers, etc. which rely on external fields.
.
