Need to get the basics well understood before engaging the pathway to explain how and why the EmDrive works and is not in violation of Newton's Laws nor CofM nor CofE.
Need to get the basics well understood before engaging the pathway to explain how and why the EmDrive works and is not in violation of Newton's Laws nor CofM nor CofE.
I agree it's good to understand the basics.
To check for conservation of momentum, simply add up the momentum vectors of all the components of your system before it starts, then run it for a while (say long enough for the EmDrive to get well on its way to Pluto), then turn the EmDrive off. Now, add up the momentum of all the components in the entire system again. Those two measurements should be exactly equal to each other in all frames of reference. If they aren't, then either you've violated conservation of momentum, or you've messed up your math, or you've left something out.
For a chemical rocket, beginners sometimes leave out the momenta of all the exhaust particles that the rocket has shot out the back. When you add all of that together (this is literally the source of the rocket equation, by the way), you get that the center of mass of the rocket/propellant system remains exactly where it started when you fired the rocket (in its initial rest frame). That is true of ALL systems that obey Newton's laws. The center of mass of the entire system doesn't change in velocity.
For the EmDrive, where is the term that cancels out the momentum of the spaceship going to Pluto? There is no exhaust and the microwave photons are all absorbed by the inside of the EmDrive cavity after it is turned off so it can't be them. (That's why many physicists are trying to think what terms might have been left out, i.e. an interaction with an external field of some sort, to explain the observations.) The EmDrive as Shawyer explains it clearly doesn't conserve momentum as Shawyer has no exhaust and does not invoke any external field.
What mass or energy (photons also have momentum) move in the opposite direction of the EmDrive after it's turned off? The power expended, mode, design factor, etc. do not affect the problem. It doesn't matter what the EmDrive does when it's running. We're just looking at the starting point when it is off and the ending point when it is also off but still moving.
How does the EmDrive conserve momentum?
This is the basic question and so far Shawyer's answer is not right.
If what you meant to say is that the force decreases with time then you have to note:
1. Still doesn't make sense because the RF source is moving with the cavity.
2. You have to redo the previous calculations accounting for variable thrust.
3. Since it magically resets if you pulse the RF, doing so clearly results in the same energy conservation problems. Energy flow from the battery and kinetic energy gain both only happen with RF on, so while you will travel farther, and it will take twice as long (assuming 50% duty cycle) to reach the same velocity, the same battery power will be spent and same kinetic energy gained, so still an energy generator....
So yes as acceleration time increases, increasing the KE draw down, the force reduces.
No OU during acceleration.
gargoyle99,
if these arguments were clear there would be more agreement. IMO, if the emdrive works as Shawyer claims then it will disprove the notion that kinetic energy is gained in proportion to the square of the velocity from the launch point and discussion on the subject of the conservation of energy can proceed with the understanding that energy of motion must be relative. Shawyer may well be right, and his experiment is the only one that can prove it one way or the other. IMO.
Guys,
There is one universal equation that defines the work that is needed to be done to move a mass a distance over a time by a force.
It matters not if the propulsion tech is a
Chem rocket.
Ion drive.
Solar sail powered by the sun or a laser.
Photon rocket.
MEGA drive.
EmDrive.
Phil
Need to get the basics well understood before engaging the pathway to explain how and why the EmDrive works and is not in violation of Newton's Laws nor CofM nor CofE.
I agree it's good to understand the basics.
To check for conservation of momentum, simply add up the momentum vectors of all the components of your system before it starts, then run it for a while (say long enough for the EmDrive to get well on its way to Pluto), then turn the EmDrive off. Now, add up the momentum of all the components in the entire system again. Those two measurements should be exactly equal to each other in all frames of reference. If they aren't, then either you've violated conservation of momentum, or you've messed up your math, or you've left something out.
For a chemical rocket, beginners sometimes leave out the momenta of all the exhaust particles that the rocket has shot out the back. When you add all of that together (this is literally the source of the rocket equation, by the way), you get that the center of mass of the rocket/propellant system remains exactly where it started when you fired the rocket (in its initial rest frame). That is true of ALL systems that obey Newton's laws. The center of mass of the entire system doesn't change in velocity.
For the EmDrive, where is the term that cancels out the momentum of the spaceship going to Pluto? There is no exhaust and the microwave photons are all absorbed by the inside of the EmDrive cavity after it is turned off so it can't be them. (That's why many physicists are trying to think what terms might have been left out, i.e. an interaction with an external field of some sort, to explain the observations.) The EmDrive as Shawyer explains it clearly doesn't conserve momentum as Shawyer has no exhaust and does not invoke any external field.
What mass or energy (photons also have momentum) move in the opposite direction of the EmDrive after it's turned off? The power expended, mode, design factor, etc. do not affect the problem. It doesn't matter what the EmDrive does when it's running. We're just looking at the starting point when it is off and the ending point when it is also off but still moving.
How does the EmDrive conserve momentum?
This is the basic question and so far Shawyer's answer is not right.gargoyle99,
if these arguments were clear there would be more agreement. IMO, if the emdrive works as Shawyer claims then it will disprove the notion that kinetic energy is gained in proportion to the square of the velocity from the launch point and discussion on the subject of the conservation of energy can proceed with the understanding that energy of motion must be relative. Shawyer may well be right, and his experiment is the only one that can prove it one way or the other. IMO.
It's a great concept for local travel where you have a mirror to reflect between and to show even photons can beat the photon rocket paradigm. Are you suggesting the EMDrive creates a virtual mirror?
No not at all.
I linked the video as proof that bouncing photons between reflecting mirrors increases the radiation pressure on the moving mirror to be very much more than 3.3uN/kW.
You see there are still those that believe any force greater than 3.3uN/kW, photon rocket force, is not possible and would be OU.
This explains why force or end plate radiation pressure increases as cavity Q increases as with increasing cavity Q there are increasing photon end plate impact events.
Need to get the basics well understood before engaging the pathway to explain how and why the EmDrive works and is not in violation of Newton's Laws nor CofM nor CofE.
To be crystal clear, the issue is if the EMDrive works as Shawyer claims, not if the EMDrive works.
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My main concern is that our Chinese friends have gone quiet. After all the buzz surrounding their secret testing and supposed space test there has not been a single word from them. Either their government put a halt on discussing the subject or people have lost interest. Both are detrimental to experimental progress and future cubesat missions. We need to push for more international LEO testing campaigns or something tangible since it seems that all theory discussion for the entire summer has not made any headway (no interesting calculations or continuation of Warptech's thrust equation). Even Peter Lauwer, who seemed to have a solid experimental setup, has gone quiet.
Still stuck on CoE and laser thrusters? Seriously? These are the oldest most worn out lines of thought and areas to debate. It almost seems like some are chatting for the sake of posting something, not contributing something new. Let's please move back to a higher level discussion involving the wide variety of actually new and relevant research and theory from Estes and Eagleworks and including peer reviewed sources fully compliant with the standard model or string theory. For example let's consider that we can now create two dimensional complicated floquet time crystals. You can start to see how a cavity lined with these may break causality for resonant particles within. Or rather that is the question: is it possible to create a macroscopic region of space with complex time... even a time machine based on the boundary conditions*? https://m.phys.org/news/2017-08-unconventional-quantum-optical-devices.html
In other research a tunable mode-based transparent metamaterial has been created allowing for a potential feedback system activating and automatically transmitting resonant waves above and below desired frequencies. This is huge for removing noise from the cavity and rejecting splatter if designed correctly and with well placed sensors, or even program the response profile into the material itself by using empirically determined eigenmode values and detected boundary incoming waveforms. http://www.sciencedirect.com/science/article/pii/S0030401817300652
Alternatively we could hypothesize about which metamaterials and permittivity would lead to the highest Q factor. There are exotic options such as near zero permittivity or time varying permittivity or even layered varying permittivity values (such as with silica wafers which can lead to lovely waveform variations depending on the metamterial. We are at the forefront of a brave new world of quantum optics and metamaterial research, why not increase the gain and tweak the properties of light which we desire in order to begin disproving theories of operation and improving thrust?
*see here also smolyaninov's old papers on symmetry breaking at negative refraction index and consider relativistic resonant electrons
"Either their government put a halt on discussing the subject or people have lost interest."
None of them. It is the third case: Test failed.
"Either their government put a halt on discussing the subject or people have lost interest."
None of them. It is the third case: Test failed.
Is that a reasonable guess, or something that's been confirmed?
"Either their government put a halt on discussing the subject or people have lost interest."
None of them. It is the third case: Test failed.
I would assume that if the test was successful (even it was not wildly successful, but showed promise) the Chinese government would either go silent, or claim the test was a failure. I'm sure the US (or pretty much any other military power) would do the same.
No offense, but since TT keeps defending Shawyer no matter what, I won't pay any attention of any kind beyond this post to whatevs TT says, till either Shawyers' flying cars are proved, or TT comes to better senses. Enough of nonsense.
I would assume that if the test was successful (even it was not wildly successful, but showed promise) the Chinese government would either go silent, or claim the test was a failure. I'm sure the US (or pretty much any other military power) would do the same.
The logic here is amusing. The claim boils down to that there are two ways to tell if a test was a success - firstly, if it was announced as a success, and secondly, if it was announced as a failure!
To be crystal clear, the issue is if the EMDrive works as Shawyer claims, not if the EMDrive works.To be even more crystal clear-er, there are only indications that the EMDrive might work, but we have yet to see it confirmed by 3rd party experiments....
There is nothing confirmed...yet...
We have yet to see tests where, by noise elimination, we have no answer except then to say "it works...".
The tests so far still carry a lot of thermal/other noise residual, but DO show some promise...
All what is needed is to keep improving the tests so there is no doubt left to where the force signal is coming from...
So...from what I've been seeing, I still have to be convinced, but at the same time I've seen things that make me hopeful....
My main concern is that our Chinese friends have gone quiet. After all the buzz surrounding their secret testing and supposed space test there has not been a single word from them. Either their government put a halt on discussing the subject or people have lost interest. Both are detrimental to experimental progress and future cubesat missions. We need to push for more international LEO testing campaigns or something tangible since it seems that all theory discussion for the entire summer has not made any headway (no interesting calculations or continuation of Warptech's thrust equation). Even Peter Lauwer, who seemed to have a solid experimental setup, has gone quiet.
Still stuck on CoE and laser thrusters? Seriously? These are the oldest most worn out lines of thought and areas to debate. It almost seems like some are chatting for the sake of posting something, not contributing something new. Let's please move back to a higher level discussion involving the wide variety of actually new and relevant research and theory from Estes and Eagleworks and including peer reviewed sources fully compliant with the standard model or string theory. For example let's consider that we can now create two dimensional complicated floquet time crystals. You can start to see how a cavity lined with these may break causality for resonant particles within. Or rather that is the question: is it possible to create a macroscopic region of space with complex time... even a time machine based on the boundary conditions*? https://m.phys.org/news/2017-08-unconventional-quantum-optical-devices.html
In other research a tunable mode-based transparent metamaterial has been created allowing for a potential feedback system activating and automatically transmitting resonant waves above and below desired frequencies. This is huge for removing noise from the cavity and rejecting splatter if designed correctly and with well placed sensors, or even program the response profile into the material itself by using empirically determined eigenmode values and detected boundary incoming waveforms. http://www.sciencedirect.com/science/article/pii/S0030401817300652
Alternatively we could hypothesize about which metamaterials and permittivity would lead to the highest Q factor. There are exotic options such as near zero permittivity or time varying permittivity or even layered varying permittivity values (such as with silica wafers which can lead to lovely waveform variations depending on the metamterial. We are at the forefront of a brave new world of quantum optics and metamaterial research, why not increase the gain and tweak the properties of light which we desire in order to begin disproving theories of operation and improving thrust?
*see here also smolyaninov's old papers on symmetry breaking at negative refraction index and consider relativistic resonant electrons
"Either their government put a halt on discussing the subject or people have lost interest."
None of them. It is the third case: Test failed.