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[gaugebozo]

Why do people says it violates conservation of momentum?

If you input some energy, and get more, it doesn't mean you broke the laws of physics, it just mean you got more energy, somehow. Could well be that something somewhere else is providing its energy into the experiment. It might look like energy came out of nowhere, but for all we know it just comes from somewhere we didn't know existed, or something outside the experiment.

If it is possible to have two particles that are far away from one another behave as if they were next to each other, then it's possible that in a controlled experiment, you would only see the increased energy without seeing the decrease wherever else it's happening, somewhere. In a computer program, you could easily represent this by coding it so that two physical objects interact with one another as if they were as close to one another as possible, in the physics' calculation, even if in the rendering code you render both in much different positions. The idea that in our universe, our perception of space negates the ability of particles to interact with one another beyond their relative distance, is pretty limited I think, especially with things like entanglement.

Right, missing momentum was how we discovered neutrinos.

I'm still skeptical that there is something truly different happening here though. I'm going to take some time to review their Bohemian explanation, and I'm particularly interested in how it's different from normal quantum mechanics.

 

[DEAD RABBIT]

Lets take a look at some of their supporting data from which they derive this 1.2 mN / kW number.

Looking at the spread of these points, I would have measured at more power settings.

Frankly, everyone should realize this is fringe science and most likely false. When dealing with these kinds of "black boxes" one sound approach of falsification is to vary the design of the conical cavity, maybe even use different materials, and systematically brute-force evaluate the BB's response.

 

[Xe4]

Why do people says it violates conservation of momentum?

If you input some energy, and get more, it doesn't mean you broke the laws of physics, it just mean you got more energy, somehow. Could well be that something somewhere else is providing its energy into the experiment. It might look like energy came out of nowhere, but for all we know it just comes from somewhere we didn't know existed, or something outside the experiment.

If it is possible to have two particles that are far away from one another behave as if they were next to each other, then it's possible that in a controlled experiment, you would only see the increased energy without seeing the decrease wherever else it's happening, somewhere. In a computer program, you could easily represent this by coding it so that two physical objects interact with one another as if they were as close to one another as possible, in the physics' calculation, even if in the rendering code you render both in much different positions. The idea that in our universe, our perception of space negates the ability of particles to interact with one another beyond their relative distance, is pretty limited I think, especially with things like entanglement.

I think it should be noted thst conservation of momentum and conservation of energy are two completely different topics. While this device does not violate the conservation of energy it does violate the conservation of momentum.

To see why, let's first look at the conservation of energy. Simply put, it states that Energy in = Energy out. If you were to add up all the different forms of energy, say potential energy, kinetic enrgy, and thermal energy, they would have to equal out on both sides of the equation, hence the equal sign. This device does this without problem. The energy is simply stored in a battery, or pulled from a power source elsewhere.

The problem comes in when you start talking about the conservation of momentum. There are many ways to express this property; classically it is (mass x velocity) in = (mass x velocity) out. Thinking about the equation, it is obvious where the problem comes from. The mass of the object is not decreasing, as it would be in conventional rockets, but the velocity is increasing! This is a problem, that gets worse when you consider Newtons second law of motion.

Often stated as Force = mass * acceleration, it is actually better stated as Force = change in momentum/change in time. Obviously this can't happen if the momentum doesn't change. Remember, I said the initial momentum has to equal the final momentum. If so, how does momentum change ever? The trick to this is to consider momentum locally. Globally, momentum cannot change, locally, it can by expending mass. Rockets move by ejecting mass out behind them.

This leads to an inescapable conclusion; an object with no external forces applied, and no change in mass can never accelerate. It doesn't matter how much you bounce radio signals around the cavity, the internal forces will always cancel; in fact the have to.

I hope that helped with regards to why scientists by in large are super skeptical of this machine right now. One scientific paper isn't going to change that. Shit, multiple scientific papers would only start to change opinnions. Right now, this device needs far more experimental evidence, to begin to assess whether the device truly works or not.

 

[DragonSworne]

I think it should be noted thst conservation of momentum and conservation of energy are two completely different topics. While this device does not violate the conservation of energy it does violate the conservation of momentum.

To see why, let's first look at the conservation of energy. Simply put, it states that Energy in = Energy out. If you were to add up all the different forms of energy, say potential energy, kinetic enrgy, and thermal energy, they would have to equal out on both sides of the equation, hence the equal sign. This device does this without problem. The energy is simply stored in a battery, or pulled from a power source elsewhere.

The problem comes in when you start talking about the conservation of momentum. There are many ways to express this property; classically it is (mass x velocity) in = (mass x velocity) out. Thinking about the equation, it is obvious where the problem comes from. The mass of the object is not decreasing, as it would be in conventional rockets, but the velocity is increasing! This is a problem, that gets worse when you consider Newtons second law of motion.

Often stated as Force = mass * acceleration, it is actually better stated as Force = change in momentum/change in time. Obviously this can't happen if the momentum doesn't change. Remember, I said the initial momentum has to equal the final momentum. If so, how does momentum change ever? The trick to this is to consider momentum locally. Globally, momentum cannot change, locally, it can by expending mass. Rockets move by ejecting mass out behind them.

This leads to an inescapable conclusion; an object with no external forces applied, and no change in mass can never accelerate. It doesn't matter how much you bounce radio signals around the cavity, the internal forces will always cancel; in fact the have to.

I hope that helped with regards to why scientists by in large are super skeptical of this machine right now. One scientific paper isn't going to change that. Shit, multiple scientific papers would only start to change opinnions. Right now, this device needs far more experimental evidence, to begin to assess whether the device truly works or not.

Claiming there is no force doesn't change the fact that all experiments have measured thrust.

 

[Woorloog]

Claiming there is no force doesn't change the fact that all experiments have measured thrust.

Supposedly measured thrust. Very possible it was noise or error. There is no sufficient data set to draw real conclusions yet.

 

[Crayon]

From glancing the paper it is unclear to me what the exact relationship is between their model of thrust and pilot wave theory.

This, for me. I don't get that part.

 

[Xe4]

Claiming there is no force doesn't change the fact that all experiments have measured thrust.

Well, only one experiment has measure thrust, and been confident enough to publish. One experiment doesn't mean anything; experimental error and statistical anomolies happen all the time. It doesn't help this study was published in a not well known journal. If this were published in Nature or Science, I'd take it much more seriously, even whilst being heavily skeptical, as that is an indication that their peer review thought it was a particularly well done experiment.

Minimum, it will take an independent verification for scientists to begin to take this seriously. Maybe this will go somewhere, maybe not, but we won't know until we do more studies.

 

[Ether_Snake]

I think it should be noted thst conservation of momentum and conservation of energy are two completely different topics. While this device does not violate the conservation of energy it does violate the conservation of momentum.

To see why, let's first look at the conservation of energy. Simply put, it states that Energy in = Energy out. If you were to add up all the different forms of energy, say potential energy, kinetic enrgy, and thermal energy, they would have to equal out on both sides of the equation, hence the equal sign. This device does this without problem. The energy is simply stored in a battery, or pulled from a power source elsewhere.

The problem comes in when you start talking about the conservation of momentum. There are many ways to express this property; classically it is (mass x velocity) in = (mass x velocity) out. Thinking about the equation, it is obvious where the problem comes from. The mass of the object is not decreasing, as it would be in conventional rockets, but the velocity is increasing! This is a problem, that gets worse when you consider Newtons second law of motion.

Often stated as Force = mass * acceleration, it is actually better stated as Force = change in momentum/change in time. Obviously this can't happen if the momentum doesn't change. Remember, I said the initial momentum has to equal the final momentum. If so, how does momentum change ever? The trick to this is to consider momentum locally. Globally, momentum cannot change, locally, it can by expending mass. Rockets move by ejecting mass out behind them.

This leads to an inescapable conclusion; an object with no external forces applied, and no change in mass can never accelerate. It doesn't matter how much you bounce radio signals around the cavity, the internal forces will always cancel; in fact the have to.

I hope that helped with regards to why scientists by in large are super skeptical of this machine right now. One scientific paper isn't going to change that. Shit, multiple scientific papers would only start to change opinnions. Right now, this device needs far more experimental evidence, to begin to assess whether the device truly works or not.

Well let's say I have a surface of water, and I make a lot of disturbances to cause waves. Now someone else comes but they can't see the water, and they place a rubber ducky on the water that they can't see. When the duck starts to move because of the waves that have come to where it stands, to that person wouldn't it look like there was an increase of momentum for the floating duck that couldn't be attributed to anything?

It seems to me that the EM Drive experiment just favors the likely hood that waves will influence the measured outcome compared to other setups, the equivalent of increasing the likelihood that waves will make a beach ball move by shrinking the size of the pool; the bigger the pool the less likely it is that the waves will reach the beach ball or influence its movement in a measurable way. The EM Drive has a conical shape, so maybe it helps.

 

[gaugebozo]

Lets take a look at some of their supporting data from which they derive this 1.2 mN / kW number.

Looking at the spread of these points, I would have measured at more power settings.

Frankly, everyone should realize this is fringe science and most likely false. When dealing with these kinds of "black boxes" one sound approach of falsification is to vary the design of the conical cavity, maybe even use different materials, and systematically brute-force evaluate the BB's response.

Man, they really do need more points. If that first point is just off by like two sigma, the thrust is a constant.

 

[Xe4]

Well let's say I have a surface of water, and I make a lot of disturbances to cause waves. Now someone else comes but they can't see the water, and they place a rubber ducky on the water that they can't see. When the duck starts to move because of the waves that have come to where it stands, to that person wouldn't it look like there was an increase of momentum for the floating duck that couldn't be attributed to anything?

It seems to me that the EM Drive experiment just favors the likely hood that waves will influence the measured outcome compared to other setups, the equivalent of increasing the likelihood that waves will make a beach ball move by shrinking the size of the pool; the bigger the pool the less likely it is that the waves will reach the beach ball or influence its movement in a measurable way. The EM Drive has a conical shape, so maybe it helps.

I don't think thats an entirely fair analogy. If I saw waves, I'd assume something was imparting force into the waves, causing them to move. If someone gave me a box that didn't import any force to the waves either locally or at a distance, and they claimed it made the water move, I'd be rightly skeptical. Same here.

As for waves pushing more on the front and the back, it doesn't matter. Due to the reflection of the waves, the forces would still cancel out. It has never been shown that the internal forces of an object effect the motion of an object. If this isconfirmed, it would be the first, hence why people are skeptical. It be as if you could move a ship by you personally pushing on it. As much as I wish, physics just doesn't work like that.

 

[televator]

I've always pulled for pilot wave theory. Ignorance rather than troll particles sounds better to me, in my amuture understanding.

 

[Ether_Snake]

I don't think thats an entirely fair analogy. If I saw waves, I'd assume something was imparting force into the waves, causing them to move. If someone gave me a box that didn't import any force to the waves either locally or at a distance, and they claimed it made the water move, I'd be rightly skeptical. Same here.

As for waves pushing more on the front and the back, it doesn't matter. Due to the reflection of the waves, the forces would still cancel out. It has never been shown that the internal forces of an object effect the motion of an object. If this isconfirmed, it would be the first, hence why people are skeptical. It be as if you could move a ship by you personally pushing on it. As much as I wish, physics just doesn't work like that.

Well if you place a beach ball on water, the depression it creates as it sinks into the water can to some extent influence where it will move next, especially if the wave isn't equal. In PWT the particle is moved by its own wave (if there are no other waves of course, otherwise it is its own waves and other waves, even "ghost waves", as in waves that have no particles).

 

[eot]

I think it should be noted thst conservation of momentum and conservation of energy are two completely different topics. While this device does not violate the conservation of energy it does violate the conservation of momentum.

From breaking conservation of momentum it's easy to show that you break conservation of energy as well.

 

[cebri.one]

Is this a good explanation for this? It was posted on a science thread;

No.

"The simplest explanation is this. movement requires you leave something behind"

"Rockets try to fix that problem by bringing a surface with you when you leave the surface of the earth. But eventually, you run out of surfaces. And you're stuck, and die."

That is just plain false. Rockets work on the principle of action <-> reaction. If you exert a force in one direction, another equal force pushes in the opposite direction. It doesn't have to "push" on anything.

https://spaceflightsystems.grc.nasa.gov/education/rocket/TRCRocket/rocket_principles.html

One of the most commonly asked questions about rockets is how they can work in space where there is no air for them to push against. The answer to this question comes from the third law. Imagine the skateboard again. On the ground, the only part air plays in the motions of the rider and the skateboard is to slow them down. Moving through the air causes friction, or as scientists call it, drag. The surrounding air impedes the action-reaction.

As a result rockets actually work better in space than they do in air. As the exhaust gas leaves the rocket engine it must push away the surrounding air; this uses up some of the energy of the rocket. In space, the exhaust gases can escape freely.

 

[Ether_Snake]

No.

"The simplest explanation is this. movement requires you leave something behind"

"Rockets try to fix that problem by bringing a surface with you when you leave the surface of the earth. But eventually, you run out of surfaces. And you're stuck, and die."

That is just plain false. Rockets work on the principle of action <-> reaction. If you exert a force in one direction, another equal force pushes in the opposite direction. It doesn't have to "push" on anything.

https://spaceflightsystems.grc.nasa.gov/education/rocket/TRCRocket/rocket_principles.html

Err, doesn't it push on the reactor itself?

 

[Sibylus]

I thought this would be a fascinating lil' engine with some subtle confounding error, that it was too good to be true, but the story gets more interesting all the time.

... that it could topple the Copenhagen Interpretation of QM is the biggest shock of it all though, and easily the biggest takeaway from this effort. Wow. If this works because of pilot wave, is that faster-than-light communication as a bare minimum within physical possibility?

Wait if quantum shit is deterministic, does that mean free will is an illusion?

A probabilistic universe is no friendlier to truly free will.

 

[jepense]

Yeah, this is not a breakthrough article. The paper states they see an effect, but can't rule out noise and systematic errors. The data just isn't good enough.

So the most likely explanation is that it's an error. Even if it was real, I don't see a need to invoke de Broglie-Bohm mechanics. The vacuum is full of stuff also in the Copenhagen interpretation, and being able to transfer momentum with the vacuum seems just as plausible (not very) in this view.

Of course, if you see an effect like this, you have to study it in more detail. Most likely it's nothing, but it could be a compass near a wire.

That is just plain false. Rockets work on the principle of action <-> reaction. If you exert a force in one direction, another equal force pushes in the opposite direction. It doesn't have to "push" on anything.

Yes, you do have to "push" on something, always. A rocket works by pushing on the exhaust gases. The rocket goes one way (reaction), the exhaust the other (action). Once you are out of fuel, you have no more exhaust to push against, and can't change your linear movement.

 

[Irminsul]

Lets take a look at some of their supporting data from which they derive this 1.2 mN / kW number.

Looking at the spread of these points, I would have measured at more power settings.

Wait, is this "raw data" all measurements they have taken? So 16 measurements spread across three different power settings? Well, yeah, then I'm firmly in the camp of "they're measuring statistical noise", at least for now. You don't exactly need much to throw off that fitted linear curve completely.

 

[blu]

No.

"The simplest explanation is this. movement requires you leave something behind"

"Rockets try to fix that problem by bringing a surface with you when you leave the surface of the earth. But eventually, you run out of surfaces. And you're stuck, and die."

That is just plain false. Rockets work on the principle of action <-> reaction. If you exert a force in one direction, another equal force pushes in the opposite direction. It doesn't have to "push" on anything.

Actually you do. Consider this simple experiment: If you were floating in space, holding a brick in your hand, the only difference whether you'd produce thrust by pushing the brick in some direction is whether you'd let that brick go or you don't let it go.

Actually, that'd be the most primitive of space rocket engines - a guy standing on the aft of the rocket, hurling bricks in the direction opposite to the desired velocity vector.

 

[DEAD RABBIT]

They're using a 'pendulum' to test their device. It is basically a table mounted to a very-well behaving spring. Assuming the spring is one-dimensional, the table can only travel along one axis. The displacement of the table due to an external force is measured with an optical distance sensor.

A measurement run typically looks like this:

There are two 'calibration pulses', one before and one after the turning the device on and off. This is to calibrate the force to the displacement. I don't really understand why it has to be done this way. It implies the spring is not very well-behaved. During the test-run, there is a displacement and when the device is turned off, the displacement seems to decay like an exponential function. This would indicate the pendulum spring is heavily damped.

They tested the device at three different power settings: 40W, 60W and 80W. They measured the device in two configurations: forward and reverse.

A forward measurement set from their paper:

A reverse measurement set:

The direction of the displacement reverses when the device is rotated a 180 degrees. But the displacements and forces do not appear consistent with the power setting.

Then looking at their null test data, where they orient the device perpendicular to the pendulum (hence it shouldn't register anything), they measure the following over a 90 second interval pumping the drive with 80W:

A drift in the displacement of 8 microns is observed, so roughly 1 micron per 10 seconds of systematic error. They claim this is due to some thermal effect. Whatever its cause, the erroneous displacement doesn't appear to decay back which means the pendulum didn't experience a force which is what they were trying to prove. However, this measurement does show that the pendulum has some funny behavior on the same time-scale as the actual measurements.

They also did some slope-filtering analysis, but I don't really understand what that's about.

I feel they didn't have a lot of time to perform these measurements and do the analysis. I think statistics wise, they could have done something more convincing. Since the physics is completely unknown, you might as well take the derivative of the displacements and do a correlation with the input power. Their null testing is a bit flawed and basic. It looks like some engineers just muddling about.

Honestly:

 

[ced]

Ugh.

Ok I've been following this for a long time, and I'm not in any way a physicist, but anyways.

Be skeptical people, these latest experiments are not very good. They didn't even do a control as simple as making a cylinder version to see if it generates force (the frustum shape is supposedly the key).

Here is a good video summary of this, I don't know who this guy is but to cut it short, there is still a lot of possible errors, thermal effects being the most likely.

https://www.youtube.com/watch?v=JGcvxg7jJTs

It in no way "Works", change the subject.