# How does the EmDrive engine work and why is it considered impossible?

## NASA's EmDrive engine to be tested in space

May, 2021

You shouldn't believe everything you see and write. Russia at one time launched the same engine (which allegedly contradicted the laws of physics) into space, google "gravity". Naturally, when this engine had to correct the satellite's orbit, the laws of physics turned out to be stronger than the faith of its inventors. Google the problem of obscurantism, no one is safe from it, not the politicians who provide funding for such projects, not the scientists themselves.

May, 2021

I think the principle of the engine is perfectly explained by its inventor, Roger Shawyer, in a YouTube post (Roger Shawyer Explaining The Basic Science behind #EmDrive, www.youtube.com). The operation of the engine is largely based on the independence of the microwave speeds from the speed of the resonator (picture “Independent of velocities” at the moment of time about 3.13 of the mentioned video). The independence of the microwave speeds from the resonator speed is in many respects analogous to the second postulate underlying the theory of relativity. According to the mentioned postulate, the speed of propagation of light in any so-called. the inertial reporting system is the same. In this case, in the waveguide and the resonator (the metal body of the motor can be considered a waveguide and a resonator), the speeds of electromagnetic waves or microwaves can depend on the size and shape of the resonator, but DO NOT DEPEND on the speed of the resonator (time 3.13 of the mentioned video). According to the theory of relativity, electromagnetic waves have energy and mass as the equivalent of energy and can create pressure. This should take place at school. Electromagnetic waves propagating inside the resonator towards each other with different due to the conical shape of the resonator, the so-called. group ("real) speeds"), not dependent on the speed of the resonator, create a certain so-called. the resultant force pushing and accelerating the resonator. In the process of acceleration of the resonator, the microwaves transmit an impulse to the resonator through the mentioned resultant force. For example, a falling stone, attracted by the Earth's gravitational force, accelerates in about the same way. I think that the work of the engine, if it works, of course, is an excellent confirmation of both the second postulate underlying the theory of relativity and the theory of relativity itself, and the invention itself, in my opinion, is a genius.

May, 2021

Imagine an ordinary metal bucket without a handle with a hermetically sealed top. One end of the bucket is narrower than the other, since it has a conical shape. Somewhere between the end parts (I do not know if in the middle or not, but this is not so important) a hole is made into which a high-frequency transmission line (waveguide or coaxial cable) is inserted. Somewhere outside the bucket is a magnetron, apparently the same as in your microwaves, which generates electromagnetic waves and transfers them through transmission lines into this conical metal chamber, which I called the bucket. Further, entering the chamber, the EM wave is emitted in both directions (to both ends) with the same phase velocity, but with different group velocities! It is this difference in group velocities that the author defines as the cause of the effect.

It is necessary to explain what is phase and what is group velocity. Imagine that instead of a wave, a pin-pong ball flew in there and began to jump, reflecting from the side walls, and so, the phase velocity is its speed, as it were, relative to the side walls (generally speaking, the walls, the bucket has one), that is how fast he jumps between them. The phase velocity carries neither impulse nor information and is not interesting in this case. The group speed is the speed, as it were, relative to the end walls, that is, how quickly the ball reaches the end wall, hitting the chamber. I used the word "as though", since "relative to the wall" is not quite a correct turn, but it is difficult to say otherwise. In general, the ball can jump very quickly, bouncing off the side wall, but at the same time it will fly slowly to the end in this way, much longer than if it was flying in a straight line.

Now the most important thing: the group velocity of the EM the waves will increase when moving towards the wide part of the camera and slow down when moving towards the narrow part of the camera. This is true, the same will happen with the ball. Let me give you another analogy: you have a funnel with a hole in the middle, and you pour water into this hole through the hose at some speed. If you turn the funnel with its narrow part down, water will begin to accumulate (this is like a low group velocity), if you turn it with a narrow part upwards, the water will not stay at all (this is like a large group velocity).

So, the author claims that the pressure of the EM wave (and it really presses, discovered by the great Maxwell) on a wide wall will be greater than on a narrow one! And this, supposedly, should lead to movement. Everything seems to be logical, but here's what personally alerted me to this approach: the pressure on the side wall was not taken into account. And this is strange, because the pressure vector on the side wall will be directed perpendicular to it (this does not depend on how the waves behave inside the chamber), and since the shape is conical, this vector will tilt towards the narrow part of the chamber. So the forces were compensated! By the way, it's the same with the funnel and water, because from the wide side the water falls only on the end, without touching the wall, and in the narrow part it is notand the side wall presses, and this pressure vector has a projection both purely to the side and purely to the butt, that's all.

Second: as already mentioned, the principle of conservation of momentum is violated - the principle, which, along with the principle the conservation of energy has never been violated anywhere, and if it were violated, the Universe should have collapsed.

The fact that experimenters observe a certain force does not prove anything yet, it really needs a very high accuracy and the elimination of all other effects like pickups from the power supply system, convective currents and so on.

Another point is the article itself. To me, as a person who has seen many scientific articles, and even the one who writes them, it seems very suspicious of such a format - no title page, only three links in the list of references, reasoning and calculations are so simple that it is strange why at school before that nobody thought of it. The style is very similar to the style of one university charlatan whom I knew personally and who did not care about science, he just wanted money, wrote all kinds of heresy, but disguised well, and he was given money. The author himself has an incomprehensible education, and as far as I understand, he does not have any scientific degree.

I will not swear and 100 overestimate, since quantum physics allows miracles, but the conclusion here is obvious.

May, 2021

Even its inventor does not know how this engine works. In any case, physicists consider the set of words that he utters when explaining the principle of operation of this engine is meaningless.

The main reason this engine is considered impossible is that it violates the law of conservation of momentum in a closed system , and this is a very fundamental law, and although physicists know a lot about the nature of the universe, violations of this law have never been observed anywhere else.

Therefore, a measurement error and an incorrectly staged experiment (and something like this has happened in the history of physics and will occur repeatedly) are considered a much more likely explanation for the strange results obtained by individual physicists. And the fact that even for those physicists who announced the successful reproduction of the experiment, the measured "thrust" indicators, other things being equal, differ by four orders of magnitude (the differences in the results obtained are tens of thousands of times) - these discrepancies only confirm the assumption that the experiment was staged incorrectly and measured not the thrust, but the induction from the wires, the flow of heated air, etc. side factors that are not related to the declared phenomenon.

For more details about the claims to EmDrive, see the devastating article by Anton Vershovsky (Doctor of Physical and Mathematical Sciences, main work in the field of quantum magnetometry and atomic radio-optical spectroscopy), written a year ago on the topic of publications about EmDrive: lebed.com

I would like to end with a wonderful quote from blogger and nuclear physicist Igor Ivanov, in which he writes about freakism and alternatives. It would be nice if everyone, especially science journalists, realized what he writes about:

"People who have a very poor idea of ​​what science is (ie, the majority) have a conviction that all non-trivial knowledge is literally held together by strings. And as soon as one thread is cut off, a bunch of theories and conclusions will immediately crumble to dust. They do not realize how strongly the graph of scientific knowledge is connected.

As a consequence - a feeling is developed that adding something of your own to science is also very simple. This idea is guided by the alternative people. Like, it is enough to attach your stunning idea to a single fact on a thin thread, and this will already be a solid scientific hypothesis. with such attempts, one must immediately check how this idea relates to numerous other facts, it seems to them secondary.

Most alternativeists have this point of view: here I am offering you my original idea, and you will finalize the details, you can do it better than me. It is clear that such "ideas" have no value. The value of an idea lies not in the original combination of words (“let's apply this here”), but in the variety of interesting and consistent with other facts opportunities that it opens up. "

http: //igorivanov.blogspot .ru / 2010/09 / and-yet-again.html

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upd: Fresh newsWhat about EmDrive is that its effectiveness was allegedly confirmed by Martin Taimar, a professor at the University of Dresden with his research group. It would be nice for everyone who reprints this to read the interview with Taimar himself first.

http://www.grenzwissenschaft-aktuell.de/prof-korrigiert-berichte-zu-emdrive-tests20150730/

He directly says that his experiment does not confirm anything, but does not refute anything either. The effect was actually measured, but found incl. and in those directions in which the engine should not create traction just do. In addition, the measured effect size is comparable to the measurement accuracy (in simple terms, within this accuracy, they measured an effect equal to zero). The author himself assumes that the measured effects are parasitic magnetic interaction with the cables of the measuring and power equipment, which he could not neutralize. Encourages those wishing to do more research, because he is an enthusiast of all kinds of alternative engines. He himself believes that it makes sense to continue experiments with his installation purely for didactic purposes, so that students learn to find and eliminate sources of interference in experimental installations.

## How does the e-katalog website work and work? How does it show current prices?

This probably happens somehow automatically, automatically. I'm interested in how all sites like this work.