EmDrive gets deserved attention from the scientific community
They write a lot in the news about how EmDrive will solve almost all the problems with interplanetary flights, will allow you to create cheap flying cars and God knows what else. In other articles, you can read that this is nonsense, which is not worth spending a single budget dollar. But I have not seen a single article with a simple and boring thought: perhaps, in this case, the current level of attention of the scientific community to EmDrive is exactly the one it deserves. On the one hand, it is not a perpetual motion engine to drop it without considering; on the other hand, it is too early to launch large programs, even if the effect turns out to be real in the end. Need to wait and see. This article argues this view.
The first news about EmDrive caused a violent reaction: as articles with headlines like Impossible engine can get to the Moon in 4 hours , so many denials, for example "How to deceive the world with bad science"
Here is the device in question. Asymmetric camera, inside which radio waves jump and reflect (more specifically, microwaves, the same as in the microwave). The inventors claim that as a result there is a non-zero thrust, although the waves do not go out of the chamber. So far, the level of this thrust is expressed in micronewtons, but the inventors claim that it can be greatly increased in the future.
')
But after these first two waves of news there was another one, with a refutation of refutations. I think you should pay attention to them, since many have not read them.
Scientists who produce research are not responsible for media hype. Yes, some of the inventors are making rather extraordinary statements: for example, in this video, Scheuer claims that EmDrive will solve many global problems.
But other experimenters are simply exploring this interesting scientific anomaly and are not rushing to conclusions.
Critics often "refute" what the experimenters have not stated, or do not understand the descriptions of the experiments. I would like to draw attention to several such errors that have repeatedly recurred: confusion with the “zero” experiment, allegations that the engine necessarily violates the law of conservation of momentum, and objections associated with a delay in response. Then we will see that they are based on misunderstanding, and consider an example of a remarkable scientific achievement based on an experiment, which also - at first glance - violated the laws of conservation of energy and momentum.
If you watch the video from the conference Eagleworks [group of NASA, which published the first results of experiments], the statements may look very bold, for example, at 49:00.
But it must be taken into account that their task is precisely to study the potential possibilities of new engines for space exploration, no matter how small the effects may be at the moment.
From the statement on the basis of the laboratory :
It is this context that must be taken into account: their research is very long-term and they deal with very small effects, which some day, in decades, can lead to new physical principles.
Journalists from the presentation might have the impression that these engines would be used in space quite soon, especially considering the statements of the inventors themselves. But this was not discussed at the report.
This is one of the most common arguments of critics. An annotation to the scientific article Eagleworks says:
After reading this, you can first think - everything, there is nothing further to read, it is clear from here that it is not the engine that produces the traction. But with careful reading it turns out that the zero apparatus is zero not for the engine itself, but for the grooves inside it, which one of the inventors considered necessary. This experiment showed that the absence of these grooves had no effect on the level of thrust.
A zero experiment for the engine — sending radio waves to an empty test chamber — was also produced and showed no traction. All this is explained in the article. If you read only the annotation, you can misunderstand, but if you read the article, it becomes clear that the experiment, called “null” in the annotation, related only to the hypothesis of the need for grooves, and the hypothesis about the need for an asymmetric camera was tested separately.
So the authors of the refutations read what they are denying, inattentively. But if they did not understand such a simple thing, which is very clearly explained in the article, then what else were they wrong? So, on this point doubts are caused precisely by the disprovers. Yes, it is possible that the authors of the article should have written the abstract more clearly, but if you have ever written scientific articles, you yourself know how difficult it is to describe your results in several sentences.
[Approx. translator: see geektimes.ru/post/259460 ]
Another common in articles and social networks quote :
Yes, if you carefully read the article by German researchers, they clearly say that they did not confirm EmDrive. So the authors of the media have read the article inattentively, but its authors are not to blame here.
The article says that according to their measurements, the device gave traction in a vacuum, but they did not rule out other explanations. On the other hand, they did not confirm any of them, so it’s impossible to say that the article refutes EmDrive.
The article simply reports interesting intermediate results of experiments, without drawing far-reaching conclusions - this is how science usually works.
Due to the fact that the traction did not appear immediately after the supply of electricity and lasted some time after it was turned off, many rushed to explain it by the action of heat. But again, after reading the article carefully, you will see that the experimenters considered this possible explanation. For example, they isolated the engine from the test chamber so that the temperature in it increased by only 4 degrees (which did not affect the size of the horizontal thrust). And the thermal effects were confirmed, but, as expected, in the vertical direction, which allows to separate them from the studied effect of horizontal thrust.
And the delay of the effect is exactly what should be expected if (for example) the camera is somehow “charged”, such as an increase in electric charge or pressure difference (this is an analogy, not an explanation I suggested). If the effect appeared and disappeared immediately after switching on / off electricity, skeptics would also declare it as proof that it is explained by magnetism from the wire or something like that.
Many claim that the engine is impossible, because it violates the laws of conservation of energy or momentum [approx. translator - serious allegations that he violates the zone, I have not seen]. But new physical phenomena can easily seem to violate these laws. For example, imagine that we know these laws, but have just met with gravity and do not take it into account in our calculations. Then the falling objects clearly violate both laws: the object is accelerated, receiving kinetic energy and impulse of movement from nowhere, and stops, colliding with the Earth, losing momentum again, nowhere.
Our physics explains the first by the existence of the potential of a gravitational field, and when it falls, this potential decreases and turns into kinetic energy (we will dwell on Newtonian mechanics and we will not go into the theory of relativity). And the impulse is maintained due to the fact that the Earth is slightly accelerating towards the falling object - but we have no practical possibility to measure this acceleration! This is only the conclusion of experiments made on a smaller scale.
Moreover, sometimes in experiments there are indeed apparent violations of these laws. For example, during beta decay. Pauli proposed the neutrino, as an explanation of this phenomenon in 1930 (calling it "neutron" - the particle that is now called so, was not yet discovered):
(translation taken from www.nkj.ru/archive/articles/6592 )
Neutrinos were experimentally detected only in 1956, a quarter of a century after the Pauli hypothesis. All this time, according to experiments, it turned out that during beta decay, energy is not conserved.
I do not claim that EmDrive creates neutrinos, but there may be some other particles that interact even more weakly and are able to transfer momentum. Or some other unknown and unrecorded phenomena explaining the conservation of momentum and energy in EmDrive.
There is something that is really impossible under the laws of conservation: perpetual motion. A system that returns exactly to its original state, while producing energy, is in no way compatible with conservation laws. But no one claims that EmDrive is such a system! He receives external energy.
Despite any considerations about the laws of conservation, it is necessary to base on the results of observations. Scientists must explain and understand them. Experiments should not be discarded only because their results are not consistent with your scientific beliefs.
Isaac Azimov has a nice story about how one physicist suddenly discovered that he knows how to levitate. He cannot find an explanation for this, and he cannot convince anyone to investigate this phenomenon, since no scientist wants to believe it (the story is called “Faith” ). Why does this never really happen? Is it possible, and if not, why? The physicist cannot give an answer to such questions.
So, if we find seeming violations of the laws of physics, this is not a reason to reject the experimental data, as scientists did in Azimov’s story. This is not consistent with the principles of science.
In ordinary spaceships with high exhaust velocity, most of the energy goes to the exhaust, and not to the movement of the ship.
As a thought experiment, imagine that you have a friend flying a parallel course and ready to give you as much mass as you want on the exhaust, but not energy for it. Then it is much better to throw out 1 kg at a speed of 1 m / s than 1 mg at a speed of 1000 m / s: they give the same impetus, and in the first case it will take 1,000 times less energy. And accordingly, it is even better to release 1000 kg at 0.001 m / s. So, in this artificial situation, with a limited amount of energy and an unlimited amount of mass dropped, we want to throw out the maximum possible mass at the minimum possible speed.
In conventional ion engines, the situation is reversed — since the mass is limited, they are forced to use a high exhaust rate, although in terms of energy, this is much less efficient.
Thus, the main question about EmDrive - if it saves the impulse, then where does the mass for the impulse, the opposite of the one it produces, come from?
If it arises from the supplied energy, then in principle the situation is close to an ordinary ion engine - we have an RTG that turns mass into energy, then EmDrive turns part of this energy into mass and uses it to disperse this mass. In this case, the mass of the ship is still used, but not directly.
Similarly, when using solar cells, we use photons (created by mass conversion into energy inside the Sun) as energy, convert some of them into mass, and use the remainder for acceleration. In this case, the mass of the ship itself is not wasted, and this can work more efficiently than the photon engine, provided that the exhaust rate is quite low.
If EmDrive somehow uses the surrounding mass, then it is closer to the situation described above with a friend and requires a significantly larger explanation of where the mass comes from, moving at the same speed as our ship.
The easiest way to explain this (without inventing problematic ideas like "virtual plasma"), if the mass still does not move as fast as a spaceship. Then energy consumption is required for its acceleration, but still this may be the point, by analogy with the Bassard ramjet engine .
For example, it may be that the “vacuum” has a mass, and in fact it is some kind of plasma, which, for example, rests relative to the background radiation. This does not violate any laws of physics. If the Big Bang somehow set the structure of the vacuum, and since then it has simply expanded, then in this sense a “preferred frame of reference” may exist. Of course, there are many assumptions, but all this is a hypothetical new physics [approx. the translator - how this differs from the “problematic ideas” mentioned above, is incomprehensible to me].
In this case, it turns out that the efficiency of the engine depends on the speed relative to the background radiation; In a sense, this is similar to its use as a fuel.
Or it may turn out that something else is being used, distributed in space that we have not yet discovered. Perhaps some kind of environment, stationary relative to our galaxy, or rotating around its center with the same speed as the solar system, or stationary relative to the sun - there are many options here.
In all these cases, we can expect a loss of efficiency with an increase in speed relative to the “source material”, whatever that may be. This could potentially be detected in future experiments, if it suddenly turns out that the thrust depends on the velocity relative to the relic radiation, or one of the other sources - which may appear depending on the time of year or on the time of day.
The idea that the matter may be in some weakly interacting particles is not my own - it was already expressed in the Eagleworks report, together with more exotic versions of how the engine can work without violating the conservation laws.
Answer some common questions:
Roger Scheuer believes that the engine is fully explained by standard electrodynamics. His explanation is based on the difference between the group and phase velocity of electromagnetic waves. Some scientists believe that his calculations contain errors.
Guido Fetta believes that Cannae Drive (an EmDrive variant with additional grooves inside) creates a certain difference in the quantum vacuum, from which it repels.
Perhaps some of the radiation still comes out of the engine and this is what creates the thrust.
To begin with, the photon jet engines are in principle well studied. This is not an inertia-free engine - photons have energy and momentum. But the photon engine needs at least 300 MW (this is the power of a small power plant) to create a thrust of 1 newton . Therefore, we do not use them in spacecraft. Since EmDrive already gives micronewtons of thrust per watt, we get, even without increasing efficiency, the order of the ratio of newtons per megawatt, which is two or three orders of magnitude more efficient than the ideal photon engine.
But this efficiency is ideal if each photon is used only once. It can be exceeded if we have two spaceships with mirrors, between which the photon flux is reflected many times, up to hundreds of thousands - this will allow to receive much more momentum from each photon. In this case, the spacecraft are accelerated in opposite directions. This is the so-called photon laser engine .
But in order for it to explain EmDrive, it’s necessary that its camera not only release photons, but they are reflected from something outside, fall back into the EmDrive, and so many, many times. How can this happen in the conditions of this experiment, I can not even imagine.
The trouble is that if we do not understand the principle of operation, there is no certainty that a straightforward increase in size and power will give the same increase in result. For example, we can create small prototypes of thermonuclear reactors, but when they increase, the plasma will no longer be held.
Several possible results:
For small devices, the effect is already observed, and this, in any case, requires an explanation.
Yes, it makes sense to build devices of a somewhat larger size, but if the effect of this does not increase, it will not disprove its existence; these will simply be additional experimental results.
It seems to me that at the current level of understanding it is not justified to spend much money on a large version of the engine. In addition, while we do not know whether the linear increases with the growth of power. If so, then you need about 1 megawatt for thrust, which is quite a lot. And if it grows like the root of power (just as an example)? Then, for the same Newton, we need terawatts, and we cannot build such a device.
Finally, powerful devices are more dangerous. In general, let the experimenters decide for themselves exactly with what sizes it is better for them to work.
The idea is that if the engine does not need mass, then the impetus it imparts does not depend on the current speed.
Suppose at first the spacecraft is at rest relative to you and can, having expended some energy, accelerate to 1 m / s. Then, having expended twice more energy, it will accelerate to 2 m / s. But then it turns out that the resulting kinetic energy grows as a square spent and no matter how small the coefficient, in the end it will be greater. It seems to allow you to create a perpetual motion machine.
For example, if we put our engine on the rim of the wheel and start it, then in the end the kinetic energy of the wheel should be greater than the energy that we supply to the engine. After that, connect the wheel to the engine inlet and voila!
Note that if the engine requires a reactive mass (it doesn’t matter if it's a rocket engine, ion or photon), then its speed also increases, and the engine weight drops. With the help of calculations it can be shown that the perpetual motion in this way does not work.
So the question has the right to exist. I can offer several possible explanations (this is not an exhaustive set):
This was also discussed on Reddit .
Despite all the above, I believe that the engine most likely does not work and in the end we will find another explanation for the results of these experiments, as happened with the "superluminal neutrinos".
I just wanted to explain why I consider many existing refutations scientifically unfounded. There is nothing surprising in this - their authors are by no means experts in this field, but scientists, after all, people outside of their field can easily be grossly mistaken. Some of these errors are quite subtle, and I'm not sure that I would have noticed them myself; I read about them in other articles, unfortunately, which did not receive sufficient popularity.
I sympathize with experimenters who did not deserve such denials from people who did not read their work carefully enough. I also understand the desire to refute the apparent violation of the basic laws of physics - after all, the vast majority of such violations are indeed experimental errors, and not major discoveries.
This does not mean that I believe that EmDrive works. I do not have an opinion on this matter, but I think that it is worth a detailed check, until we finally find an explanation for the error or still make sure that it is not available.
Yes, I think that most likely it will turn out to be a mistake, simply because the majority of such sensations turn out to be them. But sometimes - rarely - such experiments become the basis of a scientific revolution. And they will not be if experimenters stop experimenting only because their results do not agree with the well-known science.
Of course, if you eventually find a mistake, this will also be a step forward in science.
Even if the effect is real, it’s too early to talk about practical applications. Scheuer claims that he will soon create versions of the device with a Newtonian order — a million times more than the current one. If he succeeds, then they can be of practical use.
But it is quite possible that this effect is so small that it will never turn into a useful device. Or it will be practical only in specific situations, like an ion engine. Even in an interesting case, if it allows discovering new physical principles, it will not necessarily allow the creation of flying cars.
Yes, I believe that some scientists, journalists and bloggers unfairly downplay their importance. And others are unjustly exaggerated.
But I would not say that the scientific community as a whole falls into one of these extremes. As shown by the same German experiments, it carefully and carefully checks them.
But the media too publicize both sides. And there is nothing surprising in the fact that scientists, who are often not experts in this field and are not connected with experiments, make mistakes and misunderstandings because of an excessive desire to support "their" side.
But the final verdict will not come from online discussions or news. The only way to find out who is right is to continue the experiments. Science in the real world does not work as it does in films, where the result of one or two observations immediately allows you to create an error-free new theory. We will have to wait.
EmDrive in the news
The first news about EmDrive caused a violent reaction: as articles with headlines like Impossible engine can get to the Moon in 4 hours , so many denials, for example "How to deceive the world with bad science"
Here is the device in question. Asymmetric camera, inside which radio waves jump and reflect (more specifically, microwaves, the same as in the microwave). The inventors claim that as a result there is a non-zero thrust, although the waves do not go out of the chamber. So far, the level of this thrust is expressed in micronewtons, but the inventors claim that it can be greatly increased in the future.
')
But after these first two waves of news there was another one, with a refutation of refutations. I think you should pay attention to them, since many have not read them.
Scientists who produce research are not responsible for media hype. Yes, some of the inventors are making rather extraordinary statements: for example, in this video, Scheuer claims that EmDrive will solve many global problems.
But other experimenters are simply exploring this interesting scientific anomaly and are not rushing to conclusions.
Critics often "refute" what the experimenters have not stated, or do not understand the descriptions of the experiments. I would like to draw attention to several such errors that have repeatedly recurred: confusion with the “zero” experiment, allegations that the engine necessarily violates the law of conservation of momentum, and objections associated with a delay in response. Then we will see that they are based on misunderstanding, and consider an example of a remarkable scientific achievement based on an experiment, which also - at first glance - violated the laws of conservation of energy and momentum.
What does Eagleworks do
If you watch the video from the conference Eagleworks [group of NASA, which published the first results of experiments], the statements may look very bold, for example, at 49:00.
But it must be taken into account that their task is precisely to study the potential possibilities of new engines for space exploration, no matter how small the effects may be at the moment.
From the statement on the basis of the laboratory :
The Lyndon Johnson Space Center has created a laboratory of advanced motion forms, informally called Eagleworks, to study motion technologies that can allow interplanetary flights over the next 50 years and interstellar flights by the end of the century.
... The results of White allow the theoretical possibility of artificial influence on space-time with the creation of conditions similar to those that cause the expansion of the Universe. The expected magnitude of this phenomenon is very small, but such an achievement could be an analogue of the Chicago woodpile in this area of ​​physics.
It is this context that must be taken into account: their research is very long-term and they deal with very small effects, which some day, in decades, can lead to new physical principles.
Journalists from the presentation might have the impression that these engines would be used in space quite soon, especially considering the statements of the inventors themselves. But this was not discussed at the report.
Error with "zero experiment"
This is one of the most common arguments of critics. An annotation to the scientific article Eagleworks says:
Traction was observed in both experimental instruments, although for one of them there was a lack of traction. One experimental apparatus contained internal changes designed to create thrust, and the other (hereinafter referred to as "zero") did not contain them.
After reading this, you can first think - everything, there is nothing further to read, it is clear from here that it is not the engine that produces the traction. But with careful reading it turns out that the zero apparatus is zero not for the engine itself, but for the grooves inside it, which one of the inventors considered necessary. This experiment showed that the absence of these grooves had no effect on the level of thrust.
A zero experiment for the engine — sending radio waves to an empty test chamber — was also produced and showed no traction. All this is explained in the article. If you read only the annotation, you can misunderstand, but if you read the article, it becomes clear that the experiment, called “null” in the annotation, related only to the hypothesis of the need for grooves, and the hypothesis about the need for an asymmetric camera was tested separately.
So the authors of the refutations read what they are denying, inattentively. But if they did not understand such a simple thing, which is very clearly explained in the article, then what else were they wrong? So, on this point doubts are caused precisely by the disprovers. Yes, it is possible that the authors of the article should have written the abstract more clearly, but if you have ever written scientific articles, you yourself know how difficult it is to describe your results in several sentences.
Misunderstanding of the latest experiments of German scientists
[Approx. translator: see geektimes.ru/post/259460 ]
Another common in articles and social networks quote :
Sean Carroll, a physicist at the California Institute of Technology, with whom we have already spoken about the possibility of EmDrive, agrees with Davis:“In my opinion, EmDrive is nonsense and a waste of time. They are right in the annotation saying: "Our tests can neither confirm nor deny the statements about EmDrive", so I don’t see what the news is here. I am personally going to think about those ideas that do not violate the law of conservation of momentum. "
Yes, if you carefully read the article by German researchers, they clearly say that they did not confirm EmDrive. So the authors of the media have read the article inattentively, but its authors are not to blame here.
The article says that according to their measurements, the device gave traction in a vacuum, but they did not rule out other explanations. On the other hand, they did not confirm any of them, so it’s impossible to say that the article refutes EmDrive.
The article simply reports interesting intermediate results of experiments, without drawing far-reaching conclusions - this is how science usually works.
Delay and explanation through heat
Due to the fact that the traction did not appear immediately after the supply of electricity and lasted some time after it was turned off, many rushed to explain it by the action of heat. But again, after reading the article carefully, you will see that the experimenters considered this possible explanation. For example, they isolated the engine from the test chamber so that the temperature in it increased by only 4 degrees (which did not affect the size of the horizontal thrust). And the thermal effects were confirmed, but, as expected, in the vertical direction, which allows to separate them from the studied effect of horizontal thrust.
And the delay of the effect is exactly what should be expected if (for example) the camera is somehow “charged”, such as an increase in electric charge or pressure difference (this is an analogy, not an explanation I suggested). If the effect appeared and disappeared immediately after switching on / off electricity, skeptics would also declare it as proof that it is explained by magnetism from the wire or something like that.
Denials through conservation laws
Many claim that the engine is impossible, because it violates the laws of conservation of energy or momentum [approx. translator - serious allegations that he violates the zone, I have not seen]. But new physical phenomena can easily seem to violate these laws. For example, imagine that we know these laws, but have just met with gravity and do not take it into account in our calculations. Then the falling objects clearly violate both laws: the object is accelerated, receiving kinetic energy and impulse of movement from nowhere, and stops, colliding with the Earth, losing momentum again, nowhere.
Our physics explains the first by the existence of the potential of a gravitational field, and when it falls, this potential decreases and turns into kinetic energy (we will dwell on Newtonian mechanics and we will not go into the theory of relativity). And the impulse is maintained due to the fact that the Earth is slightly accelerating towards the falling object - but we have no practical possibility to measure this acceleration! This is only the conclusion of experiments made on a smaller scale.
Moreover, sometimes in experiments there are indeed apparent violations of these laws. For example, during beta decay. Pauli proposed the neutrino, as an explanation of this phenomenon in 1930 (calling it "neutron" - the particle that is now called so, was not yet discovered):
“Dear radioactive ladies and gentlemen. I ask you to listen with attention at the most convenient moment of the messenger who delivered this letter. He will tell you that I have found a great tool for conservation law and correct statistics. It consists in the possibility of the existence of electrically neutral particles ... The continuity of the -spectrum will become understandable if we assume that during-decay such an “neutron” is emitted with each electron, and the sum of the energies of the “neutron” and the electron is constant ... "
(translation taken from www.nkj.ru/archive/articles/6592 )
Neutrinos were experimentally detected only in 1956, a quarter of a century after the Pauli hypothesis. All this time, according to experiments, it turned out that during beta decay, energy is not conserved.
I do not claim that EmDrive creates neutrinos, but there may be some other particles that interact even more weakly and are able to transfer momentum. Or some other unknown and unrecorded phenomena explaining the conservation of momentum and energy in EmDrive.
There is something that is really impossible under the laws of conservation: perpetual motion. A system that returns exactly to its original state, while producing energy, is in no way compatible with conservation laws. But no one claims that EmDrive is such a system! He receives external energy.
Experimenters have to look at the data, even when it seems impossible.
Despite any considerations about the laws of conservation, it is necessary to base on the results of observations. Scientists must explain and understand them. Experiments should not be discarded only because their results are not consistent with your scientific beliefs.
Isaac Azimov has a nice story about how one physicist suddenly discovered that he knows how to levitate. He cannot find an explanation for this, and he cannot convince anyone to investigate this phenomenon, since no scientist wants to believe it (the story is called “Faith” ). Why does this never really happen? Is it possible, and if not, why? The physicist cannot give an answer to such questions.
So, if we find seeming violations of the laws of physics, this is not a reason to reject the experimental data, as scientists did in Azimov’s story. This is not consistent with the principles of science.
Why ion engines use high exhaust rates
In ordinary spaceships with high exhaust velocity, most of the energy goes to the exhaust, and not to the movement of the ship.
As a thought experiment, imagine that you have a friend flying a parallel course and ready to give you as much mass as you want on the exhaust, but not energy for it. Then it is much better to throw out 1 kg at a speed of 1 m / s than 1 mg at a speed of 1000 m / s: they give the same impetus, and in the first case it will take 1,000 times less energy. And accordingly, it is even better to release 1000 kg at 0.001 m / s. So, in this artificial situation, with a limited amount of energy and an unlimited amount of mass dropped, we want to throw out the maximum possible mass at the minimum possible speed.
In conventional ion engines, the situation is reversed — since the mass is limited, they are forced to use a high exhaust rate, although in terms of energy, this is much less efficient.
Where does the mass come from to change the EmDrive pulse?
Thus, the main question about EmDrive - if it saves the impulse, then where does the mass for the impulse, the opposite of the one it produces, come from?
Option 1: energy conversion
If it arises from the supplied energy, then in principle the situation is close to an ordinary ion engine - we have an RTG that turns mass into energy, then EmDrive turns part of this energy into mass and uses it to disperse this mass. In this case, the mass of the ship is still used, but not directly.
Similarly, when using solar cells, we use photons (created by mass conversion into energy inside the Sun) as energy, convert some of them into mass, and use the remainder for acceleration. In this case, the mass of the ship itself is not wasted, and this can work more efficiently than the photon engine, provided that the exhaust rate is quite low.
Option 2: from the environment
If EmDrive somehow uses the surrounding mass, then it is closer to the situation described above with a friend and requires a significantly larger explanation of where the mass comes from, moving at the same speed as our ship.
The easiest way to explain this (without inventing problematic ideas like "virtual plasma"), if the mass still does not move as fast as a spaceship. Then energy consumption is required for its acceleration, but still this may be the point, by analogy with the Bassard ramjet engine .
For example, it may be that the “vacuum” has a mass, and in fact it is some kind of plasma, which, for example, rests relative to the background radiation. This does not violate any laws of physics. If the Big Bang somehow set the structure of the vacuum, and since then it has simply expanded, then in this sense a “preferred frame of reference” may exist. Of course, there are many assumptions, but all this is a hypothetical new physics [approx. the translator - how this differs from the “problematic ideas” mentioned above, is incomprehensible to me].
In this case, it turns out that the efficiency of the engine depends on the speed relative to the background radiation; In a sense, this is similar to its use as a fuel.
Or it may turn out that something else is being used, distributed in space that we have not yet discovered. Perhaps some kind of environment, stationary relative to our galaxy, or rotating around its center with the same speed as the solar system, or stationary relative to the sun - there are many options here.
In all these cases, we can expect a loss of efficiency with an increase in speed relative to the “source material”, whatever that may be. This could potentially be detected in future experiments, if it suddenly turns out that the thrust depends on the velocity relative to the relic radiation, or one of the other sources - which may appear depending on the time of year or on the time of day.
The idea that the matter may be in some weakly interacting particles is not my own - it was already expressed in the Eagleworks report, together with more exotic versions of how the engine can work without violating the conservation laws.
Frequently asked Questions
Answer some common questions:
How do the inventors themselves work?
Roger Scheuer believes that the engine is fully explained by standard electrodynamics. His explanation is based on the difference between the group and phase velocity of electromagnetic waves. Some scientists believe that his calculations contain errors.
Guido Fetta believes that Cannae Drive (an EmDrive variant with additional grooves inside) creates a certain difference in the quantum vacuum, from which it repels.
Maybe it's just a photon engine?
Perhaps some of the radiation still comes out of the engine and this is what creates the thrust.
To begin with, the photon jet engines are in principle well studied. This is not an inertia-free engine - photons have energy and momentum. But the photon engine needs at least 300 MW (this is the power of a small power plant) to create a thrust of 1 newton . Therefore, we do not use them in spacecraft. Since EmDrive already gives micronewtons of thrust per watt, we get, even without increasing efficiency, the order of the ratio of newtons per megawatt, which is two or three orders of magnitude more efficient than the ideal photon engine.
But this efficiency is ideal if each photon is used only once. It can be exceeded if we have two spaceships with mirrors, between which the photon flux is reflected many times, up to hundreds of thousands - this will allow to receive much more momentum from each photon. In this case, the spacecraft are accelerated in opposite directions. This is the so-called photon laser engine .
But in order for it to explain EmDrive, it’s necessary that its camera not only release photons, but they are reflected from something outside, fall back into the EmDrive, and so many, many times. How can this happen in the conditions of this experiment, I can not even imagine.
We can simply increase the device and get an easily measurable effect.
The trouble is that if we do not understand the principle of operation, there is no certainty that a straightforward increase in size and power will give the same increase in result. For example, we can create small prototypes of thermonuclear reactors, but when they increase, the plasma will no longer be held.
Several possible results:
- Enlarged versions may be so unstable that nothing will happen.
- Or those grooves are really necessary, but only for fairly large devices.
- Or you need something else instead.
For small devices, the effect is already observed, and this, in any case, requires an explanation.
Yes, it makes sense to build devices of a somewhat larger size, but if the effect of this does not increase, it will not disprove its existence; these will simply be additional experimental results.
It seems to me that at the current level of understanding it is not justified to spend much money on a large version of the engine. In addition, while we do not know whether the linear increases with the growth of power. If so, then you need about 1 megawatt for thrust, which is quite a lot. And if it grows like the root of power (just as an example)? Then, for the same Newton, we need terawatts, and we cannot build such a device.
Finally, powerful devices are more dangerous. In general, let the experimenters decide for themselves exactly with what sizes it is better for them to work.
Suppose this is not a perpetual motion - but if the effect existed, could we build a perpetual motion based on it?
The idea is that if the engine does not need mass, then the impetus it imparts does not depend on the current speed.
Suppose at first the spacecraft is at rest relative to you and can, having expended some energy, accelerate to 1 m / s. Then, having expended twice more energy, it will accelerate to 2 m / s. But then it turns out that the resulting kinetic energy grows as a square spent and no matter how small the coefficient, in the end it will be greater. It seems to allow you to create a perpetual motion machine.
For example, if we put our engine on the rim of the wheel and start it, then in the end the kinetic energy of the wheel should be greater than the energy that we supply to the engine. After that, connect the wheel to the engine inlet and voila!
Note that if the engine requires a reactive mass (it doesn’t matter if it's a rocket engine, ion or photon), then its speed also increases, and the engine weight drops. With the help of calculations it can be shown that the perpetual motion in this way does not work.
So the question has the right to exist. I can offer several possible explanations (this is not an exhaustive set):
- With an increase in thrust, we find that the mass is still decreasing, similar to the ion engine.
- The impulse depends on the speed with respect to a certain medium, like that of the Bassard engine, which also does not violate the laws of conservation.
- The engine bends space, similar to the engine of Alcubierre. In this case, the standard pulse calculations are not applicable, since in fact the engine is stationary, and the space around it changes.
- Some still unknown physical principle that changes the state of the universe when the engine is operated in a non-local way (similar to the Earth, accelerating towards the stone in the example given above).
This was also discussed on Reddit .
And yet, how likely is the effect to be real?
Despite all the above, I believe that the engine most likely does not work and in the end we will find another explanation for the results of these experiments, as happened with the "superluminal neutrinos".
I just wanted to explain why I consider many existing refutations scientifically unfounded. There is nothing surprising in this - their authors are by no means experts in this field, but scientists, after all, people outside of their field can easily be grossly mistaken. Some of these errors are quite subtle, and I'm not sure that I would have noticed them myself; I read about them in other articles, unfortunately, which did not receive sufficient popularity.
I sympathize with experimenters who did not deserve such denials from people who did not read their work carefully enough. I also understand the desire to refute the apparent violation of the basic laws of physics - after all, the vast majority of such violations are indeed experimental errors, and not major discoveries.
This does not mean that I believe that EmDrive works. I do not have an opinion on this matter, but I think that it is worth a detailed check, until we finally find an explanation for the error or still make sure that it is not available.
Yes, I think that most likely it will turn out to be a mistake, simply because the majority of such sensations turn out to be them. But sometimes - rarely - such experiments become the basis of a scientific revolution. And they will not be if experimenters stop experimenting only because their results do not agree with the well-known science.
Of course, if you eventually find a mistake, this will also be a step forward in science.
Do not rush to book a vacation on the moon
Even if the effect is real, it’s too early to talk about practical applications. Scheuer claims that he will soon create versions of the device with a Newtonian order — a million times more than the current one. If he succeeds, then they can be of practical use.
But it is quite possible that this effect is so small that it will never turn into a useful device. Or it will be practical only in specific situations, like an ion engine. Even in an interesting case, if it allows discovering new physical principles, it will not necessarily allow the creation of flying cars.
So is the significance of these experiments minimized?
Yes, I believe that some scientists, journalists and bloggers unfairly downplay their importance. And others are unjustly exaggerated.
But I would not say that the scientific community as a whole falls into one of these extremes. As shown by the same German experiments, it carefully and carefully checks them.
But the media too publicize both sides. And there is nothing surprising in the fact that scientists, who are often not experts in this field and are not connected with experiments, make mistakes and misunderstandings because of an excessive desire to support "their" side.
But the final verdict will not come from online discussions or news. The only way to find out who is right is to continue the experiments. Science in the real world does not work as it does in films, where the result of one or two observations immediately allows you to create an error-free new theory. We will have to wait.
Source: https://habr.com/ru/post/365993/
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