Journalist Alexander Berezin discusses what kind of real physics can be behind the fantastic project of the "impossible" EmDrive engine and why it can be connected with the history of the Universe before the Big Bang.
According to the American Institute of Aeronautics and Astronautics, which publishes the Journal of Propulsion and Power, an article on the EmDrive electromagnetic engines has been accepted. Moreover, it has even passed the scientific reviewers, and it will be published before the end of this year. Let's call a spade a spade: this news sounds the same as if the institute had announced that the Earth did hit the celestial axis. The very fact of such a publication is a loud scandal, and here's why.
The laws of physics are merciless - in order for something to move forward, it must push something back. We push off from the ground under our feet, spaceships - in the absence of "heavenly firmament" - throw back the fuel. Because of this, a trip to the Moon still requires hundreds of tons of fuel per person. In this situation, it is even scary to think about flights to more distant bodies. Delivery of one ship to Mars and back costs like a megaHPP. There are options with a nuclear reactor, but it is only within the means of the United States, which simply does not have such technologies. Here, for example, they are in much better shape. But there is no money for a real flight to the Red Planet, even in such a cheap version. And before the (so far hypothetical) flight of the Americans there, they are unlikely to appear.
It is clear that from such despair with distant space flights, some begin to see colored dreams in reality. One of them was engineer Roger Scheuer. In 2003, he took a copper bucket, inserted a magnetron from a household microwave oven into it, and claimed that he had created an engine that gives thrust without throwing anything back at all. He explained this at first by the fact that the bucket supposedly holds in itself a standing wave of electromagnetic oscillations in a closed resonator. The wave, they say, is the source of thrust. From a physical point of view, this is nonsense. Try to climb into an inflatable pool and get the thrust that moves the pool by simply creating a wave in it.
Theoretical physicists only laughed at such statements. However, experimental physicists decided to go beyond simple ridicule and test Scheuer's claims in practice. And then the trouble began. The thrust was indeed created, and no attempts by the experimenters to find sources of error in the measurements yielded results. The apotheosis in this regard was the work of Martin Tajmar, head of the German Institute for Aerospace Engineering at the Technical University in Dresden. In the world of experimental physics, this man is known as a professional "destroyer of legends", scrupulous organization and rechecking of the experiment, able to find almost any mistake.
When he failed, even theoretical physicists got worried. They expressed their concern in a rather peculiar way: "EmDrive is complete …" (Sean Carroll from California Tech). Some overcame themselves and yet expressed the same opinion more gently: “Due to the lack of a theoretical explanation for violation of the conservation of momentum, reviewers in journals will not accept this work,” insisted Eric Davis of the Institute for Advanced Research in Austin, USA.
In this regard, the fact that the work of people from NASA, dedicated to their EmDrive tests, has passed the peer review in a decent magazine, sounds revolutionary. This would not have happened if the work had errors detected "on paper". Obviously, the evidence that the device was working was so strong that even respect for the law of conservation of momentum did not allow to "kill" the work. So is it time to bury the law? Let's face it: hardly.
So far, there are no generally accepted scientifically acceptable explanations for the operation of the "impossible engine". NASA, in response to the question of why it works, begins to tell very dubious things. For example, about the fact that the engine is "repelled" by virtual particles. Yes, modern physics believes that virtual particles constantly appear and disappear in a vacuum. Particles come and go so quickly that they cannot be registered. However, the well-known Casimir effect shows that they can give real attraction of two close plates in a void. One thing is bad - all this has nothing to do with the Shoeira bucket. Virtual particles do not have a clearly defined place in space, and coupled with other factors, this does not allow them to "push off".
Promotional video:
However, quite recently, another explanation for the operation of the "impossible engine" has appeared. It was put forward by Nikolai Gorkavy from the Greenwich Institute (USA), already known to us from an extremely exotic hypothesis about the origin of the Universe. As we remember, the physicist suggested that in the last cycle of the existence of the Universe, it contracted until all black holes merged in it. With each merger cycle, a pair of black holes loses 5-15% of the mass that goes into gravitational waves. Therefore, multiple mergers in the "past Universe" should have turned almost all of its mass into waves. The universe, from which the mass so tragically disappeared, has dramatically "impoverished" in terms of gravity. Because of this "antigravity", compression was replaced by expansion - and this is how our Universe arose. According to Gorkavy's hypothesis, only part of the energy of those relict gravitational waves was spent on the formation of the substance of our Universea significant part is still "roaming" around here. We do not see it just because these waves are high-frequency, and our detectors are still able to register only low-frequency gravitational waves.
Well, that is, they "knew how." According to Gorkavy, the Scheuer bucket is the first accidentally constructed relic gravity wave detector. In the framework of his hypothesis, the CMB energy level is not limited "from above" and can be very high. The scientist believes that EmDrive felt the background of high-frequency gravitational waves and draws energy from there for its thrust. Then it works as an antenna, which due to resonance becomes sensitive to oscillations from relic gravitational waves of gigahertz frequencies. In this case, the "impossible engine" is not a closed system with a "standing wave", but an open one, "repelling" from the waves of a whole sea of gravitational waves. This does not mean that it will give a fantastic thrust: it also takes energy to bring the copper cone into resonance. And so far no one has tried to optimize the device properly (how to debug the incomprehensible?). But due to the use of external waves, it really doesn't need to eject fuel. If so, the prospects for such an engine, for all its weakness, are enormous. According to calculations, an Earth probe to Pluto would reach this planet with EmDrive on board in 18 months, not many years. Today, terrestrial cosmonautics cannot even dream of traveling billions of kilometers in months.
So far, this is the only explanation of the EmDrive operation that has not been subjected to serious theoretical criticism. However, everything may still be ahead - after all, the Gorkavy's hypothesis itself is just beginning to be properly discussed in the scientific community. Fortunately, it looks like there is a way to check if she is right or not in the "impossible engine" case. They want to test EmDrive in space, aboard a small satellite. Such tests will be impossible to question. On Earth, the registration of thrust can always be attributed to an experimental error. But in space the spacecraft either deviates from its base trajectory (from point A to point B), or "stands" on it. If the first happens, the interaction with relict gravitational waves from the "past Universe" may not be such an exotic explanation of "impossible thrust".