A group of scientists from the OPERA experiment in collaboration with European organization nuclear research(CERN) published the sensational results of an experiment to overcome the speed of light. The results of the experiment refute Albert Einstein's special theory of relativity, on which the entire modern physics. The theory says that the speed of light is 299,792,458 m/s, and elementary particles cannot move. faster speed Sveta.

Nevertheless, scientists recorded its excess by a neutrino beam by 60 nanoseconds when overcoming 732 km. This happened on September 22 during an experiment conducted by an international group of nuclear physicists from Italy, France, Russia, Korea, Japan and other countries.

The experiment proceeded as follows: a proton beam was accelerated in a special accelerator and hit with it at the center of a special target. This is how mesons were born - particles consisting of quarks.

During the decay of mesons, neutrinos are born, - Academician of the Russian Academy of Sciences Valery Rubakov, chief researcher at the Institute for Nuclear Research of the Russian Academy of Sciences, explained to Izvestia. - The beam is positioned so that the neutrino flies 732 km and hits the Italian underground laboratory in Gran Sasso. It has a special detector that records the speed of the neutrino beam.

The results of the study split scientific world. Some scientists refuse to believe the results.

What they did at CERN is impossible from the modern standpoint of physics, - Academician of the Russian Academy of Sciences Spartak Belyaev, scientific director of the Institute of General and Nuclear Physics, told Izvestia. - It is necessary to check this experiment and its results - perhaps they were simply mistaken. All the experiments carried out before that fit into the existing theory, and because of one once conducted experiment, it is not worth raising a panic.

At the same time, Academician Belyaev admits that if it is possible to prove that neutrinos can move faster than the speed of light, this will be a revolution.

We then have to break all the physics, he said.

If the results are confirmed, this is a revolution, Academician Rubakov agrees. - It is difficult to say how it will turn out for the townsfolk. In general, of course, it is possible to change the special theory of relativity, but it is extremely difficult to do this, and it is not entirely clear which theory will crystallize as a result.

Rubakov drew attention to the fact that the report states that over the three years of the experiment, 15,000 events were recorded and measured.

The statistics are very good, and an international group of reputable scientists participated in the experiment,” Rubakov sums up.

Academicians stressed that the world is regularly attempting to experimentally refute the special theory of relativity. However, none of them has given positive results so far.

Dedicated to direct measurement of the speed of neutrinos. The results sound sensational: the speed of the neutrino turned out to be slightly - but statistically significant! - more than the speed of light. The collaboration article contains an analysis of various sources of errors and uncertainties, however, the reaction of the vast majority of physicists remains very skeptical, primarily because such a result does not agree with other experimental data on the properties of neutrinos.

Rice. 1.

Experiment Details

The idea of ​​the experiment (see OPERA experiment) is very simple. The neutrino beam is born at CERN, flies through the Earth to the Italian laboratory Gran Sasso and passes through a special OPERA neutrino detector there. Neutrinos interact very weakly with matter, but due to the fact that their flux from CERN is very large, some neutrinos still collide with atoms inside the detector. There they generate a cascade of charged particles and thus leave their signal in the detector. Neutrinos at CERN are not born continuously, but in "bursts", and if we know the moment of birth of a neutrino and the moment of its absorption in the detector, as well as the distance between the two laboratories, we can calculate the speed of the neutrino.

The distance between the source and the detector in a straight line is about 730 km and it was measured with an accuracy of 20 cm (the exact distance between the reference points is 730534.61 ± 0.20 meters). True, the process leading to the birth of a neutrino is not at all localized with such accuracy. At CERN, a beam of high-energy protons flies out of the SPS accelerator, is dropped onto a graphite target and generates secondary particles in it, including mesons. They continue to fly forward at near-light speed and decay into muons on the fly with the emission of neutrinos. Muons also decay and give rise to additional neutrinos. Then all particles, except for neutrinos, are absorbed in the thickness of the substance, and they freely reach the place of detection. General scheme this part of the experiment is shown in Fig. 1.

The entire cascade leading to the appearance of a neutrino beam can stretch for hundreds of meters. However, since All particles in this bunch fly forward at near-light speed, there is practically no difference for the detection time, whether a neutrino was born immediately or after a kilometer of the way (however, it has great importance, when exactly the original proton, which led to the birth of this neutrino, flew out of the accelerator). As a result, the produced neutrinos by and large simply repeat the profile of the original proton beam. Therefore, the key parameter here is precisely the time profile of the proton beam emitted from the accelerator, in particular, the exact position of its leading and trailing edges, and this profile is measured with good time s m resolution (see Fig. 2).

Each session of dropping a proton beam onto a target (in English such a session is called spill, "splash") lasts about 10 microseconds and leads to the birth of a huge number of neutrinos. However, almost all of them fly through the Earth (and the detector) without interaction. In the same rare cases when the detector does register a neutrino, it is impossible to say at what exact moment during the 10-microsecond interval it was emitted. The analysis can be carried out only statistically, that is, to accumulate many cases of neutrino detection and construct their time distribution relative to the starting point for each session. In the detector, the point of time is taken as the origin when the conditional signal moving at the speed of light and emitted exactly at the moment of the leading edge of the proton beam reaches the detector. Accurate measurement of this moment was made possible by synchronizing the clocks in the two laboratories to within a few nanoseconds.

On fig. 3 shows an example of such a distribution. The black dots are real neutrino data recorded by the detector and summed over a large number sessions. The red curve shows a conventional "reference" signal that would move at the speed of light. You can see that the data starts at about 1048.5 ns. earlier reference signal. This, however, does not yet mean that the neutrino is actually ahead of the light by a microsecond, but is only a reason to carefully measure all cable lengths, equipment response speeds, electronics delay times, and so on. This recheck was done and found to shift the "reference" moment by 988 ns. Thus, it turns out that the neutrino signal actually outruns the reference one, but only by about 60 nanoseconds. In terms of the neutrino speed, this corresponds to an excess of the speed of light by about 0.0025%.

The error of this measurement was estimated by the authors of the analysis at 10 nanoseconds, which includes both statistical and systematic errors. Thus, the authors claim that they "see" the superluminal motion of neutrinos at a level of statistical significance of six standard deviations.

The difference between the results and expectations by six standard deviations is already quite large and is called in elementary particle physics the loud word "discovery". However, this number must be understood correctly: it only means that the probability statistical fluctuations in the data is very small, but does not indicate how reliable the data processing technique is and how well physicists have taken into account all instrumental errors. After all, there are many examples in elementary particle physics where unusual signals have not been confirmed by other experiments with exceptionally high statistical certainty.

What do superluminal neutrinos contradict?

Contrary to popular belief, special relativity does not in itself prohibit the existence of particles moving at superluminal speeds. However, for such particles (they are generally called "tachyons"), the speed of light is also a limit, but only from below - they cannot move slower than it. In this case, the dependence of the energy of particles on the speed turns out to be inverse: the greater the energy, the closer the speed of tachyons to the speed of light.

Much more serious problems begin in quantum field theory. This theory is replacing quantum mechanics when talking about quantum particles with great energies. In this theory, particles are not points, but, relatively speaking, clumps of the material field, and they cannot be considered separately from the field. It turns out that tachyons lower the energy of the field, which means they make the vacuum unstable. It is then more profitable for the void to spontaneously break up into a huge number of these particles, and therefore it is simply meaningless to consider the movement of one tachyon in ordinary empty space. We can say that a tachyon is not a particle, but an instability of the vacuum.

In the case of tachyon-fermions, the situation is somewhat more complicated, but even there, comparable difficulties arise that hinder the creation of a self-consistent tachyon quantum field theory, including the usual theory of relativity.

However, this is also not the last word in theory. Just as experimenters measure everything that can be measured, theorists also test all possible hypothetical models that do not contradict the available data. In particular, there are theories in which a slight, not yet noticed deviation from the postulates of the theory of relativity is allowed - for example, the speed of light itself can be variable. Such theories do not yet have direct experimental support, but they have not yet been closed.

This brief sketch of the theoretical possibilities can be summed up as follows: despite the fact that in some theoretical models the movement with superluminal speed is possible, they remain only hypothetical constructions. All currently available experimental data are described by standard theories without superluminal motion. Therefore, if it were reliably confirmed for at least some particles, quantum field theory would have to be radically redone.

Is it worth considering the result of OPERA in this sense as the "first sign"? Not yet. Perhaps the most important reason for skepticism is the fact that the OPERA result does not agree with other experimental data on neutrinos.

First, during the famous supernova SN1987A, neutrinos were also registered, which arrived a few hours before the light pulse. This does not mean that neutrinos traveled faster than light, but only reflects the fact that neutrinos are emitted at an earlier stage of the collapse of the nucleus during a supernova explosion than light. However, since neutrinos and light, having spent 170,000 years on the road, did not separate by more than a few hours, it means that their speeds are very close and differ by no more than billionths. The OPERA experiment shows a thousand times stronger discrepancy.

Here, of course, we can say that neutrinos produced during supernova explosions and CERN neutrinos differ greatly in energy (several tens of MeV in supernovae and 10–40 GeV in the described experiment), and the neutrino velocity varies depending on the energy. But this change in this case works in the “wrong” direction: after all, the higher the energy of tachyons, the closer their speed should be to the speed of light. Of course, even here it is possible to come up with some modification of the tachyon theory, in which this dependence would be completely different, but in this case it will be necessary to discuss the “double-hypothetical” model.

Further, from the set of experimental data on neutrino oscillations obtained for last years, it follows that the masses of all neutrinos differ from each other only by fractions of an electronvolt. If the OPERA result is perceived as a manifestation of the superluminal motion of a neutrino, then the value of the square of the mass of at least one neutrino will be of the order of –(100 MeV) 2 (the negative square of the mass is the mathematical manifestation of the fact that the particle is considered a tachyon). Then you have to admit that All varieties of neutrinos are tachyons and have approximately the same mass. On the other side, direct measurement neutrino mass in the beta decay of tritium nuclei shows that the neutrino mass (modulo) should not exceed 2 electron volts. In other words, it will not be possible to reconcile all these data with each other.

The conclusion from this can be drawn as follows: the declared result of the OPERA collaboration is difficult to fit into any, even the most exotic, theoretical models.

What's next?

In all large collaborations in elementary particle physics, the normal practice is that each specific analysis is performed by a small group of participants, and only then the results are submitted for general discussion. In this case, apparently, this stage was too short, as a result of which not all the participants in the collaboration agreed to put their signature under the article (the full list includes 216 participants in the experiment, and the preprint has only 174 authors). Therefore, in the near future, most likely, many additional checks will be carried out within the collaboration, and only after that the article will be sent to print.

Of course, now one can also expect a stream of theoretical papers with various exotic explanations of this result. However, until the claimed result is reliably rechecked, it cannot be considered a full-fledged discovery.

Physicists have discovered that particles of light (photons) can live for about 1 trillion years, and after decay, in turn, emit very light particles that can travel faster than light! Over time, many particles are subject to natural decay. For example, unstable radioactive atoms at a certain moment break up into small particles and release a burst of energy.

Just recently, scientists were sure that photons did not decay, because it was believed that they had no mass. However, scientists now assume that photons do have mass, it's just that it's so small that it can't be measured with today's instruments.

The current upper limit on the mass of a photon is so small that it is less than one billionth, billionth, billionth of the mass of a proton. Based on this indicator, scientists calculated that a photon in visible spectrum can live for about 1 trillion years. However, this extremely long lifetime is not shared by all photons, it is calculated on average. There is a possibility that some photons live very short lives. Our universe, which came into being as a result of the Big Bang, is currently about 13.7 billion years old. And ongoing scientific projects designed not only to measure the afterglow of the Big Bang, but also to possibly detect signs of the early decay of photons.

If the photon is broken, the decay should produce even lighter particles, those that can travel through our universe faster than the speed of light. These ghostly particles (neutrinos) very rarely interact with ordinary matter. Countless streams of neutrinos rush every fraction of a second not only through space, stars and bodies, but also through every person living on Earth, without affecting our matter.

When decaying, each photon releases two light neutrinos, which, being lighter than light, move faster than photons. The discovery of the neutrino would seem to violate Einstein's law of relativity that nothing can travel faster than light, but this is not the case, since the theory is based on the fact that the photon has no mass. And the theory says that no particle can move faster than a massless particle.

In addition, Einstein's theory of relativity suggests that particles move extremely fast while in a distorted time space. That is, if they were conscious, they would have the impression that everything that happens around them is in very slow motion mode. This means that in our time space, photons should live for about 1 trillion years, and in their time stream - only about three years.

Sergei Vasilenkov

We were taught from school that it is impossible to exceed the speed of light, and therefore the movement of a person in outer space is a big insoluble problem (how to fly to the nearest solar system if light can overcome this distance only in a few thousand years?). Perhaps American scientists have found a way to fly at superspeeds, not only without cheating, but also following the fundamental laws of Albert Einstein. In any case, Harold White, the author of the project of the space deformation engine, says so.

We at the editorial office considered the news absolutely fantastic, so today, on the eve of Cosmonautics Day, we are publishing a report by Konstantin Kakaes for Popular Science magazine about a phenomenal NASA project, if successful, a person will be able to go beyond solar system.

In September 2012, several hundred scientists, engineers and space enthusiasts came together for the group's second public meeting called 100 Year Starship. The group is led by former astronaut May Jemison and founded by DARPA. The goal of the conference is "to make possible human travel beyond the solar system to other stars within the next hundred years." Most of the conference participants admit that progress in manned space exploration is too small. Despite the billions of dollars spent in the last few quarters, the space agencies can do almost as much as they could in the 1960s. Actually, 100 Year Starship is convened to fix all this.

But more to the point. After a few days of the conference, its participants reached the most fantastic topics: organ regeneration, the problem of organized religion on board the ship, and so on. One of the more intriguing presentations at the 100 Year Starship meeting was called Warp Field Mechanics 102, and was delivered by NASA's Harold "Sonny" White. An agency veteran, White runs the Advanced Pulse Program at the Johnson Space Center (JSC). Together with five colleagues, he created the "Roadmap of Space Propulsion Systems", which voices the goals of NASA in the coming space travel. The plan lists all kinds of propulsion projects, from advanced chemical rockets to far-reaching developments like antimatter or nuclear machines. But White's area of ​​research is the most futuristic of all: it concerns the space warp engine.

this is how Alcubierre's bubble is usually depicted

According to the plan, such an engine will provide movement in space at a speed exceeding the speed of light. It is generally accepted that this is impossible, since it is a clear violation of Einstein's theory of relativity. But White argues otherwise. As confirmation of his words, he appeals to the so-called Alcubierre bubbles (equations derived from Einstein's theory, according to which a body in outer space is capable of reaching superluminal speeds, in contrast to a body in normal conditions). In the presentation, he told how he recently managed to achieve theoretical results that directly lead to the creation of a real space warp engine.

It is clear that this all sounds absolutely fantastic: such developments are a real revolution that will untie the hands of all astrophysicists in the world. Instead of spending 75,000 years traveling to Alpha Centauri, the nearest star system, astronauts on a ship with such an engine will be able to make this trip in a couple of weeks.

In light of the shutdown of the shuttle program and the growing role of private flights to low Earth orbit, NASA says it is refocusing on far-reaching, much bolder plans that go far beyond traveling to the moon. These goals can only be achieved through the development of new propulsion systems - the sooner the better. A few days after the conference, NASA chief Charles Bolden echoed White's words: "We want to travel faster than the speed of light and non-stop on Mars."

HOW DO WE KNOW ABOUT THIS ENGINE

The first popular use of the expression "space warp engine" dates back to 1966, when Jen Roddenberry released " Star Trek". For the next 30 years, this engine existed only as part of this fantasy series. A physicist named Miguel Alcubierre watched an episode of the series just as he was working on his doctorate in general relativity and was wondering if it was possible to create a space warp drive in reality. In 1994, he published a paper setting out this position.

Alcubierre imagined a bubble in space. In the front of the bubble, time-space is contracting, and in the back it is expanding (as it was with big bang, according to physicists). The deformation will cause the ship to glide smoothly through outer space, as if it were surfing a wave, despite the surrounding noise. In principle, a deformed bubble can move arbitrarily fast; the limitations in the speed of light, according to Einstein's theory, apply only in the context of space-time, but not in such distortions of space-time. Inside the bubble, Alcubierre predicted, space-time would not change and space travelers would not be harmed.

Einstein's equations in general relativity are tricky to solve in one direction, figuring out how matter curves space, but it's doable. Using them, Alcubierre determined that the distribution of matter is a necessary condition for the creation of a deformed bubble. The only problem is that the decisions led to indefinite form matter called negative energy.

talking plain language, gravity is the force of attraction between two objects. Each object, regardless of its size, exerts some force of attraction on the surrounding matter. According to Einstein, this force is a curvature of space-time. Negative energy, however, is gravitationally negative, that is, repulsive. Instead of connecting time and space, negative energy repels and separates them. Roughly speaking, for this model to work, Alcubierra needs negative energy to expand the space-time behind the ship.

Despite the fact that no one has ever specifically measured negative energy, according to quantum mechanics, it exists, and scientists have learned how to create it in the laboratory. One way to recreate it is through the Kazimirov effect: two parallel conductive plates placed close to each other create some amount of negative energy. The weak point of the Alcubierre model is that its implementation requires a huge amount of negative energy, several orders of magnitude higher than, according to scientists, it can be produced.

White says he has found a way around this limitation. In a computer simulation, White altered the geometry of the warp field so that, in theory, it could produce a deformed bubble using millions of times less negative energy than Alcubierra estimated required, and perhaps little enough for a spacecraft to carry its means of production. "The discoveries," says White, "change Alcubierre's method from impractical to quite plausible."

REPORT FROM WHITE'S LAB

The Johnson Space Center is located next to the Houston lagoons, from where the path to Galveston Bay opens. The center is a bit like a suburban college campus, only aimed at training astronauts. On the day of my visit, White meets me at Building 15, a multi-story maze of corridors, offices, and engine testing labs. White is wearing an Eagleworks polo shirt, as he calls his engine experiments, embroidered with an eagle soaring over a futuristic spaceship.

White began his career as an engineer doing research as part of a robotic group. Over time, he took command of the entire ISS robotic wing while completing his PhD in plasma physics. It wasn't until 2009 that he shifted his focus to the study of motion, and this topic captured him enough to become the main reason he went to work for NASA.

"He's quite an unusual person," says his boss, John Applewhite, who heads the propulsion systems division. - He is definitely a big dreamer, but at the same time a talented engineer. He knows how to turn his fantasies into a real engineering product.” Around the same time that he joined NASA, White asked permission to open his own laboratory dedicated to advanced propulsion systems. He himself came up with the name Eagleworks and even asked NASA to create a logo for his specialty. Then this work began.

White leads me to his office, which he shares with a colleague who searches for water on the Moon, and then leads me down to Eagleworks. On the way, he tells me about his request to open a laboratory and calls it "a long and difficult process of finding an advanced movement to help man explore space."

White shows me the object and shows me its central function, something he calls a "Quantum Vacuum Plasma Thruster" (QVPT). This device looks like a huge red velvet donut with wires tightly braided around the core. This is one of two Eagleworks initiatives (the other is the warp engine). It's also a secret development. When I ask what it is, White replies that he can only say that this technology is even cooler than the warp engine). According to a 2011 NASA report written by White, the craft uses quantum fluctuations in empty space as its fuel source, meaning that a QVPT-powered spacecraft does not require fuel.

The engine uses quantum fluctuations in empty space as a fuel source,
which means spaceship
powered by QVPT, does not require fuel.

When the device works, White's system looks cinematically perfect: the color of the laser is red, and the two beams are crossed like sabers. Inside the ring are four ceramic capacitors made of barium titanate, which White charges up to 23,000 volts. White has spent the last two and a half years developing the experiment, and he says that capacitors show tremendous potential energy. However, when I ask how to create the negative energy needed for warped space-time, he evades the answer. He explains that he signed a non-disclosure agreement, and therefore cannot reveal details. I ask with whom he made these agreements. He says: “With people. They come and want to talk. I can't give you more details."

OPPOSITORS OF THE ENGINE IDEA

So far, the warped travel theory is pretty intuitive - warping time and space to create a moving bubble - and it has a few significant flaws. Even if White significantly reduces the amount of negative energy Alcubierra asks for, it will still require more than scientists can produce, says Lawrence Ford, a theoretical physicist at Tufts University who has written numerous papers on the subject of negative energy over the past 30 years. Ford and other physicists claim that there are fundamental physical limitations, and it's not so much engineering imperfections, but that such an amount of negative energy cannot exist in one place for a long time.

Another complication: to create a deformation ball that moves faster than light, scientists will need to generate negative energy around the spacecraft, including above it. White doesn't think this is a problem; he replies very vaguely that the engine will most likely work due to some available “apparatus that creates the necessary conditions". However, creating these conditions in front of the ship would mean providing a constant supply of negative energy traveling faster than the speed of light, again contradicting general relativity.

Finally, the space warp engine raises a conceptual question. In general relativity, FTL travel is equivalent to time travel. If such an engine is real, White creates a time machine.

These obstacles give rise to some serious doubts. “I don’t think the physics we know and its laws allow us to assume that he will achieve anything with his experiments,” says Ken Olum, a physicist at Tufts University, who also participated in the debate about exotic movement at the Starship 100th Anniversary meeting. ". Noah Graham, a physicist at Middlebury College who read two of White's papers at my request, emailed me: "I don't see any valuable scientific evidence, in addition to references to his previous work."

Alcubierre, now a physicist at the National Autonomous University of Mexico, has his own doubts. "Even if I stand on spaceship and I have negative energy available, there's no way I can put it where it's needed,” he tells me over the phone from his home in Mexico City. - No, the idea is magical, I like it, I wrote it myself. But it has a couple of serious flaws that I already see over the years, and I don’t know a single way to fix them. ”

THE FUTURE OF SUPERSPEEDS

To the left of Johnson's main gate scientific center the Saturn-V rocket lies on its side, its stages are separated to show the internal contents. It's gigantic - the size of one of the many engines is the size of a small car, and the rocket itself is a couple of feet longer than a football field. This, of course, is quite eloquent evidence of the peculiarities of space navigation. Besides, she's 40 years old and the time she represents - when NASA was part of a huge national plan to send a man to the moon - is long gone. JSC today is just a place that was once great but has since left the space avant-garde.

A breakthrough in traffic could mean a new era for JSC and NASA, and to some extent part of that era is already beginning. The Dawn probe, launched in 2007, studies the ring of asteroids using ion thrusters. In 2010, the Japanese commissioned the Icarus, the first interplanetary starship powered by a solar sail, another kind of experimental propulsion. And in 2016, the scientists plan to test VASMIR, a plasma-powered system made specifically for high propulsion at the ISS. But when these systems possibly get astronauts to Mars, they still won't be able to take them outside the solar system. To achieve this, White said, NASA will need to take on more risky projects.

The Warp Drive is perhaps the most far-fetched of NASA's motion design efforts. The scientific community says that White cannot create it. Experts say it works against the laws of nature and physics. Despite this, NASA is behind the project. “It's not being subsidized at the high government level it should be,” says Applewhite. - I think that the management has some special interest in him continuing his work; it's one of those theoretical concepts that, if successful, completely changes the game."

In January, White assembled his warp interferometer and moved on to his next target. Eagleworks has outgrown its own home. The new lab is larger and, as he enthusiastically states, "seismically isolated," meaning that it is protected from vibrations. But perhaps the best new laboratory(and most impressive) is that NASA gave White the same conditions that Neil Armstrong and Buzz Aldrin had on the moon. Well, let's see.

We often talk about maximum speed of light in our universe, and that there is nothing that can move faster than the speed of light in a vacuum. And even more so - we. Approaching the near-light speed, the object acquires mass and energy, which either destroys it or contradicts Einstein's general theory of relativity. Suppose we believe in this and look for workarounds (like or we will figure it out) in order to fly to the nearest star not for 75,000 years, but for a couple of weeks. But since few of us have a higher physical education, it is not clear why they say on the streets that the speed of light is maximum, constant and equal to 300,000 km/s?

There are many simple and intuitive explanations for why this is so, but you can start to hate them. An Internet search will lead you to the concept of "relativistic mass" and that it requires more force to accelerate an object that is already moving at high speed. This is the usual way of interpreting the mathematical apparatus of special relativity, but it misleads many, and especially you, our dear readers. Since many of you (and us too) try high physics it tastes like dipping one finger into its salty water before entering for a swim. As a result, it becomes much more complex and less beautiful than it really is.

Let's discuss this question in terms of a geometric interpretation that is consistent with general theory relativity. It's less obvious, but a little more complicated than drawing arrows on paper, so many of you will immediately understand the theory behind abstractions like "force" and outright lies like "relativistic mass."

First, let's define what a direction is in order to clearly mark your place. "Down" is the direction. It is defined as the direction in which things fall when you let them go. "Up" is the opposite direction of "down". Pick up a compass and determine additional directions: north, south, west and east. All these directions are defined by serious uncles as "an orthonormal (or orthogonal) basis", but it's better not to think about it now. Let's assume that these six directions are absolute, since they will exist where we will deal with our complex issue.

Now let's add two more directions: to the future and to the past. You cannot easily move in these directions of your own free will, but it should be easy enough for you to imagine them. The future is the direction where tomorrow comes; the past is the direction where yesterday is.

These eight basic directions - up, down, north, south, west, east, past and future - describe the fundamental geometry of the universe. We can call each pair of these directions a "dimension", so we live in a four-dimensional universe. Another term for this 4D understanding would be "space-time", but we will try to avoid using that term. Just remember that in our context "space-time" will be equivalent to the concept of "universe".

Welcome to the stage. Let's look at the actors.

Sitting in front of the computer now, you are on the move. You don't feel it. You feel like you are at rest. But this is only because everything around you also moves relative to you. No, do not think that we are talking about the fact that the Earth is spinning around the Sun or the Sun is moving through the galaxy and pulling us along. This, of course, is true, but we are not talking about that now. By movement, we mean movement in the direction of the "future".

Imagine that you are in a train car with the windows closed. You can't see the street, and let's say the rails are so perfect that you don't know if the train is moving or not. Therefore, just sitting inside the train, you cannot say whether you are actually traveling or not. Look out into the street - and realize that the landscape is rushing past. But the windows are closed.

There is only one way to know if you are moving or not. Just sit and wait. If the train stops at the station, nothing will happen. But if the train is moving, sooner or later you will arrive at a new station.

In this metaphor, the car represents everything that we can see in the world around us - a house, Vaska the cat, stars in the sky, etc. "The next station is Tomorrow."

If you sit motionless, and the cat Vaska peacefully sleeps his hours put in the day, you will not feel movement. But tomorrow will surely come.

This is what it means to move towards the future. Only time will tell which is true: movement or parking.

So far, it should have been pretty easy for you to imagine all this. It may be difficult to think of time as a direction, and even more so of yourself as an object passing through time. But you will understand. Now turn on your imagination.

Imagine that while you are driving in your car, something terrible happens: the brakes fail. By a strange coincidence, at the same moment, the gas and gearbox are jammed. You can neither accelerate nor stop. The only thing you have is a steering wheel. You can change the direction of the movement, but not its speed.

Of course, the first thing you will do is try to drive into a soft bush and somehow gently stop the car. But let's not use this technique for now. Let's just focus on the features of your broken car: you can change direction, but not speed.

This is how we move through the universe. You have a steering wheel but no pedal. Sitting and reading this article, you are rolling into a bright future at maximum speed. And when you get up to make yourself a seagull, you change the direction of movement in space-time, but not its speed. If you move very quickly through space, time will flow a little slower.

This is easy to imagine by drawing a couple of axes on paper. The axis that will go up and down is the axis of time, up means the future. The horizontal axis represents space. We can only draw one dimension of space, since a sheet of paper is two-dimensional, but let's just imagine that this concept applies to all three dimensions of space.

Draw an arrow from the origin of the coordinate axis where they converge and point it up along the vertical axis. It doesn't matter how long it is, just keep in mind that it will only have one length. This arrow, now pointing into the future, is what physicists call "four-velocity." This is the speed of your movement through space-time. Right now you are in a stationary state, so the arrow is directed only to the future.

If you want to move through space - to the right on the coordinate axis - you need to change your four-velocity and turn on the horizontal component. It turns out that you need to rotate the arrow. But once you do that, you'll notice that the arrow isn't as confidently pointing up into the future as it was before. You are now moving through space, but you have to sacrifice future motion as the four-speed needle can only rotate, never expand or contract.

This is where the famous “time slowdown” effect begins, which is talked about by everyone even a little initiated into the special theory of relativity. If you are moving through space, you are not moving through time as fast as you could if you were sitting still. Your clock will keep time slower than the clock of a person who is not moving.

And now we come to the resolution of the question why the phrase "faster than light" does not make sense in our universe. See what happens if you want to move through space as quickly as possible. You turn the four-speed needle all the way until it points along the horizontal axis. We remember that the arrow cannot stretch. She can only rotate. So, you have increased the speed in space as much as possible. But it became impossible to move even faster. The arrow has nowhere to turn, otherwise it will become "straighter than straight" or "more horizontal than horizontal". To this concept and equate "faster than light." It is simply impossible how to feed a huge people with three fish and seven loaves of bread.

This is why nothing in our universe can move faster than light. Because the phrase "faster than light" in our universe is equivalent to the phrase "straighter than straight" or "more horizontal than horizontal."

Yes, you have a few questions. Why can four-velocity vectors only rotate but not expand? There is an answer to this question, but it is related to the invariance of the speed of light, and we will leave it for later. And if you just believe it, you will be a little less informed on this subject than the most brilliant physicists who have ever existed on our planet.

Skeptics may question why we use a simplified model of the geometry of space when talking about Euclidean rotations and circles. In the real world, the space-time geometry obeys the Minkowski geometry, and the rotations are hyperbolic. But a simple version of the explanation has the right to life.

As well as a simple explanation for that, .