Image copyright Getty November 25, 1915, Albert Einstein announced the full mathematical details of general relativity. In the general theory of relativity (GTR) to the three spatial dimensions of added time, and the world is four-dimensional.
Since then, the theory repeatedly tested in practice and, in general, has proved its worth, but not all and not everywhere . And attempts to merge it with another brainchild of science XX century – quantum mechanics – and a general theory of “anything” as long as no to no avail.
Yes, and Einstein, as they say, the end of life trying to change certain provisions of his theory, but something had went wrong. As far as modern science has progressed in the past hundred years?
Visiting program “Fifth floor,” which are Mikhail Smotryaev and Alexander Kahn, – Andrey Starinetz, researcher at the Center for Theoretical Physics Rudolf Peierls Oxford University.
Download the podcast program “Fifth floor” here.
Andrew Starinetz: First, let’s sum up the line under the concepts of what we speak. The general theory of relativity, whose centenary we celebrate this year – it is a theory of gravitation. This is a generalization of Newton’s theory of gravitation, which was formulated in the XVII century, and it’s great we have served and continue to serve. The deviation from the Newtonian theory of gravity in ordinary situations, for example, on the surface of the Earth – it is the effects of the order of ten to the minus seven, minus ten in the eighth, that is, it is not very large deviations. However, they are visible, they are measurable and can be theoretically predicted by Einstein that has been done.
That is the general theory of relativity – a compilation of already existing at this time Newton’s theory of gravitation. Secondly, like any physical theory which is a generalization of the theory of №1, Einstein’s theory of relativity has its scope and its limits. Nothing bad will happen if after some time it turns out that we need to modify this theory or replace it with a more general. This is not a refutation of the theory of relativity, both special and general relativity, because and both theory confirmed by experiments. Then do not talk about.
The only people who want something to be glorified, constantly write some treatises about refutation of Einstein. This is nonsense.
It is the synthesis, that is, to find a theory that generalizes the theory of relativity to the extent, in the areas of applicability, where the theory of relativity stops working for whatever his inner reasons For example, the description of the singularities of black holes or the description of the Big Bang, the earliest moments of the Big Bang, when the classical equations of general relativity no longer work, and the theory itself tells us about it. The question is – and physicists are working on it very hard – that summarize what Einstein did a hundred years ago.
MS.: On the one hand indeed there is no end of work, on the other hand – from time to time heard from the camp of Theoretical Physics statement that “we are close.” It began with the unification of the weak and electromagnetic interactions. Very popular were grandmodeli. Who is talking about it less.
The man, far from theoretical physics in its current, the current version, there can be such a representation only at the household level, the scientists are engaged in a compound of any one they understood concepts for To make this beautiful look, roughly speaking, is not only reinventing the wheel, but it significantly complicate, because to understand string theory with their many dimensions – we have four dimensions in the head fit very hard, simple, Einstein, and add to seven , and if I had not enough, another twenty-two – this is beyond the scope.
Say, physics generally understood in the fingers, what they do, and it has long gone beyond human perception at that level, at the level of receptors in the brain that are given to us by nature?
AS.: I think the physics well enough to understand what they are doing. So, what you said – you need to keep in mind, that certainly is necessary to separate the purely scientific problems, the evolution of a purely scientific things from some sociological effects that inevitably accompany them.
You talked about a burst of enthusiasm associated with the successful unification of electromagnetism and weak interactions in the 70s with the formulation of string theory in its original form. This was in such a good form in 1984. This was accompanied by a certain burst of enthusiasm in the first place, the physicists themselves, and then in the society, because it is like the waves on the water, often in distorted form, was passed in the wider population.
People thought Now that we formulate a theory of all interactions that we will explain not only the standard model of interaction between the particles, quantum gravity, combine all this together, and we will have a breakthrough grand scale – understandable cosmology and everything else. That has not happened in recent decades, and some disappointment in this connection is. This does not mean that people do not understand what they are working, that they were wrong all these 20-30 years, did everything wrong.
There are some specific scientific processes that go on as usual and there sociology, some journalistic thing and other sociological effects that need to very clearly separate from research. Problems still open.
What problems? Einstein in 1915 actually solved the problem of unification of special relativity, which has a finite speed of propagation of interactions, that is, the speed of light, the theory of gravity. This is the general theory of relativity, in which gravity propagates at the speed of light, but not at infinite speed, as it was in Newton’s theory. This problem was solved.
The problem that has not been solved so far – an association of general relativity, ie the relativistic theory of gravity with quantum mechanics and quantum field theory. String theory – an attempt to solve this problem and in the process unite the four existing interactions. This attempt continues. Will it lead to success, I can not say, because a lot of effort, as you rightly pointed out, be spent on this, prospects rather vague because it is with enormous technical complexity theory facing physics. People are working on it.
This does not mean that there is no other attempts to somehow explain or link gravity with quantum mechanics, quantum field theory. No relevant string theory. Such attempts also exist. This free version of the search of many – dozens, maybe even hundreds – of people who definitely understand what they are doing. Another thing is that this work is very, very difficult.
Alexander Kahn: I just am one of those people who in general in all practically do not understand. I even tried for a while to understand, but I have thrown this venture, and not going to try to ask you something else to explain. I was interested in something else, like a man deeply humanitarian. Why is the theory of relativity, this is one of the most important aspects of the world of physics, which, as you say, a few hundred people are involved, why this theory has become one of the truly popular scientific theories of the XX century?
In fact, it is not on the degree of their comprehension and popularity to pop science. On it everyone says, everyone knows, cartoons removed, it appears almost in jokes. Where is this theory has been so widespread in the world?
AS.: I think there are several aspects, one of which is associated with really Certain features of the theory of relativity. The fact is that, unlike so many physical theories, which were created as a direct generalization of experimental data collected for decades, with a lot of errors, prior theories, general relativity all went wrong.
General relativity – is an example of how to actually force of pure reason or, if you will, of pure genius could radically change the idea of the structure of space, time and the structure of the universe theoretically. Of course there were certain prerequisites were certain contradictions that prompted Einstein to think about all this. Still, it was not very similar to what happened with other physical theories.
In a sense, this triumph. The fact that mathematics in general relativity – is mathematics, which in those years, 100 years ago, has not been studied in the Faculty of Physics. These were some quite exotic mathematical structures, which Einstein himself did not know. He had friends of mathematics, which he explained how to work with these technical terms, and he learned from them is actually this.
That is some kind of power of pure reason, pure genius could, however, offer sufficient complex non-linear system of equations, which proved to be correct. Then with the help of pilot tests, observations and so on these ideas turned out to be absolutely true. It has played a significant role in the popularity of the general theory of relativity.
In fact, I think it had an influence on how theoretical physics in general developed in the XX century, including string theory, because it is an example of what can be a certain system of logic, mathematics, intuition, and so on to formulate a correct theory of a very general nature. It dominates.
The second aspect, which I have to mention, because he certainly played a significant role – is a person of Einstein, and the historical background, and all the vicissitudes of the time – 20 years, then the coming to power of Nazism, the fact that Einstein was in difficult relations with the Reich, for obvious reasons – such sociological component that, in the promotion, in drawing attention to this subject by journalists, also played a role.
MS.: O. Andrew, do not you think in this case that a certain degree of general relativity and its further development has become a hostage of its own popularity , time and author? This idea of unification of general relativity, the theory of gravitation, which is, in fact, the classical theory, quantum mechanics, quantum field theory, there is, in many ways, due to the fact that both theories in their limits, the limits of applicability, well-behaved proven and perfectly combined with experiments.
Is not there a certain inertia? In the end, a hundred years we have a general theory of relativity, it works perfectly. Why invent something new completely from scratch? Let’s continue to try to build a standard model based on it.
AS.: The first hundred years of the theory of relativity was very well developed. The equations of the theory itself has not changed, except for the little things, which I shall not touch, but the most important equation written by Einstein, are the same as were in 1915.
But it does not mean that the theory is not developed . Solutions have been found, it was found the interpretation of these decisions, and so on, that is, there was great progress in the development of the theory itself. As for your main question, then, I think the answer is no, that is, I do not think that we are talking about a hostage, certain sociological impact.
This can be explained in a simple manner. In fact, Einstein’s equations represent a single line in a compact form, where on the left there are some purely geometric mathematical expressions that are related to the curvature of space-time. On the right side is the energy-momentum tensor of matter and energy, that is, it is our standard model, that is, those particles, fields that we have in the universe live.
These fields and particles described by quantum field theory – we perfectly know it – and they described it perfectly. That is, the quantum theory is right and the left are the classical equations.
This means that only within certain limits, when we can talk about the quasi-classical transition from quantum to classical fields, we can trust this equation. At the classical level, it works fine. But since the right side is quantized, consequently, the left side must somehow account for these quantum effects. Therefore, in a sense, it seems to me that the quantization of gravity and the creation of quantum theory of gravity – it is simply a necessity, not a consequence of sociological inertia.
MS.: Since we came to this, the forecasts is not grateful, of course, but if it is necessary, when, according to you, in one form or another must wait for the general theory of everything? We remember how in the late XIX – early XX century physics proclaimed the end of the theoretical science for 10-15 years, and then came Einstein, then he had a dialogue with Bohr, this all broke Planck and disentangle the effects we are still ?
AS.: Yes, we disentangle the effects, including referring to the huge number of technologies that have been created on the basis of quantum mechanics and the whole the rest of what happened in the XX century. The question, of course, extremely difficult.
Indeed incredibly difficult to assess the prospects for the creation of quantum gravity, I’m not even talking about string theory. String theory is a prime candidate for the development of a theory of quantum gravity, gravity because there is enough naturally fits with the other interactions. Do not need to take any theoretical clumsy attempts, all happens quite naturally. But, as I said, string theory may not experiencing the best years in that sense, because it became clear that this theory is incredibly difficult.
Usually occurs as? Any formulation of the theory, there are some equations, such as Einstein’s equation. They can be solved, of which something follows some physical effects, and then someone goes and physical effects of these checks, it measures. It turned out – well, then, the theory is correct, did not work – it is necessary to think further.
With the string theory very difficult situation. Part of the equation of string theory formulated and partially even the effects can be said to have been predicted. For example, we know that in the same general theory of relativity, string theory predicts the amendment. But these amendments are extremely small. They are so small that the current level of experimental techniques, even if some hypothetical progress in experimental techniques to measure them will be virtually impossible. In any case, no one would know until the situations in which they can measure.
string theory itself is not complete, the equations of the theory is not fully discharged. In this situation, to answer the question, when do we get quantum theory of gravity, I’m afraid, is simply impossible. The most pessimistic forecast – a physicist, as usual, is considering limiting transitions – zero, infinity, and so on – it’s never. You can talk, so that there are some things that, with all the splendor of human thought, perhaps, will remain unexplored at the level at which there is human consciousness. But this is a very pessimistic forecast.
With regard to the optimistic forecast, I think that string theory will certainly be further developed, and over the next twenty, maybe thirty years it will be clear whether it is possible to give an answer in the framework of the ideas of string theory, with which it was originally formulated. If not – it means that you need to enter the game some extra performance. This, of course, it is impossible to speculate in any form.
MS.: Is that very quantum form the basis from the fact that it’s all probabilistic process – or will be, or not.
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