Hawking's theory of everything. The main ideas of Stephen Hawking. There are a huge number of Universes

31.03.2020

Stephen Hawking

Theory of everything

Translation of the original edition:

The Theory of Everything

Reprinted with permission Waterside Productions Inc and the literary agency "Synopsis".

Introduction

In this series of lectures, I will try to outline our understanding of the history of the Universe from the Big Bang to the formation of black holes. The first lecture is dedicated to brief overview ideas about the structure of the Universe that were held in the past, and the story of how the modern picture of the world was built. This part can be called the history of the development of ideas about the history of the Universe.

In the second lecture, I will describe how Newton's and Einstein's theories of gravity led to the understanding that the Universe cannot remain unchanged - it must either expand or contract. From this, in turn, it follows that at some time in the interval from 10 to 20 billion years ago the density of the Universe was infinite. This point on the time axis is called the Big Bang. Apparently, this moment was the beginning of the existence of the Universe.

In the third lecture I will talk about black holes. They are formed when a massive star or larger cosmic body collapses under its own gravity. According to general theory According to Einstein's relativity, anyone stupid enough to fall into a black hole will remain there forever. No one will be able to get out of there. At the singularity, the history of the existence of any object comes to an end. However, the general theory of relativity is a classical theory, that is, it does not take into account the quantum mechanical principle of uncertainty.

In the fourth lecture, I will explain how quantum mechanics allows energy to escape from a black hole. Black holes are not as black as they are made out to be.

In the fifth lecture, I will talk about the application of the ideas of quantum mechanics to solving questions related to the Big Bang and the origin of the Universe. This will lead us to understand that spacetime can be finite, but have no boundary or edge. It resembles the surface of the Earth, but with two more dimensions added.

In the sixth lecture I will show how this new boundary assumption can explain why the past is so different from the future even though the laws of physics are time symmetrical.

Finally, in the seventh lecture, I will talk about attempts to formulate a unified theory that covers quantum mechanics, gravity, and all other physical interactions. If we succeed, we will truly be able to understand the Universe and our place in it.

Lecture one

Ideas about the Universe

Back in 340 BC. e. Aristotle, in his treatise On the Heavens, formulated two compelling arguments in favor of the fact that the Earth is spherical and not flat like a plate. Firstly, he realized that lunar eclipses caused by the passage of the Earth between the Sun and Moon. The shadow of the Earth on the Moon is always round, and this is only possible if the Earth has a spherical shape. If the Earth were a flat disk, the shadow would be elongated and elliptical unless the Sun was directly above the center of the disk at the time of the eclipse.

Secondly, from the experience of their travels the Greeks knew that in southern regions The North Star is lower above the horizon than in more northern regions. Based on the difference in the apparent positions of the North Star in Egypt and Greece, Aristotle even gives an estimate of the circumference of the Earth - 400 thousand stadia. It is not known exactly what one stage is equal to (perhaps about 180 meters). Aristotle's estimate is then almost twice the value currently accepted.

The ancient Greeks also had a third argument in favor of the fact that the Earth should be spherical: otherwise why do the sails of an approaching ship first appear on the horizon and only then does its hull become visible? Aristotle thought that the Earth was stationary, and the Sun, Moon, planets and stars moved in circular orbits around it. He thought so because, due to mystical considerations, he was convinced that the Earth is the center of the Universe, and circular motion is the most perfect.

Aristotle believed that the Earth is motionless, and the Sun, Moon, planets and stars move in circular orbits around it.

In the 1st century AD e. this idea was developed by Ptolemy into a holistic cosmological model. The Earth is located in the center, surrounded by eight spheres bearing the Moon, Sun, stars and the five planets known at that time: Mercury, Venus, Mars, Jupiter and Saturn. The planets move in circles of smaller radii, which are associated with the corresponding spheres. This was required to explain their rather complex observed trajectories of movement across the sky. On the outer sphere there are the so-called fixed stars, which maintain their positions relative to each other, but all together make a circular motion across the sky. What lies beyond the outer sphere remained unclear, but this part of the Universe was undoubtedly inaccessible to observation.

Ptolemy's model made it possible to quite accurately predict the positions of celestial bodies in the sky. But to do this, Ptolemy had to admit that sometimes the Moon comes twice as close to the Earth as at other moments of its movement along the predicted trajectory. This meant that periodically the Moon should appear twice its normal size. Ptolemy was aware of this shortcoming, but despite this, his model was accepted by most, although not all. It received the approval of the Christian Church as a picture of the world consistent with Holy Scripture. After all, this model had a huge advantage, since it left enough space for heaven and hell behind the sphere of the fixed stars.

An ancient drawing depicting various cosmological models that explained the movement of the planets. The central diagram shows a heliocentric (the Sun is in the center) model of the movement of the six planets known at that time, their satellites and other celestial bodies revolving around the Sun. From the second century, the geocentric (Earth in the center) Ptolemaic system (top left) became the dominant model. It was succeeded by Copernicus's heliocentric system, published in 1543 (bottom right). The Egyptian model (bottom left) and Tycho Brahe's model (top right) attempted to preserve the idea of a stationary Earth as the center of the universe. Details of the orbits of the planets are given on the left and right.

From the Illustrated Atlas by Johann Georg Heck, 1860.

However, in 1514, the Polish priest Nicolaus Copernicus proposed a much simpler model. At first, fearing accusations of heresy, he published his model anonymously. He believed that the stationary Sun was in the center, and the Earth and planets moved around it in circular orbits. Unfortunately for Copernicus, it was almost a hundred years before his ideas were taken seriously. Then two astronomers - the German Johannes Kepler and the Italian Galileo Galilei - publicly came out in support of the Copernican theory, despite the fact that the orbits predicted on the basis of this theory were somewhat different from those observed. The dominance of the Aristotle-Ptolemy theory came to an end in 1609, when Galileo Galilei began studying the night sky using the newly invented telescope.

In 1609, Galileo Galilei began studying the night sky using a newly invented telescope.

While observing Jupiter, Galileo noticed that the planet was accompanied by several small satellites (moons) that orbited around it. This meant that not everyone celestial bodies must revolve around the Earth, as Aristotle and Ptolemy thought. Of course, it was still possible to assume that the Earth is motionless and located at the center of the Universe, and the satellites of Jupiter move along extremely complex trajectories around the Earth, so that the appearance of their revolution around Jupiter is created. However, Copernicus' theory was much simpler.

At the same time, Kepler developed the Copernican theory, suggesting that the planets move not in circular orbits, but in elliptical ones. Now the theory's predictions have finally coincided with observations. As far as Kepler was concerned, elliptical orbits were only an artificial hypothesis, and a very unfortunate one, since the ellipse was considered a less perfect figure than a circle. Having discovered (almost by accident) that elliptical orbits corresponded well with observations, he could not reconcile this with his idea that the planets revolve around the Sun under the influence of magnetic forces.

The explanation was found much later, in 1687, when Newton published his work "Mathematical principles of natural philosophy". This is perhaps the most important work on physics ever published. In it, Newton not only proposed a theory of the movement of bodies in space and time, but also developed a mathematical apparatus for analyzing this movement. In addition, he formulated the law universal gravity. This law states that all bodies in the Universe are attracted to each other with a force, which is greater, the greater the mass of the bodies and the closer to each other they are located. This is the same force that causes objects to fall to the ground. The story of the apple falling on Newton is almost certainly fictional. Newton himself only mentioned that the idea of gravity came to him when he was in a contemplative mood and noticed an apple falling.

On January 8, 1942, 300 years after the death of Galileo, Stephen William Hawking was born in Oxford, England. Approximately 200 thousand other children were also born that day, but only one became the greatest theoretical physicist and cosmologist. In the early 1960s, Hawking began to show signs of amyotrophic lateral sclerosis (Lou Gehrig's disease), which led to paralysis.

“An almost perfect embodiment of a free spirit, a huge intellect, a person who courageously overcomes physical weakness, devoting all his strength to deciphering the “divine plan,” this is how the German popularizer of science Hubert Mania describes Hawking in his book.

Hawking's achievements in science are undeniable. "RG" will talk about some of the most popular theories of the great physicist.

Hawking radiation is a hypothetical process of “evaporation” of black holes, that is, the emission of various elementary particles(mainly photons).

The process was predicted by Hawking in 1974. His work, by the way, was preceded by a visit to Moscow in 1973, where he met with Soviet scientists: one of the creators of atomic and hydrogen bomb Yakov Zeldovich and one of the founders of the theory of the early Universe, Alexei Starobinsky.

“When a huge star contracts, its gravity becomes so strong that even light can no longer escape its confines. The area from which nothing can escape is called a “black hole”. And its boundaries are called the “event horizon,” explains Hawking.

Note that the concept of a black hole as an object that does not emit anything, but can only absorb matter, is valid as long as quantum effects are not taken into account.

It was Hawking who began to study the behavior of elementary particles near a black hole from the point of view of quantum mechanics. He found out that particles can go beyond its boundaries and that a black hole cannot be completely black, that is, there is residual radiation. Fellow scientists applauded: everything has changed now! Information about the discovery spread like a hurricane in the scientific community. And it had a similar effect.

Hawking later discovered a mechanism by which black holes can emit radiation. He explained that from the point of view of quantum mechanics, space is filled with virtual particles. They constantly materialize in pairs, “separate”, “meet” again and annihilate. Near a black hole, one of a pair of particles can fall into it, and then the second will have no pair left to annihilate. Such “thrown” particles form the radiation that the black hole emits.

From this, Hawking concludes that black holes do not exist forever: they emit increasingly strong winds and, in the end, disappear as a result of a giant explosion.

“Einstein never accepted quantum mechanics because of the element of randomness and uncertainty associated with it. He said: God doesn't play dice. It looks like Einstein was wrong twice. The quantum effect of a black hole suggests that God not only plays dice, but also sometimes throws them where they cannot be seen,” says Hawking.

Black hole radiation—or Hawking radiation—showed that gravitational compression is not as permanent as previously thought: “If an astronaut falls into a black hole, it will then return to the outer part of the Universe in the form of radiation. So, in a sense, the astronaut will be redesigned."

The Question of God's Existence

In 1981, Hawking attended a conference on cosmology in the Vatican. After the conference, the Pope gave an audience to its participants and told them that they could study the development of the Universe after the big bang, but not the big bang itself, since this was the moment of creation and therefore the work of God.

Hawking later admitted that he was glad that the Pope did not know the topic of the lecture that the scientist had given before. It was precisely about the theory according to which the Universe did not have a beginning, a moment of creation as such.

There were similar theories in the early 1970s, they spoke of a fixed space and time that was empty throughout eternity. Then, for some unknown reason, a point formed - the universal core - and an explosion occurred.

Hawking believes that “if we move backwards in time, we reach a big bang singularity in which the laws of physics do not apply. But there is another direction of movement in time that avoids the singularity: it is called the imaginary direction of time. In it one can dispense with the singularity, which is the beginning or the end of time.”

That is, a moment appears in the present, which is not necessarily accompanied by a chain of moments in the past.

“If the universe had a beginning, we can assume that it also had a creator. But if the Universe is self-sufficient, has no border or edge, then it was not created and will not be destroyed. She simply exists. Where then is the place for its creator? - asks the theoretical physicist.

"From the Big Bang to Black Holes"

With this subtitle, Hawking's book A Brief History of Time was published in April 1988, which instantly became a bestseller.

Eccentric and supremely intelligent, Hawking is actively involved in the popularization of science. Although his book talks about the emergence of the Universe, the nature of space and time, black holes, there is only one formula - E=mc² (energy is equal to mass multiplied by the square of the speed of light in free space).

Until the 20th century, it was believed that the Universe was eternal and unchanging. Hawking argued in very accessible language that this is not so.

“Light from distant galaxies is shifted towards the red part of the spectrum. This means that they are moving away from us, that the Universe is expanding,” he says.

A static Universe seems more attractive: it exists and can continue to exist forever. It is something unshakable: a person ages, but the Universe is always as young as at the moment of formation.

The expansion of the Universe suggests that it had a beginning at some point in the past. This moment when the Universe began to exist is called the big bang.

“A dying star, contracting under its own gravity, eventually turns into a singularity - a point of infinite density and zero size. If we reverse the course of time so that contraction becomes expansion, it will be possible to prove that the universe had a beginning. However, the proof based on Einstein's theory of relativity also showed that it was impossible to understand how the Universe began: it demonstrated that all theories did not apply at the moment the Universe began,” the scientist notes.

Humanity awaits destruction

The cup can be seen falling off the table and breaking. But you can’t see how it comes back together from the fragments. The increase in disorder—entropy—is precisely what distinguishes the past from the future and gives direction to time.

Hawking asked the question: what will happen when the Universe stops expanding and begins to contract? Will we see broken cups being put back together?

“It seemed to me that when the compression began, the Universe would return to an ordered state. In this case, with the beginning of compression, time should have turned back. People at this stage would live their lives backwards and get younger as the Universe contracts,” he said.

Attempts to create a mathematical model of the theory were unsuccessful. Hawking later admitted his mistake. In his opinion, it was that he used too simple a model of the Universe. Time will not turn back when the Universe begins to shrink.

“In the real time in which we live, the Universe has two possible fates. It can continue to expand forever. Or it may begin to shrink and cease to exist at the moment of the “big flattening.” It will be like a big explosion, only in reverse,” the physicist believes.

Hawking admits that the Universe still faces an ending. However, it is stipulated that he, as the prophet of the end of the world, will not have the opportunity to be at that time - after many billions of years - and realize his mistake.

According to Hawking's theory, humanity can only be saved in this situation by the ability to break away from the Earth.

Aliens exist

People send unmanned vehicles into space with images of people and coordinates indicating the location of our planet. Radio signals are sent into space in the hope that alien civilizations will notice them.

According to Hawking, meetings with representatives of other planets do not bode well for earthlings. Based on his knowledge, he does not deny the possibility of the existence of an extraterrestrial civilization, but hopes that the meeting will not occur.

In a documentary television series on the Discovery Channel, he expressed the opinion that if alien technology surpasses that of Earth, they will definitely form their own colony on Earth and enslave humanity. Hawking compared this process to the arrival of Columbus in America and the consequences that awaited indigenous people continent.

“In a Universe with 100 billion galaxies, each containing hundreds of millions of stars, it is unlikely that Earth is the only place where life develops. From a purely mathematical point of view, numbers alone allow one to accept the idea of the existence alien life as absolutely reasonable. The real problem is what aliens might look like and whether earthlings will like their appearance. After all, they could be microbes or single-celled animals, or worms that inhabited the Earth for millions of years,” says Hawking.

Even the cosmologist’s relatives and friends note that one cannot believe his every word. He is a seeker. But in such a matter there are more assumptions than facts, and mistakes are inevitable. But even so, his research gives a person food for thought, a point from which one can begin to search for an answer to the question of the existence of man and the Universe.

“The answer to this question will be the greatest triumph of the human mind, because then we will know the mind of God,” says Hawking.

Stephen Hawking, who has done a lot scientific discoveries and assumptions about the structure of the world, was one of the most famous and popular physicists of our time. Hawking's main area of research is cosmology and quantum gravity.

For his achievements, Hawking became a member of the Royal Society of London in 1974, and in 1975, thanks to the development of the theory of the quantum process of “evaporation” of black holes, he became a world famous scientist. The discovery of this radiation, which leads to the elimination of black holes, is named after Stephen Hawking.
The essence of the Hawking Radiation phenomenon is the process of emission of various elementary particles by a black hole. According to this theory, a black hole not only absorbs everything around it, but also emits various particles itself, mainly photons. When a black hole has nothing left to absorb around itself, it must begin to shrink, that is, emit particles outward. This should ultimately lead to her disappearance through an explosion in the final stages. This emission is called “Hawking Radiation” or Black Hole Evaporation.

According to Einstein's general theory of relativity, primordial black holes could be born during the formation of the Universe, and some of them should theoretically finish evaporating in our time. Since with decreasing size black hole the intensity of evaporation, on the contrary, increases, then the last stages should, in fact, be an explosion of a black hole. However, no such explosions have been recorded so far.
By the way, Hawking radiation turned out to be a serious argument for the assumption of the emergence of small black holes during experiments conducted at the Large Hadron Collider. However, a microscopic black hole formed in this way, according to the same assumption, should instantly evaporate due to Hawking radiation and cannot pose a threat to the life of earthlings...
…. “I think that our mind is a program, while our brain is analogous to a computer. It is theoretically possible to copy the contents of the brain onto a computer and thus create a form of eternal life. Today, however, this is not in our power,” Hawking concluded.
According to Hawking, the past is just a possibility. One of the implications of the theory of quantum mechanics is that events that happened in the past did not happen in any particular way. Instead, they happened in every possible way. This is difficult for us to understand, and is due to the probabilistic nature of matter and energy according to quantum mechanics: until there is an outside observer, everything will float in uncertainty.....
…..Based on his knowledge, Stephen Hawking warns that artificial intelligence may well put an end to the human race, and the first contact with an intelligent extraterrestrial civilization may well be the last. According to him: if alien technology surpasses that of Earth, they will definitely form their own colony on Earth and enslave humanity.
But there is also good news. Recently a famous English physicist stated that modern science is on the eve of a revolution, when a unified theory will be created that explains all the fundamental foundations of the physical world and existence. Moreover, according to Hawking, the discovery will be made within the framework of the M-theory, which assumes the presence parallel worlds and numerous physical forces still unknown to modern science.
The so-called M-theory or “Theory of Everything,” proposed by Edward Witten in the 90s of the 20th century, was conceptualized and refined by Hawking and his colleague Leonard Mlodinow. M-theory is a branch of string theory and describes the entire Universe at once. According to it, at the smallest level, all particles consist of branes - multidimensional membranes, the properties of which can explain absolutely all processes occurring in our Universe. By the way, this theory also assumes the existence of a huge number of universes in which physical laws, different from ours.
Hawking claims that the creation of the Last Theory will finally complete the orderly edifice of theoretical physics. "We will learn the fundamental laws that govern the Universe." Well, given the fact that over the last hundred years of its history, humanity has made a huge innovation leap, there is no reason not to trust the prediction of the supremely intelligent scientist - Stephen Hawking.

“An almost perfect embodiment of a free spirit, a huge intellect, a person who courageously overcomes physical weakness, devoting all his strength to deciphering the “divine plan,” this is how the German popularizer of science Hubert Mania describes Hawking in his book.

Hawking's achievements in science are undeniable. "RG" will talk about some of the most popular theories of the great physicist.

Hawking radiation

Hawking radiation is a hypothetical process of “evaporation” of black holes, that is, the emission of various elementary particles (mainly photons).

The process was predicted by Hawking in 1974. His work, by the way, was preceded by a visit to Moscow in 1973, where he met with Soviet scientists: one of the creators of the atomic and hydrogen bombs, Yakov Zeldovich, and one of the founders of the theory of the early Universe, Alexei Starobinsky.

“When a huge star collapses, its gravity becomes so strong that even light can no longer escape its boundaries. The region from which nothing can escape is called a “black hole.” And its boundaries are called the “event horizon,” he explains Hawking.

Note that the concept of a black hole as an object that does not emit anything, but can only absorb matter, is valid as long as quantum effects are not taken into account.

From this, Hawking concludes that black holes do not exist forever: they emit increasingly strong winds and, in the end, disappear as a result of a giant explosion.

"Einstein never accepted quantum mechanics because of the element of randomness and uncertainty associated with it. He said: God does not play dice. It seems that Einstein was wrong twice. The quantum effect of a black hole suggests that God not only plays dice, but sometimes he throws them where they can’t be seen,” says Hawking.

Black hole radiation - or Hawking radiation - showed that gravitational compression is not as final as previously thought: "If an astronaut falls into a black hole, he will then return to the outer part of the Universe in the form of radiation. So, in a sense, The astronaut will be redesigned."

The Question of God's Existence

Hawking believes that "if we move backwards in time, we reach the big bang singularity, in which the laws of physics do not apply. But there is another direction of movement in time that avoids the singularity: it is called the imaginary direction of time. In this, we can do without singularity, which is the beginning or the end of time."

That is, a moment appears in the present, which is not necessarily accompanied by a chain of moments in the past.

"If the Universe had a beginning, we can assume that it had a creator. But if the Universe is self-sufficient, has no border or edge, then it was not created and will not be destroyed. It simply exists. Where then is the place for its creator?" - asks the theoretical physicist.

"From the Big Bang to Black Holes"

With this subtitle, Hawking's book A Brief History of Time was published in April 1988, which instantly became a bestseller.

Eccentric and supremely intelligent, Hawking is actively involved in the popularization of science. Although his book talks about the emergence of the Universe, the nature of space and time, black holes, there is only one formula - E=mc² (energy equals mass times the square of the speed of light in free space).

Until the 20th century, it was believed that the Universe was eternal and unchanging. Hawking argued in very accessible language that this is not so.

"The light from distant galaxies is shifted towards the red part of the spectrum. This means that they are moving away from us, that the Universe is expanding," he says.

A static Universe seems more attractive: it exists and can continue to exist forever. It is something unshakable: a person ages, but the Universe is always as young as at the moment of formation.

The expansion of the Universe suggests that it had a beginning at some point in the past. This moment when the Universe began to exist is called the big bang.

“A dying star, contracting under its own gravity, eventually collapses into a singularity—a point of infinite density and zero size. If we reverse the course of time so that contraction turns into expansion, it will be possible to prove that the Universe had a beginning. However, "The proof based on Einstein's theory of relativity also showed that it was impossible to understand how the universe came into being: it demonstrated that all theories did not apply at the moment the universe began," the scientist notes.

Humanity awaits destruction

The cup can be seen falling off the table and breaking. But you can’t see how it comes back together from the fragments. The increase in disorder - entropy - is precisely what distinguishes the past from the future and gives direction to time.

Hawking asked the question: what will happen when the Universe stops expanding and begins to contract? Will we see broken cups being put back together?

“It seemed to me that when the compression began, the Universe would return to an orderly state. In this case, with the beginning of the compression, time should have turned back. People at this stage would live their lives backwards and get younger as the Universe contracts,” he said.

"In the real time in which we live, the Universe has two possible fates. It can continue to expand forever. Or it can begin to contract and cease to exist at the moment of the 'big flattening'. It will be like a big bang, but in reverse." , - the physicist believes.

According to Hawking's theory, humanity can only be saved in this situation by the ability to break away from the Earth.

Aliens exist

“In a Universe with 100 billion galaxies, each containing hundreds of millions of stars, it is unlikely that Earth is the only place where life develops. From a purely mathematical point of view, the numbers alone make the idea of the existence of alien life absolutely reasonable. A real problem "is what aliens might look like, whether earthlings would like their appearance. After all, they could be microbes or single-celled animals, or worms that have inhabited the Earth for millions of years," Hawking said.

"The answer to this question will be the greatest triumph of the human mind, because then we will know the mind of God," says Hawking.

In the book, published in 1988, Hawking talks about what each of us has probably thought about at one time or another: how the Universe came into being, what the nature of space and time is, what black holes are, and how the theory of superstrings was born. The author also writes about some mathematical problems, but gives only one formula - E = mc².

Over 20 years, more than 10 million copies of this book have been sold.

17 years after the release of " Brief history” and the American physicist Leonard Mlodinow wrote a sequel. They used the latest data obtained from astronomical laboratories. The authors tell you what black matter and black energy are, whether time travel is possible, what the past and future of the Universe are, and dive even deeper into string theory.

This is also the history of the Universe, complemented by stunning illustrations - photographs from the Hubble Space Telescope. Hawking talks witty and accessible about the Big Bang and the ongoing search for a theory of everything - unified theory field, the “holy grail of modern physics.” Its appearance, according to the author, will mean the triumph of the human mind.

The book, written in 2006, brings together seven of Hawking's lectures.

A funny story about space adventures in which the boy George and his neighbors, the scientist Eric and his daughter Anna, find themselves. The authors talk in a very interesting and accessible way about quasars, asteroids, black holes, parallel and galaxies.

The book, based on Hawking's lecture at the University of California, was published in 1980. But later it was supplemented and translated into Russian in 2017. This is a collection that includes 13 essays by the scientist and his extensive interview.

The topics covered are very interesting. For example, how black holes can give life to young universes.

Together with Leonard Mlodinow, Hawking sings an ode to science. He claims that "it is impossible to prove the non-existence of God, but science makes it unnecessary." And therefore Big Bang may be a consequence of laws and nothing more.

A book that describes the essence of M-theory, which unites fundamental interactions, was published in 2010 and became a bestseller within a few days.

Hawking wrote his autobiographical book only in 2013. The reason is simple - he believed that popularizing science was more important than talking about himself. But the louder his name sounded, the more people wanted to know more about Hawking. And he decided to talk about his illness, family, science.

In this book, the scientist answered even the most uncomfortable and personal questions.

samarapedsovet.ru

The Question of God's Existence

"From the Big Bang to Black Holes"

Humanity awaits destruction

Aliens exist