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So, a tiny part of this proto-matter behaved very strangely and suddenly began to expand.

Hubble was the first to measure the distance to other galaxies through a comparative analysis of the observed luminosity of reference light sources: pulsars are considered to be such, and their relative brightness can be used to estimate the distances to galaxies in which they are located. He also managed to measure the speed of distant galaxies using the Doppler shift.

Here is its diagram, and it shows that almost all galaxies are moving away from us – and are moving away very quickly, at a speed of hundreds and thousands of kilometers per second. And by dividing the observed speed by the distance, we get the time it took for the galaxies to move away from us at the distance at which we are now observing them.

Moreover, the speed at which other galaxies move away from us seems to be proportional to the distance to them! Now we divide the distance by the speed – and we get the age of the Universe.

So, in 1929, when Hubble made this discovery, it was not just important. It was so important that it came as a complete surprise to the whole world. All the news, all the main newspaper headlines around the world were devoted to him – and the news of this extraordinary discovery seemed to people much more important, and most importantly – much more pleasant than the next news about the global economic crisis that broke out in the same year.

On the next slide, I have collected portraits of some of the famous scientists who worked on the issue of interest to us. Top center – Albert Einstein, this is a very famous photograph of him. In 1916, he gave us the general theory of relativity, according to which gravitational influences lead to the curvature of space-time. This was an amazing, simply improbable prediction, but soon it was confirmed by experimental measurements.

At the top left, you see Alexander Fridman, who in 1922, while working in Leningrad, declared: «Okay, I understand and accept Einstein’s equations, but based on them, I predict that the universe arose from a starting point and has been expanding since then.» To which Einstein replied: «This cannot be!»

In 1927, George Lemaitre, whom we see in the center with Einstein, repeated Friedman’s calculations and obtained the same result, and again Einstein declared that this was impossible.

Two years later, Hubble published the graph that I had just shown you before, and here Einstein could only apologize for being impolite to his colleagues and admit his misunderstanding of the nature of the Universe.

There are also portraits of scientists of the next generation: in the upper right corner – Georgy (George) Gamow, a native of Odessa, who emigrated to the United States. In 1948, Gamow, together with two young American physicists – Robert Herman and Ralph Alfer (you see them in the lower left corner) – invented and substantiated the Big Bang theory, and according to their calculations, it turned out that the entire Universe should be permeated with relic radiation, a thermal background left over from the Big Bang. This radiation should have been sufficiently «bright» – with a power of about 1 µW / m2. And then, in 1948, they predicted it correctly. Only the technical capabilities of primitive devices of that time were not enough to detect it.

Finally, in the lower right corner, I have placed two quite modern scientists. These are Rashid Sunyaev and Jim Peebles, who for many years have been doing calculations and predicting what we should see and what results of astrophysical measurements we will get. They are pioneers in this kind of theoretical calculations.

With the next picture, I want to explain that, although in the general view the universe originated at some starting point, we, astronomers, cannot say this. In reality, we see neither the center nor the edge of the universe. And all astronomers, when they calculate the parameters of the expansion of the Universe according to the Hubble’s law, proceed, in fact, from the fact that we ourselves are at the center of the Universe.

Well, if they think so, then they really are in the center, because the center, as such, simply does not exist. At least until now, no one has proven that the center of the universe exists – just as no one has denied the possibility of its existence. However, no observations have found any signs of the existence of the center or edge of the universe. Such an amazing result is obtained from the totality of all calculations.

And this means that we cannot draw up a corresponding visual picture either. So we will simply display on a forbidding red background the fact that we cannot draw a visual picture.

We, ordinary human beings, live in a four-dimensional world with three spatial dimensions and one temporal. And in order to look at the Universe from the outside, additional dimensions are needed, which we can only speculatively imagine, but cannot graphically represent. So, excuse me, we cannot draw you a visual picture, we cannot see the center of the Universe or its borders, even if there are such.

Here I would like to briefly outline our current ideas about the history of the origin of the early Universe.

Let us imagine that primordial matter, whatever it is, actually stretched infinitely in all dimensions, and there could be more dimensions than the four that we now know.

So, a tiny part of this proto-matter behaved very strangely and suddenly began to expand. Moreover, it expanded so rapidly that even light could not keep up with the expanding matter.

And this small volume of matter – ten centimeters in diameter – as we now believe, has rapidly accelerated, and marked the beginning of the entire expanding Universe that we now observe.

An extremely implausible story, but no one has come up with anything better than it – at least for the moment.

You ask: how could the entire Universe fit entirely in such a small volume, which I mentioned? There are several aspects to consider here.

First, outer space is practically completely empty of matter: the stars are at a great distance from each other.

Even atoms – and they consist of almost a continuous void. The dimensions of atomic nuclei are incomparably small compared to the dimensions of whole atoms. And if we had the opportunity to penetrate into atomic nuclei, we would easily dismember them and find out that they consist of even smaller particles – quarks and gluons.

So: calculations show that it is not at all as incredible as it might seem – that the entire modern Universe originated from such a small volume of primordial matter.

Here, in short, is the whole history of what is now commonly called the «inflationary stage» of the origin of the Universe, which theoretical physicists have known about since the mid-1980s.

And here the next question arises, requiring an answer from us: how did our very existence become possible? Since the universe is expanding, why aren’t we expanding ourselves? How do we even exist?

In short, the answer should be sought in the field of the properties of gravity, acting throughout the universe. The forces of gravitational attraction prevent the expansion of formations, the density of which exceeds the average. In some regions of the young Universe, originally formed as a result of the Big Bang, the average density of matter turned out to be higher – and these regions stopped expanding, and over time galaxies and clusters of galaxies began to form there, and then stars to form.

This made it possible for the Sun to appear first, then the Earth and, finally, the whole variety of complex organic life on Earth. All this was due to the ability of gravity to stop the expansion of certain areas of the universe.

That is why we exist.

The next slide is a brief history of the early universe. Above – a picture of the Big Bang, recreated from the results of measurements of the cosmic background radiation, obtained at the WMAP observatory.

Galaxies, according to our ideas, were formed from the smallest particles, which gradually flocked to denser clumps of matter, like rivulets merging into huge rivers.

Finally, in the lower left corner, you see a snapshot of the nearest neighboring galaxy, more precisely, the closest large galaxy to us. This is the Andromeda Nebula. Look how beautiful she is. And it even has two satellites – two small galaxies orbiting around it.

Further I will skip some part of the story about the history of the Universe. I will only mention the key events.

When our universe was about three minutes old, the first atomic helium nuclei were formed from protons and neutrons.

When the Universe was about 389,000 years old, electrons were captured by atomic nuclei – and transparent gas clouds formed in place of an opaque hot plasma.

As soon as the Universe became transparent, the primary thermal radiation, which until then could only travel short distances, immediately spread throughout the entire Universe – from edge to edge.

And now, being on Earth, we can observe this relict background radiation in the form that it took, as soon as outer space became transparent, when the Universe was 389 thousand years old.

Well, then the first stars began to form, and although their formation is too far from us in time or distance and we cannot personally observe this process, we can theoretically calculate what exactly caused their formation from gas.

And then, about 5 billion years ago, an amazing thing happened: the rate of expansion of the universe began to accelerate again! And now it is expanding every year faster and faster. Unbelievable, but it is a fact!

Now I would like to illustrate some of the events that probably happened to the Earth. The sun and the first solids in the solar system were formed 4.567 billion years ago – that is, the solar system is about three times the age of the universe. We can judge this by the most accurate radioisotope measurements of the age of the oldest microscopic inclusions extracted from meteorites.

Then, about 90 million years after that, a small planet about the size of modern Mars – astronomers gave it the name Theia – collided with the Earth and literally swept everything from its face. At the same time, lighter chemical elements, such as carbon and hydrogen, were thrown into near-earth space. All these debris and space debris formed, as a result, the Earth in its present form and the Moon. This happened, I repeat, about 90 million years after the formation of the solar system. And after that, the Earth began to gradually cool down.

Then, several hundred million years later, Jupiter and Saturn are believed to have changed their orbits twice under mutual gravitational influence. During this period, the Earth was subjected to powerful bombardment by a great variety of asteroids, meteorites and comets, together with which, as it is believed, water and carbon hit the Earth in sufficient quantities.

And at the end of this turbulent period, presumably, life began on Earth. There is extensive and full-fledged evidence that life could have arisen as soon as all the necessary conditions arose for this on Earth: the ambient temperature dropped and enough water accumulated to support and reproduce life.

Another interesting fact is that solar activity during that period was probably much more intense: there were many spots on the Sun, it flared up more and more brighter – and gradually warmed up the Earth. In this scenario, it is possible that some life forms came to Earth in a completely frozen state along with blocks of space ice – and subsequently thawed.

As you undoubtedly know, the earth’s continents drifted, and the associated tectonic activity sometimes caused dramatic changes in the chemical composition of the planet’s atmosphere. Sometimes, it seems, the atmosphere became simply poisonous – so much carbon dioxide and hydrogen sulfide were thrown into it. But over time, the molecules of these organic compounds, destructive to life, were again absorbed by the rocks due to various biochemical processes.

Geophysicists and geographers have recreated all the continents that formed over time on their maps. The last, relatively recently – «only» a hundred million years ago, opened the Atlantic Ocean, separating North and South America from Eurasia, and then Africa.

And quite recently, by cosmic standards, the first humanoid creatures appeared in Africa. It happened only some 150 thousand years ago, during the next ice age, when a significant part of the earth’s land was dehydrated or covered with glaciers and bound by permafrost.

I’m not going to talk in detail about the origin of man and the history of mankind – there is simply not enough time for this. I will only note that this year we are celebrating the 400th anniversary of instrumental astronomy: in 1609, Galileo Galilei sent his first weak optical telescope into the sky for the first time. Therefore, 2009 has been declared the International Year of Astronomy.

So I’ll get right to the bad news: there will be a lot of trouble in the future. Perhaps, as a result of biochemical processes taking place in the biosphere of the planet, all carbon dioxide from the earth’s atmosphere will be pumped out and deposited in limestones. After that, the Earth will become very, very cold, because without carbon dioxide, the «greenhouse effect» will stop. But this is just one of the hypotheses, and, perhaps, it will not be confirmed, since we are not very strong in geophysical forecasting yet.

Then, about a billion years later, the Sun will flare up so brightly that it will become unbearably hot for us on Earth, no matter what we do.

Finally, after about 5 billion years, the Sun will inevitably begin to grow in size – and swell to the point where its surface reaches Earth’s orbit. Here already, the Earth, presumably, will perish as such.

And approximately at the same time, our Galaxy – the Milky Way – will collide with the beautiful Andromeda Nebula, a photograph of which I showed you a few minutes ago. It will be a marvelous sight for astronomers, provided that by then we have moved to another planet. Well, if we don’t find a way, some alien astronomers will admire it.

In about 7.6 billion years, the Sun will burn out and turn into a «white dwarf» star.

And after many billions of centuries, as we assume, if the Universe continues to expand with acceleration, galaxies will disappear from the limits of visibility, the stars will burn out – and the Universe will plunge into darkness.

But this is just one of the theoretical hypotheses. There are others. It is possible that the expansion of the Universe will stop and then turn back – and the galaxies will again collapse into a heap, and then a universal collapse will occur. It’s not for us to judge, of course.

Now let’s tell you a little about the work that I personally did – and which led me, in the end, to receive the Nobel Prize.

In 1974, I graduated from the University of California at Berkeley and, as a thesis, tried, together with colleagues, to measure the https://123helpme.me/1984-summary/ intensity of the residual thermal radiation of the Big Bang – alas, unsuccessfully.