We see the starry sky all the time. The cosmos seems mysterious and immense, and we are only a tiny part of this vast world, mysterious and silent.
Throughout its life, humanity has been asking different questions. What is out there outside our galaxy? Is there something beyond the boundary of space? And does space have a border? Even scientists have been pondering these questions for a long time. Is space infinite? This article provides information that scientists currently have.
The boundaries of the endless
It is believed that our solar system was formed as a result of the Big Bang. It occurred due to the strong compression of matter and tore it apart, scattering gases in different directions. This explosion gave birth to galaxies and solar systems. The Milky Way was previously thought to be 4.5 billion years old. However, in 2013, the Planck telescope allowed scientists to recalculate the age of the solar system. It is now estimated to be 13.82 billion years old.
The most modern technology cannot cover the entire cosmos. Although the latest devices are able to catch the light of stars 15 billion light-years distant from our planet! It may even be stars that have already died, but their light is still traveling through space.
Our solar system is just a small part of a huge galaxy called the Milky Way. The Universe itself contains thousands of such galaxies. And whether space is infinite is unknown ...
The fact that the Universe is constantly expanding, forming more and more new cosmic bodies, is a scientific fact. Its appearance is probably constantly changing, which is why millions of years ago, as some scientists are sure, it looked completely different than it does today. And if the universe is growing, then it definitely has boundaries? How many Universes exist behind it? Alas, no one knows this.
Expansion of space
Scientists today claim that space is expanding very rapidly. Faster than they previously thought. Due to the expansion of the Universe, exoplanets and galaxies are moving away from us at different speeds. But at the same time, the rate of its growth is the same and uniform. It's just that these bodies are at different distances from us. Thus, the closest star to the Sun "runs away" from our Earth at a speed of 9 cm / s.
Now scientists are looking for an answer to another question. What makes the universe expand?
Dark matter and dark energy
Dark matter is a hypothetical substance. It does not produce energy or light, but it takes up 80% of the space. Scientists guessed about the presence of this elusive substance in space back in the 50s of the last century. Although there was no direct evidence of its existence, there were more and more supporters of this theory every day. Perhaps it contains substances unknown to us.
How did the theory of dark matter come about? The fact is that galaxy clusters would have collapsed long ago if only the materials visible to us constituted their mass. As a result, it turns out that most of our world is represented by an elusive substance that is still unknown to us.
In 1990, the so-called dark energy was discovered. After all, physicists used to think that the force of gravity works to slow down, one day the expansion of the Universe will stop. But both teams that took on this theory unexpectedly found expansion acceleration. Imagine that you toss an apple into the air and wait for it to fall, but instead it starts to move away from you. This suggests that the expansion is influenced by a certain force, which was called dark energy.
Today scientists are tired of arguing about whether space is infinite or not. They are trying to understand what the universe looked like before the Big Bang. However, this question doesn't make sense. After all, time and space by themselves are also infinite. So, let's consider several theories of scientists about space and its boundaries.
Infinity is ...
Such a concept as "infinity" is one of the most surprising and relative concepts. Scientists have been interested in it for a long time. In the real world in which we live, everything has an end, including life. Therefore, infinity beckons with its mystery and even some kind of mysticism. Infinity is hard to imagine. But it does exist. After all, it is with its help that many problems are solved, and not only mathematical ones.
Infinity and zero
Many scientists are convinced of the theory of infinity. However, Israeli mathematician Doron Selberger does not share their opinion. He claims that there is a huge number and if you add one to it, the end result will be zero. However, this number lies so far beyond human comprehension that its existence will never be proven. It is on this fact that the mathematical philosophy called "Ultrainfinity" is based.
Endless space
Is there a chance that adding two identical numbers will end up with the same number? At first glance, this seems absolutely impossible, but if we are talking about the Universe ... According to the calculations of scientists, when one subtracts from infinity, infinity is obtained. When two infinities are added together, infinity comes out again. But if you subtract infinity from infinity, most likely you get one.
Ancient scientists also wondered if there was a boundary in space. Their logic was simple and ingenious at the same time. Their theory is expressed as follows. Imagine that you have reached the edge of the universe. Stretched out their hand for its border. However, the framework of the world has expanded. And so it is endless. It is very difficult to imagine this. But it is even more difficult to imagine what exists abroad, if it really is.
Thousands of worlds
This theory says that the cosmos is infinite. It probably contains millions, billions of other galaxies, which contain billions of other stars. After all, if you think broadly, everything in our life begins over and over again - films follow one another, life, ending in one person, begins in another.
In world science today, the concept of a multicomponent Universe is considered to be generally accepted. But how many Universes are there? None of us know this. In other galaxies, there may be completely different celestial bodies. These worlds are dominated by completely different laws of physics. But how to prove their existence experimentally?
This can be done only by discovering the interaction between our Universe and others. This interaction takes place through some kind of wormholes. But how do you find them? One of the latest assumptions by scientists says that there is such a hole right in the center of our solar system.
Scientists suggest that if space is infinite, somewhere in its vastness there is a twin of our planet, and possibly the entire solar system.
Another dimension
Another theory is that there are limits to the size of the cosmos. The thing is that we see the nearest one as it was a million years ago. Farther still means even earlier. It is not space that is expanding; space is expanding. If we can exceed the speed of light, go beyond the boundary of space, then we will find ourselves in the past state of the Universe.
And what is beyond this notorious border? Perhaps another dimension, without space and time, which only our consciousness can imagine.
Probably the most popular question in science that each of us thought about. Universe. Its size, its boundaries. Are they there? If so, what is behind them? Where is she from and where.
In short, let's start with the global one. At the same time, look, in general, what's going on in my head, is it worth reading this further, or maybe it's time for me to go crazy, in general)))
First, let's define what the universe is. Its first definition, given by Google, is the whole system of the universe, the whole world. Well, in general, this is how I will consider it.
Before writing, I, as promised, googled this kind of theory. Not found. Maybe I was looking badly, but I did not see anything like it. So, I don't know my scientific competitors. If you come across, be sure to write in the comments.
And so, today part of scientists looks through telescopes and tries to understand what is happening there, in space ... Another part looks into microscopes and tries to understand from what all this is arranged. People are doing the same thing - studying the universe. From its basic materials - atoms, quarks, and so on to how it generally looks and where it ends.
Let's go from small. The most controversial and popular among scientists today is the "basic" particle-atom. It is the atoms that determine the properties of the substance, which consists of them, which is probably why it (the atom) is such a key object for science.
The first mentions of atoms were made by the philosophers of ancient Greece. The point is that the scientists of ancient Greek men advanced the theory that everything in the world consists of indivisible particles-atoms. Well, that is, they assumed that everything that exists (not to be confused with what is) somewhere inside consists of "finite", indivisible into smaller components, particles.
Further, this theory developed, overgrown with myths, disputes, until in the XX century, the atom was not yet discovered. And everything would be fine, but the discoveries flooded further. It turned out that the nifig atom is not an indivisible particle. It, in turn, consists of protons, electrons, quarks, gluons and the devil knows what else. In general, the theory of an indivisible, finite particle fell down.
By the way, in translation from Greek the word “atom” means “indivisible”. From so that!
So, if we abstract from all this scientific gimmick and think. Simple, logical. Could there be some finite particle? Here, it is there and that's it, it can't be finer. Everything, the limit. Personally, this cannot fit in my head. How so ?!
Hence the conclusion - the universe is infinitely small. It has no "lower" boundaries. It is endlessly divided into its component parts. These parts that we are observing are just some segment along the way.
Here is such a beautiful picture-diagram of an atom. But the scheme is very crude. Most likely, the scale is not respected - electrons, protons, neutrons, in theory, should be smaller. Indeed, according to the latest scientific data, 99% of an atom is a void, in which nuclei-quarks-electrons fly. And, probably, the atom does not look like a perfectly flat ball ...
Do you think an atom might look like this in reality? I think it can. There is even an article in which it is indicated that, at last, an image of an atom has been obtained and this picture has been attached. In fact, the image of the atom turned out to be some kind of black and white crap, barely noticeable. Marked that the black dot in the corner is an atom. In short, nifiga is not interesting to us, ordinary people. And this picture was stuck by some kind of publisher to make the article more attractive among ordinary people.
It is actually the planetary nebula Eskimo (NGC 2392), which was captured by the Hubble Telescope as the Astronomical Picture of the Day (APOD) on December 7, 2003.
It’s a pity, but how similar!
But, considering what we know about atoms, that they consist of a nucleus, protons, neutrons, quarks. But the nucleus makes up 99% of the mass of the entire atom, and 99% of the space of the atom is emptiness, then it is quite possible to assume that it looks like this.
Let's leave the microscope, look through the telescope.
Scientists believe that this is what the visible part of the universe looks like in space.
And this is the Tarantula Nebula. It is not important which of the nebulae to consider, but this particular photograph makes it possible to compare the foggy with the model of the universe. The structure is similar. That is, we can assume that the universe visible in space is the same nebula as, for example, Tarantula, or Eskimo, but it consists of galaxies, and nebulae of stars and planets. The scale is different, but the essence is the same.
Well, now, we pre-assumed that we have a universe - a large nebula, a cluster of galaxies. What's next then? If it is finite, what is there, "behind the fence?" if infinite, then is it really all? One continuous, endless structure of galaxies. That is, the highest form of existence of matter and everything in general. It couldn't be bigger. Oh, is it? Can this fit in your head? I do not have.
If the atom y in our theory resembles a nebula and the cosmic universe resembles it too, then isn't the atom and the cosmic universe one and the same, only on different scales?
That is, the universe is not only infinitely small, but also infinitely large. And the cosmic universe, like the atom, is a particle. Only, more global substance. The atom for what macrocosm in our understanding, and the cosmic universe visible to that world, is also, in turn, a particle of something even more global and this process of fission of particles is endless from smaller for us to large. And we are just inhabitants of some gap in this endless construction site. For some, it is macro-giants, and for some it is the micro-inhabitants of the atom.
Dealt with the space. Now let's try with time. How long does this construction process last when it began. Never. More precisely, it has always been. Is your brain exploding already?
Everything here is also quite simple. We recall the basic laws of physics - conservation of matter and energy. In short, these laws say that nothing can come out of nowhere. Matter cannot arise from nothing and energy out of the blue. Everything happens as a result of the interaction of already existing matter and energy. And neither one nor the other, nor more, can not become less. Form, content can change, for example, energy becomes matter and vice versa. But the array of energy and matter in the universe is always one. Since, we came to the conclusion that the universe is infinite in space, which means that its energy and matter are also infinite. Well, you have to supply this whole array with matter and energy!
And what does time have to do with it? Moreover! If the space of the universe is infinite, its energy and matter are infinite, then the time of its existence is infinite. Well, without beginning.
But the time is not just here, it’s out for a walk. We are used to measuring it in our own way, depending on the revolution of our planet around the Sun for hours or years. Time is such a thing, although its quantity depends on the quantitative indicators of the universe, but it itself does not depend on anything. Goes to itself and goes. But, I think its perception at different levels of construction is different. We have this, we are trying to measure the age of the visible cosmic universe in billions of years. And consider the "life" of atoms in much smaller intervals. It is known that some exist for a split second, others for centuries. We will not go deep into atomic physics, we will simply conclude that atoms can exist for a negligible amount of time, if we compare it with the time of existence of the cosmic universe.
So it turns out that for the smaller worlds for us, which are in atoms, time is perceived faster. If we turn on fantasy and assume that an exact copy of our cosmic universe exists in an atom, and our cosmic universe looks like an atom in a copy of the same macrocosm and we live small and huge somewhere there, then while I was writing this text, these same we who live in atom have already arisen, evolved and perished. For them, billions, hundreds of billions of years have already passed, while for the large of us, only a fraction of a second has passed.
So much for the infinity of time. Somewhere seconds, but somewhere billions of years. But seconds and billions of years are conventions. The time is the same for all levels of construction. His perception is different. Everything happens quickly in microcosms, and slow in macrocosms. Fast and slow for us. It seems normal to those living there.
Brief conclusion: The universe is infinitely small and infinitely large at the same time. And it has existed for an infinite amount of time.
This is how I imagine our world. I do not ask questions, but what is behind the stars, or what is everything in the world made of. This is interconnected and I know both. And I'm sure I'm right. The opposite has not yet been proven.
Where does the cosmos begin and where does the universe end? How scientists define the boundaries of important parameters in outer space. Everything is not so simple and depends on what is considered to be the cosmos, how many Universes there are. However - below everything is detailed. And interesting.
The "official" border between the atmosphere and space is the Karman line, which runs at an altitude of about 100 km. It was chosen not only because of the round number: at about this altitude, the air density is already so low that no apparatus can fly, supported by aerodynamic forces alone. To create sufficient lift, it will be necessary to develop the first space velocity. Such an apparatus no longer needs wings, so it is at a 100-kilometer altitude that the border between aeronautics and astronautics passes.
But the planet's air envelope at an altitude of 100 km, of course, does not end there. Its outer part - the exosphere - extends up to 10 thousand km, although it already consists mainly of rare hydrogen atoms that can easily leave it.
solar system
It’s probably no secret to anyone that the plastic models of the solar system, to which we are so accustomed from school, do not show the true distances between a star and its planets. The school model is designed so that all the planets fit on the stand. In reality, everything is much larger.
So, the center of our system - the Sun - a star with a diameter of almost 1.4 million kilometers. The planets closest to it - Mercury, Venus, Earth and Mars - make up the inner region of the solar system. All of them have a small number of satellites, are composed of solid minerals and (with the exception of Mercury) have an atmosphere. Conventionally, the boundary of the inner region of the Solar System can be drawn along the Asteroid Belt, which is located between the orbits of Mars and Jupiter, about 2-3 times farther from the Sun than the Earth.
This is the kingdom of giant planets and their many satellites. And the first of these is, of course, the huge Jupiter, located about five times farther from the Sun than the Earth. It is followed by Saturn, Uranus and Neptune, the distance to which is already breathtakingly great - more than 4.5 billion km. From here to the Sun is already 30 times farther than from the Earth.
If we compress the solar system to the size of a football field with the Sun as a gate, then Mercury will be located 2.5 m from the extreme line, Uranus - at the opposite gate, and Neptune - somewhere in the nearest parking lot.
The most distant galaxy that astronomers have been able to observe from Earth is z8_GND_5296, located at a distance of about 30 billion light years. But the most distant object that can be observed in principle is the relic radiation, which has been preserved practically from the time of the Big Bang.
The scope of the observable Universe, limited by it, includes more than 170 billion galaxies. Imagine: if suddenly they turned into peas, they could fill an entire stadium "with a slide." There are hundreds of sextillions (thousands of billions) of stars here. It spans a space that stretches 46 billion light years in all directions. But what lies behind it - and where does the universe end?
In fact, there is still no answer to this question: the dimensions of the entire Universe are unknown - perhaps it is generally infinite. Or maybe there are other Universes beyond its borders, but how they relate to each other, what they are - is already too vague a story, which we will tell you about some other time.
Belt, cloud, sphere
Pluto, as you know, lost its status as a full-fledged planet, passing into the family of dwarfs. These include Eris, Haumea, and other minor planets and Kuiper belt bodies rotating nearby.
This region is extremely distant and vast, it stretches from 35 distances from the Earth to the Sun, and up to 50. It is from the Kuiper belt that short-period comets fly into the inner regions of the solar system. If you remember our soccer field, the Kuiper belt would be a few blocks away. But here, too, the boundaries of the solar system are still far away.
The Oort cloud is still a hypothetical place: it is too far away. However, there is a lot of indirect evidence that somewhere out there, 50-100 thousand times farther from the Sun than we are, there is a vast accumulation of icy objects, from where long-period comets fly to us. This distance is so great that it is already a whole light year - a quarter of the way to the nearest star, and in our analogy with a football field - thousands of kilometers from the gate.
But the sun's gravitational influence, albeit weak, extends even further: the outer edge of the Oort cloud - Hill's sphere - is two light-years away.
Figure illustrating the proposed view of the Oort cloud
The heliosphere and the heliopause
Do not forget that all these boundaries are rather arbitrary, like the same Karman line. For such a conditional boundary of the solar system, it is not the Oort cloud that is considered, but the region in which the pressure of the solar wind is inferior to interstellar matter - the edge of its heliosphere. The first signs of this are observed at a distance of about 90 times farther from the Sun than the Earth's orbit, at the so-called boundary of the shock wave.
The final stop of the solar wind should occur in the heliopause, already at 130 such distances. Not a single probe has ever reached such a distance, except for the American Voyager-1 and Voyager-2, launched back in the 1970s. These are the most distant artificial objects to date: last year, the devices crossed the boundary of the shock wave, and scientists are excitedly watching the data that the probes send home to Earth from time to time.
All this - and the Earth is with us, and Saturn with rings, and the icy comets of the Oort cloud, and the Sun itself - rushes in a very rarefied Local interstellar cloud, from the influence of which we are just protected by the solar wind: beyond the boundaries of the shock wave, cloud particles are practically do not penetrate.
At such distances, the example of a football field finally loses its convenience, and we will have to limit ourselves to more scientific measures of length, such as a light year. The local interstellar cloud stretches for about 30 light years, and after a couple of tens of thousands of years we will leave it, entering the neighboring (and more extensive) G-cloud, where the neighboring stars are now - Alpha Centauri, Altair and others.
All these clouds appeared as a result of several ancient supernova explosions that formed the Local Bubble, in which we have been moving for at least the last 5 billion years. It stretches for 300 light years and is part of the Orion arm, one of several arms of the Milky Way. Although it is much smaller than the other arms of our spiral galaxy, its dimensions are orders of magnitude larger than the Local Bubble: more than 11 thousand light years in length and 3.5 thousand in thickness.
3D representation of the Local Bubble (White) with the adjacent Local Interstellar Cloud (pink) and a portion of Bubble I (green).
The milky way in its group
The distance from the Sun to the center of our galaxy is 26 thousand light years, and the diameter of the entire Milky Way reaches 100 thousand light years. The Sun and I remain at its periphery, revolving around the center together with neighboring stars and making a full circle in about 200 - 240 million years. Surprisingly, when dinosaurs reigned on Earth, we were on the opposite side of the galaxy!
Two powerful arms approach the disk of the galaxy - the Magellanic stream, which includes gas pulled by the Milky Way from two neighboring dwarf galaxies (the Large and Small Magellanic clouds), and the Sagittarius stream, which includes stars "torn off" from another dwarf neighbor. Several small globular clusters are also associated with our galaxy, and it itself is part of the gravitationally bound Local Group of Galaxies, where there are about fifty of them.
The nearest galaxy to us is the Andromeda Nebula. It is several times larger than the Milky Way and contains about a trillion stars, located 2.5 million light years from us. The boundary of the Local Group is located at a staggering distance: its diameter is estimated in megaparsec - to overcome this distance, light will take about 3.2 million years.
But the Local Group also pales against the backdrop of a large-scale structure about 200 million light years across. This is the Local Supercluster of galaxies, which includes about a hundred such groups and clusters of galaxies, as well as tens of thousands of individual galaxies stretched out in long chains - filaments. Further only - the boundaries of the observable Universe.
Universe and beyond?
In fact, there is still no answer to this question: the dimensions of the entire Universe are unknown - perhaps it is generally infinite. And maybe there are other Universes beyond its borders, but how they relate to each other, what they are - is already too vague history.
