Radius of the observable universe. Visible Universe
The portal site is an information resource where you can get a lot of useful and interesting knowledge related to Space. First of all, we will talk about our and other Universes, about celestial bodies, black holes and phenomena in the depths of outer space.
The totality of everything that exists, matter, individual particles and the space between these particles is called the Universe. According to scientists and astrologers, the age of the Universe is approximately 14 billion years. The size of the visible part of the Universe occupies about 14 billion light years. And some claim that the Universe extends over 90 billion light years. For greater convenience, it is customary to use the parsec value in calculating such distances. One parsec is equal to 3.2616 light years, that is, a parsec is the distance over which the average radius of the Earth's orbit is viewed at an angle of one arcsecond.
Armed with these indicators, you can calculate the cosmic distance from one object to another. For example, the distance from our planet to the Moon is 300,000 km, or 1 light second. Consequently, this distance to the Sun increases to 8.31 light minutes.
Throughout history, people have tried to solve mysteries related to Space and the Universe. In the articles on the portal site you can learn not only about the Universe, but also about modern scientific approaches to its study. All material is based on the most advanced theories and facts.
It should be noted that the Universe includes a large number of different objects known to people. The most widely known among them are planets, stars, satellites, black holes, asteroids and comets. At the moment, most of all is understood about the planets, since we live on one of them. Some planets have their own satellites. So, the Earth has its own satellite - the Moon. Besides our planet, there are 8 more that revolve around the Sun.
There are many stars in Space, but each of them is different from each other. They have different temperatures, sizes and brightness. Since all stars are different, they are classified as follows:
White dwarfs;
Giants;
Supergiants;
Neutron stars;
Quasars;
Pulsars.
The densest substance we know is lead. In some planets, the density of their substance can be thousands of times higher than the density of lead, which raises many questions for scientists.
All planets revolve around the Sun, but it also does not stand still. Stars can gather into clusters, which, in turn, also revolve around a center still unknown to us. These clusters are called galaxies. Our galaxy is called the Milky Way. All studies conducted so far indicate that most of the matter that galaxies create is so far invisible to humans. Because of this, it was called dark matter.
The centers of galaxies are considered the most interesting. Some astronomers believe that the possible center of the galaxy is a black hole. This is a unique phenomenon formed as a result of the evolution of a star. But for now, these are all just theories. Conducting experiments or studying such phenomena is not yet possible.
In addition to galaxies, the Universe contains nebulae (interstellar clouds consisting of gas, dust and plasma), cosmic microwave background radiation that permeates the entire space of the Universe, and many other little-known and even completely unknown objects.
Circulation of the ether of the Universe
Symmetry and balance of material phenomena is the main principle of structural organization and interaction in nature. Moreover, in all forms: stellar plasma and matter, world and released ethers. The whole essence of such phenomena lies in their interactions and transformations, most of which are represented by the invisible ether. It is also called relict radiation. This is microwave cosmic background radiation with a temperature of 2.7 K. There is an opinion that it is this vibrating ether that is the fundamental basis for everything filling the Universe. The anisotropy of the distribution of ether is associated with the directions and intensity of its movement in different areas of invisible and visible space. The whole difficulty of studying and research is quite comparable with the difficulties of studying turbulent processes in gases, plasmas and liquids of matter.
Why do many scientists believe that the Universe is multidimensional?
After conducting experiments in laboratories and in Space itself, data was obtained from which it can be assumed that we live in a Universe in which the location of any object can be characterized by time and three spatial coordinates. Because of this, the assumption arises that the Universe is four-dimensional. However, some scientists, developing theories of elementary particles and quantum gravity, may come to the conclusion that the existence of a large number of dimensions is simply necessary. Some models of the Universe do not exclude as many as 11 dimensions.
It should be taken into account that the existence of a multidimensional Universe is possible with high-energy phenomena - black holes, the big bang, bursters. At least, this is one of the ideas of leading cosmologists.
The expanding Universe model is based on the general theory of relativity. It was proposed to adequately explain the redshift structure. The expansion began at the same time as the Big Bang. Its condition is illustrated by the surface of an inflated rubber ball, on which dots - extragalactic objects - were applied. When such a ball is inflated, all its points move away from each other, regardless of position. According to the theory, the Universe can either expand indefinitely or contract.
Baryonic asymmetry of the Universe
The significant increase in the number of elementary particles over the entire number of antiparticles observed in the Universe is called baryon asymmetry. Baryons include neutrons, protons and some other short-lived elementary particles. This disproportion occurred during the era of annihilation, namely three seconds after the Big Bang. Up to this point, the number of baryons and antibaryons corresponded to each other. During the mass annihilation of elementary antiparticles and particles, most of them combined into pairs and disappeared, thereby generating electromagnetic radiation.
Age of the Universe on the portal website
Modern scientists believe that our Universe is approximately 16 billion years old. According to estimates, the minimum age may be 12-15 billion years. The minimum is repelled by the oldest stars in our Galaxy. Its real age can only be determined using Hubble's law, but real does not mean accurate.
Visibility horizon
A sphere with a radius equal to the distance that light travels during the entire existence of the Universe is called its visibility horizon. The existence of a horizon is directly proportional to the expansion and contraction of the Universe. According to Friedman's cosmological model, the Universe began to expand from a singular distance approximately 15-20 billion years ago. During all the time, light travels a residual distance in the expanding Universe, namely 109 light years. Because of this, each observer at moment t0 after the start of the expansion process can observe only a small part, limited by a sphere, which at that moment has radius I. Those bodies and objects that are at this moment beyond this boundary are, in principle, not observable. The light reflected from them simply does not have time to reach the observer. This is not possible even if the light came out when the expansion process began.
Due to absorption and scattering in the early Universe, given the high density, photons could not propagate in a free direction. Therefore, an observer is able to detect only that radiation that appeared in the era of the Universe transparent to radiation. This epoch is determined by the time t»300,000 years, the density of the substance r»10-20 g/cm3 and the moment of hydrogen recombination. From all of the above it follows that the closer the source is in the galaxy, the greater the redshift value for it will be.
Big Bang
The moment the Universe began is called the Big Bang. This concept is based on the fact that initially there was a point (singularity point) in which all energy and all matter were present. The basis of the characteristic is considered to be the high density of matter. What happened before this singularity is unknown.
There is no exact information regarding the events and conditions that occurred at the time of 5*10-44 seconds (the moment of the end of the 1st time quantum). In physical terms of that era, one can only assume that then the temperature was approximately 1.3 * 1032 degrees with a matter density of approximately 1096 kg/m 3. These values are the limits for the application of existing ideas. They appear due to the relationship between the gravitational constant, the speed of light, the Boltzmann and Planck constants and are called “Planck constants”.
Those events that are associated with 5*10-44 to 10-36 seconds reflect the model of the “inflationary Universe”. The moment of 10-36 seconds is referred to as the “hot Universe” model.
In the period from 1-3 to 100-120 seconds, helium nuclei and a small number of nuclei of other light chemical elements were formed. From this moment on, a ratio began to be established in the gas: hydrogen 78%, helium 22%. Before one million years, the temperature in the Universe began to drop to 3000-45000 K, and the era of recombination began. Previously free electrons began to combine with light protons and atomic nuclei. Atoms of helium, hydrogen and a small number of lithium atoms began to appear. The substance became transparent, and the radiation, which is still observed today, was disconnected from it.
The next billion years of the existence of the Universe was marked by a decrease in temperature from 3000-45000 K to 300 K. Scientists called this period for the Universe the “Dark Age” due to the fact that no sources of electromagnetic radiation had yet appeared. During the same period, the heterogeneity of the mixture of initial gases became denser due to the influence of gravitational forces. Having simulated these processes on a computer, astronomers saw that this irreversibly led to the appearance of giant stars that exceeded the mass of the Sun by millions of times. Because they were so massive, these stars heated to incredibly high temperatures and evolved over a period of tens of millions of years, after which they exploded as supernovae. Heating to high temperatures, the surfaces of such stars created strong streams of ultraviolet radiation. Thus, a period of reionization began. The plasma that was formed as a result of such phenomena began to strongly scatter electromagnetic radiation in its spectral short-wave ranges. In a sense, the Universe began to plunge into a thick fog.
These huge stars became the first sources in the Universe of chemical elements that are much heavier than lithium. Space objects of the 2nd generation began to form, which contained the nuclei of these atoms. These stars began to be created from mixtures of heavy atoms. A repeated type of recombination of most of the atoms of intergalactic and interstellar gases occurred, which, in turn, led to a new transparency of space for electromagnetic radiation. The Universe has become exactly what we can observe now.
Observable structure of the Universe on the website portal
The observed part is spatially inhomogeneous. Most galaxy clusters and individual galaxies form its cellular or honeycomb structure. They construct cell walls that are a couple of megaparsecs thick. These cells are called "voids". They are characterized by a large size, tens of megaparsecs, and at the same time they do not contain substances with electromagnetic radiation. The void accounts for about 50% of the total volume of the Universe.
Did you know that the Universe we observe has fairly definite boundaries? We are used to associating the Universe with something infinite and incomprehensible. However, modern science, when asked about the “infinity” of the Universe, offers a completely different answer to such an “obvious” question.
According to modern concepts, the size of the observable Universe is approximately 45.7 billion light years (or 14.6 gigaparsecs). But what do these numbers mean?
The first question that comes to the mind of an ordinary person is how can the Universe not be infinite? It would seem that it is indisputable that the container of all that exists around us should have no boundaries. If these boundaries exist, what exactly are they?
Let's say some astronaut reaches the boundaries of the Universe. What will he see in front of him? A solid wall? Fire barrier? And what is behind it - emptiness? Another Universe? But can emptiness or another Universe mean that we are on the border of the universe? After all, this does not mean that there is “nothing” there. Emptiness and another Universe are also “something”. But the Universe is something that contains absolutely everything “something”.
We arrive at an absolute contradiction. It turns out that the boundary of the Universe must hide from us something that should not exist. Or the boundary of the Universe should fence off “everything” from “something”, but this “something” should also be part of “everything”. In general, complete absurdity. Then how can scientists declare the limiting size, mass and even age of our Universe? These values, although unimaginably large, are still finite. Does science argue with the obvious? To understand this, let's first trace how people came to our modern understanding of the Universe.
Expanding the boundaries
Since time immemorial, people have been interested in what the world around them is like. There is no need to give examples of the three pillars and other attempts of the ancients to explain the universe. As a rule, in the end it all came down to the fact that the basis of all things is the earth's surface. Even in the times of antiquity and the Middle Ages, when astronomers had extensive knowledge of the laws of planetary movement along the “fixed” celestial sphere, the Earth remained the center of the Universe.
Naturally, even in Ancient Greece there were those who believed that the Earth revolves around the Sun. There were those who spoke about the many worlds and the infinity of the Universe. But constructive justifications for these theories arose only at the turn of the scientific revolution.
In the 16th century, Polish astronomer Nicolaus Copernicus made the first major breakthrough in knowledge of the Universe. He firmly proved that the Earth is only one of the planets revolving around the Sun. Such a system greatly simplified the explanation of such a complex and intricate movement of planets in the celestial sphere. In the case of a stationary Earth, astronomers had to come up with all sorts of clever theories to explain this behavior of the planets. On the other hand, if the Earth is accepted as moving, then an explanation for such intricate movements comes naturally. Thus, a new paradigm called “heliocentrism” took hold in astronomy.
Many Suns
However, even after this, astronomers continued to limit the Universe to the “sphere of fixed stars.” Until the 19th century, they were unable to estimate the distance to the stars. For several centuries, astronomers have tried to no avail to detect deviations in the position of stars relative to the Earth’s orbital movement (annual parallaxes). The instruments of those times did not allow such precise measurements.
Finally, in 1837, the Russian-German astronomer Vasily Struve measured parallax. This marked a new step in understanding the scale of space. Now scientists could safely say that the stars are distant similarities to the Sun. And our luminary is no longer the center of everything, but an equal “resident” of an endless star cluster.
Astronomers have come even closer to understanding the scale of the Universe, because the distances to the stars turned out to be truly monstrous. Even the size of the planets’ orbits seemed insignificant in comparison. Next it was necessary to understand how the stars are concentrated in .
Many Milky Ways
The famous philosopher Immanuel Kant anticipated the foundations of the modern understanding of the large-scale structure of the Universe back in 1755. He hypothesized that the Milky Way is a huge rotating star cluster. In turn, many of the observed nebulae are also more distant “milky ways” - galaxies. Despite this, until the 20th century, astronomers believed that all nebulae are sources of star formation and are part of the Milky Way.
The situation changed when astronomers learned to measure distances between galaxies using . The absolute luminosity of stars of this type strictly depends on the period of their variability. By comparing their absolute luminosity with the visible one, it is possible to determine the distance to them with high accuracy. This method was developed in the early 20th century by Einar Hertzschrung and Harlow Scelpi. Thanks to him, the Soviet astronomer Ernst Epic in 1922 determined the distance to Andromeda, which turned out to be an order of magnitude larger than the size of the Milky Way.
Edwin Hubble continued Epic's initiative. By measuring the brightness of Cepheids in other galaxies, he measured their distance and compared it with the redshift in their spectra. So in 1929 he developed his famous law. His work definitively disproved the established view that the Milky Way is the edge of the Universe. Now it was one of many galaxies that had once been considered part of it. Kant's hypothesis was confirmed almost two centuries after its development.
Subsequently, the connection discovered by Hubble between the distance of a galaxy from an observer relative to the speed of its removal from him, made it possible to draw a complete picture of the large-scale structure of the Universe. It turned out that the galaxies were only an insignificant part of it. They connected into clusters, clusters into superclusters. In turn, superclusters form the largest known structures in the Universe - filaments and walls. These structures, adjacent to huge supervoids (), constitute the large-scale structure of the currently known Universe.
Apparent infinity
It follows from the above that in just a few centuries, science has gradually fluttered from geocentrism to a modern understanding of the Universe. However, this does not answer why we limit the Universe today. After all, until now we were talking only about the scale of space, and not about its very nature.
The first who decided to justify the infinity of the Universe was Isaac Newton. Having discovered the law of universal gravitation, he believed that if space were finite, all its bodies would sooner or later merge into a single whole. Before him, if anyone expressed the idea of the infinity of the Universe, it was exclusively in a philosophical vein. Without any scientific basis. An example of this is Giordano Bruno. By the way, like Kant, he was many centuries ahead of science. He was the first to declare that stars are distant suns, and planets also revolve around them.
It would seem that the very fact of infinity is quite justified and obvious, but the turning points of science of the 20th century shook this “truth”.
Stationary Universe
The first significant step towards developing a modern model of the Universe was taken by Albert Einstein. The famous physicist introduced his model of a stationary Universe in 1917. This model was based on the general theory of relativity, which he had developed a year earlier. According to his model, the Universe is infinite in time and finite in space. But, as noted earlier, according to Newton, a Universe with a finite size must collapse. To do this, Einstein introduced a cosmological constant, which compensated for the gravitational attraction of distant objects.
No matter how paradoxical it may sound, Einstein did not limit the very finitude of the Universe. In his opinion, the Universe is a closed shell of a hypersphere. An analogy is the surface of an ordinary three-dimensional sphere, for example, a globe or the Earth. No matter how much a traveler travels across the Earth, he will never reach its edge. However, this does not mean that the Earth is infinite. The traveler will simply return to the place from which he began his journey.
On the surface of the hypersphere
In the same way, a space wanderer, traversing Einstein’s Universe on a starship, can return back to Earth. Only this time the wanderer will move not along the two-dimensional surface of a sphere, but along the three-dimensional surface of a hypersphere. This means that the Universe has a finite volume, and therefore a finite number of stars and mass. However, the Universe has neither boundaries nor any center.
Einstein came to these conclusions by connecting space, time and gravity in his famous theory. Before him, these concepts were considered separate, which is why the space of the Universe was purely Euclidean. Einstein proved that gravity itself is a curvature of space-time. This radically changed early ideas about the nature of the Universe, based on classical Newtonian mechanics and Euclidean geometry.
Expanding Universe
Even the discoverer of the “new Universe” himself was not a stranger to delusions. Although Einstein limited the Universe in space, he continued to consider it static. According to his model, the Universe was and remains eternal, and its size always remains the same. In 1922, Soviet physicist Alexander Friedman significantly expanded this model. According to his calculations, the Universe is not static at all. It can expand or contract over time. It is noteworthy that Friedman came to such a model based on the same theory of relativity. He managed to apply this theory more correctly, bypassing the cosmological constant.
Albert Einstein did not immediately accept this “amendment.” This new model came to the aid of the previously mentioned Hubble discovery. The recession of galaxies indisputably proved the fact of the expansion of the Universe. So Einstein had to admit his mistake. Now the Universe had a certain age, which strictly depends on the Hubble constant, which characterizes the rate of its expansion.
Further development of cosmology
As scientists tried to solve this question, many other important components of the Universe were discovered and various models of it were developed. So in 1948, George Gamow introduced the “hot Universe” hypothesis, which would later turn into the big bang theory. The discovery in 1965 confirmed his suspicions. Now astronomers could observe the light that came from the moment when the Universe became transparent.
Dark matter, predicted in 1932 by Fritz Zwicky, was confirmed in 1975. Dark matter actually explains the very existence of galaxies, galaxy clusters and the Universal structure itself as a whole. This is how scientists learned that most of the mass of the Universe is completely invisible.
Finally, in 1998, during a study of the distance to, it was discovered that the Universe is expanding at an accelerating rate. This latest turning point in science gave birth to our modern understanding of the nature of the universe. The cosmological coefficient, introduced by Einstein and refuted by Friedman, again found its place in the model of the Universe. The presence of a cosmological coefficient (cosmological constant) explains its accelerated expansion. To explain the presence of the cosmological constant, the concept was introduced - a hypothetical field containing most of the mass of the Universe.
Modern understanding of the size of the observable Universe
The modern model of the Universe is also called the ΛCDM model. The letter "Λ" means the presence of a cosmological constant, which explains the accelerated expansion of the Universe. "CDM" means that the Universe is filled with cold dark matter. Recent studies indicate that the Hubble constant is about 71 (km/s)/Mpc, which corresponds to the age of the Universe 13.75 billion years. Knowing the age of the Universe, we can estimate the size of its observable region.
According to the theory of relativity, information about any object cannot reach an observer at a speed greater than the speed of light (299,792,458 m/s). It turns out that the observer sees not just an object, but its past. The farther an object is from him, the more distant the past he looks. For example, looking at the Moon, we see the way it was a little more than a second ago, the Sun - more than eight minutes ago, the nearest stars - years, galaxies - millions of years ago, etc. In Einstein's stationary model, the Universe has no age limit, which means its observable region is also not limited by anything. The observer, armed with increasingly sophisticated astronomical instruments, will observe increasingly distant and ancient objects.
We have a different picture with the modern model of the Universe. According to it, the Universe has an age, and therefore a limit of observation. That is, since the birth of the Universe, no photon could have traveled a distance greater than 13.75 billion light years. It turns out that we can say that the observable Universe is limited from the observer to a spherical region with a radius of 13.75 billion light years. However, this is not quite true. We should not forget about the expansion of the space of the Universe. By the time the photon reaches the observer, the object that emitted it will be already 45.7 billion light years away from us. years. This size is the horizon of particles, it is the boundary of the observable Universe.
Over the horizon
So, the size of the observable Universe is divided into two types. Apparent size, also called the Hubble radius (13.75 billion light years). And the real size, called the particle horizon (45.7 billion light years). The important thing is that both of these horizons do not at all characterize the real size of the Universe. Firstly, they depend on the position of the observer in space. Secondly, they change over time. In the case of the ΛCDM model, the particle horizon expands at a speed greater than the Hubble horizon. Modern science does not answer the question of whether this trend will change in the future. But if we assume that the Universe continues to expand with acceleration, then all those objects that we see now will sooner or later disappear from our “field of vision”.
Currently, the most distant light observed by astronomers is the cosmic microwave background radiation. Peering into it, scientists see the Universe as it was 380 thousand years after the Big Bang. At this moment, the Universe cooled down enough that it was able to emit free photons, which are detected today with the help of radio telescopes. At that time, there were no stars or galaxies in the Universe, but only a continuous cloud of hydrogen, helium and an insignificant amount of other elements. From the inhomogeneities observed in this cloud, galaxy clusters will subsequently form. It turns out that precisely those objects that will be formed from inhomogeneities in the cosmic microwave background radiation are located closest to the particle horizon.
True Boundaries
Whether the Universe has true, unobservable boundaries is still a matter of pseudoscientific speculation. One way or another, everyone agrees on the infinity of the Universe, but interprets this infinity in completely different ways. Some consider the Universe to be multidimensional, where our “local” three-dimensional Universe is only one of its layers. Others say that the Universe is fractal - which means that our local Universe may be a particle of another. We should not forget about the various models of the Multiverse with its closed, open, parallel Universes, and wormholes. And there are many, many different versions, the number of which is limited only by human imagination.
But if we turn on cold realism or simply step back from all these hypotheses, then we can assume that our Universe is an infinite homogeneous container of all stars and galaxies. Moreover, at any very distant point, be it billions of gigaparsecs from us, all the conditions will be exactly the same. At this point, the particle horizon and the Hubble sphere will be exactly the same, with the same relict radiation at their edge. There will be the same stars and galaxies around. Interestingly, this does not contradict the expansion of the Universe. After all, it is not just the Universe that is expanding, but its space itself. The fact that at the moment of the Big Bang the Universe arose from one point only means that the infinitely small (practically zero) dimensions that were then have now turned into unimaginably large ones. In the future, we will use precisely this hypothesis in order to clearly understand the scale of the observable Universe.
Visual representation
Various sources provide all sorts of visual models that allow people to understand the scale of the Universe. However, it is not enough for us to realize how big the cosmos is. It is important to imagine how concepts such as the Hubble horizon and the particle horizon actually manifest themselves. To do this, let's imagine our model step by step.
Let's forget that modern science does not know about the “foreign” region of the Universe. Discarding versions of multiverses, the fractal Universe and its other “varieties”, let’s imagine that it is simply infinite. As noted earlier, this does not contradict the expansion of its space. Of course, we take into account that its Hubble sphere and particle sphere are respectively 13.75 and 45.7 billion light years.
Scale of the Universe
Press the START button and discover a new, unknown world!
First, let's try to understand how large the Universal scale is. If you have traveled around our planet, you can well imagine how big the Earth is for us. Now imagine our planet as a grain of buckwheat moving in orbit around a watermelon-Sun the size of half a football field. In this case, Neptune's orbit will correspond to the size of a small city, the area will correspond to the Moon, and the area of the border of the Sun's influence will correspond to Mars. It turns out that our Solar System is as much larger than the Earth as Mars is larger than buckwheat! But this is just the beginning.
Now let’s imagine that this buckwheat will be our system, the size of which is approximately equal to one parsec. Then the Milky Way will be the size of two football stadiums. However, this will not be enough for us. The Milky Way will also have to be reduced to centimeter size. It will somewhat resemble coffee foam wrapped in a whirlpool in the middle of coffee-black intergalactic space. Twenty centimeters from it there is the same spiral “crumb” - the Andromeda Nebula. Around them there will be a swarm of small galaxies of our Local Cluster. The apparent size of our Universe will be 9.2 kilometers. We have come to an understanding of the Universal dimensions.
Inside the universal bubble
However, it is not enough for us to understand the scale itself. It is important to realize the Universe in dynamics. Let's imagine ourselves as giants, for whom the Milky Way has a centimeter diameter. As noted just now, we will find ourselves inside a ball with a radius of 4.57 and a diameter of 9.24 kilometers. Let’s imagine that we are able to float inside this ball, travel, covering entire megaparsecs in a second. What will we see if our Universe is infinite?
Of course, countless galaxies of all kinds will appear before us. Elliptical, spiral, irregular. Some areas will be teeming with them, others will be empty. The main feature will be that visually they will all be motionless while we are motionless. But as soon as we take a step, the galaxies themselves will begin to move. For example, if we are able to discern a microscopic Solar System in the centimeter-long Milky Way, we will be able to observe its development. Moving 600 meters away from our galaxy, we will see the protostar Sun and the protoplanetary disk at the moment of formation. Approaching it, we will see how the Earth appears, life arises and man appears. In the same way, we will see how galaxies change and move as we move away from or approach them.
Consequently, the more distant galaxies we look at, the more ancient they will be for us. So the most distant galaxies will be located further than 1300 meters from us, and at the turn of 1380 meters we will already see relict radiation. True, this distance will be imaginary for us. However, as we get closer to the cosmic microwave background radiation, we will see an interesting picture. Naturally, we will observe how galaxies will form and develop from the initial cloud of hydrogen. When we reach one of these formed galaxies, we will understand that we have covered not 1.375 kilometers at all, but all 4.57.
Zooming out
As a result, we will increase in size even more. Now we can place entire voids and walls in the fist. So we will find ourselves in a rather small bubble from which it is impossible to get out. Not only will the distance to objects at the edge of the bubble increase as they get closer, but the edge itself will shift indefinitely. This is the whole point of the size of the observable Universe.
No matter how big the Universe is, for an observer it will always remain a limited bubble. The observer will always be at the center of this bubble, in fact he is its center. Trying to get to any object at the edge of the bubble, the observer will shift its center. As you approach an object, this object will move further and further from the edge of the bubble and at the same time change. For example, from a shapeless hydrogen cloud it will turn into a full-fledged galaxy or, further, a galactic cluster. In addition, the path to this object will increase as you approach it, since the surrounding space itself will change. Having reached this object, we will only move it from the edge of the bubble to its center. At the edge of the Universe, relict radiation will still flicker.
If we assume that the Universe will continue to expand at an accelerated rate, then being in the center of the bubble and moving time forward by billions, trillions and even higher orders of years, we will notice an even more interesting picture. Although our bubble will also increase in size, its changing components will move away from us even faster, leaving the edge of this bubble, until each particle of the Universe wanders separately in its lonely bubble without the opportunity to interact with other particles.
So, modern science does not have information about the real size of the Universe and whether it has boundaries. But we know for sure that the observable Universe has a visible and true boundary, called respectively the Hubble radius (13.75 billion light years) and the particle radius (45.7 billion light years). These boundaries depend entirely on the observer's position in space and expand over time. If the Hubble radius expands strictly at the speed of light, then the expansion of the particle horizon is accelerated. The question of whether its acceleration of the particle horizon will continue further and whether it will be replaced by compression remains open.
The diameter of the Moon is 3000 km, the Earth is 12800 km, the Sun is 1.4 million kilometers, while the distance from the Sun to the Earth is 150 million km. The diameter of Jupiter, the largest planet in our solar system, is 150 thousand km. It’s not for nothing that they say that Jupiter could be a star; in the video, next to Jupiter is located working star, its size () is even smaller than Jupiter. By the way, since we touched on Jupiter, you may not have heard, but Jupiter does not revolve around the Sun. The fact is that the mass of Jupiter is so large that the center of rotation of Jupiter and the Sun is located outside the Sun, thus both the Sun and Jupiter rotate together around a common center of rotation.
According to some calculations, there are 400 billion stars in our galaxy, which is called the Milky Way. This is far from the largest galaxy; neighboring Andromeda has more than a trillion stars.
As stated in the video at 4:35, in a few billion years our Milky Way will collide with Andromeda. According to some calculations, using any technology known to us, even improved in the future, we will not be able to reach other galaxies, since they are constantly moving away from us. Only teleportation can help us. This is bad news.
The good news is that you and I were born at a fortunate time when scientists see other galaxies and can theorize about the Big Bang and other phenomena. If we had been born much later, when all the galaxies would have scattered far from each other, then most likely we would not have been able to find out how the universe arose, whether there were other galaxies, whether there was a Big Bang, etc. We would believe that our Milky Way (united by that time with Andromeda) is the only one and unique in the entire cosmos. But we are lucky and we know something. Maybe.
Let's get back to the numbers. Our small Milky Way contains up to 400 billion stars, neighboring Andromeda has more than a trillion, and in total there are more than 100 billion such galaxies in the observable universe. And many of them contain several trillion stars. It may seem incredible that there are so many stars in space, but somehow the Americans took and pointed their mighty Hubble telescope at a completely empty space in our sky. After watching him for several days, they received this photograph:
In a completely empty area of our sky, they found 10 thousand galaxies (not stars), each of which contains billions and trillions of stars. Here is this square in our sky, for scale.
And we don’t know what’s going on outside the observable universe. The size of the universe that we see is about 91.5 billion light years. What's next is unknown. Perhaps our entire universe is just a bubble in a swirling ocean of multiverses. In which other laws of physics may even apply, for example, Archimedes’ law does not work and the sum of the angles is not equal to 360 degrees.
Enjoy. Dimensions of the universe on video:
Instructions
“The abyss has opened and is full of stars; the stars have no number, the abyss has its bottom,” wrote the brilliant Russian scientist Mikhail Vasilyevich Lomonosov in one of his poems. This is a poetic statement of the infinity of the Universe.
The age of “existence” of the observable Universe is about 13.7 billion Earth years. Light that comes from distant galaxies “from the edge of the world” takes more than 14 billion years to reach Earth. It turns out that the diametrical dimensions of the Universe can be calculated if approximately 13.7 is multiplied by two, that is, 27.4 billion light years. The radial size of the spherical model is approximately 78 billion light years, and the diameter is 156 billion light years. This is one of the latest versions of American scientists, the result of many years of astronomical observations and calculations.
There are 170 billion galaxies like ours in the observable universe. Ours seems to be in the center of a giant ball. From the most distant space objects, a relict light is visible - fantastically ancient from the point of view of mankind. If you penetrate very deep into the space-time system, you can see the youth of planet Earth.
There is a finite limit to the age of luminous space objects observed from Earth. Having calculated the maximum age, knowing the time it took light to travel the distance from them to the surface of the Earth, and knowing the constant, the speed of light, using the formula S = Vxt (path = speed multiplied by time) known from school, scientists determined the probable dimensions of the observable Universe.
Representing the Universe in the form of a three-dimensional ball is not the only way to build a model of the Universe. There are hypotheses suggesting that the Universe has not three, but an infinite number of dimensions. There are versions that it, like a nesting doll, consists of an infinite number of spherical formations nested within each other and spaced apart from each other.
There is an assumption that the Universe is inexhaustible according to various criteria and different coordinate axes. People considered the smallest particle of matter to be a “corpuscle”, then a “molecule”, then an “atom”, then “protons and electrons”, then they started talking about elementary particles, which turned out to be not elementary at all, about quanta, neutrinos and quarks... And no one will give a guarantee , that inside the next supermicrominiparticle of matter there is not another Universe. And vice versa - that the visible Universe is not just a microparticle of matter of the Super-Mega-Universe, the dimensions of which no one can even imagine and calculate, they are so large.
Usually, when they talk about the size of the Universe, they mean local fragment of the Universe (Universe), which is available to our observation.
This is the so-called observable Universe - the region of space visible to us from Earth.
And since the Universe is about 13,800,000,000 years old, no matter which direction we look, we see light that took 13.8 billion years to reach us.
So, based on this, it is logical to think that the observable Universe should be 13.8 x 2 = 27,600,000,000 light years across.
But that's not true! Because over time, space expands. And those distant objects that emitted light 13.8 billion years ago have flown even further during this time. Today they are already more than 46.5 billion light years away from us. Doubling this gives us 93 billion light years.
Thus, the real diameter of the observable universe is 93 billion light years. years.
A visual (in the form of a sphere) representation of the three-dimensional structure of the observable Universe, visible from our position (the center of the circle).
White lines the boundaries of the observable Universe are indicated.
Specks of light- These are clusters of clusters of galaxies - superclusters - the largest known structures in space.
Scale bar: one division above is 1 billion light years, below - 1 billion parsecs.
Our house (in the center) here designated as the Virgo Supercluster, it is a system that includes tens of thousands of galaxies, including our own, the Milky Way.
A more visual idea of the scale of the observable Universe is given by the following image:
Map of the location of the Earth in the observable Universe - a series of eight maps
from left to right top row: Earth – Solar System – Nearest Stars – Milky Way Galaxy, bottom row: Local Group of Galaxies – Virgo Cluster – Local Supercluster – Observable Universe.
To better feel and understand what colossal scales we are talking about, incomparable to our earthly ideas, it is worth watching enlarged image of this diagram V media viewer .
What can you say about the entire Universe? The size of the entire Universe (Universe, Metaverse), presumably, is much larger!
But what this entire Universe is like and how it is structured remains a mystery to us...
What about the center of the universe? The observable Universe has a center - it is us! We are at the center of the observable Universe because the observable Universe is simply a region of space visible to us from Earth.
And just as from a high tower we see a circular area with the center at the tower itself, we also see a region of space with the center away from the observer. In fact, more precisely, each of us is the center of our own observable universe.
But this does not mean that we are in the center of the entire Universe, just as the tower is by no means the center of the world, but only the center of that piece of the world that can be seen from it - to the horizon.
It's the same with the observable Universe.
When we look into the sky, we see light that has traveled 13.8 billion years to us from places that are already 46.5 billion light years away.
We do not see what is beyond this horizon.
