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The scale of the cosmos is difficult to imagine and even more difficult to accurately determine. But thanks to the ingenious insights of physicists, we think we have a good idea of how big the cosmos is. "Let's take a walk through" - such an invitation was made by American astronomer Harlow Shapley to an audience in Washington, DC, in 1920. He took part in the so-called Great Debate on the scale of the universe, along with colleague Heber Curtis.
Shapley believed that our galaxy was 300,000 across. This is three times more than they think now, but for that time the measurements were quite good. In particular, he calculated the generally correct proportional distances within the Milky Way - our position relative to the center, for example.
At the beginning of the 20th century, however, 300,000 light years seemed to many of Shapley's contemporaries somehow absurd. a large number. And the idea that others like the Milky Way - which were visible in - were just as big, was generally not taken seriously.
Yes, and Shapley himself believed that the Milky Way should be special. "Even if the spirals are present, they are not comparable in size to our star system," he told his listeners.
Curtis disagreed. He thought, and rightly so, that there were many other galaxies in the universe scattered like ours. But his starting point was the assumption that the Milky Way was much smaller than Shapley had calculated. According to Curtis's calculations, the Milky Way was only 30,000 light-years in diameter - or three times smaller than modern calculations show.
Three times more, three times less - we are talking about such huge distances that it is quite understandable that astronomers, thinking on this subject a hundred years ago, could be so wrong.
Today we are pretty sure that the Milky Way is somewhere between 100,000 and 150,000 light years across. The observable universe is, of course, much larger. It is believed that its diameter is 93 billion light years. But why such confidence? How can you even measure something like that with ?
Ever since Copernicus declared that the Earth is not the center, we have always struggled to rewrite our ideas about what the universe is - and especially how big it can be. Even today, as we shall see, we are gathering new evidence that the entire universe may be much larger than we recently thought.
Caitlin Casey, an astronomer at the University of Texas at Austin, studies the universe. She says astronomers have developed a set of ingenious tools and measurement systems to calculate not only the distance from Earth to other bodies in our solar system, but also the gaps between galaxies and even to the very end of the observable universe.
The steps to measuring all this go through the scale of distances in astronomy. The first step of this scale is quite simple and relies on modern technology these days.
“We can just bounce radio waves off the nearest ones in the solar system, like and , and measure the time it takes for those waves to get back to Earth,” Casey says. “Measurements will thus be very accurate.”
Large radio telescopes like those in Puerto Rico can do the job - but they can also do more. Arecibo, for example, can detect flying around our solar system and even create images of them, depending on how radio waves bounce off the asteroid's surface.
But using radio waves to measure distances outside of our solar system is impractical. The next step in this cosmic scale is the measurement of parallax. We do it all the time without even realizing it. Humans, like many animals, intuitively understand the distance between themselves and objects, thanks to the fact that we have two eyes.
If you hold an object in front of you - a hand, for example - and look at it with one eye open, and then switch to the other eye, you will see your hand move slightly. This is called parallax. The difference between these two observations can be used to determine the distance to the object.
Our brains do this naturally with information from both eyes, and astronomers do the same with nearby stars, only using a different sense: telescopes.
Imagine two eyes floating in space, on either side of our sun. Thanks to the orbit of the Earth, we have these eyes, and we can observe the displacement of stars relative to objects in the background using this method.
“We measure the position of the stars in the sky in, say, January, and then we wait six months and measure the positions of the same stars in July when we are on the other side of the Sun,” Casey says.
However, there is a threshold beyond which objects are already so far away - around 100 light-years - that the observed displacement is too small to provide a useful calculation. At this distance, we will still be far from the edge of our own galaxy.
The next step is the main sequence installation. It relies on our knowledge of how stars of a certain size - known as main sequence stars - evolve over time.
First, they change color, becoming redder with age. By accurately measuring their color and brightness, and then comparing this to what is known about the distance to main sequence stars, as measured by trigonometric parallax, we can estimate the position of these more distant stars.
The principle behind these calculations is that stars of the same mass and age would appear equally bright to us if they were the same distance from us. But since this is often not the case, we can use the difference in measurements to figure out how far they really are.
The main sequence stars that are used for this analysis are considered one of the types of "standard candles" - bodies whose magnitude (or brightness) we can calculate mathematically. These candles are scattered throughout the cosmos and illuminate the universe in a predictable way. But main sequence stars are not the only examples.
This understanding of how brightness is related to distance allows us to understand the distances to even more distant objects, like stars in other galaxies. The main sequence approach won't work anymore, because the light from these stars - which are millions of light-years away, if not more - is difficult to analyze accurately.
But in 1908, a scientist named Henrietta Swan Leavitt of Harvard made a fantastic discovery that helped us measure these colossal distances as well. Swan Leavitt realized that there is a special class of stars -.
“She noticed that a certain type of star changes its brightness over time, and this change in brightness, in the pulsation of these stars, is directly related to how bright they are by nature,” says Casey.
In other words, a brighter Cepheid star will "pulse" more slowly (over many days) than a dimmer Cepheid. Because astronomers can quite easily measure the pulse of a Cepheid, they can tell how bright a star is. Then, by observing how bright it appears to us, they can calculate its distance.
This principle is similar to the approach main sequence in the sense that the key is brightness. However, the important thing is that the distance can be measured different ways. And the more ways we have to measure distances, the better we can understand the true scale of our cosmic backyard.
It was the discovery of such stars in our own galaxy that convinced Harlow Shapley of its large size.
In the early 1920s, Edwin Hubble discovered the nearest Cepheid and concluded that it was only a million light-years away.
Today, by our best estimate, this galaxy is 2.54 million light-years away. So Hubble was wrong. But this does not detract from his merits. Because we are still trying to calculate the distance to Andromeda. 2.54 million years is, in fact, the result of relatively recent calculations.
Even now, the scale of the universe is difficult to imagine. We can estimate it, and very well, but, in truth, it is very difficult to accurately calculate the distances between galaxies. The universe is incredibly big. And our galaxy is not limited.
Hubble also measured the brightness of exploding - type 1A. They can be seen in fairly distant galaxies, billions of light years away. Since the brightness of these calculations can be calculated, we can determine how far they are, as we did with the Cepheids. Type 1A supernovae and Cepheids are examples of what astronomers call standard candles.
There is one more feature of the universe that can help us measure really long distances. This is redshift.
If the siren of an ambulance or police car has ever rushed past you, you are familiar with the Doppler effect. When the ambulance approaches, the siren sounds louder, and when it moves away, the siren subsides again.
The same thing happens with waves of light, only on a small scale. We can fix this change by analyzing the light spectrum of distant bodies. There will be dark lines in this spectrum as individual colors are absorbed by elements in and around the light source - the surfaces of stars, for example.
The farther objects are from us, the further these lines will shift towards the red end of the spectrum. And this is not only because the objects are far from us, but because they are also moving away from us over time, due to the expansion of the Universe. And the observation of the redshift of light from distant galaxies, in fact, provides us with evidence that the Universe is indeed expanding.
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In cosmology, there is still no clear answer to the question that affects the age, shape and size of the Universe, and there is no consensus about its finiteness. Because if the universe is finite, then it must either contract or expand. In the event that it is infinite, many assumptions lose their meaning.
Back in 1744, the astronomer J.F. Shezo was the first to doubt that the universe
Infinite: after all, if the number of stars has no limits, then why does the sky not sparkle and why is it dark? In 1823, G. Olbes argued the existence of the boundaries of the Universe by the fact that the light coming to the Earth from distant stars should become weaker due to absorption by the substance that is in their path. But in this case, this substance itself should heat up and glow no worse than any star. found its confirmation in modern science, which claims that the vacuum is "nothing", but at the same time it has real physical properties. Of course, absorption by vacuum leads to an increase in its temperature, which results in the fact that vacuum becomes a secondary source of radiation. Therefore, in the event that the dimensions of the Universe are indeed infinite, then the light of stars that have reached the limiting distance has such a strong redshift that it begins to merge with the background (secondary) vacuum radiation.
At the same time, it can be said that the observed by mankind are finite, since the distance of 24 Gigaparsex itself is finite and is the boundary of the light cosmic horizon. However, due to the fact that it is increasing, the end of the universe is at a distance of 93 billion
The most important result of cosmology was the fact of the expansion of the universe. It was obtained from redshift observations and then quantified according to Hubble's law. This led scientists to conclude that the Big Bang theory is being confirmed. According to NASA,
which were obtained using WMAP, starting from the moment of the Big Bang, equals 13.7 billion years. However given result is possible only if we assume that the model underlying the analysis is correct. When using other estimation methods, completely different data are obtained.
Touching upon the structure of the Universe, one cannot but say about its form. Until now, that three-dimensional figure has not been found that would best represent her image. This difficulty is due to the fact that it is still not known exactly whether the Universe is flat. The second aspect is related to the fact that it is not known for certain about its multiple connection. Accordingly, if the dimensions of the Universe are spatially limited, then when moving in a straight line and in any direction, one can end up at the starting point.
As we can see, technological progress has not yet reached the level to accurately answer questions regarding the age, structure and size of the universe. So far, many theories in cosmology have not been confirmed, but they have not been refuted either.
Each of us at least once wondered what wide world we are living. Our planet is an insane amount of cities, villages, roads, forests, rivers. Most people never see half of it in their lifetime. It is difficult to imagine the grandiose scale of the planet, but there is an even harder task. The size of the Universe is something that, perhaps, even the most developed mind cannot imagine. Let's try to figure out what modern science thinks about this.
Basic concept
The universe is everything that surrounds us, about which we know and guess what was, is and will be. If we reduce the intensity of romanticism, then this concept defines everything in science that exists physically, taking into account the temporal aspect and the laws governing the functioning, interconnection of all elements, and so on.
Naturally, it is quite difficult to imagine the real dimensions of the Universe. In science, this issue is widely discussed and there is no consensus yet. In their assumptions, astronomers rely on existing theories of the formation of the world as we know it, as well as on the data obtained as a result of observation.
Metagalaxy
Various hypotheses define the universe as a dimensionless or unspeakably vast space, much of which we know little about. To bring clarity and the possibility of discussing the area available for study, the concept of Metagalaxy was introduced. This term refers to the part of the universe available for observation by astronomical methods. Thanks to the improvement of technology and knowledge, it is constantly increasing. The metagalaxy is a part of the so-called observable Universe - the space in which matter during the period of its existence managed to reach current situation. When it comes to understanding what the size of the Universe is, in most cases they talk about the Metagalaxy. The current level of technological development makes it possible to observe objects located at a distance of up to 15 billion light years from the Earth. Time in determining this parameter plays, apparently, no less a role than space.
Age and size
According to some models of the universe, it never appeared, but exists forever. However, the Big Bang theory that dominates today provides our world with a “starting point”. According to astronomers, the age of the universe is about 13.7 billion years. If you move back in time, you can return to the Big Bang. Regardless of whether the dimensions of the Universe are infinite, the observable part of it has boundaries, since the speed of light is finite. It includes all those locations that can have an impact on the terrestrial observer since the Big Bang. The dimensions of the observable universe are increasing due to its constant expansion. According to the latest estimates, it occupies a space of 93 billion light years.
A bunch of
Let's see what the universe is. Dimensions outer space, expressed in dry numbers, of course, are striking, but difficult to understand. For many, it will be easier to realize the scale of the world around them if they know how many systems, like the Solar, fit in it.
Our star and its surrounding planets are only a tiny part of the Milky Way. According to astronomers, the Galaxy has approximately 100 billion stars. Some of them have already discovered exoplanets. It is not only the size of the Universe that is striking - already the space occupied by its insignificant part, the Milky Way, inspires respect. It takes a hundred thousand years for light to travel through our galaxy!
local group
Extragalactic astronomy, which began to develop after the discoveries of Edwin Hubble, describes many structures similar to milky way. Its closest neighbors are the Andromeda Nebula and the Large and Small Magellanic Clouds. Together with several other "satellites" they make up the local group of galaxies. It is separated from the neighboring similar formation by approximately 3 million light years. It’s even scary to imagine how much time it would take for a modern aircraft to cover such a distance!
Observed
All local groups are separated by a vast space. The metagalaxy includes several billion structures similar to the Milky Way. The size of the universe is truly amazing. It takes 2 million years for a light beam to travel from the Milky Way to the Andromeda Nebula.
The farther away from us is a piece of space, the less we know about its current state. Due to the finiteness of the speed of light, scientists can only get information about the past of such objects. For the same reasons, as already mentioned, the area of the universe available for astronomical research is limited.
Other worlds
However, this is not all the amazing information that characterizes the universe. The dimensions of outer space, apparently, significantly exceed the Metagalaxy and the observable part. The theory of inflation introduces such a concept as the Multiverse. It consists of many worlds, probably formed simultaneously, not intersecting with each other and developing independently. The current level of development of technology does not give hope for the knowledge of similar neighboring Universes. One of the reasons is the same finiteness of the speed of light.
The rapid development of space science is changing our understanding of how big the universe is. The current state of astronomy, its theories and calculations of scientists are difficult to understand for the uninitiated. However, even a superficial study of the issue shows how vast the world of which we are a part, and how little we still know about it.
The portal site is an information resource where you can get a lot of useful and interesting knowledge associated with 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 is about 14 billion light years. And some argue that the universe extends over 90 billion light-years. For greater convenience, in calculating such distances, it is customary to use the parsec value. 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 arc second.
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 its history, people have tried to solve the mysteries associated with the Cosmos and the Universe. In the articles of 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 big number known to people various objects. The most widely known among them are planets, stars, satellites, black holes, asteroids and comets. The planets are the most understood at the moment, since we live on one of them. Some planets have their own moons. So, the Earth has its own satellite - the Moon. In addition to our planet, there are 8 more that revolve around the sun.
There are many stars in the Cosmos, but each of them is not similar to 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 known to us is lead. In some planets, the density of their own substance can be thousands of times greater than the density of lead, which poses many questions for scientists.
All the 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 that is not yet known to us. These clusters are called galaxies. Our galaxy is called Milky Way. All studies conducted so far say that most of the matter that galaxies create is still invisible to humans. Because of this, it was called dark matter.
The centers of galaxies are considered the most interesting. Some astronomers believe that a black hole is the possible center of the galaxy. This is a unique phenomenon formed as a result of the evolution of a star. But for now, these are just theories. It is not yet possible to conduct experiments or study such phenomena.
In addition to galaxies, the Universe contains nebulae (interstellar clouds consisting of gas, dust and plasma), relic radiation that permeates the entire space of the Universe, and many other little-known and even generally unknown objects.
The 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 consists in their interactions and transformations, most of which are represented by the invisible ether. It is also called relic radiation. This is a microwave cosmic background radiation with a temperature of 2.7 K. There is an opinion that it is this oscillating ether that is the fundamental basis for everything that fills the Universe. The anisotropy of the ether distribution is related to the directions and intensity of its movement in different areas invisible and visible space. The whole difficulty of studying and researching 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 the Cosmos itself, data were 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 a large number measurements are essential. Some models of the Universe do not exclude such a number as 11 dimensions.
It should be taken into account that the existence of a multidimensional Universe is possible with high-energy phenomena - black holes, big bang, bursters. At least, this is one of the ideas of leading cosmologists.
The expanding universe model is based on general theory relativity. It was proposed to adequately explain the redshift structure. The expansion began at the same time as the Big Bang. Its state is illustrated by the surface of an inflated rubber ball, on which dots were applied - extragalactic objects. When such a balloon 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.
Baryon asymmetry of the Universe
The significant increase in the number of elementary particles observed in the Universe over the entire number of antiparticles is called baryon asymmetry. Baryons include neutrons, protons, and some other short-lived elementary particles. This disproportion happened in 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 paired up and disappeared, thereby giving rise to electromagnetic radiation.
Age of the Universe on the portal website
Modern scientists believe that our universe is about 16 billion years old. According to estimates, the minimum age can be 12-15 billion years. The minimum is repelled by the oldest stars in our galaxy. Its real age can be determined only with the help of Hubble's law, but real does not mean exact.
visibility horizon
Sphere with equal to the distance the radius that light travels during the entire existence of the universe is called its visibility horizon. The existence of the horizon is directly proportional to the expansion and contraction of the universe. According to cosmological model Friedman, the Universe began to expand from a singular distance about 15-20 billion years ago. For all the time, light travels a residual distance in the expanding universe, namely 109 light years. Because of this, each observer of the moment t0 after the start of the expansion process can view only a small part, bounded by a sphere, which at that moment has radius I. Those bodies and objects that are at that moment outside 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 at the moment the expansion process began.
Due to absorption and scattering in early universe, given the high density, photons could not propagate in a free direction. Therefore, the observer is able to fix only the 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 matter r»10-20 g/cm3, and the moment of hydrogen recombination. It follows from the foregoing that the closer the source is in the galaxy, the greater the redshift will be for it.
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 a high density of matter. What happened before this singularity is unknown.
Regarding the events and conditions that took place before the moment 5 * 10-44 seconds (the moment of the end of the 1st time quantum), there is no exact information. In the physical sense 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 limiting for the application of existing ideas. They appear due to the ratio of the gravitational constant, the speed of light, the Boltzmann and Planck constants and are referred to as "Planck".
Those events that are associated with 5 * 10-44 to 10-36 seconds reflect the "inflationary Universe" model. The moment of 10-36 seconds is attributed to the "hot universe" model.
In the period from 1-3 to 100-120 seconds, helium nuclei and a small number of nuclei of the remaining lungs were formed chemical elements. From that moment, the 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, the era of recombination began. Formerly free electrons began to combine with light protons and atomic nuclei. Helium atoms, hydrogen atoms, and a small number of lithium atoms began to appear. The substance became transparent, and the radiation, which is still observed, detached 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 have yet appeared. During the same period, the inhomogeneities of the initial gas mixtures were condensed due to the effect of gravitational forces. Having simulated these processes on a computer, astronomers saw that this irreversibly led to the appearance of giant stars, exceeding the mass of the Sun by millions of times. Due to such a large mass, these stars were heated to unimaginably high temperatures and evolved over a period of tens of millions of years, after which they exploded as supernovae. Heating up to high temperatures, the surfaces of such stars created strong fluxes 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-wavelength ranges. In a sense, the universe began to sink into a dense 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 form from mixtures of heavy atoms. A repeated type of recombination of most of the atoms of intergalactic and interstellar gases took place, which, in turn, led to a new transparency of space for electromagnetic radiation. The universe has become exactly what we can observe now.
The observed structure of the universe on the portal website
The observed part is spatially inhomogeneous. Most clusters of galaxies 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 any substance with electromagnetic radiation. About 50% of the total volume of the Universe falls to the share of "voids".
Instruction
“The abyss has opened, full of stars; there are no stars, the abyss is the bottom, ”the brilliant Russian wrote in one of his poems. scientist Mikhail Vasilievich Lomonosov. This is the poetic statement of the infinity of the universe.
The age of "existence" of the observable Universe is about 13.7 billion Earth years. The light that comes from distant galaxies "from the edge of the world" takes more than 14 billion years to reach the 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 latest versions American scientists, the result of many years of astronomical observations and calculations.
There are 170 billion galaxies in the observable universe like ours. Ours, as it were, is in the center of a giant ball. Relic light is visible from the most distant space objects - fantastically ancient from the point of view of mankind. If you go very deep into the space-time system, you can see the youth of the planet Earth.
There is a finite age limit for luminous space objects observed from Earth. Having calculated the age limit, knowing the time it took for 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 times 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, like a nesting doll, it consists of an infinite number spherical formations nested in each other and separated from each other.
There is an assumption that the Universe is inexhaustible according to various criteria and different coordinate axes. People considered the "corpuscle" as the smallest particle of matter, then the "molecule", then the "atom", then "protons and electrons", then they started talking about elementary particles, which turned out to be not at all elementary, about quanta, neutrinos and quarks ... And no one can guarantee that another Universe is not inside the next supermicro-particle of matter. And vice versa - what visible universe does not represent only a microparticle of the matter of the Super-Mega-Universe, the dimensions of which no one can even imagine and calculate, they are so large.
