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.

0 👁 1 360

The scale of space is difficult to imagine and even more difficult to accurately determine. But thanks to the ingenious guesses of physicists, we think we have a good idea of ​​how big the cosmos is. “Let us take a walk around,” was the invitation American astronomer Harlow Shapley made to an audience in Washington, D.C., in 1920. He took part in the so-called Great Debate on the scale of the Universe, along with his colleague Heber Curtis.

Shapley believed that our galaxy was 300,000 in diameter. This is three times more than is thought 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 to be some kind of absurdly large number. And the idea that others like the Milky Way - which were visible in - were as large was not taken seriously at all.

And Shapley himself believed that Milky Way must be special. “Even if the spirals are represented, 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 who thought about this topic a hundred years ago could be so wrong.

Today we are fairly confident that the Milky Way is somewhere between 100,000 and 150,000 light years across. The observable Universe is, of course, much, much larger. It is believed to be 93 billion light years in diameter. But why such confidence? How can you even measure something like this 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 will 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 sophisticated instruments 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 of this go through the distance scale of astronomy. The first stage of this scale is quite simple and these days relies on modern technology.

“We can simply bounce radio waves off nearby ones in the solar system, like and, and measure the time it takes for those waves to return to Earth,” Casey says. “The measurements will thus be very accurate.”

Large radio telescopes like the one in Puerto Rico can do this 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 are reflected from the surface of the asteroid.

But using radio waves to measure distances beyond our solar system is impractical. The next step in this cosmic scale is the measurement of parallax. We do this all the time without even realizing it. Humans, like many animals, intuitively understand the distance between themselves and objects due to the fact that we have two eyes.

If you hold an object in front of you - your 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 they use a different sense: telescopes.

Imagine two eyes floating in space, on either side of our Sun. Thanks to the Earth's orbit, we have these eyes, and we can observe the displacement of stars relative to objects in the background using this method.

“We measure the positions of stars in the sky in, say, January, and then 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 - about 100 light years - that the observed shift 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 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 as they age. By accurately measuring their color and brightness, and then comparing this with 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 at 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 used for this analysis are considered to be one of the types of "standard candles" - bodies whose magnitude (or brightness) we can calculate mathematically. These candles are scattered throughout space and predictably illuminate the Universe. But main sequence stars are not the only examples.

This understanding of how brightness relates to distance allows us to understand distances to even more distant objects - like stars in other galaxies. The main sequence approach will no longer work because the light from these stars - which are millions of light years away, if not more - is difficult to accurately analyze.

But in 1908, a scientist named Henrietta Swan Leavitt from Harvard made a fantastic discovery that helped us measure these colossal distances. Swan Leavitt realized that there was 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," Casey says.

In other words, a brighter Cepheid star will "pulse" more slowly (over many days) than a fainter Cepheid. Because astronomers can quite easily measure the Cepheid's pulse, they can tell how bright the star is. Then, by observing how bright it appears to us, they can calculate its distance.

This principle is similar to the main sequence approach in that brightness is key. 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 a Cepheid at the nearest one and concluded that it was only a million light years away.

Today, our best estimate is that this galaxy is 2.54 million light-years away. Therefore, Hubble was wrong. But this in no way detracts from his merits. Because we're still trying to calculate the distance to Andromeda. 2.54 million years - this number is essentially 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 it is not limited to our galaxy.

Hubble also measured the brightness of the exploding type 1A. They can be seen in fairly distant galaxies, billions of light years away. Because the brightness of these calculations can be calculated, we can determine how far away they are, just as we did with Cepheids. Type 1A supernovae and Cepheids are examples of what astronomers call standard candles.

There is another feature of the Universe that can help us measure truly large distances. This is redshift.

If you've ever heard the siren of an ambulance or police car rush past you, you're familiar with the Doppler effect. When the ambulance approaches, the siren sounds shriller, and when it moves away, the siren fades again.

The same thing happens with light waves, only on a small scale. We can detect this change by analyzing the light spectrum of distant bodies. There will be dark lines in this spectrum because individual colors are absorbed by elements in and around the light source - the surfaces of stars, for example.

The further objects are from us, the further towards the red end of the spectrum these lines will shift. And this is not only because objects are far from us, but because they are also moving away from us over time, due to the expansion of the Universe. And observing the redshift of light from distant galaxies actually provides us with evidence that the Universe is indeed expanding.

NEW ARTICLES

New comments

Survey

Do we need to send signals into space with Earth coordinates?

The universe is everything that exists. The universe is limitless. Therefore, when discussing the size of the Universe, we can only talk about the size of its observable part - the observable Universe.

The observable Universe is a ball with a center on Earth (the observer’s place), has two sizes: 1. apparent size - Hubble radius - 13.75 billion light years, 2. real size - particle horizon radius - 45.7 billion light years .

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 km/s). It turns out, 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 as 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.

Dimensions of the observable universe

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. This size is the horizon of particles, it is the boundary of the observable Universe.

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. The question is whether this trend will change in the future. modern science does not give an answer. 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 . 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.

Real size of the Universe

So, we have decided on the size of the observable Universe. But what about the real size of the entire Universe? modern science does not have information about the real size of the Universe and whether it has boundaries. But most scientists agree that the Universe is limitless.

Conclusion

The observable Universe has an apparent 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 and whether it will be replaced by compression remains open.

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 big number known to people various objects. 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 are main principle structural organization and interactions 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 general theory 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 in the era of annihilation, namely three seconds after 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 the remaining lungs were formed chemical elements. 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.

Space is called the Metagalaxy. It is also called our Universe. This colossal structure consists of a billion, and is just a speck of dust in this collection of star systems, the boundaries of which are rapidly expanding. Active research into the Metagalaxy began with the construction of telescopes with a sufficient degree of magnification. With their help, it was possible to look into very distant space. For example, it was found that many bright spots are not just light spots, but entire systems of galaxies.

Structure

If we take the average density of the substance of the Metagalaxy, it will be 10 -31 – 10 -32 g/cm 3 . Of course, not all space is of the same type; there are heterogeneities of significant scale, and there are also voids. Some galaxies are grouped into systems. They can be double or more numerous, up to hundreds, thousands and even tens of thousands of galaxies. Such superclusters are called clouds. For example, the Milky Way, and a dozen other galaxies, are part of the local group, which is part of a huge cloud. The central part of this cloud is the core, consisting of a cluster of several thousand galaxies. This formation, located in the constellations Coma Berenices and Virgo, is only 40 million light years away. But very little is known about the structure of the Metagalaxy. The same applies to its shape and size. What is clear is that there is no decrease in the density of distribution of galaxies in any direction. This indicates the absence of boundaries to our Universe. Or the area subject to research is not large enough. In fact, the structure of the Metagalaxy looks like a honeycomb, and the dimensions of their cells are 100 - 300 million light years. Internal cavities of honeycombs – voids– are practically empty, and clusters of galaxy clusters are located along the walls.

What are its dimensions

As we found out, the Metagalaxy is the Universe that we are able to survey. It began to expand immediately after its appearance (after the Big Bang). Its boundaries after the explosion are determined by the relict radiation, the surface of the last scattering The surface of last scattering - the remote region of space on which today's CMB photons were last scattered by ionized matter, now appears from Earth as a spherical shell. Closer than this surface, the Universe was essentially already transparent to radiation. Although the surface has a finite thickness, it is a relatively sharp boundary. is the most distant object of observation.

Beyond the boundaries of the Metagalaxy there are objects that arose independently of the results of the Big Bang of our Universe, about which practically nothing is known.

Distances to ultra-distant objects

The latest measurements of the most distant object - the cosmic microwave background radiation - gave a value of about 14 billion parsecs. Such dimensions were obtained in all directions, from which it follows that the Metagalaxy most likely has the shape of a ball. And the diameter of this ball is almost 93 billion light years. If we calculate its volume, it will be about 11.5 trillion. Mpk 3. But it is known that the Universe itself is much broader than the boundaries of observation. The most distant galaxy discovered is UDFj-39546284. It is visible only in the infrared range. It is 13.2 billion light years away, and it appears in the same form as it was when the Universe was only 480 million years old.