How was the phenomenon of expansion of galaxies discovered. Scientists cannot explain the rapid expansion of galaxies from the Milky Way. How big is the observable universe

The next step in the organization of matter in the universe is galaxies. A typical example is our galaxy, the Milky Way. It contains about 10 11 stars and has the shape of a thin disk with a thickening in the center.
On fig. 39 schematically shows the structure of our Milky Way galaxy and indicates the position of the Sun in one of the spiral arms of the galaxy.

Rice. 39. The structure of the Milky Way galaxy.

On fig. 40 shows a projection onto a plane of 16 nearest neighbors of our galaxy.

Rice. 40. 16 nearest neighbors of our Galaxy, projected onto a plane. LMC and MMO − Large and Small Magellanic Cloud

Stars in galaxies are unevenly distributed.
The sizes of galaxies vary from 15 to 800 thousand light years. The mass of galaxies varies from 10 7 to 10 12 solar masses. Most of the stars and cold gas are concentrated in galaxies. Stars in galaxies are held together by the total gravitational field of the galaxy and dark matter.
Our Milky Way galaxy is a typical spiral system. The stars in the galaxy, along with the general rotation of the galaxies, also have their own velocities relative to the galaxy. The orbital speed of the Sun in our galaxy is 230 km/s. The Sun's own velocity relative to the galaxy is
20 km/s.

The discovery of the world of galaxies belongs to E. Hubble. In 1923–1924, observing changes in the luminosity of Cepheids located in individual nebulae, he showed that the nebulae he discovered were galaxies located outside our galaxy, the Milky Way. In particular, he discovered that the Andromeda Nebula is another star system - a galaxy that is not part of our Milky Way galaxy. The Andromeda Nebula is a spiral galaxy located at a distance of 520 kpc. The transverse size of the Andromeda Nebula is 50 kpc.
By studying the radial velocities of individual galaxies, Hubble made an outstanding discovery:

H = 73.8 ± 2.4 km s -1 megaparsec -1 is the Hubble parameter.

Rice. 41. Original Hubble graph from a 1929 paper.

Rice. 42. The speed of removal of galaxies depending on the distance to the Earth.

On fig. 42 at the origin of coordinates, a square shows the region of galactic velocities and distances to them, on the basis of which E. Hubble derived relation (9).
Hubble's discovery had a prehistory. In 1914, astronomer V. Slifer showed that the Andromeda nebula and several other nebulae are moving relative to the solar system at speeds of about 1000 km/h. E. Hubble, who worked on the world's largest telescope with a main mirror with a diameter of 2.5 m at the Mount Wilson Observatory in California (USA), managed to resolve individual stars in the Andromeda nebula for the first time. Among these stars were Cepheid stars, for which the dependence between the period of luminosity change and luminosity is known.
Knowing the luminosity of the star and the speed of the star, E. Hubble obtained the dependence of the speed of removal of stars from the solar system depending on the distance. On fig. 41 shows a graph from the original work of E. Hubble.

Rice. 43. Hubble Space Telescope

The radial velocity of motion of celestial objects - stars, galaxies - is determined by measuring the change in the frequency of spectral lines. As the radiation source moves away from the observer, the wavelengths shift towards longer wavelengths (redshift). When the radiation source approaches the observer, the wavelengths shift towards shorter wavelengths (blue shift). By increasing the width of the spectral line distribution, one can determine the temperature of the emitting object.
Hubble divided galaxies according to their appearance into three broad classes:

elliptical (E),

spiral (S),

irregular (Ir).

Rice. 44. Types of galaxies (spiral, elliptical, irregular).

A characteristic feature of spiral galaxies is the spiral arms extending from the center across the stellar disk.
Elliptical galaxies are structureless elliptical systems.
Irregular galaxies are distinguished by an outwardly chaotic, ragged structure and do not have any definite shape.
Such a classification of galaxies reflects not only their external forms, but also the properties of their constituent stars.
Elliptical galaxies are mostly composed of old stars. In irregular galaxies, stars younger than the Sun make the main contribution to the radiation. Spiral galaxies contain stars of all ages. Thus, the difference in the appearance of galaxies is determined by the nature of their evolution. In elliptical galaxies, star formation virtually ceased billions of years ago. Spiral galaxies continue to form stars. In irregular galaxies, star formation is as intense as it was billions of years ago. Almost all stars are concentrated in a wide disk, the bulk of which is interstellar gas.
Table 19 shows a relative comparison of these three types of galaxies and a comparison of their properties based on E. Hubble's analysis.

Table 19

In relative proximity to our Milky Way galaxy, astronomers have discovered several small galaxies that have forced them to think about the laws of gravity they know. These galaxies form a whole ring with a diameter of 10 million light years and fly away from us at such a high speed that scientists cannot find a clear explanation for such a rapid expansion.

Finding analogies between the discovered structure and the Big Bang, scientists are sure that it was formed and gained speed due to the convergence of the Milky Way and the Andromeda galaxy in the distant past.

There is only one problem: scientists cannot understand why these small galaxies got such a high speed with such a spread.

“If Einstein’s theory of gravity is correct, our galaxy could never get close enough to Andromeda to eject something at such a speed,” explained Zhao Hongsheng from the University of St. Andrews (Scotland), author of a study published in the journal MNRAS .

Zhao and colleagues are studying the movements of this ring of small galaxies, which, along with the Milky Way and the Andromeda galaxy, are part of the so-called Local Group, which includes at least 54 galaxies. Our spiral galaxy the Milky Way and the neighboring Andromeda galaxy are separated by 2.5 million light years, but unlike most known galaxies, our neighbor does not move away from us, but flies towards us at a speed of more than 400 km / s.

Using the Standard Cosmological Model (the so-called ΛCDM model) in their calculations, scientists suggest that in 3.75 billion years two galaxies should collide, and after a few billion years this collision will lead to the strong destruction of both galaxies and the formation of a new one. But if these galaxies are approaching now, could they have been approaching in the past?

In 2013, the Zhao team suggested that 7-11 billion years ago the Milky Way and Andromeda already flew past each other at a very close distance.

This gave rise to "tsunami-like" waves in them, thanks to which smaller galaxies were thrown out, which are observed today flying away from us.

Similar approaches of two galaxies are known to astronomers (in the illustration to the note - the approach of the galaxies NGC 5426 and NGC 5427). However, they fly apart too quickly. “The high galactocentric radial velocities of some of the Local Group galaxies were caused by forces acting on them that our model does not take into account,” they concluded in the paper. Moreover, there is no doubt about the common past of the Milky Way, Andromeda and these expanding galaxies, if only because they are approximately in the same plane, scientists argue.

“The ring-shaped distribution is very specific. These small galaxies look like raindrops flying from a rotating umbrella, said study co-author Indranil Banik.

“By my estimation, the chance of randomly distributed galaxies lining up in this way is 1/640.

I traced their origin to a dynamic event that happened when the universe was half its age."

ΛCDM-model - , which takes into account the presence in the Universe of ordinary (baryon matter, dark energy, described in the Einstein equations in the form of a constant Λ) and cold dark matter.

The problem of the described scenario of the expansion of small galaxies is not only in the hypothetical violation of the ΛCDM model. Calculations show that such a close approach of the Milky Way and Andromeda in the past should have led to their merger, which, as is known, did not happen.

“Such a high speed (of the expansion of galaxies) requires 60 times more mass of stars than we see today in the Milky Way and Andromeda. However, the friction that would have developed between the massive dark matter halo at the center of the galaxies and these stars would have led to their merger, rather than the 2.5 million light-year separation that occurred,” explained Banik.

“Science evolves through challenges,” said Marcel Pawlowski, an astrophysicist at the University of California, Irvine. “This giant ring poses a serious challenge to the standard paradigm.”

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This article discusses the speed of the Sun and the Galaxy relative to different frames of reference:

The speed of the Sun in the Galaxy relative to the nearest stars, visible stars and the center of the Milky Way;

Velocity of the Galaxy relative to the local group of galaxies, distant star clusters and cosmic background radiation.

Brief description of the Milky Way Galaxy.

Description of the Galaxy.

Before proceeding to the study of the speed of the Sun and the Galaxy in the Universe, let's get to know our Galaxy better.

We live, as it were, in a gigantic "star city". Or rather, our Sun “lives” in it. The population of this "city" is a variety of stars, and more than two hundred billion of them "live" in it. A myriad of suns are born in it, going through their youth, middle age and old age - they go through a long and difficult life path lasting billions of years.

The dimensions of this "star city" - the Galaxy are enormous. The distances between neighboring stars are, on average, thousands of billions of kilometers (6*1013 km). And there are more than 200 billion such neighbors.

If we raced from one end of the Galaxy to the other at the speed of light (300,000 km/sec), it would take about 100,000 years.

Our entire star system slowly rotates like a giant wheel made up of billions of suns.

Orbit of the Sun

In the center of the Galaxy, apparently, there is a supermassive black hole (Sagittarius A *) (about 4.3 million solar masses) around which, presumably, a black hole of average mass from 1000 to 10,000 solar masses rotates and has an orbital period of about 100 years and several thousand relatively small ones. Their combined gravitational action on neighboring stars causes the latter to move along unusual trajectories. There is an assumption that most galaxies have supermassive black holes in their core.

The central regions of the Galaxy are characterized by a strong concentration of stars: each cubic parsec near the center contains many thousands of them. Distances between stars are tens and hundreds of times less than in the vicinity of the Sun.

The core of the Galaxy with great force attracts all other stars. But a huge number of stars are settled throughout the "star city". And they also attract each other in different directions, and this has a complex effect on the movement of each star. Therefore, the Sun and billions of other stars mostly move in circular paths or ellipses around the center of the Galaxy. But that's just "basically" - if we look closely, we'd see them moving in more complex curved, meandering paths among the surrounding stars.

Feature of the Milky Way Galaxy:

Location of the Sun in the Galaxy.

Where in the Galaxy is the Sun and does it move (and with it the Earth, and you and me)? Are we in the "city center" or at least somewhere close to it? Studies have shown that the Sun and the solar system are located at a great distance from the center of the Galaxy, closer to the "urban outskirts" (26,000 ± 1,400 light years).

The Sun is located in the plane of our Galaxy and is removed from its center by 8 kpc and from the plane of the Galaxy by about 25 pc (1 pc (parsec) = 3.2616 light years). In the region of the Galaxy where the Sun is located, the stellar density is 0.12 stars per pc3.

model of our galaxy

The speed of the Sun in the Galaxy.

The speed of the Sun in the Galaxy is usually considered relative to different frames of reference:

relative to nearby stars.

Relative to all bright stars visible to the naked eye.

Regarding interstellar gas.

Relative to the center of the Galaxy.

1. The speed of the Sun in the Galaxy relative to the nearest stars.

Just as the speed of a flying aircraft is considered in relation to the Earth, not taking into account the flight of the Earth itself, so the speed of the Sun can be determined relative to the stars closest to it. Such as the stars of the Sirius system, Alpha Centauri, etc.

This velocity of the Sun in the Galaxy is relatively small: only 20 km/sec or 4 AU. (1 astronomical unit is equal to the average distance from the Earth to the Sun - 149.6 million km.)

The Sun, relative to the nearest stars, moves towards a point (apex) lying on the border of the constellations Hercules and Lyra, approximately at an angle of 25 ° to the plane of the Galaxy. Equatorial coordinates of the apex = 270°, = 30°.

2. The speed of the Sun in the Galaxy relative to the visible stars.

If we consider the movement of the Sun in the Milky Way Galaxy relative to all the stars visible without a telescope, then its speed is even less.

The speed of the Sun in the Galaxy relative to the visible stars is 15 km/sec or 3 AU.

The apex of the motion of the Sun in this case also lies in the constellation Hercules and has the following equatorial coordinates: = 265°, = 21°.

The speed of the Sun relative to nearby stars and interstellar gas

3. The speed of the Sun in the Galaxy relative to the interstellar gas.

The next object of the Galaxy, with respect to which we will consider the speed of the Sun, is interstellar gas.

The expanses of the universe are far from being as desolate as it was thought for a long time. Although in small quantities, interstellar gas is present everywhere, filling all corners of the universe. The interstellar gas, with the apparent emptiness of the unfilled space of the Universe, accounts for almost 99% of the total mass of all space objects. Dense and cold forms of interstellar gas containing hydrogen, helium and minimal amounts of heavy elements (iron, aluminum, nickel, titanium, calcium) are in a molecular state, connecting into vast cloud fields. Usually, in the composition of the interstellar gas, the elements are distributed as follows: hydrogen - 89%, helium - 9%, carbon, oxygen, nitrogen - about 0.2-0.3%.

A tadpole-like cloud of interstellar gas and dust IRAS 20324+4057 that hides a growing star

Clouds of interstellar gas can not only rotate in an orderly manner around galactic centers, but also have unstable acceleration. Over the course of several tens of millions of years, they catch up with each other and collide, forming complexes of dust and gas.

In our Galaxy, the main volume of interstellar gas is concentrated in spiral arms, one of the corridors of which is located near the solar system.

The speed of the Sun in the Galaxy relative to the interstellar gas: 22-25 km/sec.

Interstellar gas in the immediate vicinity of the Sun has a significant intrinsic velocity (20-25 km/s) relative to the nearest stars. Under its influence, the apex of the Sun's motion shifts towards the constellation Ophiuchus (= 258°, = -17°). The difference in direction of movement is about 45°.

4. The speed of the Sun in the Galaxy relative to the center of the Galaxy.

In the three points discussed above, we are talking about the so-called peculiar, relative speed of the Sun. In other words, peculiar speed is the speed relative to the cosmic frame of reference.

But the Sun, the stars closest to it, and the local interstellar cloud are all involved in a larger movement - movement around the center of the Galaxy.

And here we are talking about completely different speeds.

The speed of the Sun around the center of the Galaxy is huge by earthly standards - 200-220 km / s (about 850,000 km / h) or more than 40 AU. / year.

It is impossible to determine the exact speed of the Sun around the center of the Galaxy, because the center of the Galaxy is hidden from us behind dense clouds of interstellar dust. However, more and more new discoveries in this area are decreasing the estimated speed of our sun. More recently, they talked about 230-240 km / s.

The solar system in the galaxy is moving towards the constellation Cygnus.

The motion of the Sun in the Galaxy occurs perpendicular to the direction to the center of the Galaxy. Hence the galactic coordinates of the apex: l = 90°, b = 0° or in more familiar equatorial coordinates - = 318°, = 48°. Since this is a reversal motion, the apex shifts and completes a full circle in a "galactic year", approximately 250 million years; its angular velocity is ~5" / 1000 years, i.e. the coordinates of the apex shift by one and a half degrees per million years.

Our Earth is about 30 such "galactic years" old.

The speed of the Sun in the Galaxy relative to the center of the Galaxy

By the way, an interesting fact about the speed of the Sun in the Galaxy:

The speed of rotation of the Sun around the center of the Galaxy almost coincides with the speed of the compression wave that forms the spiral arm. This situation is atypical for the Galaxy as a whole: the spiral arms rotate at a constant angular velocity, like spokes in wheels, and the movement of stars occurs with a different pattern, so almost the entire stellar population of the disk either gets inside the spiral arms or falls out of them. The only place where the speeds of stars and spiral arms coincide is the so-called corotation circle, and it is on it that the Sun is located.

For the Earth, this circumstance is extremely important, since violent processes occur in the spiral arms, which form powerful radiation that is destructive to all living things. And no atmosphere could protect him from it. But our planet exists in a relatively quiet place in the Galaxy and has not been affected by these cosmic cataclysms for hundreds of millions (or even billions) of years. Perhaps that is why life was able to originate and survive on Earth.

The speed of movement of the Galaxy in the Universe.

The speed of movement of the Galaxy in the Universe is usually considered relative to different frames of reference:

Relative to the Local Group of galaxies (speed of approach to the Andromeda galaxy).

Relative to distant galaxies and clusters of galaxies (the speed of movement of the Galaxy as part of the local group of galaxies to the constellation Virgo).

Regarding the relic radiation (the speed of movement of all galaxies in the part of the Universe closest to us to the Great Attractor - a cluster of huge supergalaxies).

Let's take a closer look at each of the points.

1. Velocity of movement of the Milky Way Galaxy towards Andromeda.

Our Milky Way Galaxy also does not stand still, but is gravitationally attracted and approaches the Andromeda galaxy at a speed of 100-150 km/s. The main component of the speed of approach of galaxies belongs to the Milky Way.

The lateral component of the motion is not precisely known, and it is premature to worry about a collision. An additional contribution to this motion is made by the massive galaxy M33, located approximately in the same direction as the Andromeda galaxy. In general, the speed of our Galaxy relative to the barycenter of the Local Group of galaxies is about 100 km / s approximately in the Andromeda/Lizard direction (l = 100, b = -4, = 333, = 52), however, these data are still very approximate. This is a very modest relative speed: the Galaxy is displaced by its own diameter in two or three hundred million years, or, very approximately, in a galactic year.

2. Velocity of movement of the Milky Way Galaxy towards the Virgo cluster.

In turn, the group of galaxies, which includes our Milky Way, as a whole, is moving towards the large cluster of Virgo at a speed of 400 km/s. This movement is also due to gravitational forces and is carried out relative to distant clusters of galaxies.

Velocity of the Milky Way Galaxy towards the Virgo Cluster

3. Speed ​​of movement of the Galaxy in the Universe. To the Great Attractor!

Relic radiation.

According to the Big Bang theory, the early Universe was a hot plasma consisting of electrons, baryons, and constantly emitted, absorbed, and re-emitted photons.

As the Universe expanded, the plasma cooled down and at a certain stage, slowed down electrons got the opportunity to combine with slowed down protons (hydrogen nuclei) and alpha particles (helium nuclei), forming atoms (this process is called recombination).

This happened at a plasma temperature of about 3,000 K and an approximate age of the universe of 400,000 years. There is more free space between particles, fewer charged particles, photons no longer scatter so often and can now move freely in space, practically without interacting with matter.

Those photons that were emitted at that time by the plasma towards the future location of the Earth still reach our planet through the space of the universe that continues to expand. These photons make up the relic radiation, which is thermal radiation that evenly fills the Universe.

The existence of relic radiation was theoretically predicted by G. Gamow in the framework of the Big Bang theory. Its existence was experimentally confirmed in 1965.

Velocity of movement of the Galaxy relative to the cosmic background radiation.

Later, the study of the speed of movement of galaxies relative to the cosmic background radiation began. This movement is determined by measuring the non-uniformity of the temperature of the relict radiation in different directions.

The radiation temperature has a maximum in the direction of motion and a minimum in the opposite direction. The degree of deviation of the temperature distribution from isotropic (2.7 K) depends on the magnitude of the velocity. It follows from the analysis of the observational data that the Sun moves relative to the cosmic microwave background at a speed of 400 km/s in the direction =11.6, =-12.

Such measurements also showed another important thing: all galaxies in the part of the Universe closest to us, including not only ours local group, but also the Virgo cluster and other clusters, move relative to the background cosmic microwave background at an unexpectedly high speed.

For the Local Group of galaxies, it is 600-650 km / s with an apex in the constellation Hydra (=166, =-27). It looks like that somewhere in the depths of the Universe there is a huge cluster of many superclusters that attract the matter of our part of the Universe. This cluster was named Great Attractor- from the English word "attract" - to attract.

Since the galaxies that make up the Great Attractor are hidden by interstellar dust that is part of the Milky Way, it has only been possible to map the Attractor in recent years with the help of radio telescopes.

The Great Attractor is located at the intersection of several superclusters of galaxies. The average density of matter in this region is not much greater than the average density of the Universe. But due to its gigantic size, its mass turns out to be so great and the force of attraction is so huge that not only our star system, but also other galaxies and their clusters nearby move in the direction of the Great Attractor, forming a huge stream of galaxies.

The speed of movement of the Galaxy in the Universe. To the Great Attractor!

So, let's sum up.

The speed of the Sun in the Galaxy and the Galaxy in the Universe. Pivot table.

Hierarchy of movements in which our planet takes part:

The rotation of the Earth around the Sun;

Rotation together with the Sun around the center of our Galaxy;

Movement relative to the center of the Local Group of galaxies together with the entire Galaxy under the influence of the gravitational attraction of the constellation Andromeda (galaxy M31);

Movement towards a cluster of galaxies in the constellation Virgo;

Movement to the Great Attractor.

The speed of the Sun in the Galaxy and the speed of the Milky Way Galaxy in the Universe. Pivot table.

It is difficult to imagine, and even more difficult to calculate, how far we move every second. These distances are huge, and the errors in such calculations are still quite large. Here is what science has to date.

If someone thinks that the word "scatter" has a purely sporting, in extreme cases, "anti-marital" character, then they are mistaken. There are much more interesting interpretations. For example, the Hubble Cosmological Law indicates that… galaxies are running away!

Three kinds of nebulae

Imagine: in a black, vast airless space, star systems are quietly and slowly moving away from each other: “Farewell! Goodbye! Goodbye!". Perhaps, let's leave aside the "lyrical digressions" and turn to scientific information. In 1929, the most influential astronomer of the 20th century, the American scientist Edwin Powell Hubble (1889-1953), came to the conclusion that the universe is steadily expanding.

A man who devoted his entire adult life to unraveling the structure of the cosmos, was born in Marshfield From an early age he was interested in astronomy, although he eventually became a certified lawyer. After graduating from Cambridge University, Edwin worked in Chicago at the York Observatory. In the First World War (1914-1918) he fought. The front-line years only pushed the discovery back in time. Today, the entire scientific world knows what the Hubble constant is.

On the way to discovery

Returning from the front, the scientist turned his attention to the high mountain observatory Mount Wilson (California). He was hired there. In love with astronomy, the young man spent a lot of time looking into the lenses of huge telescopes measuring 60 and 100 inches. For that time - the largest, almost fantastic! The inventors have been working on the devices for almost a decade, achieving the highest possible magnification and image clarity.

Recall that the visible boundary of the Universe is called the Metagalaxy. It proceeds to the state at the time of the Big Bang (cosmological singularity). Modern provisions state that the values ​​of physical constants are homogeneous (meaning the speed of light, elementary charge, etc.). It is believed that the Metagalaxy contains 80 billion galaxies (an amazing figure still sounds like this: 10 sextillion and 1 septillion stars). Shape, mass and size - for the Universe, these are completely different concepts than those accepted on Earth.

Mysterious Cepheids

To substantiate the theory explaining the expansion of the universe, it took long-term deep research, complex comparisons and calculations. In the early twenties of the XX century, yesterday's soldier was finally able to classify the nebulae observed separately from the Milky Way. According to his discovery, they are spiral, elliptical and irregular (three kinds).

In the nearest but not the closest spiral nebula to us, Edwin saw Cepheids (a class of pulsating stars). Hubble's law is closer than ever to its final formation. The astronomer calculated the distance to these beacons and the size of the largest. According to his findings, Andromeda contains about one trillion stars (2.5-5 times the size of the Milky Way).

Constant

Some scientists, explaining the nature of Cepheids, compare them with inflatable rubber balls. They increase, then decrease, then approach, then move away. The radial velocity fluctuates in this case. When compressed, the temperature of the "travelers" increases (although the surface decreases). Pulsating stars are an unusual pendulum that, sooner or later, will stop.

Like the rest of the nebulae, Andromeda is characterized by scientists as an island universe space, reminiscent of our galaxy. In 1929, Edwin discovered that the radial velocities of galaxies and their distances are interrelated, linearly dependent. A coefficient expressed in km/s per megaparsec, the so-called Hubble constant, was determined. The Universe expands - the constant changes. But at a particular moment in all points of the system of the universe it is the same. In 2016 - 66.93 ± 0.62 (km/s)/Mpc.

Ideas about the system of the universe, continuing evolution, expanding, then received an observational basis. The process was actively studied by the astronomer until the very beginning of World War II. In 1942, he headed the External Ballistics Division at the Aberdeen Proving Ground (USA). Did an associate of perhaps the most mysterious science in the world dream of this? No, he wanted to "decipher" the laws of the hidden corners of distant galaxies! As for political views, the astronomer openly condemned the leader of the Third Reich, Adolf Hitler. At the end of his life, Hubble was known as a powerful opponent of the use of weapons of mass destruction. But back to nebulae.

Great Edwin

Many astronomical constants are corrected over time, new discoveries appear. But all of them do not compare with the Law of expansion of the Universe. The famous astronomer of the 20th century, Hubble (since the time of Copernicus, he has not been equal!) is put on a par with the founder of experimental physics, Galileo Galilei and the author of an innovative conclusion about the existence of stellar systems, William Herschel.

Even before the Hubble law was discovered, its author became a member of the National Academy of Sciences of the United States of America, later academies in different countries, has many awards. Many have probably heard about the fact that more than ten years ago the Hubble Space Telescope was put into orbit and is successfully operating. This is the name of one of the minor planets revolving between the orbits of Mars and Jupiter (an asteroid).

It would not be entirely fair to say that the astronomer only dreamed of perpetuating his name, but there is circumstantial evidence that Edwin liked to attract attention. There are photos where he cheerfully poses next to movie stars. Below we will talk about his attempts to “fix” the achievement at the laureate level, and thus enter the history of cosmology.

Henrietta Leavitt Method

The famous British astrophysicist, in his book A Brief History of Time, wrote that "the discovery that the universe is expanding was the greatest intellectual revolution of the 20th century." Hubble was lucky enough to be in the right place at the right time. The Mount Wilson Observatory was the center of the observational work that underpinned the new astrophysics (later called cosmology). The most powerful Hooker telescope on Earth had just entered service.

But the Hubble constant was hardly discovered by luck alone. Patience, perseverance, and the ability to defeat scientific rivals were required. So the American astronomer Harlow Shapley offered his model of the Galaxy. He was already known as the scientist who determined the size of the Milky Way. He made extensive use of the method of determining distances from Cepheids, using a method compiled in 1908 by Henrietta Swan Leavitt. She set the distance to the object, based on the standard variations of light from bright stars (Cepheid variables).

Not dust and gas, but other galaxies

Harlow Shapley believed that the width of the galaxy is 300,000 light-years (about ten times the allowable value). However, Shapley, like most astronomers of that time, was sure: the Milky Way is the whole Universe. Despite a suggestion first made by William Herschel in the 18th century, he shared the common belief that all nebulae for relatively nearby objects are just patches of dust and gas in the sky.

How many bitter, cold nights Hubble spent sitting in front of the powerful Hooker telescope before he was able to prove Shapley wrong. In October 1923, Edwin noticed a “flashed” object in the M31 nebula (the constellation Andromeda) and suggested that it did not belong to the Milky Way. After carefully examining photographic plates that captured the same area previously explored by other astronomers, including Shapley, Edwin realized that this was a Cepheid.

Cosmos Discovered

Hubble used Shapley's method to measure the distance to a variable star. It turned out that it is estimated at millions of light years from Earth, which is far beyond the Milky Way. The galaxy itself contains millions of stars. The known Universe expanded dramatically on the same day and - in a sense - the Cosmos itself was discovered!

The New York Times wrote: "The discovered spiral nebulae are star systems. Dr. Hubbel (sic) confirms the view that they are like 'island universes' similar to our own." The discovery was of great importance to the astronomical world, but Hubble's greatest moment was yet to come.

No static

As we said, the victory for Copernicus No. 2 came in 1929, when he classified all known nebulae and measured their speeds from the spectra of emitted light. His startling discovery that all galaxies are receding from us at speeds that increase in proportion to their distance from the Milky Way shocked the world. Hubble's law overturned the traditional view of a static universe and showed that it itself is full of dynamics. Einstein himself bowed his head to such amazing powers of observation.

The author of the theory of relativity corrected his own equations, which he used to justify the expansion of the Universe. Now Hubble has shown that Einstein was right. Hubble time is the reciprocal of the Hubble constant (t H = 1/H). This is the characteristic time of the expansion of the Universe at the current moment.

Exploded and scattered

If the constant in 2016 is 66.93 ± 0.62 (km/s)/Mpc, then the expansion is currently characterized by the following figures: (4.61 ± 0.05) 10 17 s or (14.610 ± 0.016) 10 9 years old. And again, a little humor. Optimists say it's good that the galaxies are "running apart". If you imagine that they are getting closer, sooner or later there would be a Big Bang. But it was with him that the birth of the universe began.

The galaxies "rushed" (started moving) in different directions at the same time. If the removal speed was not proportional to the distance, the explosion theory is meaningless. Another derivative constant is the Hubble distance - the product of time and the speed of light: D H = ct H = c/H. At the current moment - (1.382 ± 0.015) 10 26 m or (14.610 ± 0.016) 10 9 light years.

And again about the inflatable ball. It is believed that even astronomers do not always correctly interpret the expansion of the universe. Some connoisseurs believe that it swells like a rubber ball, without knowing any physical limitations. At the same time, the galaxies themselves not only move away from us, but also randomly "bustle" inside the motionless clusters. Others claim that distant galaxies “float away” as fragments of the Big Bang, but they do it sedately.

Could be a Nobel laureate

Hubble was trying to win the Nobel Prize. In the late 1940s, he even hired an advertising agent (now he would be called a PR manager) to promote the case. But the efforts were in vain: there was no category for astronomers. Edwin died in 1953, in the course of scientific research. For several nights he observed extragalactic objects.

His last ambitious dream remained unfulfilled. But the scientist would certainly be glad that a space telescope was named after him. And generations of brothers in mind continue to explore the vast and wonderful space. It still holds many mysteries. How many discoveries are ahead! And Hubble's derivative constants will surely help one of the young scientists to become Copernicus No. 3.

Challenging Aristotle

What will be proven or refuted, as when the theory of infinity, eternity and the immutability of space around the Earth, which Aristotle himself supported, flew to smithereens? He attributed symmetry and perfection to the universe. The cosmological principle confirmed: everything flows, everything changes.

It is believed that in billions of years the skies will be empty and dark. The expansion will “carry away” galaxies beyond the cosmic horizon, from where light cannot reach us. Will the Hubble constant be relevant for an empty universe? What will become of the science of cosmology? Will she disappear? All of these are assumptions.

Redshift

In the meantime, the Hubble telescope has taken a picture that shows that we are still far from the universal void. In a professional environment, there is an opinion that the discovery of Edwin Hubble is valuable, but not his law. However, it was he who was almost immediately recognized in the scientific circles of that time. Observations of the "redshift" not only won the right to exist, it is also relevant in the XXI century.

And today, when determining the distance to galaxies, they rely on the scientist's super-discovery. Optimists say that even if our galaxy remains the only one, we will not be "bored". There will be billions of dwarf stars and planets. This means that next to us there will still be “parallel worlds” that will need to be explored.

The great physicists of the past I. Newton and A. Einstein saw the Universe as static. The Soviet physicist A. Fridman in 1924 came up with the theory of "receding" galaxies. Friedman predicted the expansion of the universe. This was a revolutionary upheaval in the physical representation of our world.

American astronomer Edwin Hubble explored the Andromeda nebula. By 1923, he was able to consider that its outskirts are clusters of individual stars. Hubble calculated the distance to the nebula. It turned out to be 900,000 light years (a more accurately calculated distance today is 2.3 million light years). That is, the nebula is located far beyond the Milky Way - Our Galaxy. After observing this and other nebulae, Hubble came to a conclusion about the structure of the Universe.

The universe is made up of a collection of huge star clusters - galaxies.

It is they who appear to us in the sky as distant foggy "clouds", since we simply cannot consider individual stars at such a great distance.

E. Hubble noticed an important aspect in the data obtained, which astronomers had observed before, but found it difficult to interpret. Namely: the observed length of the spectral light waves emitted by the atoms of distant galaxies is somewhat longer than the length of the spectral waves emitted by the same atoms under the conditions of terrestrial laboratories. That is, in the emission spectrum of neighboring galaxies, a light quantum emitted by an atom during an electron jump from orbit to orbit is shifted in frequency in the direction of the red part of the spectrum compared to a similar quantum emitted by the same atom on Earth. Hubble took it upon himself to interpret this observation as a manifestation of the Doppler effect.

All observed neighboring galaxies are moving away from the Earth, since almost all galactic objects outside the Milky Way have a red spectral shift proportional to the speed of their removal.

Most importantly, Hubble was able to compare the results of his measurements of the distances to neighboring galaxies with the measurements of their removal rates (by redshift).

Mathematically, the law is formulated very simply:

where v is the speed of the galaxy moving away from us,

r is the distance to it,

H is the Hubble constant.

And, although initially Hubble came to this law as a result of observing only a few galaxies closest to us, not one of the many new galaxies of the visible Universe discovered since then, more and more distant from the Milky Way, does not fall out of this law.

So, the main consequence of Hubble's law:

The universe is expanding.

The very fabric of world space is expanding. All observers (and we are no exception) consider themselves to be at the center of the universe.

4. The Big Bang Theory

From the experimental fact of the recession of galaxies, the age of the Universe was estimated. It turned out to be equal - about 15 billion years! Thus began the era of modern cosmology.

Naturally, the question arises: what happened in the beginning? In total, it took scientists about 20 years to completely turn over the ideas about the Universe again.

The answer was proposed by the outstanding physicist G. Gamow (1904 - 1968) in the 40s. The history of our world began with the Big Bang. This is exactly what most astrophysicists think today.

The Big Bang is a rapid drop in the initially huge density, temperature and pressure of matter concentrated in a very small volume of the Universe. All the matter of the universe was compressed into a dense lump of protomatter, enclosed in a very small volume compared to the current scale of the Universe.

The idea of ​​the Universe, which was born from a superdense clot of superhot matter and has been expanding and cooling since then, is called the Big Bang theory.

There is no more successful cosmological model of the origin and evolution of the Universe today.

According to the Big Bang theory, the early universe consisted of photons, electrons, and other particles. Photons constantly interacted with other particles. As the universe expanded, it cooled, and at a certain stage, electrons began to combine with the nuclei of hydrogen and helium and form atoms. This happened at a temperature of about 3000 K and the approximate age of the universe is 400,000 years. From that moment on, photons were able to move freely in space, practically without interacting with matter. But we are left with "witnesses" of that era - these are relic photons. It is believed that the relic radiation has been preserved from the initial stages of the existence of the Universe and evenly fills it. As a result of further cooling of the radiation, its temperature decreased and now is about 3 K.

The existence of the CMB was predicted theoretically within the framework of the Big Bang theory. It is regarded as one of the main confirmations of the Big Bang theory.