What is the period of rotation of the sun around the center of the galaxy. What does the Sun revolve around? The speed of the Sun in the Galaxy relative to visible stars

You sit, stand or lie reading this article and do not feel that the Earth is spinning on its axis at a breakneck speed - approximately 1,700 km/h at the equator. However, the rotation speed does not seem that fast when converted to km/s. The result is 0.5 km/s - a barely noticeable blip on the radar, in comparison with other speeds around us.

Just like other planets in the solar system, the Earth revolves around the Sun. And in order to stay in its orbit, it moves at a speed of 30 km/s. Venus and Mercury, which are closer to the Sun, move faster, Mars, whose orbit passes behind the Earth’s orbit, moves much slower.

But even the Sun does not stand in one place. Our Milky Way galaxy is huge, massive and also mobile! All stars, planets, gas clouds, dust particles, black holes, dark matter - all of this moves relative to a common center of mass.

According to scientists, the Sun is located at a distance of 25,000 light years from the center of our galaxy and moves in an elliptical orbit, making a full revolution every 220–250 million years. It turns out that the speed of the Sun is about 200–220 km/s, which is hundreds of times higher than the speed of the Earth around its axis and tens of times higher than the speed of its movement around the Sun. This is what the movement of our solar system looks like.

Is the galaxy stationary? Not again. Giant space objects have a large mass, and therefore create strong gravitational fields. Give the Universe some time (and we've had it for about 13.8 billion years), and everything will start moving in the direction of greatest gravity. That is why the Universe is not homogeneous, but consists of galaxies and groups of galaxies.

What does this mean for us?

This means that the Milky Way is pulled towards it by other galaxies and groups of galaxies located nearby. This means that massive objects dominate the process. And this means that not only our galaxy, but also everyone around us is influenced by these “tractors”. We are getting closer to understanding what happens to us in outer space, but we still lack facts, for example:

what were the initial conditions under which the Universe began;
how the different masses in the galaxy move and change over time;
how the Milky Way and surrounding galaxies and clusters were formed;
and how it is happening now.

However, there is a trick that will help us figure it out.

The Universe is filled with relict radiation with a temperature of 2.725 K, which has been preserved since the Big Bang. Here and there there are tiny deviations - about 100 μK, but the overall temperature background is constant.

This is because the Universe was formed by the Big Bang 13.8 billion years ago and is still expanding and cooling.

380,000 years after the Big Bang, the Universe cooled to such a temperature that the formation of hydrogen atoms became possible. Before this, photons constantly interacted with other plasma particles: they collided with them and exchanged energy. As the Universe cooled, there were fewer charged particles and more space between them. Photons were able to move freely in space. CMB radiation is photons that were emitted by the plasma towards the future location of the Earth, but escaped scattering because recombination had already begun. They reach the Earth through the space of the Universe, which continues to expand.

You can “see” this radiation yourself. The interference that occurs on a blank TV channel if you use a simple antenna that looks like a rabbit's ears is 1% caused by the CMB.

Still, the temperature of the relict background is not the same in all directions. According to the results of research by the Planck mission, the temperature differs slightly in the opposite hemispheres of the celestial sphere: it is slightly higher in parts of the sky south of the ecliptic - about 2.728 K, and lower in the other half - about 2.722 K.

Map of the microwave background made with the Planck telescope.

This difference is almost 100 times larger than other observed temperature variations in the CMB, and is misleading. Why is this happening? The answer is obvious - this difference is not due to fluctuations in the cosmic microwave background radiation, it appears because there is movement!

When you approach a light source or it approaches you, the spectral lines in the source's spectrum shift towards short waves (violet shift), when you move away from it or it moves away from you, the spectral lines shift towards long waves (red shift).

CMB radiation cannot be more or less energetic, which means we are moving through space. The Doppler effect helps determine that our Solar System is moving relative to the CMB at a speed of 368 ± 2 km/s, and the local group of galaxies, including the Milky Way, the Andromeda Galaxy and the Triangulum Galaxy, is moving at a speed of 627 ± 22 km/s relative to the CMB. These are the so-called peculiar velocities of galaxies, which amount to several hundred km/s. In addition to them, there are also cosmological velocities due to the expansion of the Universe and calculated according to Hubble’s law.

Thanks to residual radiation from the Big Bang, we can observe that everything in the Universe is constantly moving and changing. And our galaxy is only part of this process.

The moon moves in orbit at a speed of 1 km per second. The Earth and the Moon make a full revolution around the Sun in 365 days at a speed of 108 thousand kilometers per hour or 30 km per second.

Until recently, scientists were limited to such data. But with the invention of powerful telescopes, it became clear that the solar system is not limited to just the planets. It is much larger and extends over a distance of 100 thousand distances from the Earth to the Sun (astronomical). This is the area covered by the gravity of our star. It is named after the astronomer Jan Oort, who proved its existence. The Oort Cloud is a world of icy comets that periodically approach the Sun, crossing the Earth's orbit. Only beyond this cloud does the Solar System end and interstellar space begin.

Oort also, based on the radial velocities and proper motions of stars, substantiated the hypothesis about the motion of the galaxy around its center. Consequently, the Sun and its entire system, as a single whole, together with all neighboring stars, moves in the galactic disk around a common center.

Thanks to the development of science, scientists have at their disposal quite powerful and accurate instruments, with the help of which they are getting closer and closer to unraveling the structure of the universe. It was possible to find out where in the Milky Way visible in the sky its center is located. It found itself in the direction of the constellation Sagittarius, hidden by dense dark clouds of gas and dust. If there were no these clouds, then a huge blurry white spot would be visible in the night sky, tens of times larger than the Moon and of the same luminosity.

Modern clarifications

The distance to the center of the galaxy turned out to be greater than expected. 26 thousand light years. This is a huge number. The Voyager satellite, launched in 1977 and just now leaving the solar system, would reach the center of the galaxy within a billion years. Thanks to artificial satellites and mathematical calculations, it was possible to determine the trajectory of the solar system in the galaxy.

Today we know that the Sun lies in a relatively quiet region of the Milky Way between the two large spiral arms of Perseus and Sagittarius and another, slightly smaller Orion arm. All of them are visible in the night sky as foggy streaks. Those - The outer spiral arm, the Carina arm, is visible only through powerful telescopes.

The Sun, one might say, is lucky that it is located in an area where the influence of neighboring stars is not so great. If it were in a spiral arm, perhaps life would never have arisen on Earth. But still, the Sun does not move around the center of the galaxy in a straight line. The movement looks like a whirlwind: over time, it is closer to the arms, then further away. And thus it circles the circumference of the galactic disk together with neighboring stars in 215 million years, at a speed of 230 km per second.

Meanwhile, our local group is racing towards the center of the Virgo Cluster at 150 million kilometers per hour.

The Milky Way and its neighbor Andromeda, along with 30 smaller galaxies, as well as thousands of Virgo galaxies, are all attracted by the Great Attractor. Given velocities at these scales, the invisible mass occupying the voids between galaxies and galaxy clusters must be at least ten times the visible matter.

Even so, by adding this invisible material to the visible material and getting the average mass of the universe, we get only 10-30% of the critical density that is needed to “close” the universe. This phenomenon suggests that the universe is “open.” Cosmologists continue to argue on this topic in the same way as they try, or “dark matter”.

It is believed to determine the structure of the Universe on enormous scales. Dark matter gravitationally interacts with normal matter, which is what allows astronomers to observe the formation of long, thin walls of supergalactic clusters.

Recent measurements (using telescopes and space probes) of the mass distribution in M31, the largest galaxy in the vicinity of the Milky Way, and other galaxies have led to the recognition that galaxies are filled with dark matter, and have shown that a mysterious force is filling the vacuum of empty space. accelerating the expansion of the Universe.

Astronomers now understand that the ultimate fate of the universe is inextricably linked to the presence of dark energy and dark matter. The current standard model for cosmology suggests that the universe is 70% dark energy, 25% dark matter, and just 5% normal matter.

We don't know what dark energy is or why it exists. On the other hand, particle theory suggests that at the microscopic level, even a perfect vacuum is bubbled with quantum particles, which are a natural source of dark energy. But basic calculations show that the dark energy that is produced from the vacuum is 10,120 times greater than what we observe. Some unknown physical processes should eliminate most, but not all, of the vacuum energy, leaving enough to accelerate the expansion of the universe.

A new theory of elementary particles will have to explain this physical process. New theories of “dark attractors” hide behind the so-called Copernican principle, which says that it is not surprising that we observers assume that the universe is heterogeneous. Such alternative theories explain the observed accelerated expansion of the Universe without the involvement of dark energy, and instead suggest that we are close to the center of the void, beyond which a denser “dark” attractor is pulling us towards it.

In an article published in Physical Review Letters, Pengzhi Zhang from the Shanghai Astronomical Observatory and Albert Stebbins showed at the Fermilab exhibition that the popular void model and many others can well replace dark energy without conflicting with telescope observations.

Surveys show that the universe is homogeneous, at least on scales up to gigaparsecs. Zhang and Stebbins argue that if large-scale irregularities exist, they should be detected as a temperature shift in the cosmic microwave background of relict photons produced 400,000 years after the Big Bang. This occurs due to electron-photon scattering (the inverse of Compton scattering).

Focusing on the Hubble Bubble model of emptiness, the scientists showed that in such a scenario, some regions of the universe would expand faster than others, resulting in a larger temperature shift than expected. But telescopes that study the CMB do not see such a big shift.

Well, as Carl Sagan said, “extraordinary claims require extraordinary evidence.”

This article examines the speed of movement of the Sun and the Galaxy relative to different reference systems:

the speed of the Sun's movement in the Galaxy relative to the nearest stars, visible stars and the center of the Milky Way;
the speed of motion of the Galaxy relative to the local group of galaxies, distant star clusters and cosmic microwave background radiation.

Brief description of the Milky Way Galaxy.

Description of the Galaxy.

Before we begin to study the speed of movement of the Sun and the Galaxy in the Universe, let’s take a closer look at our Galaxy.

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, experience their youth, middle age and old age - they go through a long and complex life path, lasting billions of years.

The size of this “star city” - the Galaxy - is enormous. The distances between neighboring stars are on average thousands of billions of kilometers (6 * 10 13 km). And there are over 200 billion such neighbors.

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

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

In the center of the Galaxy, there is apparently a supermassive black hole (Sagittarius A*) (about 4.3 million solar masses) around which, presumably, a black hole of average mass with an average mass of 1000 to 10,000 solar masses and an orbital period of about 100 years rotates. several thousand relatively small ones. Their combined gravitational effect 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. The distances between stars are tens and hundreds of times smaller than in the vicinity of the Sun.

The core of the Galaxy attracts all other stars with enormous force. But a huge number of stars are scattered 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 generally move in circular paths, or ellipses, around the center of the Galaxy. But this is only “mostly” - if we looked closely, we would see that they move along more complex curves, meandering paths among the surrounding stars.

Characteristics of the Milky Way Galaxy:

The location of the Sun in the Galaxy.

Where is the Sun in the Galaxy and is it moving (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 an enormous 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 approximately 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 pc 3 .

Rice. Model of our Galaxy

The speed of the Sun's movement in the Galaxy.

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

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 movement of the Sun in the Galaxy relative to the nearest stars.

Just as the speed of a flying airplane is considered in relation to the Earth, without 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 speed of the Sun's movement 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, at approximately an angle of 25° to the plane of the Galaxy. Equatorial coordinates of the apex α = 270°, δ = 30°.

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

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

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

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

The next object in the Galaxy, relative to which we will consider the speed of movement of the Sun, is interstellar gas.

The vastness of the universe is not nearly as deserted as it was thought for a long time. Although in small quantities, interstellar gas is present everywhere, filling all corners of the universe. Interstellar gas, despite the apparent emptiness of the unfilled space of the Universe, accounts for almost 99% of the total mass of all cosmic 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, combining into vast cloud fields. Typically, elements in interstellar gas are distributed as follows: hydrogen - 89%, helium - 9%, carbon, oxygen, nitrogen - about 0.2-0.3%.

Rice. Gas and dust cloud IRAS 20324+4057 of interstellar gas and dust is 1 light year long, similar to a tadpole, in which a growing star is hidden.

Clouds of interstellar gas can not only rotate orderly 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 bulk 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 speed (20-25 km/s) relative to the nearest stars. Under its influence, the apex of the Sun's movement shifts towards the constellation Ophiuchus (α = 258°, δ = -17°). The difference in the direction of movement is about 45°.

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 speed relative to the cosmic frame of reference.

But the Sun, the stars closest to it, and the local interstellar cloud all together participate 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 enormous by earthly standards - 200-220 km/sec (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 reducing the estimated speed of our sun. Just recently they were talking about 230-240 km/sec.

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

The movement of the Sun in the Galaxy occurs perpendicular to the direction towards the center of the Galaxy. Hence the galactic coordinates of the apex: l = 90°, b = 0° or in more familiar equatorial coordinates - α = 318°, δ = 48°. Because this is a movement of reversal, the apex moves 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.

Rice. The speed of the Sun's movement 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 the Sun's rotation around the center of the Galaxy almost coincides with the speed of the compaction 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 a wheel, and the movement of stars occurs according to a different pattern, so almost the entire stellar population of the disk either falls inside the spiral arms or falls out of them. The only place where the velocities 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, generating powerful radiation that is destructive for all living things. And no atmosphere could protect from it. But our planet exists in a relatively calm place in the Galaxy and has not been affected by these cosmic cataclysms for hundreds of millions (or even billions) of years. Perhaps this 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 reference systems:

Relative to the Local Group of galaxies (approach speed with 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 towards the constellation Virgo).
Regarding the cosmic microwave background radiation (the speed of movement of all galaxies in the part of the Universe closest to us towards the Great Attractor - a cluster of huge supergalaxies).

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

1. The speed 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 concerns about a collision are premature. An additional contribution to this movement is made by the massive galaxy M33, located in approximately the same direction as the Andromeda galaxy. In general, the speed of motion of our Galaxy relative to the barycenter Local group of galaxies about 100 km/sec approximately in the Andromeda/Lizard direction (l = 100, b = -4, α = 333, δ = 52), but these data are still very approximate. This is a very modest relative speed: the Galaxy shifts to its own diameter in two to three hundred million years, or, very approximately, in galactic year.

2. The speed of movement of the Milky Way Galaxy towards the Virgo cluster.

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

Rice. The speed of movement of the Milky Way Galaxy towards the Virgo cluster.

CMB radiation.

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

As the Universe expanded, the plasma cooled and at a certain stage, the slowed down electrons were able 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 3000 K and an approximate age of the Universe of 400,000 years. There was more free space between particles, there were fewer charged particles, photons stopped scattering so often and could now move freely in space, practically without interacting with matter.

Those photons that were at that time emitted 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 cosmic microwave background radiation, which is thermal radiation uniformly filling the Universe.

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

The speed of movement of the Galaxy relative to the cosmic microwave background radiation.

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

The radiation temperature has a maximum in the direction of movement and a minimum in the opposite direction. The degree of deviation of the temperature distribution from isotropic (2.7 K) depends on the velocity. From the analysis of observational data it follows that that the Sun moves relative to the CMB at a speed of 400 km/s in the direction α=11.6, δ=-12 .

Such measurements also showed another important thing: all the galaxies in the part of the Universe closest to us, including not only our Local Group, but also the Virgo cluster and other clusters, are moving relative to the background cosmic microwave background radiation at unexpectedly high speeds.

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

Because the galaxies that make up the Great Attractor are hidden by the interstellar dust that makes up the Milky Way, mapping of the Attractor has only been possible in recent years using 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 enormous 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.

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

So, let's summarize.

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

Hierarchy of movements in which our planet takes part:

rotation of the Earth around the Sun;
rotation with the Sun around the center of our Galaxy;
movement relative to the center of the Local Group of galaxies along 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 towards the Great Attractor.

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

It is difficult to imagine, and even more difficult to calculate, how far we travel every second. These distances are enormous, and the errors in such calculations are still quite large. This is the data science has today.

Movement of the Sun and Galaxy relative to the object of the Universe	Speed of movement of the Sun or Galaxy	Apex
Local: The Sun relative to nearby stars	20 km/sec	Hercules
Standard: Sun relative to bright stars	15 km/sec	Hercules
Sun relative to interstellar gas	22-25 km/sec	Ophiuchus
Sun relative to the galactic center	~200 km/sec
Sun relative to the Local Group of galaxies	300 km/sec
Galaxy relative to the Local Group of galaxies	~100 km/sec	Andromeda / Lizard
Galaxy relative to clusters	400 km/sec
Sun relative to the CMB	390 km/sec	Lion/ Chalice
Galaxy relative to the CMB	550-600 km/sec	Leo/Hydra
Local group of galaxies relative to the CMB	600-650 km/sec

That's all about the speed of movement of the Sun in the Galaxy and Galaxies in the Universe. If you have any questions or clarifications, please leave comments below. Let's figure it out together! :)

With respect to my readers,

Akhmerova Zulfiya.

Special thanks to the following sites as sources for the article:

http://spacegid.com

http://www.astromyth.ru

http://teleskop.slovarik.org

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This article examines the speed of movement of the Sun and the Galaxy relative to different reference systems:

The speed of the Sun's movement in the Galaxy relative to nearby stars, visible stars and the center of the Milky Way;

The speed of motion of the Galaxy relative to the local group of galaxies, distant star clusters and cosmic microwave background radiation.

Brief description of the Milky Way Galaxy.

Description of the Galaxy.

Before we begin to study the speed of movement of the Sun and the Galaxy in the Universe, let’s take a closer look at our Galaxy.

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, experience their youth, middle age and old age - they go through a long and complex life path, lasting billions of years.

The size of this “star city” - the Galaxy - is enormous. The distances between neighboring stars are on average thousands of billions of kilometers (6*1013 km). And there are over 200 billion such neighbors.

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

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

Orbit of the Sun

Characteristics of the Milky Way Galaxy:

The location of the Sun in the Galaxy.

Model of our Galaxy

The speed of the Sun's movement in the Galaxy.

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

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 movement of the Sun in the Galaxy relative to the nearest stars.

This speed of the Sun's movement 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.)

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

The apex of the Sun's movement 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 movement of the Sun in the Galaxy relative to the interstellar gas.

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

Gas and dust cloud IRAS 20324+4057 of interstellar gas and dust is 1 light year long, similar to a tadpole, in which a growing star is hidden

In our Galaxy, the bulk 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 speed (20-25 km/s) relative to the nearest stars. Under its influence, the apex of the Sun's movement shifts towards the constellation Ophiuchus (= 258°, = -17°). The difference in the direction of movement is about 45°.

4. The speed of movement 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 speed relative to the cosmic frame of reference.

But the Sun, the stars closest to it, and the local interstellar cloud all together participate 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 enormous by earthly standards - 200-220 km/sec (about 850,000 km/h) or more than 40 AU. / year.

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

The movement of the Sun in the Galaxy occurs perpendicular to the direction towards the center of the Galaxy. Hence the galactic coordinates of the apex: l = 90°, b = 0° or in more familiar equatorial coordinates - = 318°, = 48°. Because this is a movement of reversal, the apex moves 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.

Speed of movement 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 movement of the Galaxy in the Universe.

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

Relative to the Local Group of galaxies (approach speed with 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 towards the constellation Virgo).

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

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

1. The speed of movement of the Milky Way Galaxy towards Andromeda.

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

2. The speed of movement of the Milky Way Galaxy towards the Virgo cluster.

Velocity of the Milky Way Galaxy towards the Virgo Cluster

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

CMB radiation.

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

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

Those photons that were at that time emitted 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 cosmic microwave background radiation, which is thermal radiation uniformly filling the Universe.

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

The speed of movement of the Galaxy relative to the cosmic microwave background radiation.

The radiation temperature has a maximum in the direction of movement and a minimum in the opposite direction. The degree of deviation of the temperature distribution from isotropic (2.7 K) depends on the velocity. From the analysis of observational data it follows that the Sun moves relative to the CMB 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 are moving relative to the background CMB at unexpectedly high speeds.

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

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

So, let's summarize.

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

Hierarchy of movements in which our planet takes part:

The rotation of the Earth around the Sun;

Rotation with the Sun around the center of our Galaxy;

Movement relative to the center of the Local Group of galaxies along 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 towards the Great Attractor.

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