Before Nicolaus Copernicus (1473–1543), scientists believed that the Earth was at the center of the World, and all the planets, then five of them were known (Mercury, Venus, Mars, Jupiter and Saturn) and the Sun revolved around the Earth. I'm not even talking about the hypotheses of the Earth being on the back of an elephant, turtle or any other reptile or mammal.
In the year of Copernicus’s death (1543), his multi-volume work “On the Revolution of the Celestial Spheres” was published in Latin, describing a new system of the universe, in the center of which was the Sun, and all the planets, already six in number (with the addition of the five known planets and the Earth) rotate in circular orbits around the center - the Sun.
The next step in building the solar system was taken in 1609 by Johannes Kepler (1571–1630), who proved, using precise astrometric observations of planetary motion (mainly made by the Danish astronomer Tycho Brahe (1546–1601), that the planets do not move in circles, but in ellipses with the Sun at their focus.
Experimental, i.e., observational, confirmation of Copernicus’ theory was obtained by Galileo Galilei (1564–1642), who observed the phases of Venus and Mercury through a telescope, which confirmed the Copernican (i.e., heliocentric) system of the universe.
And finally, Isaac Newton (1642–1727) derived differential equations of celestial mechanics, which made it possible to calculate the coordinates of the planets of the solar system and explained why they move, to a first approximation, in ellipses. Subsequently, through the works of great mechanics and mathematicians of the 18th and 19th centuries, a perturbation theory was created, which made it possible to take into account the gravitational interaction of planets on each other. It was in this way, by comparing observations and calculations, that the distant planets Neptune (Adams and Le Verrier, 1856) and Pluto (1932) were discovered, although last year Pluto was administratively removed from the list of planets. Today, there are already six trans-Neptunean planets the size of Pluto and even a little more.
By the middle of the 19th century, the astrometric accuracy of determining the coordinates of stars reached hundredths of a second of arc. Then for some bright stars it was noticed that their coordinates differed from the coordinates measured several centuries earlier. The first such ancient catalog was that of Hipparchus and Ptolemy (190 BC), and in the much later era of the early Renaissance, the catalog of Ulugh Beg (1394–1449). The concept of “proper motion of stars” appeared, which before, and even now, by tradition, were called “fixed stars”.
Carefully studying these proper motions, William Herschel (1738–1822) drew attention to their systematic distribution and drew from this a correct and very non-trivial conclusion: part of the proper motion of stars is not the motion of these stars, but a reflection of the motion of our Sun relative to stars close to the Sun. This is exactly how we see the movement of close trees relative to distant ones when we drive a car (or, even better, a horse) along a forest road.
By increasing the number of stars with measured proper motions, it was possible to determine that our Sun flies in the direction of the constellation Hercules, to a point called the apex, with coordinates α= 270° and δ= 30°, at a speed of 19.2 km/s. This is the own “peculiar” movement of the Sun with all the planets, interplanetary dust, asteroids relative to about a hundred stars closest to us. The distances to these stars are small, about 100–300 light years. All these stars also participate in the general motion around the center of our Galaxy at a speed of about 250 km/s. The center of the Galaxy itself is located in the constellation Sagittarius, at a distance from the Sun about 25 thousand light years. The movement of the Sun among the stars resembles the movement of a midge in a cloud, while the entire cloud flies at a much higher speed relative to the trees in the forest.
Of course, our entire giant Galaxy itself flies relative to other galaxies. The speeds of individual galaxies reach hundreds and thousands of km/s. Some galaxies are approaching us, such as the famous Andromeda nebula, while others are moving away from us.
All galaxies and galaxy clusters also participate in the general cosmological expansion, which is noticeable, however, only on scales greater than 10–30 million light years. The magnitude of this expansion rate depends linearly on the distance between galaxies or their clusters and is equal, according to modern measurements, to about 25 km/s at a distance between galaxies of a million light years.
However, it is also possible to identify a special reference system, namely the field of relict 3K submillimeter radiation. Where we are flying, the temperature of this radiation is slightly higher, and where we are flying from, it is lower. The difference between these temperatures is 0.006706 K. This is the so-called “dipole component” of the anisotropy of the cosmic microwave background radiation. The speed of the Sun's movement relative to the cosmic microwave background radiation is 627 ± 22 km/s, and without taking into account the movement of the Local Group of galaxies - 370 km/s in the direction of the Virgo constellation.
So it is difficult to answer the question of where our Sun is flying and at what speed. We must immediately determine: relative to what and in what coordinate system.
In 1961, our group from the State Astronomical Institute named after. P.K. Sternberg Moscow State University conducted observations of scattered solar ultraviolet radiation in the lines of hydrogen (1215A) and oxygen (1300A) from high-altitude geophysical rockets rising to an altitude of 500 km. At this time, thanks to the proposal of Academician S.P. Korolev, the Soviet Union began to systematically launch interplanetary stations, both flyby and landing, to Mars and Venus. Naturally, we decided to try to detect the same extended hydrogen coronas on Venus and Mars as on Earth.
With these launches, we were able to trace traces of neutral atomic hydrogen up to 125,000 km from Earth, i.e., up to 25 Earth radii. The density of hydrogen at such distances from the Earth was only about 1 atom per cm 3, which is 19 orders of magnitude less than the concentration of air at sea level! However, to our great surprise, it turned out that the intensity of the scattered radiation in the Lyman-alpha line with a wavelength of 1215 A does not fall to zero at even greater distances, but remains constant and quite high, and the intensity changes by a factor of 2, depending on where our small telescope was looking.
At first we believed that it was distant stars shining, but calculations showed that such a glow should be many orders of magnitude lower. An insignificant amount of cosmic dust in the interstellar medium would completely “eat up” this radiation. The extended solar corona, according to the theory, should have been almost completely ionized, and there should have been no neutral atoms there.
All that remained was the interstellar medium, which could be largely neutral near the Sun, which explained the effect we discovered. Two years after our publication, J.-E. Blamont and J.-Y. Berto from the French Aeronomy Service from the American OGO-V satellite discovered the geometric parallax of the region of maximum glow in the Lyman-alpha line, which made it possible to immediately estimate the distances to it. This value turned out to be approximately 25 astronomical units. The coordinates of this maximum were also determined. The picture began to become clearer. A decisive contribution to this problem was made by two German physicists - P. W. Bloom and H. J. Fahr, who pointed out the role of the movement of the Sun relative to the interstellar medium. In order to measure all the parameters of this movement, in 1975, we, together with the already mentioned French specialists, carried out two special experiments on the domestic satellites “Prognoz-5” and “Prognoz-6”. These satellites made it possible to map the entire sky in the Lyman alpha line, as well as measure the temperature of neutral hydrogen atoms in the interstellar medium. The density of these atoms “at infinity” was determined, i.e., far from the Sun, the speed and direction of the Sun’s movement relative to the local interstellar medium.
The atomic density turned out to be 0.06 atoms/cm 3 , and the speed was 25 km/s. A theory of the penetration of atoms of the interstellar medium into the Solar System was also developed. It turned out that neutral hydrogen atoms, flying close to the Sun along hyperbolic trajectories, are ionized by two mechanisms. The first of them is photoionization by ultraviolet and X-ray radiation from the Sun with wavelengths shorter than 912A, and the second mechanism is charge exchange (electron exchange) with solar wind protons that permeate the entire Solar System. The second ionization mechanism turned out to be 2–3 times more effective than the first. The solar wind is stopped by the interstellar magnetic field at a distance of approximately 100 astronomical units, and the interstellar medium flowing into the solar system is stopped at a distance of 200 AU.
Between these two shock waves (probably supersonic) there is a region of very hot, fully ionized plasma with a temperature of 10 7 or even 10 8 K. The question of the interaction of incident neutral hydrogen atoms with hot plasma in this intermediate region is extremely interesting. When interstellar, relatively cold atoms of the interstellar medium are recharged with hot protons in this region, neutral atoms are formed with a very high temperature and the corresponding speed given above. They permeate the entire solar system and can be detected near the Earth. For this purpose, the United States launched a special Earth satellite, IBEX, 2 years ago, which successfully works to solve these and related problems. The effect of “running on” of the interstellar medium that we discovered was called “interstellar wind”.
In order to get around this unclear issue, our group conducted a series of observations with the Prognoz satellite in the neutral helium line with a wavelength of 584A. Helium does not participate in the charge exchange process with solar wind protons and is almost not ionized by solar ultraviolet radiation. It is thanks to this that neutral helium atoms, flying along hyperbolas past the Sun, are focused behind it, forming a cone with increased density, which we observed. The axis of this cone gives us the direction of motion of the Sun relative to the local interstellar medium, and its divergence makes it possible to determine the temperature of helium atoms in the interstellar medium far from the Sun.
Our results for helium were in excellent agreement with measurements for atomic hydrogen. The density of atomic helium “at infinity” turned out to be equal to 0.018 atom/cm 3, which made it possible to determine the degree of ionization of atomic hydrogen, assuming that the abundance of helium is equal to the standard for the interstellar medium. This corresponds to a 10–30% degree of ionization of atomic hydrogen. The density and temperature of atomic hydrogen that we found exactly correspond to the zone of neutral hydrogen with a slightly elevated temperature - 12000 K.
In 2000, German astronomers led by H. Rosenbauer were able to directly detect neutral helium atoms flying into the Solar System from the interstellar medium using the extra-ecliptic Ulysses spacecraft. They determined the parameters of the “interstellar wind” (density of atomic helium, speed and direction of motion of the Sun relative to the local interstellar medium). The results of direct measurements of helium atoms agreed perfectly with our optical measurements.
This is the story of the discovery of another movement of our Sun.
Any person, even lying on the couch or sitting near the computer, is in constant motion. This continuous movement in outer space has a variety of directions and enormous speeds. First of all, the Earth moves around its axis. In addition, the planet rotates around the Sun. But that's not all. We cover much more impressive distances together with the Solar System.
The Sun is one of the stars located in the plane of the Milky Way, or simply the Galaxy. It is distant from the center by 8 kpc, and the distance from the plane of the Galaxy is 25 pc. The stellar density in our region of the Galaxy is approximately 0.12 stars per 1 pc3. The position of the Solar System is not constant: it is in constant motion relative to nearby stars, interstellar gas, and finally, around the center of the Milky Way. The movement of the Solar System in the Galaxy was first noticed by William Herschel.
Moving relative to nearby stars
The speed of movement of the Sun to the border of the constellations Hercules and Lyra is 4 a.s. per year, or 20 km/s. The velocity vector is directed towards the so-called apex - the point towards which the movement of other nearby stars is also directed. Directions of star velocities, incl. The suns intersect at a point opposite the apex, called the antiapex.
Moving relative to visible stars
The movement of the Sun in relation to bright stars that can be seen without a telescope is measured separately. This is an indicator of the standard movement of the Sun. The speed of such movement is 3 AU. per year or 15 km/s.
Moving relative to interstellar space
In relation to interstellar space, the Solar system is already moving faster, the speed is 22-25 km/s. At the same time, under the influence of the “interstellar wind”, which “blows” from the southern region of the Galaxy, the apex shifts to the constellation Ophiuchus. The shift is estimated to be approximately 50.
Navigating around the center of the Milky Way
The solar system is in motion relative to the center of our Galaxy. It moves towards the constellation Cygnus. The speed is about 40 AU. per year, or 200 km/s. It takes 220 million years to complete a revolution. It is impossible to determine the exact speed, because the apex (the center of the Galaxy) is hidden from us behind dense clouds of interstellar dust. The apex shifts by 1.5° every million years, and completes a full circle in 250 million years, or 1 galactic year.
Journey to the edge of the Milky Way
Movement of the Galaxy in outer space
Our Galaxy also does not stand still, but is approaching the Andromeda Galaxy at a speed of 100-150 km/s. A group of galaxies, which includes the Milky Way, is moving towards the large Virgo cluster at a speed of 400 km/s. 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 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. The 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 velocity is velocity relative to the cosmic reference frame.
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 | Swan |
| Sun relative to the Local Group of galaxies | 300 km/sec | Lizard |
| Galaxy relative to the Local Group of galaxies | ~100 km/sec | Andromeda / Lizard |
| Galaxy relative to clusters | 400 km/sec | Virgo |
| 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 | Hydra |
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
There is no such thing in life as eternal peace of mind. Life itself is movement, and cannot exist without desires, fear, and feelings.
Thomas Hobbs
A reader asks:
I found a video on YouTube with a theory about the spiral motion of the solar system through our galaxy. I didn't find it convincing, but I'd like to hear it from you. Is it scientifically correct?
First let's watch the video itself:
Some of the statements in this video are true. For example:
- the planets revolve around the Sun in approximately the same plane
- The solar system moves through the galaxy with an angle of 60° between the galactic plane and the plane of rotation of the planets
- The Sun, as it orbits the Milky Way, moves up and down and in and out relative to the rest of the galaxy.
All this is true, but the video shows all these facts incorrectly.
It is known that the planets move around the Sun in ellipses, according to the laws of Kepler, Newton and Einstein. But the picture on the left is wrong in terms of scale. It is irregular in terms of shapes, sizes and eccentricities. And although the orbits in the diagram on the right look less like ellipses, the orbits of the planets look something like this in terms of scale.
Let's take another example - the orbit of the Moon.
It is known that the Moon revolves around the Earth with a period of just under a month, and the Earth revolves around the Sun with a period of 12 months. Which of the presented pictures better demonstrates the movement of the Moon around the Sun? If we compare the distances from the Sun to the Earth and from the Earth to the Moon, as well as the speed of rotation of the Moon around the Earth, and the Earth/Moon system around the Sun, it turns out that option D best demonstrates the situation. They can be exaggerated to achieve some effects , but quantitatively options A, B and C are incorrect.
Now let's move on to the movement of the solar system through the galaxy.
How many inaccuracies does it contain? Firstly, all planets are in the same plane at any given time. There is no lag that planets more distant from the Sun would demonstrate in relation to less distant ones.
Secondly, let us remember the real speeds of the planets. Mercury moves faster than all others in our system, revolving around the Sun at a speed of 47 km/s. This is 60% faster than Earth's orbital speed, about 4 times faster than Jupiter, and 9 times faster than Neptune, which orbits at 5.4 km/s. And the Sun flies through the galaxy at a speed of 220 km/s.
In the time it takes Mercury to complete one revolution, the entire solar system travels 1.7 billion kilometers in its intragalactic elliptical orbit. At the same time, the radius of Mercury's orbit is only 58 million kilometers, or only 3.4% of the distance to which the entire solar system moves.
If we plotted the movement of the Solar System across the galaxy on a scale and looked at how the planets move, we would see the following:
Imagine that the entire system - the Sun, the moon, all the planets, asteroids, comets - are moving at high speed at an angle of about 60° relative to the plane of the Solar System. Something like this:
If we put all this together, we get a more accurate picture:
What about precession? And also about the oscillations down-up and in-out? This is all true, but the video shows it in an overly exaggerated and misinterpreted way.
Indeed, the precession of the solar system occurs with a period of 26,000 years. But there is no spiral motion, neither in the Sun nor in the planets. Precession is carried out not by the orbits of the planets, but by the axis of rotation of the Earth.
The North Star is not constantly located directly above the North Pole. Most of the time we don't have a pole star. 3000 years ago Kohab was closer to the pole than the North Star. In 5500 years, Alderamin will become the polar star. And in 12,000 years, Vega, the second brightest star in the Northern Hemisphere, will be just 2 degrees away from the pole. But this is what changes with a frequency of once every 26,000 years, and not the movement of the Sun or planets.
What about solar wind?
This is radiation coming from the Sun (and all the stars), and not what we crash into as we move through the galaxy. Hot stars emit fast-moving charged particles. The boundary of the solar system passes where the solar wind no longer has the ability to push away the interstellar medium. There is the boundary of the heliosphere.
Now about the movements up and down and in and out in relation to the galaxy.
Since the Sun and Solar System are subject to gravity, it is gravity that dominates their movement. Now the Sun is located at a distance of 25-27 thousand light years from the center of the galaxy, and moves around it in an ellipse. At the same time, all other stars, gas, dust, also move through the galaxy in ellipses. And the ellipse of the Sun is different from all the others.
With a period of 220 million years, the Sun makes a complete revolution around the galaxy, passing slightly above and below the center of the galactic plane. But since all the other matter in the galaxy moves in the same way, the orientation of the galactic plane changes over time. We may be moving in an ellipse, but the galaxy is a spinning plate, so we move up and down it every 63 million years, although our inward and outward motion occurs every 220 million years.
But the planets do not spin, their motion is distorted beyond recognition, the video incorrectly talks about precession and the solar wind, and the text is full of errors. The simulation is very nicely done, but it would be much more beautiful if it were correct.
Our star, shot through filters
When observed from Earth, the measured rotation speed is 24.47 days, but if we subtract the speed of rotation of the Earth itself around the Sun, it is 25.38 Earth days.
Astronomers call this the sidereal rotation period, which differs from the synodic period in the amount of time it takes for sunspots to rotate around the Sun when observed from Earth.
The speed of rotation of the spots decreases as they approach the poles, so that at the poles the period of rotation around the axis can reach 38 days.
Rotation observations
The movement of the Sun is clearly visible if you observe its spots. All spots move on the surface. This movement is part of the overall movement of the star around its axis.
Observations show that it does not rotate like a rigid body, but in a differentiated manner.
This means that it moves faster at the equator and slower at the poles. Gas giants: Jupiter and Saturn also have differential rotation.
Astronomers measured the speed of rotation of the Sun from a latitude of 26° from the equator, and found that one revolution around its axis takes 25.38 Earth days. Its axis of rotation makes an angle of 7 degrees and 15 minutes.
The inner regions and core rotate together as a rigid body. And the outer layers, the convective zone and the photosphere, rotate at different speeds.
The Sun's revolution around the center of the galaxy
Our star and we, together with it, revolve around the center of the Milky Way galaxy. The average speed is 828,000 km/h. One revolution takes about 230 million years. The Milky Way is a spiral galaxy. It is believed that it consists of a central core, 4 main arms with several short segments.