The Milky Way is ... The history of discovery, characteristics, structure

In our century, lit by hundreds of electric lights, the inhabitants of the city do not have the opportunity to see the Milky Way. This phenomenon, which occurs on our horizon only in a certain period of the year, is observed only far from large settlements. In our latitudes it is especially beautiful in August. In the last month of the summer the Milky Way rises above the Earth in the form of a giant celestial arch. This weak, fuzzy strip of light denser and brighter in the direction of Scorpio and Sagittarius, and paler and more diffuse - near the constellations of Andromeda and Perseus.

The Star Mystery

The Milky Way is an unusual phenomenon, the mystery of which has not been revealed to people for a whole string of centuries. In the legends and myths of many peoples it was called in different ways. The amazing glow was the mysterious Star Bridge leading to the paradise booths, Dear Gods and the magic Heavenly River carrying divine milk. At the same time, all nations believed that the Milky Way is something sacred. Worshiped the radiance. In honor of it, even temples were built.

Few people know that our New Year tree is an echo of the cults of people who lived in former times. In ancient times, it was believed that the Milky Way is the axis of the Universe or the World Tree, on the branches of which stars ripen. That is why at the beginning of the annual cycle and decorated the Christmas tree. The earthly tree was an imitation of the eternally fruiting tree of heaven. Such a ritual gave hope to the favor of the gods and a good harvest. So great was the importance of the Milky Way for our ancestors.

Scientific Assumptions

What is the Milky Way? The history of the discovery of this phenomenon is almost 2000 years old. Plato also called this strip of light a seam connecting the heavenly hemispheres. In contrast, Anaxagoras and Demoksid argued that the Milky Way (this is what color, we will consider) - a kind of highlighting of the stars. She is the decoration of the night sky. Aristotle explained that the Milky Way is a special radiance in the air of our planet luminous near-moon fumes.

There were many other assumptions. Thus, the Roman Mark Manilius said that the Milky Way is a constellation of small heavenly bodies. It was he who was closest to the truth, but he could not confirm his assumptions at a time when the sky was being watched only with the naked eye. All ancient researchers believed that the Milky Way is part of the solar system.

The discovery of Galileo

The Milky Way opened its secret only in 1610. It was then that the first telescope was invented, which Galileo Galilei used. The famous scientist saw in the device that the Milky Way is a real cluster of stars that, when viewed with the naked eye, merged into a continuous faintly flickering strip. Galileo even managed to explain the heterogeneity of the structure of this band.

It was caused by the presence in the celestial phenomenon of not only star clusters. There are also dark clouds. The combination of these two elements creates an amazing image of the nocturnal phenomenon.

The discovery of William Herschel

The study of the Milky Way continued in the 18th century. During this period, his most active researcher was William Herschel. A well-known composer and musician was engaged in the manufacture of telescopes and studied the science of the stars. The Great Plan of the Universe became the most important discovery of Herschel. This scientist observed in the telescope of the planet and made their calculations in different parts of the sky. Studies have made it possible to conclude that the Milky Way is a peculiar star island, in which our Sun is also located. Herschel even drew a schematic outline of his discovery. In the figure, the star system was represented as a millstone and had an elongated irregular shape. The sun was inside this ring that surrounded our world. That's how all our scientists represented our Galaxy until the beginning of the last century.

Only in the 1920s saw the light of the work of Jacobus Kaptein, in which the Milky Way was described in the most detail. At the same time, the author gave a diagram of the star island, which is the most similar to the one that is known to us at the present time. Today we know that the Milky Way is the Galaxy, in which the Solar system, the Earth and those individual stars that are visible to man with the naked eye are located.

The structure of galaxies

With the development of science astronomical telescopes became more powerful and powerful. At the same time, the structure of the observed galaxies became more and more clear. It turned out that they do not resemble each other. Were among them wrong. Their structure had no symmetry.

The galaxies were also elliptical and spiral. To which of these types is the Milky Way? This is our Galaxy, and, being inside, it is very difficult to determine its structure. However, scientists have found the answer to this question. Now we know what the Milky Way is. Its definition was given by researchers who established that it is a disk having an inner core.

general characteristics

The Milky Way refers to galaxies of a spiral type. At the same time, it has a jumper in the form of a huge star system, connected by gravitational forces.

It is believed that the Milky Way has existed for more than thirteen billion years. This is the period during which in this galaxy formed about 400 billion constellations and stars, over a thousand huge in size gaseous nebulae, clusters and clouds.

The shape of the Milky Way is clearly visible on the map of the universe. When you consider it, it becomes clear that this cluster of stars is a disk, whose diameter is 100 thousand light years (one such light-year is ten trillion kilometers). The thickness of the star cluster is 15 thousand, and the depth is about 8 thousand light years.

How much does the Milky Way weigh? This (the definition of its mass is a very difficult task) it is not possible to calculate it. It is difficult to determine the mass of dark matter, which does not interact with electromagnetic radiation. That is why astronomers can not finally answer this question. But there are rough estimates, according to which, the weight of the Galaxy is in the range from 500 to 3000 billion of the mass of the Sun.

The Milky Way is like all heavenly bodies. It makes revolutions around its axis, moving around in the universe. Astronomers point to the uneven, even chaotic movement of our Galaxy. This is due to the fact that each of the star systems and nebulaes that make up its structure has its own speed, different from others, and also different forms and types of orbits.

From which parts does the Milky Way consist? This core and jumpers, a disk and spiral arms, as well as a crown. Let us consider them in more detail.

Core

This part of the Milky Way is located in the constellation of Sagittarius. In the core there is a source of nonthermal radiation, having a temperature of about ten million degrees. At the center of this part of the Milky Way is a seal called the bulge. This is a whole string of old stars, which moves along an elongated orbit. For most of these celestial bodies, the life cycle is already coming to an end.

In the central part of the nucleus of the Milky Way is a supermassive black hole. This part of outer space, whose weight is equal to the mass of three million suns, has the most powerful gravity. Around it rotates another black hole, only a smaller size. Such a system creates such a strong gravitational field that nearby constellations and stars move along very unusual trajectories.

The center of the Milky Way has other features. So, for him is characterized by a large cluster of stars. And the distance between them is hundreds of times smaller than what is observed on the periphery of education.

It is also interesting that when observing the nuclei of other galaxies, astronomers note their bright glow. But why can not you see it in the Milky Way? Some researchers even suggested that there is no nucleus in our Galaxy. However, it was determined that dark interlayers exist in spiral nebulae, which are interstellar clusters of dust and gas. They are also in the Milky Way. These huge sizes are dark clouds and do not allow the earthly observer to see the radiance of the nucleus. If such a formation did not interfere with earthlings, we could observe the nucleus in the form of a radiant ellipsoid, the size of which would exceed the diameter of a hundred moons.

To answer this question, people were helped by modern telescopes that are able to work in special ranges of the electromagnetic spectrum of radiation. With the help of this modern technique, which was able to bypass the dust shield, scientists managed to see the core of the Milky Way.

Jumper

This element of the Milky Way crosses its central section and has a size of 27 thousand light years. There is a jumper of 22 million red stars, which have an impressive age. Around this formation is a gas ring, which contains a large percentage of molecular oxygen. All this suggests that the jumper of the Milky Way is the site where the stars form in the largest number.

Disk

This form is the Milky Way itself, which is in constant rotational motion. It is interesting that the speed of this process depends on the distance of one or another section from the nucleus. So, in the center it is zero. At a distance from the nucleus at two thousand light-years, the rotation speed is 250 kilometers per hour.

The outer side of the Milky Way is surrounded by a layer of atomic hydrogen. Its thickness is 1,5 thousand light years.

On the outskirts of the Galaxy, astronomers have discovered the presence of dense gas accumulations with a temperature of 10 thousand degrees. The thickness of such formations is several thousand light years.

Five spiral arms

This is another constituent part of the Milky Way, located directly behind the gas ring. Spiral arms cross the constellations Cygnus and Perseus, Orion and Sagittarius, as well as Centauri. These formations are unequally filled with molecular gas. Such a composition introduces errors into the rules of rotation of the Galaxy.
Spiral arms emerge directly from the core of the starry island. We are observing them with the naked eye, calling the light strip the Milky Way.

The spiral arms project onto one another, which makes understanding of their structure difficult. Scientists suggest that such sleeves were formed because of the presence in the Milky Way of giant waves of rarefaction and compression of interstellar gas, which move from the nucleus to the galactic disk.

Crown

The Milky Way has a spherical halo. This is his crown. This formation consists of individual stars and clusters of constellations. And the dimensions of the spherical halo are such that it extends beyond the boundaries of the Galaxy for 50 light years.

As a part of the crown of the Milky Way, there are, as a rule, low-mass and old stars, as well as dwarf galaxies and hot gas accumulations. All these components produce motion along elongated orbits around the nucleus, making random rotation.

There is a hypothesis, according to which, the appearance of the corona was the result of the absorption of the Milky Way by small galaxies. According to astronomers, the age of the halo is about twelve billion years.

Location of stars

On the cloudless night sky, the Milky Way is visible from anywhere in the world. However, only part of the Galaxy, which is a system of stars inside the Orion's arm, is accessible to the human eye.

What is the Milky Way? The definition in space of all its parts becomes most clear, if we consider a star map. In this case, it becomes clear that the Sun, illuminating the Earth, is located almost on the disk. This is almost the edge of the Galaxy, where the distance from the nucleus is 26-28 thousand light years. Moving at a speed of 240 kilometers per hour, Svetliy spends one revolution around the nucleus 200 million years, so that for all of its existence it traveled around the disk, skirting the core, only thirty times.

Our planet is in the so-called corotation circle. This is a place in which the speed of rotation of arms and stars is identical. This range is characterized by an elevated level of radiation. That's why life, scientists believe, could only occur on a planet near which there is a small number of stars.

Such a planet was our Earth. It is located on the periphery of the Galaxy, in its tranquil place. That is why on our planet for several billion years there were no global cataclysms that often occur in the universe.

Forecast for the future

Scientists suggest that in the future, very likely collisions between the Milky Way and other galaxies, the largest of which is the Andromeda galaxy. But at the same time, it is not possible to talk specifically about anything. This requires knowledge of the magnitude of the transverse velocities of extragalactic objects, which are not yet available for modern researchers.

In September 2014, one of the models for the development of events was published in the media. According to her, four billion years will pass, and the Milky Way will absorb the Magellanic clouds (Big and Small), and a billion years later he himself will become part of the Andromeda Nebula.