In our century, lit by hundreds of electric lights, residents of the city do not have the opportunity to see the Milky Way. This phenomenon, which occurs in 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 summer, the Milky Way rises above the Earth in the form of a giant heavenly arch. This faint, blurry streak of light looks denser and brighter in the direction of Scorpio and Sagittarius, and paler and scatter - near the constellations of Andromeda and Perseus.
Mystery of the Star
The Milky Way is an unusual phenomenon, the secret of which has not been revealed to people for a whole string of centuries. In the legends and myths of many peoples, he was called differently. The amazing glow was the mysterious Star Bridge leading to paradise, the Road of the Gods and the magical Heavenly River carrying divine milk. Moreover, all nations believed that the Milky Way is something sacred. The radiance was worshiped. Even temples were built in his honor.
Few people know that our New Year tree is an echo of the cults of people who lived in former times. Indeed, in ancient times it was believed that the Milky Way is the axis of the Universe or the World Tree, on whose branches stars ripen. That is why at the beginning of the annual cycle they decorated the Christmas tree. The earthly tree was an imitation of the ever-bearing tree of heaven. Such a ritual gave hope for the favor of the gods and a good harvest. So great was the significance of the Milky Way for our ancestors.
Scientific Assumptions
What is the Milky Way? The history of the discovery of this phenomenon has almost 2000 years. Even Plato called this streak of light a seam connecting the celestial hemispheres. In contrast, Anaxagoras and Demoxid claimed that the Milky Way (what color is it, we will consider) is a kind of highlighting of 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 of luminous moonlight vapors.
There were many other assumptions. So, the Roman Marcus Manilius said that the Milky Way is a constellation of small celestial bodies. It was he who was closest to the truth, but he could not confirm his assumptions in those days when the sky was watched only with the naked eye. All ancient researchers believed that the Milky Way is part of the solar system.
Discovery of Galileo
The Milky Way revealed its secret only in 1610. It was then that the first telescope was invented, which Galileo Galilei used. The famous scientist saw through the device that the Milky Way is a real cluster of stars that, when examined with the naked eye, merged into a continuous faintly flickering band. 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. Dark clouds are also present there. The combination of these two elements creates an amazing image of the night phenomenon.
The discovery of William Herschel
The study of the Milky Way continued in the 18th century. During this period, William Herschel was his most active researcher. The famous composer and musician was engaged in the manufacture of telescopes and studied the science of stars. The most important discovery of Herschel was the Great Plan of the Universe. This scientist observed through the telescope of the planet and counted them in different parts of the sky. Studies have led to the conclusion that the Milky Way is a kind of star island, in which our Sun is located. Herschel even drew a schematic plan of his discovery. In the figure, the star system was depicted as a millstone and had an elongated irregular shape. At the same time, the sun was inside this ring that surrounded our world. That is how all scientists represented our Galaxy until the beginning of the last century.
It was only in the 1920s that the work of Jacobus Kaptein saw the light, in which the Milky Way was described in more detail. At the same time, the author gave a diagram of a star island, as similar as possible to the one that is currently known to us. Today we know that the Milky Way is a galaxy, which includes the solar system, the Earth and those individual stars that are visible to the human eye.
Galaxy structure
With the development of science, astronomical telescopes became more powerful and more powerful. Moreover, the structure of the observed galaxies was becoming clearer. It turned out that they are not alike. Were among them wrong. Their structure did not have symmetry.
Elliptical and spiral galaxies were also observed. To which of these types does the Milky Way belong? 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 this is a disk having an inner core.
general characteristics
The Milky Way refers to spiral galaxies. Moreover, it has a jumper in the form of a huge star system, interconnected by gravitational forces.
The Milky Way is believed to have existed for more than thirteen billion years. This is the period during which about 400 billion constellations and stars formed in this galaxy, over a thousand gas nebulae, clusters and clouds huge in size.
The shape of the Milky Way is clearly visible on the map of the Universe. When considering 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 (determining its mass is a very difficult task) is not possible to calculate. Difficulties are caused by the determination of the mass of dark matter, which does not interact with electromagnetic radiation. That is why astronomers cannot 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 solar masses.
The Milky Way is like all celestial bodies. It makes revolutions around its axis, moving in the universe. Astronomers point to the uneven, even chaotic movement of our Galaxy. This is due to the fact that each of its constituent stellar systems and nebulae has its own speed, different from the others, as well as different shapes and types of orbits.
What are the links of the Milky Way? This is the core and jumpers, the disk and spiral arms, as well as the crown. Let's consider them in more detail.
Nucleus
This part of the Milky Way is located in the constellation Sagittarius. In the core is a non-thermal radiation source having a temperature of the order of 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 that moves in an elongated orbit. For most of these celestial bodies, the life cycle is coming to an end.
In the central part of the core of the Milky Way there is a supermassive black hole. This piece of outer space, whose weight is equal to the mass of three million suns, has powerful gravity. Around it is another black hole, only a smaller one. Such a system creates such a strong gravitational field that the nearby constellations and stars move along very unusual trajectories.
The center of the Milky Way has other features. So, it is characterized by a large cluster of stars. Moreover, the distance between them is hundreds of times smaller than that observed on the periphery of the formation.
It is also interesting that, observing the nuclei of other galaxies, astronomers note their bright radiance. But why is it not visible in the Milky Way? Some researchers have even suggested that there is no nucleus in our galaxy. However, it was determined that there are dark interlayers in spiral nebulae, which are interstellar clusters of dust and gas. They are 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, then we could observe the core in the form of a shining ellipsoid, the size of which would exceed the diameter of a hundred moons.
Modern telescopes, which are able to work in special ranges of the electromagnetic spectrum of radiation, have helped people answer this question. With the help of this modern technique, which was able to bypass the dust shield, scientists were able 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 with 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 in which the stars are formed in the greatest number.
Disk
The Milky Way itself, which is in constant rotational motion, has this form. Interestingly, the speed of this process depends on the distance of a particular site from the core. So, in the very center, it is zero. At a distance of two thousand light-years from the core, 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 clusters of gas with a temperature of 10 thousand degrees. The thickness of such formations is several thousand light years.
Five spiral sleeves
These are another constituent parts of the Milky Way, located directly behind the gas ring. The spiral arms cross the constellations of Cygnus and Perseus, Orion and Sagittarius, as well as the Centaurus. These formations are not uniformly filled with molecular gas. Such a composition introduces errors in the rules of rotation of the Galaxy.
Spiral arms extend directly from the core of a star island. We observe them with the naked eye, calling the light band the Milky Way.
Spiral branches are projected onto each other, which makes it difficult to understand their structure. Scientists suggest that such arms were formed due to 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. Moreover, the dimensions of the spherical halo are such that it extends beyond the boundaries of the Galaxy for 50 light years.
The corona of the Milky Way contains, as a rule, low-mass and old stars, as well as dwarf galaxies and clusters of hot gas. All these components produce motion in 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 small galaxies by the Milky Way. According to astronomers, the halo is about twelve billion years old.
Star location
In a 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 arm of Orion, is accessible to the human eye.
What is the Milky Way? The definition in space of all its parts becomes most understandable if we consider the 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 core is 26-28 thousand light years. Moving at a speed of 240 kilometers per hour, the luminary spends 200 million years around the core, so for all its existence it traveled around the disk, circling the core, only thirty times.
Our planet is in the so-called corotation circle. This is such a place in which the rotation speed of the sleeves and stars are identical. This circle is characterized by an increased level of radiation. That is why life, as scientists believe, could only arise on that planet, near which there are a small number of stars.
Such a planet was our Earth. It is located on the periphery of the Galaxy, in its most peaceful place. That is why on our planet for several billion years there have been no global disasters that often occur in the Universe.
Forecast for the future
Scientists suggest that in the future, collisions between the Milky Way and other galaxies are very likely, the largest of which is the Andromeda galaxy. But at the same time, it is not possible to specifically talk about anything. This requires knowledge of the transverse velocities of extragalactic objects, which are not yet available to modern researchers.
In September 2014, one of the development models was published in the media. According to it, four billion years will pass, and the Milky Way will absorb the Magellanic clouds (Big and Small), and after another billion years, he himself will become part of the Andromeda Nebula.