The Milky Way galaxy is of most interest to astronomers, since it contains the solar system, where the earth is. Astronomers daily study the Milky Way and make discoveries that help to form a common understanding about the structure of the cosmos.
What shape does the Milky Way have?
Edwin Hubble, when observing space and studying galaxies, established that they can have two forms: spiral and elliptical. The former visually look like a rotating disk, consisting of curved sleeves that fit tightly together. The Milky Way also applies to this view.
Before the invention of radio telescopes, mankind was not able to accurately determine the size and shape of the galaxy. Since dust is present in outer space, it prevents the passage of light from stars. This gives rise to errors in the study. However, these telescopes allow you to observe the radio waves that pass through the past.
The invention helped determine the exact distance of most stars of the Milky Way and establish their speed. After combining data about each object, it became clear that they all rotate in a spiral and are in separate arms.
Milky Way: Key Features
One of the main features of the galaxy lies in its name. There is an ancient Greek legend that the titan Kronos ate the babies that Ray gave birth to from him. Mother greatly grieved about this, and when five children were eaten, she decided to save Zeus, the last son. Rhea wrapped a stone in a blanket and carried it to Kronos. He felt the bundle and asked to feed the baby so that he gained weight. The girl splashed milk on a stone, and it bounced off him, settling in the sky in the form of the Milky Way. When Zeus grew up, he overthrew the titan and became the main among the gods.
Another feature of the galaxy is the ability to absorb others. Around the milky way, several star clusters located in different constellations are gradually moving. They fall under the influence of the Milky Way and are drawn into its sleeves.
Interesting fact: Right now, the Milky Way is swallowing a dwarf galaxy located in the constellation Sagittarius.
However, the galaxy will not always attract lesser cousins. Now she is already interacting with Andromeda, which is much larger in size. Scientists believe that in 3-4 billion years, both galaxies will collide, and the Milky Way will be swallowed.
The main characteristics and parameters of the Milky Way
Since the solar system is inside the Milky Way, this galaxy was the first that scientists began to study with the advent of appropriate technologies. Now it is well studied, and most of the parameters are set with maximum accuracy.
The characteristics of the milky way are as follows:
- refers to the type of spiral galaxies;
- together with nearby clusters it is included in the Local Group;
- the diameter of the Milky Way is approximately 100 thousand light years;
- the galaxy has between 200 and 400 billion stars;
- The sun is located 27,000 light-years distant from the center;
- The solar system rotates around the galactic center at a speed of 230 km / s;
- the total mass of the Milky Way objects is one and a half trillion solar masses.
It must be understood that due to the large size, the characteristics may have an error.
Interesting fact: The sun, together with the planets, completely flies around the center of the galaxy in 235 million years.
The structure and composition of the Milky Way
In the center of the galaxy is a bright core, consisting of billions of stars. Its size is difficult to measure, but scientists believe that the length is several thousand parsecs (1 pair = 30.86 trillion km). There is also an opinion that in the center of the Milky Way is a black hole.
A jumper with a length of 27 thousand light years passes through the middle of the galaxy.Moreover, it is located at an angle of 44 degrees relative to the Sun. The Milky Way consists mainly of stars, dust, gas and constellations. Moreover, young objects are removed from the center.
Around the Milky Way there is a dark halo where dwarf galaxies and star clusters are present. They are influenced by such a large object and rotate relative to it.
Sleeves move around the center, representing a spiral disk. Because of this, the galaxy is quite flat when viewed from the side. There are five main sleeves:
- Swan
- Centauri;
- Sagittarius
- Orion
- Perseus.
The solar system is located in the arm of Orion, closer to the inner side.
The size
It is generally accepted that the diameter of the Milky Way is 100,000 light-years, and 1000 light-years wide. However, several years ago, scientists from the Canary Institute conducted a detailed study and found that the length of the galaxy could be 200,000 light years.
In 2020, astrophysicists completed a new study, according to which the new diameter of the Milky Way could be 1,900,000 light-years. However, this information has not yet been confirmed.
Stars - How many stars are there in the Milky Way?
The Milky Way includes about 400 billion stars, most of which are in adjacent arms. In addition to them, the galaxy contains from 25 to 110 billion brown dwarfs. Their brightness and size are not enough to attribute to full-fledged stars.
Weight
Around the Milky Way, in the halo, contains dark matter, which makes up most of the mass. Because of this, it is difficult for scientists to calculate the exact value. In the 2009th year, it was believed that the mass of the galaxy is 6 * 10’42 kg.
But 10 years later, more accurate studies were conducted. In 2019, it was proved that for a length of 130,000 light years, this parameter is 2 times larger.
Disk
To study the disk of the Milky Way in more detail, scientists are still developing universal technologies. Thanks to this, it is possible to observe objects at large distances and to obtain new information.
Interesting fact: Until the 1980s, it was not established that the Milky Way belongs to the type of spiral galaxies. The final confirmation of this was received by the Lyman Spitzer telescope in the 2005th year.
The disk has a length of 100,000 light years and rotates constantly, and in different areas it does this in different ways. In the center, the objects are in a static state, but when moving away, some stars begin to move at a speed of 200-230 km / s, or even faster.
A flat disk consists mainly of young stars, whose age is not more than several billion years. The sleeves themselves are 10 billion years old. Far from the Milky Way are more adult objects.
Core
In the center of the Milky Way there is a large spherical seal 27 thousand light-years long, called the bulge. Presumably, it houses a large black hole Sagittarius A and another medium-sized one. They are surrounded by stars, which make the core glow.
A jumper runs through the center of the galaxy, consisting mainly of red stars, which are very old. In 2016, Japanese astronomers discovered a giant black hole at a distance of 200 light years from it, whose mass is one hundred thousand Suns. And two years later, 12 systems were discovered located near the core, inside which black holes can also be located.
Sleeves
Since the Milky Way is a spiral galaxy, it has sleeves lying in the disk plane. Around them is a halo, also called the “crown”. Since the solar system is located in the sleeve of Orion, inside the disk, scientists cannot look at its structure from the side.
However, advanced research using the properties of hydrogen helps to provide a theoretical picture of how the sleeves look.It is assumed that they are closely located to each other, moreover, among them there may be doubles having a common area. And not so long ago, astronomers advanced the theory that the Milky Way can have a four-arm structure.
Halo
The halo envelops the disk of the Milky Way and has a spherical shape. Its length in different directions is estimated to be from 5 to 10 thousand light years. It contains stars and clusters of great age.
Interesting fact: It was previously believed that the most distant stars are 100,000 light-years from the core of the Milky Way. But recently, objects have been discovered in 200,000 light years.
Allegedly, the halo formed 12 billion years ago. This is indicated by old clusters, including up to a million stars. All available objects inside the sphere rotate in elongated orbits, being influenced by the disk. They can move in different directions, but their speed is always low. And if the latter contains a lot of gas and dust from which objects are formed, then in the halo they are almost completely absent. Because of this, its structure is fully formed, and new stars do not appear in it.
Luminosity
Like most objects in the universe, the Milky Way has a certain brightness, which is approximately 21 m. The same value will result if you combine light from 10 billion suns. A similar glow is emitted by a bulb whose power is 8.3 * 10’36 watts.
Place of the Milky Way in the Universe
In 2015, scientists from the Hawaiian Astronomical Institute decided to determine the exact location of the Milky Way in the universe. In addition to the fact that the galaxy belongs to the Local Group, it is part of Lanyakeya. This is an area of 500 million light-years, where hundreds of thousands of star clusters are located.
Interesting fact: The mass of Laniakei is 100 times greater than that of a large cluster of Virgo.
But Laniakeia is far from the largest object in the universe. It is only part of the whale supercluster, which, in turn, is part of the group of Pisces - spatial areas where a huge number of galaxies are concentrated.
Scientists still can not accurately track the movement of objects inside Laniakei. At the moment, it is believed that the Milky Way is gradually moving deeper into the cluster.
Milky Way Galaxy and what surrounds it
Since the Big Bang took place and the Universe was formed, all objects in space are in continuous motion. Some are so ancient that they have already managed to pass most of their path, while others are just starting to form.
Just a couple of centuries ago, astronomers believed that the Milky Way is the Universe, and there is nothing beyond its borders. But the invention of more modern telescopes made it possible to find out that there are other galaxies.
The Milky Way is surrounded by objects that are part of the Local Group. The largest of them is Andromeda, the size of which is twice as large. Also in the distance is the spiral galaxy of the Triangle. Around these objects are their satellites. They are represented as dwarf clusters that move around.
The Local Group also includes irregular and elliptical galaxies lying in certain constellations.
Class and general structure
According to the Milky Way class, it refers to spiral galaxies with a jumper passing through the center. This type is considered the most common in the universe. Spirals make up approximately 56% of the total number of galaxies, and 65% of them have a jumper.
In the center of the Milky Way is an active core that releases a large amount of energy into space. Around it is a disk consisting of gas, dust and objects rotating at high speed. Near the center is a bulge through which a jumper passes. It consists of a large number of giant stars.
Interesting fact: the bulge is the brightest component of the Milky Way, but its light is not visible from the Earth due to the arms.
A jumper passes through the bulge to which the sleeves are attached. A large amount of gas is concentrated in it, because of which new stars still appear here. The objects inside the arms rotate at different speeds, and the area where the solar system is located can be called the calmest. There are no large clusters of galactic dust that adversely affect stars and planets.
Around the visible disk of the Milky Way is a halo - a giant spherical region in which one-time clusters are found. They also move relative to the center of the galaxy, but much more slowly and randomly than objects inside the disk. Not so long ago, astronomers found that the clusters inside the halo are former dwarf galaxies that were swallowed by the Milky Way.
Theoretical models of our galaxy
Even in ancient times, scientists believed that the stars in the night sky are part of a single whole, and they all move under the mutual influence. However, the technology of that time was not enough to build an accurate model of the galaxy. It was not until the year 1700 that William Herschel was able to prove that the Milky Way is disk-shaped.
In the second half of the 19th century, the astronomer Jacobus Corneli Kaptein composed a theoretical model of the galaxy. Its length was 70 thousand light years. The scientist also established that the solar system is not near the core, but away from it.
In the first half of the 20th century, Edwin Hubble determined that galaxies move in space. He also divided them into spiral and elliptical. This information was enough to determine the type of the Milky Way in the future and draw up its model, which is the most reliable.
The place of the sun in the galaxy
As mentioned above, the solar system is not located in the core of the Milky Way. The sun appeared between the arms of Sagittarius and Perseus. Their spiral branches are 4 thousand light-years distant.
The solar system is located closer to the edge of the galactic disk than to the center. Its distance from the latter is approximately 28 thousand light years. The sun is gradually moving around the core of the Milky Way, and a full revolution takes more than 220 million years. This suggests that the Earth from the moment of its appearance circled the galaxy about 30 times.
The sun is in the area of the Milky Way, where the spiral branches and bodies move at the same speed. Because of this, the star and planets are not exposed to continuous exposure to gas, dust and other substances. Scientists believe that the solar system is very lucky to appear in this area, because otherwise the existence of living beings on Earth would be impossible.
Star location
Any stars that the human eye can see in the sky are in the region of the Orion arm. As a rule, in good lighting, you can see about 9 thousand stars.
A large number of luminaries is located in the center of the galaxy, which is why it emits such a bright light. Further along the disk are distributed younger objects that are part of different constellations and related to one of the arms.
There are also stars in the halo, but their number is very small compared to those that “live” in the center. If clusters in the sleeves can number several billion, then in the dark region counts for millions. Moreover, the bulk of the stars in the halo have already lived most of their lives, and they are considered very old.
The history and future of the Milky Way
Scientists cannot tell the exact age of the Milky Way, but the galaxy is considered quite ancient. Proof of this is the star HD 140283. It is located in its area and is only 100 million years younger than the Universe.
It was found that all the substances that are in the space of the Milky Way and are part of its bodies, previously belonged to other stars. However, the latter did not last long and exploded.The gases released into the atmosphere were gradually attracted until they formed a galaxy.
When the Milky Way formed, he took up the absorption of his companions - dwarf galaxies. Even now, its south pole is gradually drawing gases from both Magellanic clouds.
According to scientists, the galaxy has already lived half of the time allotted to it. In its areas, there is practically no gas left to form new stars. However, the latter are still quite young, so they can exist for a long time. It is expected that the stars will go out in about 5 billion years. And then the Milky Way will begin to draw closer to Andromeda. Both galaxies will carry out mutual absorption, however, due to the large size, the latter is more likely to emerge victorious from this confrontation.
But astronomers do not guarantee that events will develop according to this scenario. Given that they are still several billion years old, during this period of time, everything can radically change.
Mythology
The mythologies of different countries have their own legends about the appearance of the Milky Way. In some Arab states, there is a story about the god Vahagn, who stole straw from Barsham and hid from it in heaven. Fleeing, he gradually lost branches and reeds, which formed the galaxy.
In Hungary, they believe that the stars of the Milky Way are sparks from under the hooves of the horse of Attila, who came down from heaven to help the sekets. In India, there is a belief that the galaxy was formed as a result of the pink cow spilling milk on the sky. In China and Japan, there are myths that the Milky Way is a river spilled across the sky. In Maori mythology, he was considered a boat on which the Gods sail through the sky.
The Indians were convinced that the galaxy was made up of ashes. He was specially scattered by a girl who wanted to show the soldiers the way home. In Finland, they believed that the Milky Way was formed as a result of bird flights through the sky. Also, other countries often associate the appearance of a galaxy with birds and their ability to fly.
