How do scientists measure the diameter of the Milky Way?

Through the results of space telescope and radio antenna array observations, the boundaries of the Milky Way are roughly demarcated, so that an image of the Milky Way is drawn, and then the diameter of the Milky Way is calculated, and the result is currently thought to be about 150,000 light-years (mainly the boundaries of the Milky Way are disputed).

In January 2009, at the 213th academic meeting of the American Astronomical Society, Governor Coast, California, Dr. Rader from the Harvard-Schmissson Center for Astrophysics announced that the use of very long baseline interferometric array radio telescopes to observe 19 star regions throughout the Milky Way, these regions of molecular clouds can amplify radio radiation and form cosmic vein radiation, which is easy to observe. By observing the apparent velocity of the target perpendicular to the line of sight, and then observing the Doppler shift of the target's radio radiation frequency, their radial velocity is obtained. Through the observation of targets on the same spiral arm, the angle of the spiral arm can be measured, and then it is concluded that there are four spiral arms in the Milky Way, namely the Rectangular Ruler Spiral Arm, the Shield-Centauri Spiral Arm, the Sagittarius Spiral Arm, and the Perseus Spiral Arm, as well as some small unformed spiral arms.

Our solar system is located on the inner side of a smaller spiral arm of Orion, which is between the Centaur arm and the Perseus arm.

It is too early to draw conclusions about the fact that the Milky Way had four spiral arms, and later that there were only two spiral arms, and that the specific model has been further observed. See me this for details.

I flipped through the "Encyclopedia of Space Knowledge" published by Hope Press in 2000, which reads: Between 1915 and 1920, Harlow Shapley determined the distance of the globular clusters at the edge of the Milky Way, thus determining the true size and shape of the Milky Way.

The diameter of the Milky Way is 100,000 light-years. On side view, its main part is flattened, like a discus, with thin and **thick edges. It is a complex galaxy composed of about 150 billion stars, galactic nebulae, interstellar gas, and dust.

The mass is 1600 times the mass of the sun. The closer you are to the center of the Milky Way, the denser the planet becomes.

The solar system is located about 10,000 light-years away from the center of the Milky Way, and its rotation speed around the center of the Milky Way is about 200 kilometers per second, and it takes more than 200 million years to rotate around the center, and its orbit is approximately circular. It is speculated that the age of the Milky Way is more than 10 billion years.

Observations

The Milky Way is different in light and dark in the sky, wide and narrow. The narrowest is only 4° 5°, and the widest is about 30°. However, the individual stars that the naked eye can see everywhere in the sky are all part of the Milky Way.

The light from this banded arc originates from the accumulation of light from stars and other celestial bodies on the plane of the Milky Way, which cannot be resolved by the naked eye.

For the Northern Hemisphere, it is an important symbol of the Milky Way summer starry sky, as well as the "Summer Triangle" composed of three bright stars, namely Vega and Cowherd on both sides of the Milky Way and Tianjin Four in the Milky Way. In summer, the Milky Way stretches north from the east side of Scorpio to the sky, and is majestic and magnificent.

The diameter of the Milky Way is measured by measuring the distance from the Sun to the center of the Milky Way and the distance from the farthest star to the Sun in the direction of the center of the Milky Way.

Milky Way

galaxy), is the solar system.

The Barred Spiral Galaxy (a type of spiral galaxy) is elliptical in shape and has a huge disk structure, and the latest research shows that the Milky Way has four well-defined and fairly symmetrical spiral arms, 4,500 light-years apart. The number of stars in the Milky Way is between 100 billion and 400 billion.

The Milky Way as a whole has a poor rotation. The rotation speed at the Sun is about 220 kilometers per second, and the Sun orbits around the galactic center for about 100 million years. The visual absolute magnitude of the Milky Way is equal, and the total mass of the Milky Way is about a trillion times the mass of the Sun.

The age of the Milky Way is about 10 billion years old, and the scientific community believes that the universe is large.

It happened about 13.8 billion years ago. The Milky Way has two companion galaxies: the Large Magellanic Galaxy and the Small Magellanic Galaxy. They are all members of the local group of galaxies and are the Virgo Supercluster.

part of the group; And it is the Laniakea supercluster.

part of the group; The Milky Way galaxy is composed from the inside to the outside, including the galactic heart, the galactic core, the galactic disk, the galactic halo, and the galactic crown. Most of the Milky Way** regions are old stars (white dwarfs.

[6], and the outer regions are mostly nascent and young stars. There are more than a dozen Euphyllum galaxies scattered around an area of hundreds of thousands of light-years, and the Milky Way grows by slowly engulfing the surrounding dwarf galaxies.

The Milky Way is a galaxy that is slightly larger than a normal galaxy, about 100,000 light-years in diameter.

There are at least 200 billion stars in the Milky Way. Among them, about 40 billion stars are concentrated on the ** bulge, surrounded by four spiral arms, an area mixed with gas and dust. The nuclear sphere is 3,000 light-years in diameter and ellipsoidal in shape, made up of an elderly planet that is more than 10 billion years old.

The Milky Way is already 15 billion light-years old.

The outer image of the Milky Way is a flat discoid thick in the middle and thin at the edges. The disc part is called a disk, which is 100,000 light-years in diameter and is made up of planets less than 10 billion years old and high in heavy metals. The main material of the Milky Way is concentrated in this disk-like structure.

The silver chain is the main body of the Milky Way, with a diameter of about 80,000 light-years, a thickness of about 10,000 light-years, and an edge thickness of about 3,000 6,000 light-years.

The Milky Way vertical collision path is 100,000ly.

The Milky Way is the barred spiral galaxy in which the solar system is located, including 1000 400 billion stars and a large number of star clusters, nebulae, and various types of interstellar gas and interstellar dust.

With a total mass of about 210 billion times that of the Sun, it belongs to the local group of galaxies, and the nearest extragalactic galaxy is the Dwarf Canis Major galaxy, 42,000 light-years away from the Milky Way.

The diameter of the Milky Way is 100,000 light years, the Milky Way, is the barred spiral galaxy where the solar system is located, in the shape of an elliptical disk, with a huge disk structure, the Milky Way from the inside to the outside are composed of a silver core, a silver core, a silver disk, a silver halo and a silver crown. Most of the Milky Way** regions are old stars, and the outer regions are mostly nascent and young stars.

The Milky Way has five main spiral arms, which are the Perseus Arm, the Orion Arm, the Bottom Centaur Arm, the Ruler Arm, and the Shield-Centaur Arm.

The Milky Way has two companion galaxies, the Large Magellanic Galaxy and the Small Magellanic Galaxy, both of which are members of the Local Group of Galaxies and are part of the Virgo Supercluster.

There are more than a dozen satellite galaxies scattered around the Milky Way in an area of hundreds of thousands of light-years, and the Milky Way grows by slowly devouring the surrounding dwarf galaxies.