What is a Galaxy?

The Milky Way (English: The Milky Way ) is a barred spiral galaxy in which the solar system is located. It includes 100 to 400 billion stars and a large number of star clusters, nebulae, and various types of interstellar gas and interstellar dust. From the earth, the Milky Way is silver White ring belt. The total mass of the Milky Way is about 1.5 trillion times that of the Sun ^[1-2] and belongs to the local galaxy group. The nearest extragalactic galaxy is the Great Canis Dwarf galaxy located 42,000 light years away from the Milky Way.

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The main part of the galaxy's material forms a thin disc, called

1750-British astronomer

Mass 10E11 Sun mass

Scientists at Columbia University refined the quality of the galaxy

Indeed, the latest results suggest that the Milky Way is about 210 billion times the mass of the Sun, including star clusters with thousands of stars on the edge of the Milky Way. Scientists obtained the Milky Way mass distribution map after running by supercomputer. The calculated Milky Way mass is the most accurate. The results of this study help us to study the structure of the Milky Way, such as the span of the Milky Way. Earlier our estimation of the mass of the Milky Way galaxy came from observing the speed of star movement, which has huge errors.

To come to this conclusion, the researchers proposed a new method to estimate the mass of the galaxy, and Andreas Kupper, a PhD from Columbia University, was responsible for the study. The research team believes that the Sloan Digital Sky Survey can be used to observe the fluctuations caused by the quality of the Milky Way. Using Columbia University's supercomputer to simulate how much mass can induce such a size of fluctuation. Of course, the speed of rotation of the Milky Way and the location of different globular clusters must also be considered. These factors have a certain effect on the generation of fluctuations. In this way, combined with the galaxy's diameter of about 120,000 light years, scientists have calculated that the mass of the galaxy is 210 billion times the mass of the sun. ^[2]

Although this number is a more accurate value as of 2015, there is still uncertainty. The deviation may reach about 20%, which is much smaller than the previous quality estimation of the Milky Way. Earlier data believed that the mass of the Milky Way is 750 billion times that of the Sun, and even reached 1 trillion times at one time, with an error rate of 100%, and it is almost impossible to determine the specific mass of the Milky Way. Although we have a better understanding of the quality of the Milky Way, scientists believe that this value is still not very accurate because the diameter of the Milky Way cannot be determined. The calculation used 120,000 light-years, but studies have shown that the true diameter of the Milky Way may reach 1.8 million light-years, and some of the material overlaps with the Andromeda galaxy.

There is still a large amount of dark matter that cannot be observed near the Milky Way. Most stars are clustered within a radius of 40,000 light-years and are almost completely dominated by dark matter. Therefore, there are many unobservable dark matter masses in the Milky Way. Scientists are using Sloan Digital Sky Surveys to more precisely locate stars in the Milky Way. The size of the Milky Way galaxy should be medium-level in the universe, not too "heavy" or too "thin". In the next step, scientists plan to continue studying the mass of the Milky Way and compare it with other galaxies in the universe. ^[25]