Globular cluster

Globular clusters are star-shaped or oblate. Compared with open clusters, they are dense clusters. These clusters contain 6,543.8+0,000 to 6,543.8+0,000 stars, and the average mass of the member stars is slightly less than that of the sun. Observed through a telescope, the stars in the center of the cluster are so dense that they cannot be separated, such as M3 in Canis Canis and M22 in Sagittarius.

More than 150 globular clusters have been discovered in the Milky Way. Their spatial distribution is quite strange. One third of them are near Sagittarius, and Sagittarius only accounts for a few percent of the whole sky area. Astronomers first realized that the sun is far from the center of the Milky Way, which is in the direction of Sagittarius. Unlike open clusters, globular clusters are not concentrated in galactic plane. Instead, they are concentrated in the center of the Milky Way. Most of them are within 60,000 light-years of the center of the Milky Way, and only a few are farther away. Globular clusters are bright and can be seen from a distance, and are unlikely to be covered by dense interstellar dust clouds. Therefore, the number of undiscovered globular clusters does not exceed 100, and the total number is much less than that of open clusters.

The diameter of globular clusters ranges from 15 to more than 300 light years. The average spatial density of member stars is about 50 times larger than that of stars near the sun, and the central density is about 1000 times larger. Globular clusters have no young stars, and the age of member stars is generally over 1000 billion years. According to speculation and observation, there are many death stars.