The Milky Way is a milky white band that stretches across the sky. The Milky Way meets the celestial equator in the constellation Aquila.

The speed of sunlight around the galactic center is about 220 km/s, and one turn takes about 220 million years. This one is called the Galactic Year.

The Milky Way is only visible on clear nights and is caused by the light of numerous dark stars. The Milky Way is a bar spiral galaxy that contains the solar system. The diameter ranges from 100,000 to 180,000 light-years. There are about 100 billion to 400 billion stars, and possibly 100 billion planets.

The solar system is about 26, 000 light-years from the galactic center, at the inner edge of a spiral arm of dense gas and dust called the Orion Arm.

In the position of the Sun, the period of revolution is about 240 million years. Seen from Earth, the Milky Way appears as a band around the celestial sphere because it is viewed from the inside of the disk structure.

The Milky Way can be seen all year round, but the brightest and most spectacular parts of the galaxy are seen at the turn of summer and autumn.

The Milky Way looks like a dim band of light, but it is made up of a large number of stars. Because these stars are so far away from us, it looks like a strip of light.

The Milky Way is a mass of gas, dust, and hundreds of billions of stars. Gravitational forces form a huge disk dotted with globular clusters of stars, emitting bright halos.

The time it takes the Earth to orbit the center of the Milky Way is increasing, suggesting that the Milky Way is expanding. Meanwhile, the solar system's orbit is lengthened along the line between the two centers of its ellipse. This means that there are neighboring galaxies outside the Milky Way that are increasingly attractive to the solar system.

It was environmental changes around the galactic center that caused many mass extinctions of life on Earth.

In the comprehensive development stage of the animal kingdom, the species of animals are increasing. And their number is decreasing, but their quality is constantly improving.

Because of this, although there have been many animal mass extinction events, the animal kingdom itself did not become extinct, but more and more prosperous, and gave birth to the higher animal-human.