Reveal the stars!

The solar system is centered on the Sun and is a collection of objects bound by the sun's gravity: eight planets, at least 165 known moons, five recognized dwarf planets, and billions of small solar bodies. Star cluster is composed of dozens to millions of stars with a common origin and strong mechanical connection between each other.

Stars are spherical or spheroidal bodies that produce their own light and heat. More massive stars have shorter lifespans, and less massive stars have longer lifespans. Most stars are between 1 billion and 10 billion years old.

A planet is usually a body orbiting a star that does not emit light of its own. It usually rotates in the same direction as the star it orbits. In general, a planet has to have a certain mass, and it has to be big enough and spherical enough that it can't undergo nuclear fusion like a star. In general, planets must be more than 800 kilometers in diameter and 500 million tons in mass. The solar system's "nine planets" are a popular term in history: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. In the resolution 5 of the 26th International Astronomical Union held in Prague on August 24, 2006, Pluto was designated as a dwarf planet and named asteroid 134340, which removed Pluto from the nine planets in the solar system. So now there are only eight planets in the solar system.

Meteor refers to the light trace produced by the friction and combustion of the atmosphere of the Earth, which is attracted by the earth's gravitational perturbation when the meteoroid (usually including cosmic dust particles and solid pieces and other space materials) is close to the Earth. Meteoroids originally move around the sun, when passing near the Earth, affected by the earth's gravity, change the orbit, so as to enter the earth's atmosphere. Meteors include single meteors, fireballs, and meteor showers. Most visible meteoroids are about the size of a grain of sand, weighing less than a gram. Meteors entered the atmosphere at speeds between 11km/s and 72km/s.The sun and the stars form a huge Milky Way. But no probe has yet left the solar system, and no probe will ever leave the Milky Way. Therefore, according to the current level of science and technology, it is not possible to film the Milky Way through scientific instruments. While probes aren't flying out of the Milky Way yet, there are other ways to build a complete picture of the Milky Way. The Milky Way emits light, mainly from stars. By measuring the distance and orientation of stars relative to the solar system, as well as the direction and speed of stars moving through the Milky Way, a three-dimensional map of the stars in the Milky Way can be constructed. The Gaia space Telescope, launched by the European Space Agency (ESA), has made a huge contribution to our understanding of the Milky Way. The Gaia Space Telescope has measured the distances, orientation and self-measurements of a billion stars in the Milky Way, creating the most comprehensive 3D map of the Milky Way to date. The results show that the Milky Way is a barred spiral galaxy with a diameter of about 100, 000 to 180, 000 light years and a thin stellar disk of about 2, 000 light years. The Milky Way looks like a disk, with a bulging core ball in the middle and a radius of about 13,000 light-years. If you look at the Milky Way, you'll also see four spiral arms: the Shield-Centaur arm, the ship-bottom Centaur arm, the Fairy arm, and the Outer rim arm. The spiral arms contain many young stars and nebulae, so they appear blue, with red nebulae interspersed.

The galactic center, around which all stars revolve, is called the galactic center, and it contains a massive black hole. In the northern hemisphere summer night sky, the brightest part of the Milky Way is toward the galactic center. The solar system is about 25,000 to 28,000 light years away from the galactic center, and we're not at the center of the Milky Way, but far from it.

The solar system lies on the Orion arm of the Milky Way galaxy, a small arm between the Fairy arm and the Centaur arm. The solar system orbits the galactic center at a speed of about 220 kilometers per second, taking about 220 million years to complete a complete orbit.

The solar system is located just right, not too far from the galactic center, right in the Milky Way's habitable zone.

If the solar system is very close to the galactic center, then there are lots of massive stars near the galactic center, and those massive stars end up exploding as supernovas. Gamma-ray bursts, which follow supernova explosions, are deadly to life on Earth, and may have triggered the first mass extinction on Earth.

If the solar system were at the edge of the disk, there would be so few massive stars that the abundance of heavy elements would be too low for earth to harbor life. A lot of our heavy elements came from the last generation of massive stars, and life could not have evolved in regions that lacked massive stars.

In both the Milky Way galaxy and the solar system, Earth is uniquely positioned to be in the habitable zone. Because of this, the colorful life on earth was born. I have to say, the earth is lucky.