To be honest, we don’t know the position of the Milky Way in the universe, because we don’t know where the edge of the universe is, but fortunately, at the scale of the Milky Way, we know the position of the solar system in the Milky Way.
The Milky Way is a giant barred spiral galaxy with an elliptical silver disk as a whole. It also has a huge disk. In such a large disk, there are 200 billion to 400 billion stars, a large number of galaxies, nebulae, and various types of interstellar gas. And interstellar dust. Most of them are distributed in a flat disk, consisting of a silver core, a silver plate and a silver halo from the inside to the outside.
The core area of this big disk is the galactic center. According to the current human cognition of the Milky Way, the center of the galactic center is a huge black hole. Although humans have not directly visually detected this black hole, various data shows that it should be there. A super black hole, named Sagittarius A star. And near this huge black hole is a protruding part, viewed from the side, it is a very bright sphere with a diameter of about 20,000 light-years and a thickness of 10,000 light-years. This giant “light bulb” is composed of high-density stars. According to rough calculations, there are about 42 million stars in the space of 3.26 light-years in length, width and height in the vicinity of the galactic center, which means that there are about 1.21 million stars per cubic light-year, which is 400 million higher than the density of stars near the solar system. Times.
The outer part of the galactic center is the most important part of the Milky Way, which contains 90% of the detectable matter of the Milky Way, that is, countless stars, nebulae, gas and dust. The shape of the silver plate is like a thin lens, which is distributed axisymmetrically near the center of silver, with a diameter of about 80,000 light-years and a thickness of about 3000-6000 light-years on the edge.
Although we are in the Milky Way galaxy, at present human beings have a large amount of outer space exploration data and used computer models to draw a full picture of our galaxy. The figure shows that the Milky Way has four huge spiral arms, namely the shield-centaur arm, the bottom-centaur arm, the perseus arm, and the ruler-outer arm, except for these four main arms. Later, people also discovered some partial arms. At present, the solar system is on a partial arm called the local arm. The local arm is located between the Perseus arm and the bottom arm of the ship. The solar system is about 25,000-28,000 light-years from the Galactic Center. between.
Here is an episode. In the 5000-year-old civilization of mankind, some ancient and modern artifacts, buildings, inlaid crafts, pottery, jewelry and costumes, even ancient, all over the world, including China, India, Israel, and Greece. This symbol can be seen on the wall paintings of the cave. It is swastika in ancient Indian language, that is, Sanskrit. It is generally believed that the word swastika is composed of “su” and “asati”. “su” means “good” and “asati” means “existence”. Putting the two words together, plus the suffix, constitutes today’s writing-Swastika. If this statement is reliable, then the literal meaning of the swastika is “goodness and virtue will last forever.” In addition, it also represents the ancient people’s cognition of the universe, that is, it constantly rotates, just like a windmill or a waterwheel. When it rotates clockwise, it represents the energy, power and wisdom of the universe; when it rotates counterclockwise, it represents compassion. The swastika also represents the harmony of the universe and the concept of balance between the two poles. This actually corresponds to the four spiral arms currently observed by human science.
The silver halo is the outermost layer of the Milky Way galaxy and is a circular area scattered around the silver disk. Like the Oort cloud around the solar system, it is a much larger area than the silver disk itself. According to a rough estimate, the area covered by the silver halo is more than 50 times that of the silver plate. The halo is composed of thin interstellar material, a small amount of gas and a small number of stars. The stars here are very old, and some of the stars are more than 10 billion years old.
Back on our planet, when we look up at night, the stars in the sky are almost all stars within our Milky Way galaxy, and most of them are stars within hundreds to thousands of light-years away from us.
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