Introduction to the sun

The sun is the central celestial body of the solar system, accounting for 99.86% of the total mass of the solar system. The eight planets, asteroids, meteors, comets, exoneptune objects and interstellar dust in the solar system all revolve around the sun, and the sun revolves around the center of the Milky Way. The sun is a star located in the center of the solar system, and it is almost an ideal sphere where hot plasma and magnetic field are intertwined. The diameter of the sun is about1392000 (1.392×10? ) kilometers, equivalent to 109 times the diameter of the earth; The volume is about 6.5438+0.3 million times that of the earth; Its mass is about 2× 10? Kilogram (330000 times that of the earth). From the chemical composition, about three-quarters of the mass of the sun is hydrogen, and the rest is almost helium, including oxygen, carbon, neon, iron and other heavy elements with mass less than 2%. Nuclear fusion is used to release light and heat into space. The sun is currently passing through the local bubble region of Orion's arm at the inner edge of the Milky Way. There are 50 nearest star systems within 0/7 light-years from Earth/Kloc-(the nearest star is a red dwarf named proxima centauri, about 4.2 light-years). The sun is a yellow dwarf (G2V spectrum). The life span of a yellow dwarf is about 654.38+000 billion years. At present, the age of the sun is about 4.57 billion years old. After about 5 billion to 6 billion years, almost all the hydrogen in the sun will be consumed, and the core of the sun will collapse, leading to an increase in temperature. This process will continue until the sun starts to condense helium into carbon. Helium fusion produces less energy than hydrogen fusion, but the temperature is also higher, so the outer layer of the sun will expand and release part of the outer atmosphere into space. When the process of turning to new elements is over, the mass of the sun will drop slightly, and the outer layer will extend to the current orbit of the earth or Mars (at this time, the two planets will be farther away from the sun due to the decline of the mass of the sun).