Nebula is a cloud-like celestial body composed of gas and dust in interstellar space. The density of matter in the nebula is very low. If measured by the standards on the earth, some places are vacuum. However, the accumulation of nebula is very large. Usually a radius of tens of light years. Nebulae and stars have a blood relationship. The gas thrown by the stars will become part of the nebula, and the nebula material will be compressed into stars under certain conditions. Under certain conditions, nebulae and stars can transform into each other.
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Nebula and stars are both gas mist celestial bodies