While scientists generally agree that this solar system's sun and planets came from the same
nebular cloud, they do not know enough about how Earth obtained its chemical composition to understand its evolution or why the other planets are different from one other.
These star - formation rate estimators include the ultraviolet light that is emitted from young stars, the infrared light that shows how much of the ultraviolet light was absorbed by dust, and the
nebular emission lines that are caused by young stars making the
clouds of gas around them glow and radiate.