a kind of nebula that shines by emitting light when electrons recombine with protons to create hydrogen atoms. The electron often approaches the proton in measures emitting energy as light whilst gets pulled in. In just one of the most typical "measures," the recombining electron produces a photon of red light. Since many atoms inside nebula do that at one time, the nebula appears purple in shade. This particular nebula is established whenever lively ultraviolet light from a hot celebrity shines on a cloud of hydrogen fuel, stripping away electrons from atoms (ionization). The free electrons may then start the process of recombination.
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Definition for "Emission nebula"
A nebula that absorbs ultraviolet radiation from stars…