emission lines

  • What are Seyfert Galaxies?

    What are Seyfert Galaxies?

    Meet NGC 1566, an intermediate spiral galaxy in the constellation Fornax. To the human eye, this galaxy looks almost like any other spiral: It has a central nucleus and spiral arms, and it’s full of gas and dust. As an…

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  • Interstellar Spectra

    Interstellar Spectra

    I often refer to what we call the interstellar medium as the galaxy’s “backstage,” and I do that for a reason: for the most part, we can’t see it. The backstage of any theater isn’t part of the show. You, as…

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  • The Atomic Spectrum

    The Atomic Spectrum

    Astronomers know that if white light passes through a prism and is bent, it’s separated out into its component colors — the colors of the rainbow. Astronomers also know that when light interacts with atoms, the building blocks of the…

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