spiral density wave theory

  • How Galaxies Evolve

    How Galaxies Evolve

    Ever since astronomers realized that the mysterious, fuzzy objects known as “spiral nebulae” were, in fact, separate galaxies beyond our own, we’ve sought to understand the stories of galaxies. We’ve since discovered that most galaxies are found in galaxy clusters.…

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  • The Milky Way Demystified

    The Milky Way Demystified

    Alright, people…time to finish off our exploration of the Milky Way Galaxy, our home in the cosmos! For the past nine weeks, we’ve covered everything from how our galaxy was “discovered” to how it may have formed. But there’s so…

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  • What Are Spiral Arms?

    What Are Spiral Arms?

    Probably the most spectacular feature of our Milky Way galaxy is its spiral arms. We can’t get a probe far enough out yet to take a galactic selfie, but astronomers are reasonably sure that we live in a spiral galaxy.…

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