Skywatch

  • June 16, 2011

    Episode 338: Hubble's Variable

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    In 1920, the nature of spiral nebulae, now known as spiral galaxies, was unknown. The scale and expansion of the universe were unknown as well. Astronomers debated whether the spiral objects they could see in the sky were within our galaxy or outside it. The astronomer Edwin Hubble devoted considerable time to observing stars in Andromeda, the largest known spiral nebula of the time. He found a variable star that demonstrated that Andromeda was far away -? and thus a separate galaxy. The first variable that Hubble found, known simply as "V1," has been observed with the Hubble Space Telescope almost 90 years after the first observations of the object.