• Question: Is it likely that our galaxy is orbiting something much bigger?

    Asked by Ben to Chris, Josh, Rebecca, Rob, Susan on 22 Jun 2015.
    • Photo: Susan Cartwright

      Susan Cartwright answered on 22 Jun 2015:

      It’s not exactly orbiting something bigger, but it is gravitationally bound as part of a larger entity. The larger entity is called the Local Group. It consists of 4 fair-sized galaxies (us, M31 in Andromeda, M33, the Large Magellanic Cloud) and about 30 smaller dwarf galaxies. Its two biggest members – us and M31 – are on a collision course and are scheduled to collide in about 3 billion years. This will convert two large spiral galaxies into one giant elliptical.

      The Local Group itself is part of the Virgo Supercluster, which contains several thousand large galaxies. There is some recent evidence that the Virgo Supercluster is in turn part of an even larger supercluster, the Laniakea Supercluster, which contains about 100000 large galaxies.

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