• Question: how big is our galaxy

    Asked by anon-269992 on 12 Nov 2020.
    • Photo: Sam Geen

      Sam Geen answered on 12 Nov 2020:

      The Milky Way is about 200 thousand light years across and has around 100 billion stars in it. We think it’s surrounded by dark matter “halo”, which is a blob of dark matter 2 million light years across and around a trillion times the mass of our Sun.

    • Photo: Roan Haggar

      Roan Haggar answered on 12 Nov 2020: last edited 12 Nov 2020 5:22 pm

      The bit of our galaxy (the Milky Way) that we can see is about 200,000 light years across, which is about 600,000,000,000,000,000 miles! Although this is huge, the Milky Way is actually quite an average sized galaxy, and some galaxies are even bigger.
      —
      A lot of the Milky Way is also made of ‘dark matter’. This part of the galaxy is invisible, but is even larger than the bit we can see, about 10 times the size!

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