• Question: how are galixys made?

    Asked by Alfie G to Heather, Helen, Hugh, Jane, Julian on 14 Nov 2014.
    • Photo: Julian Onions

      Julian Onions answered on 14 Nov 2014:

      Galaxies are made of stars – or at least that is what they look like. In actual fact galaxies contain lots of dark matter, lots of gas and lots of dust, but what we mostly see is stars.
      If we use other types of telescope such as X-ray and infra red, we can see some of the other components.

    • Photo: Helen Johnson

      Helen Johnson answered on 16 Nov 2014:

      Hi Alfie 🙂 this is an area of research that we are still very interested in, so great question! We think that shortly after the Big Bang the Universe was slightly different temperatures in different regions, and it’s these tiny fluctuations which led to structure forming.

      Galaxies form by regions of higher density gas and dust collapsing under gravity, inside of what we call a ‘dark matter halo’. We don’t know what this invisible dark matter is, but it can be thought of as the scaffolding of the Universe – what everything is built around. Some regions of gas then cool and condense into stars. There are hundreds of billions of stars in each galaxy!

      In different regions of space, and at different times, galaxies come in various shapes and sizes. We’re still figuring out how and why this came to be 🙂

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