• Question: What is the universe made of?

    Asked by Tom to Sian, Dawn, David, Dan, Christie on 15 Jun 2016.
    • Photo: Sian Thomas

      Sian Thomas answered on 15 Jun 2016:

      Not really qualified to answer this – perhaps David?

    • Photo: Dawn Lau

      Dawn Lau answered on 15 Jun 2016:

      The universe is made of matter, energy, and dark matter – the latter of which we cannot see. I’m sure others can explain more (David?) but for now here is some interesting reading: http://www.bbc.co.uk/earth/story/20150824-what-is-the-universe-made-of

    • Photo: David Robertson

      David Robertson answered on 18 Jun 2016:

      Dawn has given a good link.

      Almost everything that we can see in the universe is stars in some way, usually grouped together into galaxies or clusters. The reason we can see them is the obvious one – they give out light so we can see them from a long way away. We know there are planets round many stars, and have seen a few of these directly. All of these stars and planets are made up of “normal” matter. Atoms like Hydrogen, Helium etc mixed up in various ways.

      If we look at the way the number of stars in a galaxy and the way they move then something doesn’t work. The stars are moving as if there is more mass than we can see. This means either our equations are wrong or there is more mass there than we can see – we call this “missing mass” dark matter, which is another way of saying “we’re pretty sure there is something there, but really don’t know what it is!”.

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