• Question: what is dark matter

    Asked by jack23 to Sive, Cathal, Ciara, Michael on 21 Nov 2013. This question was also asked by bobblehead.
    • Photo: Michael Nolan

      Michael Nolan answered on 21 Nov 2013:

      Hi Jack,

      not sure how I missed this one, apologies…
      this question was similar: https://lithiumn13.imascientist.ie/2013/11/15/what-is-the-universe-made-of/

      and there I gave a great quote from Prof. Strassler that dark matter is: “something that gravitates and clumps, but doesn’t shine, either in visible light or in any other form of electromagnetic waves”

      so you can observe its presence through gravity, i.e. it clumps together but you cannot see it using our usual arsenal of electromagnetic waves (light, infra red, radio, gamma ray)…hence it is Dark, but since it interacts via gravity, it is also matter.

      This stuff makes up 75% of matter so it is important. Its nature is not yet known and all sorts of wierd ideas have been put forward.

      A mystery awaiting a smart explanation