• Question: what is dark matter?

    Asked by matt21 to Edd, Jess, Nicolas, Zara on 22 Jun 2011.
    • Photo: Zara Gladman

      Zara Gladman answered on 22 Jun 2011:

      Hi matt21

      To be honest, I haven’t the faintest idea! :O I think it’s… stuff…in space… that we can’t see! I’m sure a physicist could give you a good answer. I’ll try and find out too, and post here when I know! In fact, I bet there’s somebody in the Quantum zone (full of physics boffins!) who knows 😀 I will put the word out!

      According to the reading I’ve just done, dark matter is thought to make up about 90% of the universe! It is invisible but scientists believe it exists because they can see its gravitational effects on visible things like stars.

      Good question – it forced me to find out the answer and learn something too! 8)

      PS Dark Matter is also a film, starring Meryl Streep!

    • Photo: Edward Codling

      Edward Codling answered on 22 Jun 2011:

      Hi matt21 – a great question but we actually don’t know!

      Astronomers are able to study the way that galaxies work. Inbetween galaxies there is often clouds of very hot gas that gives off x-rays. Scientists can then study these x-ray patterns and determine how much the gas is affected by gravity. A number of studies have shown that the gravitational forces acting on these patches of gas are much higher (5 times higher) than the forces expected to be produced from things that we can actually see. Hence the theory is that there must be ‘dark matter’ – material that is invisible but still exerts a gravitational force.

      Nobody has found any dark matter though – it would be the find of the century if we did! One possibilty is that there isn’t actually any dark matter but that gravity behaves in ways we really don’t expect. Either way it is really exciting and interesting stuff to think about!

      http://imagine.gsfc.nasa.gov/docs/science/know_l1/dark_matter.html

Comments