• Question: does dark matter have an atomic structure and or a gravitational pull

    Asked by ALEX.B.R to Alice, Bose, Christian, Emma, Steve on 16 Mar 2016.
    • Photo: Steve Marsden

      Steve Marsden answered on 16 Mar 2016:


      Great question! We know that it has a gravitational pull. In fact, that’s how we know that it’s there at all.

      There are several theories that could describe dark matter. Some say that it has an atom like structure, though the particles that make up these dark-atoms are not the same as make up normal atoms. I think most theories say that it does not have an atom like structure, and is a fundamental particle.

      I may be a little biased as I’m a particle physicist, but I think the theories that suggest that it is fundamental are more likely to be correct. I’m quite interested to see what the other scientists have to say about this. 🙂

    • Photo: Alice Harpole

      Alice Harpole answered on 16 Mar 2016:


      As Steve said, the one thing that we do know about dark matter is that is has a mass and therefore has a gravitational pull.

      However, I think that it’s probably not got an atomic structure and is instead made up of ‘non-baryonic matter’ (i.e. not protons or neutrons). There are several reasons why people think this. For example, stuff like protons and baryons interact with electromagnetic radiation (light), so if there were clouds of dark matter (e.g. like those we believe occur around galaxies), we’d be able to see them. Our current understanding of the Big Bang also predicts a particular amount of neutrons and protons being made in the early universe. This is pretty much in line with the amount of protons and neutrons that we can see, suggesting that dark matter must be made of something else.

      As to what this ‘non-baryonic matter’ actually is, I have no idea. Whatever it is, it probably goes beyond our current understanding of particle physics!

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