I read in a book recently that in the universe there is "only one kind of stuff - matter". I wondered if this was still true - and also if it could only be true? With the discovery that the Universe has way more (something - gravity? mass?) than it should do, physicists have come up with the idea of dark matter in order to make up the missing stuff. My question is, will this new stuff - dark matter - be the same type of stuff that we can normally, but just concentrated or hidden in places that we can't see it (think in other rolled up dimensions, inside black holes etc) or will it be 'something else' - something that has mass, has gravitational pull, but is not matter in the sense that we have to date encountered it?
And forgetting even trying to find the stuff, does the math even allow for the existence of mass, or gravity or whatever, to be attached to something different other than matter as we know it. Can stuff even theoretically be of a different order?
Idle speculation - no matter.
