Question: what is dark matter

Adrianos Golemis answered on 26 Jan 2016:

We don’t really know yet, hence the “dark”, which actually means “undetectable, unknown”. We know there is “something” that has mass because we observe that the galaxies of the cosmos rotate faster than we would expect – and that could happen only under the influence of more mass, which generates more gravity. But what is that “something” made of? We don’t know because we don’t see it, we cannot observe it in any other way. That is why we call it “dark”. Hopefully in the next decades new scientists will uncover this mystery!