My Google searches are result in either something too complicated, or confusing non scientific journal articles. I always thought black holes were what people were referring to by dark matter. And I also was under the impression that small black holes should have all evaporated by now if they ever existed. Dark matter is some new kind of particle? What's the justification for adding a new particle? I read something that said we could be certain dark matter doesn't exist in supervoids because an overall lower temperature was measured there. But if dark matter isn't emitting light, how can it emit heat (I can't imagine things colliding much in regions that large)?