Intro

0:00So, it's something that is out there, it's passing through the Earth, probably through us right now, but because it doesn't have any interactions except gravity, we can't really tell. This fundamental prediction of cold dark matter, which is our best current theory for what it is, which is mind-blowing when you think of it, which is that every galaxy should be surrounded by an innumerable number of completely dark concentrations of matter.