It makes up most of the stuff in our universe, but we can't see it or weigh it - but we know it has to be there. This elusive substance is dark matter, and according to a new paper in the journal Nature Physics this week, it's all around us in our own galaxy - the Milky Way. To find out more about dark matter, and what this new map of the dark matter in our galaxy might tell us, Kat Arney went to speak to UCL astrophysicist Chamkaur Ghag, who's working on ways to detect dark matter here on earth. (And in case you were wondering, the tin foil is wrapped round it to help keep it cool.)