April 14th, 2015
Episode 275 of 1549 episodes
A major international effort to see where dark matter exists across the cosmos has released its first batch of results. It covers just 0.4% of the sky (the eventual aim is one-eighth) but is the most detailed map yet of this invisible cosmic web. It shows huge filaments that hold all the galaxies, separated by even bigger voids. So does this mean it is possible to map something that is meant to be invisible?Professor Sarah Bridle is Profesor of Astrophysics at the University of Manchester and co-chair of the Weak Lensing Working Group, which made the map as part of the Dark Energy Survey.