The dark Universe + Q&A (Lucie Green, Adam Riess, Risa Wechsler & Renée Hlozek)

We now think the Universe is packed with invisible materials – dark matter and dark energy – pulling and pushing the parts that we see. Join BBC Stargazing Live and Sky at Night presenter, Lucie Green as she explores this frontier of understanding with Nobel laureate Adam Riess and other leading cosmologists.