"Aún no sabemos si los universos paralelos existen": Christophe Galfard, el discípulo de Stephen Hawking, les responde a nuestros lectores You might have now completed the quiz just before. That's why you can not commence it once again. Quiz is loading... You will need to check in or sign on https://www.youtube.com/watch?v=5LF34uf-LC4