One of the theories that more represent the existence of the universe assumes that beyond our universe there are others who appear and disappear, each in his "bubble" of space and time. Usually they are not approaching each other, but sometimes some of our universe appears next, and when they do occur, there is a collision.
Collision with the whole universe would definitely have left some trace. That is, this collision would have left "scars" in the form of a disc in the cosmic microwave background radiation, and that is exactly what the cosmologists University College London found. They detected four of these "scars" that are ten times more likely to be evidence of a collision of the universe than that caused by something else we know.
However, the overall statistical significance of the traces in the cosmic microwave radiation is not great, which means that it takes a lot of data to definitively prove or reject this theory of a collision. Fortunately, Planck space observatories can make recordings that are three times higher resolution than images used in this study, so we will by 2013. receive a definitive answer to whether there is space out there floating around.