This question is related to the possibility that there are many other universes in the UNIVERSE,the multiverse, that were created during collisions between membranes, according to string theories. The mechanism is not needed to be discussed in any detail, unless it helps to answer the question.
Since there is a multitude of universes, there must be non-zero probability for “our universe” to collide with another one.
THE 2-STAGE QUESTION IS:
How can we detect by means of an experiment that our universe is in collision process with one of the many universes?
Could observations such as the accelerated expansion of our universe, or the dark flow phenomenon be an indications?