This only applies if the universe is infinite. We don't know it for sure, though we have a lower bound of the universe size at 250 Hubble volumes: http://online

This only applies if the universe is infinite. We don't know it for sure, though we have a lower bound of the universe size at 250 Hubble volumes: http://onlinelibrary.wiley.com/doi/10.1111/j.1745-3933.2011.01040.x/abstract http://onlinelibrary.wiley.com/doi/10.1111/j.1745-3933.2011.... And infinite universe brings strange phenomenons, like our doppelgangers far away, that are exactly like us.