Scientists assume, that the universe is actually a multiverse with several
small bubble like universes („Bubbleuniverses“), that expand into the empty
space. The „wall“ of bubbles represents the big bang, in direction of the
interior of the bubble time increases. In different bubbles time
can be different. But the bubbles in the multiverse are so seldom, that
two universes can hardly collide, and if they did, they would explode.