|Everything must exist now and any time inbetween now and infinity because the world and what we call reality is a cycle, constantly repeating itself over and over. So at any point within the circle we are perceiving it becomes real or reality to us, but for a circle to be complete, all points must connect to each other in a closed loop. So that means even though we are at one point within the circle at any given time, the other points are simultaneously existing at the same time and to be aware of any point is to make it the reality we see and perceive. Its only when we are aware/ perceiving it that it jumps into reality.
Since everything exist perpetually into infinity, this must give rise to alternate realities as its percpecived at different intervals within our space-time continuum giving rise to a of multitude of possible scenario