There's this one scene in Avengers:Age of Ultron where Thor leaves Clint's house to go have a vision with Erik Selvig's help. In the vision, we see four Infinity Stones and he says something along the lines of "Four Infinity Stones have shown up recently " (I think--not totally sure). Why is it that the Power Stone is on this vision? From what I can tell, Thor doesn't know about it at that time....