Our best theory of reality says things only become real when we look at them. Understanding how the universe came to be requires a better explanation.

By Jon Cartwright

WHERE, when you aren’t looking at it, is a subatomic particle? A quantum physicist would probably answer: sort of all over the place. An unobserved particle is a wisp of reality, a shimmer of existence – there isn’t a good metaphor for it, because it is vague both by definition and by nature. Until you do have a peek. Then it becomes a particle proper, it can be put into words, it is a thing with a place.