BBC地平线：我们身处哪个宇宙

<p>Imagine a world where dinosaurs still walk the earth. A world where the Germans won World War II and you are president of the United States. Imagine a world where the laws of physics no longer apply and where infinite copies of you are playing out every storyline of your life.
　　It sounds like a plot stolen straight from Hollywood, but far from it. This is the multiverse.
　　Until v...</p>