Time dilation. Length contraction. The fact that time moves faster at your face than it does at your feet. These are all experimentally verified consequences of the Special Theory of Relativity, proposed in 1905 by Albert Einstein. But the theory also helped explain one of the most nagging questions of modern physics, namely: how anything other than light can move. Minutephysics' Henry Reich explains, with the help of some sliding switcheroos. [Via Henry Reich]
To me the really spooky thing is that the instant we call "now" can be in someone else's future or past depending on their relative frame of reference. Instants in our future or past can be their "now". The evidence seems to suggest that all times past present and future are equally real. This can only mean that everything that is going to happen has already happened; we're just experiencing it a moment at a time. It's like reading a book; the whole story is there in your hands, you just experience it a page at a time.