The Reason Physicists Still Can't Explain Why Time Moves Forward

You step out into a gray, misty rain. Droplets touch your face, and soon it is pouring. You realize you forgot your umbrella and head back into your house dripping wet. Something happened between your flooded boots and soggy socks; that something was the passage of time. If time didn't march forward in the fashion that it does, you could have stepped outside, realized it was raining, and then reversed your reality. Like a movie, you could have returned inside your home to a minute earlier, remembered your umbrella, and never had to deal with drooping socks and soggy pant bottoms.

Reality doesn't work like that, and scientists can't figure out why. Time moving forward is one of the myriads of unexplained phenomena within the scientific realm. Given the fact that we walk this planet amongst millions of completely unknown species and we sail an almost entirely unexplored sea — only to go home and navigate a scientifically inexplicable stream of consciousness within our own brains — it's pretty clear that we know less than we think. For scientists the world over, the concept of time is a lot like that, too.

When we watch sand spiral downward through an hourglass as a representation of time, we understand why the sand goes down but can't move up or sideways — this is gravity at work. An hourglass is an excellent keeper of time because its shape causes the sand to move at a constant speed (via Colgate Phys 111). However, unlike its keeper, time itself doesn't move at a constant speed — or any calculable speed for that matter. This is because speed is measured by time. Oddly enough, time is a byproduct of itself. Since time needn't cave to the rules put forth by time, we should hypothetically be able to move it forward, backward, sideways, etc. Nevertheless, Popular Mechanics cites the Second Law of Thermodynamics as the reason time is unable to move in abstract directions, but the verdict on this one is still out.