Why Does Time Exist?

We know that yesterday is different from today, and that the future is different from the past. But why is that?

Mathematically speaking, the equations that govern how atoms move, how heat is transferred, or how chemical bonds are made and broken can run in reverse with no problem. But they donโ€™t. The arrow of time points forward.

Watch this weekโ€™s Itโ€™s Okay To Be Smart to find out why!