Why Does Time Move Forward, Not Backward?
Most of our lives revolve around time, from the instant our alarm clocks go off to attending afternoon appointments to the moment we call bedtime. Tick tock. But what exactly is time, and why is it always marching forward?
A new paper suggests that the arrow of time — a term given to the forward direction of time — is driven by gravity and, therefore, an inescapable result of the fundamental laws of physics in our universe.
However, “the laws of physics are ‘time-reversal invariant,’ which means that all the many phenomena we understand and describe through the laws of physics respect these same laws too if ‘played backwards’ like a movie played in rewind,” Dr. Flavio Mercati, a researcher at the Perimeter Institute for Theoretical Physics in Ontario, Canada, told The Huffington Post in an email. “This seems puzzling, considering that we see so many phenomena unfolding only in one way.”
To tackle the complex puzzle, the researchers created computer simulated universes similar to our own which is dominated by gravity. The researchers then measured how much order there was in the simulated universes using a quantity called “complexity,” which essentially corresponds to the ratio —> Read More Here