Stephen Hawking Time

Stephen Hawking (1942—) is one of the world's renowned theoretical physicists.  His view of time relies on earlier thinking by Newton and Einstein.  Hawking visualizes time as three arrows: the thermodynamic arrow, the cosmological arrow, and the psychological arrow.  The concept of these arrows helps explain why we see time as moving forward and what this flow of time actually is in terms of the expansion and contraction of the universe.  These arrows help distinguish the past from the future, and they give time a direction. 

“In our current state of the universe, all these arrows are pointing in the same direction, however, this will not always be the case, according to Hawking.  The thermodynamic arrow is derived from the second law of thermodynamics, which states that in any closed system, disorder (entropy) always increases with time.  Take an example of a glass falling from a table.  The glass begins in a state of heightened order; it is all in one piece.  As time passes, the glass hits the floor, and shatters into many pieces, increasing the disorder, or entropy, tremendously.”

Read more at Threes, Chapter 3, “Threes in Science”