Adhithiyaram Ramakrishnan's Key Ideas from The Theory of Everything
by Stephen W. Hawking

Ever wondered , what's the direction of time ? Well , we all say it moves in forward direction. But what does that mean..

So far there are 3 ways of determining the arrow of time

1. Thermodynamically , time moves in the direction of increasing entropy .
2. Psychologically, time moves in direction in which we feel, that is, in direction where we remember the past but not the future
3. Cosmologically, time moves in the direction in which the universe is expanding .