What is Time?

What is time?

When I was trying to model a time varying data, suddenly this thought came to me. What actually is time? I then googled. I found that I am not the only one confounded by this question. Since beginning of human intellect, philosophers were puzzled by time.

Is it an emergent property like color, smell, or sound? Single atom doesnot have color but aggregate of atoms can produce beautiful colors. Similarly, one atom doesnot have smell, but nasty odors can come out of aggregates of the atoms. So, is time like that? Recently, space has been shown to be an emergent property. David Gross in his 2004 Nobel lecture said that he couldn't imagine physics with time as an emergent property.

Then I rethought about the problem of time. How do we perceive time? What is the hallmark of time? Answer to both the questions is the same: change. Change makes of be aware of the passing of time. So, answer to the riddle of time lies in the origin of change. How does change happen?

In my last post, I ruminated about some fundamental rules that I thought were unbreakable. Now I say, those fundamental rules guide the mechanism of change. Those rules put the whole universe in a constant state of instability. Instability is the origin of change. So, those fundamental rules maintain the arrow of time. Stable objects on the other hand maintain status quo, hence do not experience time.