Oct. 27, 2013               Saturday            Rainy

This afternoon, I continued to read a book about the Theory of Relativity. Though I had read this kind of books before, I found some parts difficult to understand.

What is time? Even Einstein and Hawking couldn’t give certain definitions. To our ordinary people, time is everywhere. We talk about it every day and everywhere. But we cannot see it or grasp it. We just feel it.

I think time means change. If nothing is changed, time stops. Time means movement. If everything is stationary, then time has no meaning. Time is universal currency in future world. We need time. That means we need this currency to make some changes, to get something done or move from place to place. Time is space, we need this background to put things in.

We cannot completely go back to the past because the surroundings have been changed. I used to ask myself: what’s the possibility that a man died and many many many…….many years later the same man will appear with all the same background? Maybe only if the universe is cyclic, all events will cycle like what we see in replaying videos.