What is TIME
Assume, you are eating in a restaurant and suddenly the waiter comes and says, “I’m gonna ask you a question. If your answer is satisfactory, you do not have to pay the bill.”
His behaviour may astonish you. But, I think I would like to hear the question. Let’s assume you want to hear the question too. You’ll say, “Yeah, ask.”
Then he says, “What is Time?”
You’ll think whether he is mad or something. But he seems so serious. You start to hesitate. You try to give an answer, but you know it’s not gonna be satisfactory.
You start to think, ”Why haven’t I asked myself this question before? Really, what is the definition of time? If I knew, I would get the food for free right now.”
Well, it’s not a great time for disappointment. Let’s think together. Firstly, let’s see what people say about it. By people, I mean scientists or physicists or anyone who is nerd enough to know the answer.
Well, time is the measured or measurable period during which an action, process, or condition exists or continues. From this definition, it seems like time is a continuous process. But, what if it’s not a continuous process?
At present, some people are thinking time is quantized. That means it’s a collection of discrete moments. We used to think that energy is continuous. That was classical theory. But, it was wrong. Energy is not continuous. It’s discrete. Quantum mechanics can easily explain it.
Now, let’s talk about time again. We are not sure yet whether time is continuous or discrete.
Another question, does time have a direction? We know that, the quantity having both magnitude and direction is called a vector quantity like velocity.
But, some people consider time as a scalar quantity. But, we know time has a direction. It’s always moving forward, not backward. So it does have a direction and it’s forward.
Does this quality make time a vector quantity? We do not know.
Everybody knows we can’t go to the past. But, we are going to the future.
Now, anyone can ask why time is going forward? It’s a very tough question. Well, some people tried to give an answer. Let’s hear them out.
The Arrow of Time, or Time’s Arrow, is a concept developed in 1927 by the British astronomer Arthur Eddington involving the “one-way direction” or “asymmetry” of time.
Physical processes at the microscopic level are said to be either entirely or mostly time-symmetric: if the direction of time were to reverse, the statements that describe them would remain unchanged.
At the macroscopic level it often appears that it is not the case.
Let’s discuss about entropy a little. Entropy is measurement of disorder. As the universe is expanding day by day, entropy is also increasing.
We know, entropy can’t decrease. It either remains constant or increases. That’s why time also moves forward only, not backward.
Entropy is the key for the arrow of time. But, it does not give total satisfaction.
In the end, time is still a mystery for us.
So, the waiter is very clever. He knows he doesn’t have to give the food for free. Scientists will think twice before answering that question.
Shahriar Kibria