The laws of physics does not state anything the direction of time which means there is a high probability that it can move in any direction. This means entropy should increase if we look backward in time and it should also increase if we look forward in time. Moreover, because of this, the disordered loose pages of a book in the past can arrange themselves properly to a neatly bound book.
However, if this is possible, why haven’t we seen this happen? The laws of physics are constantly conflicting with the everyday experiences of our lives. Thinking about this, several physicists suggested that we are overlooking something vital for us to understand the arrow of time. The principle of entropy states that the past had to be more ordered than the present and the future. It also states that everything in the universe has a high tendency to move toward disorder. Knowing these, maybe we should not rely solely on the laws of physics to provide us with the right answers.
To simplify the theory, imagine yourself hitting a golf ball. You will be able to determine the possible places where the golf ball will land with the help of the laws of physics. However, we should also consider the initial conditions or other factors that can influence the motion of the golf ball. For example, when computing the distance and direction of the golf ball’s trajectory, we must also take into account how hard the ball was hit and what the angle of the golf club is at when it came into contact with the ball. Thinking about this, we have to realize that if the laws of physics cannot give a concrete explanation for the arrow of time, we should also consider the initial conditions of the universe when it was formed. This is the moment of the big bang.
As we move backwards in the history of the universe, the more ordered things will appear. The universe that we know at present, which consists of billions of galaxies, will turn back into clouds of dust and gas. And as we move further, these clouds of dust and gas also move closer to each other until we reach the point where their volume is so compact. And when we reach moment when the universe began, we will see that this is the ultimate source of order of low entropy.
The big bang is considered the most orderly state in all of physics. This means that everything that happened after that has been directed at the increase of disorder. Thinking about this, we can deduce that when we look back in the past, the universe will be very much different from when we look in the future. Because of this, the universe during the times closest to the big bang is more ordered than what it is today.
There’s no explanation why the entropy was low at the moment of the big bang. Nevertheless, it is still better to know that there was indeed a moment when the universe began. This point to the fact that the big bang is what directed the arrow of time on its course. This is similar to a wind-up toy where the stored energy is release as it unwinds. Ever since the big bang, the universe has began unwinding and becoming disordered.
Because the universe began from a very orderly state, time appeared to be moving towards a certain direction. There is no explanation as to why the universe began is such an orderly state. However, it also means that every time a glass bottle shatters it is actually continuing something that started billions and billions of years ago. The glass bottle shatters but it does not return to its old form because it is merely following the natural motion from order to disorder, which started with the big bang. It is only the increasing disorganization of the universe which separates the past from the future.
By: Jeffrey Slayter