Was watching Déjà Vu today. For those who haven't heard of the movie, click here. The movie might be entertaining for most of you but for me it raises quite a few questions in my mind. Suppose we devise a machine that enables us to travel to the past and observe things that have already happened, actions whose outcomes are already known. Does our presence there change anything? The ground rules dictate that we assume a universe with dimensions other than the 4 known ones. We humans are 3-dimensional creatures who perceive the world through their eyes in 3 dimensions. We also experience the fourth dimension of time as a unidirectional arrow from past to the future. However, according to the 10 dimensional concept of the universe, each point on this arrow branches off to infinitely many directions, each indicating an alternative reality. Let me illustrate this using an example. I woke up today at 11 am when my alarm clock rang. When you are a college student like me, you have to weigh your choices when the alarm rings – you either wake up, or you go back to sleep. The split-second before you make the choice is a highly symmetrical one- any of the possible outcomes can happen, and each is equally probable. However, as soon as we make the choice, we break this symmetry by choosing one of the ways. Once we have made a particular choice, it will affect our next choices and so on. Theoretically speaking, the state of the entire universe after 11 am depends on your choice at that moment. But what happens to the other choices? Since each outcome was equally probable, the symmetry must be preserved somehow. What really happens is that the other choice triggers another set of choices and we get a totally different reality that stemmed from our choice at 11 am. In other words, the outcome of the other choices does take place, although in a parallel universe of its own. Take a moment here to consider how many choices you make in your life each minute, and how many parallel universes sprout from those choices, and you will understand how immensely vast the network of space-time is. The parallel universe concept does bust one of our assumptions – that of a linear space-time arrow. As you can see from the illustration, each branch has its own past and future, and each exists in the realm of the Laws of physics, and none of these is more favourable than the other. They all simply exist. The anthropic principle of the universe dictates that we see our universe the way it is because of our own choices, causes and effects. Thus, each universe which is present is an outcome of choices. You make a choice now; all the other choices you could have made were made. You only feel the outcome of one of those choices and that becomes your universe. There are countless other universes with countless other similar yourselves So far so good, let us come back to our focus area of time-travel. Suppose I go back in the past and kill my great-grand father. Consequently, my grand-father is not born, hence my father and hence me, never came into this world. In that case – who is the one who killed my great-grandfather? Certainly, this leads into a paradox. What will happen if try to kill my grandfather? - Will I not be able to do it, Will someone stop me? Laws of physics certainly not prevent us from committing murder. What will really happen is that a parallel universe will sprout from the point that I kill my great-grandfather. In that universe, I, my father and my grandfather will never have been born. The choices that we made in our lives will never have been made. However, this universe does not alter the one in which we were born and lived. Hence, if we try to change the past, the change that we bring will be but one of the many parallel possibilities in space-time. In a layman's perspective, a deliberate change in the past does change the future, but along the same line through which the change has been made. Observing the past Let us come back to Déjà Vu. Suppose I have a screen that shows me what happened in my past. Will that affect my future? If yes, then why, and in which reality? Again let us consider the following example. I am a big gadget freak and am fascinated by the iPhone. Alas, it will not arrive in Singapore until June this year- that is when I plan to buy this baby. Suppose I use a screen to observe the past and look into the Apple Labs 3 years ago when the iPhone was being manufactured. I see that, for whatever reason, Apple have installed a chip in the iPhone that will make it self-destruct in December 2008. Note that I am simply observing the past, and am in no position to change it. But will this observation affect my decision to buy the iPhone in June 2008? Has the mere act of observation of the past affected my future? In geek lingo, does observation count as interference? As to that, I have no answer at the moment. I will refer to it as Adi's iPhone Paradox!
Changing the past
who have made other choices and are living in their own universes.
RESOURCES
1. Imagining the 10th Dimension by Rob Bryanton :Amazon.com
2. Parallel Worlds by Dr. Michio Kaku :Amazon.com
