Why is time travel impossible?
August 6, 2008
Time travel is analogous to the day to day movement we do in real time.However, while the reference point of the former is time, the later is space.I strongly believe that time travel is not possible for the following reasons:
1) Let us get back to the basics of physics.Since ages, We have been studying a basic relation between time, speed and distance .The relation states that Time is directly proportional to distance, and is indirectly proportional to speed.And, Speed is defined as the distance traveled in a given amount of time.Now Putting it in an equation, we get the following:
Speed=Distance/Time
=> Time=Distance/Speed.
When we say time travel, we should speak of Distance in terms of Time.Observe this carefully, when we speak distance in terms of time, we are not supposed to replace time with distance in the above relation.Such kind of a replacement means that we are replacing the quantity of time with distance, but we are not trying to put the relation in terms of Time Travel.On the contrary, when we travel between two different points of time.Then the distance and time taken, both should be represented in time,Which is not possible! If such a relation has to be made possible, then altogether a different coordinate system has to be developed, in which we can represent two variables like time and distance on the same axis.Added, we should be in a position to map this theoretical system to the regular system we use.
2) Absence of records about Time travelers till date: If time travel is made possible in the future, then we would have had records of travelers visiting us from the future.However, we don’t have any such records of people visiting us from the future, at least till date.
3) Failure at the roots of nature: Every small invention on this earth has its roots taken from nature.Be it accidental or intentional.For example, the invention of car has its roots from the invention of wheel, where the movement of wheel is based on the principle of circular motion.The invention of an airplane, was inspired from birds(I don’t know what inspired wright brothers, but when we get back to the roots of air travel in history-this is definitely true!).So, i would say that every invention is supported by a principle of nature. But, there is no principle, which has been discovered till date which indicates an entity traveling in time.If such an entity exists , then it would have been discovered by now!
4) Paradoxes: Consider this situation where a person goes to the past and destroys some entity to which he is related in the present.Then all the links between that person and the entity break, leading us to several paradoxes in the present.Here is one such example: Grandfather Paradox
Actually, the crux of the matter is time. First, what is time? And second, is it something that can be “traveled.” Of course, time as well as the other fundamental units, is defined circularly so there is no clear definition. I would like to present to you a very simple explanation of what time is: time is simply change; nothing more and nothing less. You can’t travel change, can you?
For example, you can have more change (like time “speeds” up), less change (like time “slows” down), or no change (like time stays “still”), but you can’t have negative change. This keeps in line with relativity, time dilation, etc.
As far as the “alternate universe” theory goes (which I HIGHLY doubt is correct) you would still NOT be traveling to the past through time; instead, you would be traveling to alternate universes which happen to be the same yet at an earlier time (how convenient.)
@tboonepickens,
I agree with your TIME=CHANGE concept…:)
But just imagine how wonderful it would be for an individual to travel in time..:)…but then, it can make a man impatient, restless, greedy, anxious, cruel..and what not…