Why is it impossible to travel to the past?

Answer 1

Time travel has some problems, but there are some physicists that think it might be possible.

Potential problems:

1) Father Paradox: If you went back in time and killed your father before you were conceived... what then?

2) Since you WERE in the past, would going back merely mean you would be where you WERE? Or would there be two of you in the past?

Some people propose there are an infinite number of "Time Lines" or alternate realities. Others say that the problems that exist with the idea show the idea is impossible.

Etc.

A.1] Perhaps if it IS possible then might there not be a "law" of some kind that prohibits the traveler from performing any direct act which would affect the current self.

A.2] I believe the question answers itself. But, if you were in the past then you would be visiting yourself (in the past) since it is your future self traveling back to see a past self consequently you would be unable to visit yourself before you were born, duh.

Similarly, should you be traveling into the future it would be a past self visiting a future self, but herein lies the possibility that the future self might not be a certainty due to the number of possible paths you might take. Example: If you visited yourself 1 hour in the future then the probability of that actually being your self might be 99.99%. Whereas visiting your future self 1 year in future might only represent a 75% probability of you actually being like that person due to the increasing number of decisions you might make, possibly exponentially. Which might mean that at some point, visiting yourself in the future would be useless as that future might never come about, or you may not even recognize yourself. But then again you should also realize that at some point in the future it would impossible for you to visit yourself in the past because you have already died. Again, duh.

It would be important to realize that at some point you are not actually visiting yourself, but a descendant representing your self, i.e. a son of a son of a son.

I'll stop here because thinking about the possibilities and probabilities, and the possible probabilities or the probable possibilities is giving me one heck of a headache. . . . whew!!

Oh! Dear. . . . ............................

Answer 2

Because of entropy. The Second Law of Thermodynamics postulates that there is a physical quantity called entropy that increases in all processes irreversibly. Physicists identify entropy as a measure of the disorder or complexity of a system. (The First Law of Thermodynamics states that the amount of energy in the universe is constant; energy cannot be created or destroyed but can be transformed from one form to another.) Thus, if we ask: What was the entropy of the universe yesterday compared with today's and tomorrow's? The answer is: Yesterday, entropy was less than today; tomorrow, it will be greater than today. As time flows from past to future, entropy always increases in the same direction, irreversibly. So there is a distinction between past, present, and future; changes do occur through the passage of time and the Second Law provides a measure of these changes through the concept of entropy. Stated differently, today's world looks different to us from yesterday's because of all the increases in entropy due to the processes, transformations, events and happenings since then. From: Time Travel: Possible, or Impossible? by Jack Hokikian, Ph.D. http://www.losfelizpublishing.com/Time%20Travel.htm

Answer 3

Revise date: July 12, 2010

Now a lot of people have spoke about traveling back in time including scientists, but they all seem to over look a very important fact. That is SOMETHING THAT WAS, COULD NOT HAVE BEEN. What that mean in simple terms, ONCE SOMETHING DONE HAD HAPPEN IT WILL ALWAYS DONE HAPPEN.

For example if burn myself. It don't matter if God himself reverse the clock , I would have still done had burn myself. Even if I was to go back in time (in a time machine), I still could not change the fact that at one time in my life I had burn myself.

There is Nothing I can do about what has already happen already. The simple fact is that going in time Don't make somthing never happen, what it does make physic and people forget it ever happen. And as for traveling forward in time. I believe you could only travel with time not though it. The different is the laws of physic will still no that you exist with it at all times.

Thank You!

--

Okay, well, that was an...interesting read. Rather painful from a grammar-snob's point of view to read, but that's not the point.

Now, time travel...ah, where to begin. Well, time is a fourth dimension; I don't believe that time and space are the same thing. Actually, I don't believe it's dimension 4, I think it's dimension 0. Because if you have no width, no height, no depth, and you're just a single point of being, you're still there, aren't you? Then time must always exist. To say that time and space are the same thing would be to say that 1- and 2-dimensional objects don't exist. (You might say they don't; but think about your shadow, a purely 2-dimensional "object". It exists, doesn't it?) So, to mess with time would be to unravel all the dimensions to get to time. You would have to open up depth, height and width and reach time, which, I don't know about you, but to me sounds nearly impossible. There might be a machine of some sort somewhere out there, at some point in time that can do such dimension-unraveling...but I think we'd have known by now if there was, wouldn't we? ;)

To recap,

Dimension 0 (D-0): Time

D-1: Height

D-2: Width

D-3: Depth

D-4: Tesseract (but that's another story...)

Or maybe time is D-1, and we are all really 4-dimensional beings? You decide. Oh, but just know that dimensions 1-3 on my list above are interchangeable, and don't necessarily go in any order as far as I know.

I hope I kinda answered your question, I know how aggravating it is to have someone post a reeeaaally long response to a question and not even answer the question that was asked, but I hope you can gather what I said into an answer, if it wasn't already straight-forward. Thank you!

(This was written by a 14-year-old who is vastly interested with dimensional relativity or whatever it's called to want to know about dimensions.) XD

Answer 4

You can not travel backwards in time, because it would mess up the entire universe, just as a solid object traveling faster than light would mess up the entire universe as we know it. The rules of the universe are: 1) No object will mass can travel at, or faster than, the speed of light. 2) No object can travel backward in time. That's the way the universe works.

Answer 5

Science tends to avoid ruling out anything in an absolute sense, since there can always be new discoveries, and many things that were once thought to be impossible (such as travel to the moon) have subsequently proved to be possible, but nonetheless, there seems to be a very strong probability that it will never be possible to travel back in time. Even if it were theoretically possible to do so, in practice it would be too difficult.

Answer 6

Idon'tthink it is. However scientist have not yetresearchedthat far tofindout how. Some people think time travel is a long line where there is a past , a present and a future. All of which you can jump yourself forward and back upon. Here is how i look at time travel. Time travelisn'ta line. Through time every one makes a choice , each choice crates another world were that choice you made wasdifferent Lets say you are at home. You have a choice. You decide towatchtv. At thatmomentyou have created a new universe where you have chosetowatchtv instead of reading a book. This means you have also created anotherparalleluniverse where that choice wasdifferent, where you decided to do something else creating acompletelydifferentworld. To the beat of abutterfly'swing to a death of a loved one , each choice you make will create adifferentworld where that choice wasdifferent. So in order to time travel youwouldn'tbe going back in time instead you would betravellingto that different world where the choice you madebeforehas not yet been made. Where you have not yet decided towatchtv and there you may change it creating worldcompletelydifferent.

Answer 7

You cannot reverse entropy.