Can we travel back in time.? Does the existing theory put a constraint on it or

1. 59

   Utkarsh rajposted 12 years ago

   Can we travel back in time.? Does the existing theory put a constraint on it or says it is possible!

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2. 90

   melporposted 12 years ago

   According to the laws of nature we cannot travel back in time even if we had the capability to time travel. Every event in the universe has a cause before an effect. The event must have a cause before you can see the effect of the event. 
   For example the Sun produces heat (the effect) because of the thermonuclear reactions of the hydrogen atoms occurring in its interior (the cause).
   
   This what the "Grandfather paradox" of time travel is all about. You cannot go back in time and kill your grandfather to stop yourself from being born. The paradox here is if you were never born you will not be able to go back in time to do this act because you will not exist to do the act.  You being born is the cause of the event to go back in time to kill your grandfather. That is the effect of the event. It cannot be done in reverse.
   
   It doesn't make sense , the the effect of you killing your grandfather cannot happen before you were born to cause this effect. That is the universal law of the universe, every event has a cause before an effect of the event can be detected.

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3. 60

   Jonesy0311posted 12 years ago

   Physicists have long since proven that effects can be observed before their causes. This is most notable in the case of tachyon (faster than light) particles which perpetually travel backward in time. Time is not a unidirectional ever-flowing stream. Rather, every possible history exists simoltaneously, each with its own probability. If you are interested in researching further, you should start with "Time Warps" by John Gribbin. Stephen Hawking covers most of the basics in layman terms in "A Brief History of Time," "The Universe in a Nutshell," and "The Grand Design."
   
   The "paradoxes" such as mentioned by melpor are irrelevant and any physicist can explain to you that time travel is not only possible, but can be achieved several different ways; theoretically. We just don't have the technology yet. There are no physical laws whatsoever that preclude the possibility of time travel or inter-dimensional travel in any direction.

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4. 63

   fatfistposted 12 years ago

   I once tried to travel on time.
   I tried to go forward and it didn't work.
   I tried to go backward and it didn't work.
   As it turns out, I was not SEATED on time so I couldn't travel on 'it'.
   Time has no edges or boundaries I could grasp and go for the ride.
   It just turned out to be all in my head.....

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5. 66

   brutishspoonposted 10 years ago

   Time travel is not possible within our understanding of how the world works.
   
   To make Time travel possible we would need to rewrite relativity to create a timeless universe.

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