Expert: Jayendra Upadhye - 8/24/2009

Question
Hi, I saw a special on the science channel that theorized that time travel was possible either through a worm hole or by the creation of a machine capable of creating a spin, so particles can exced light speed.  So that it would be possible to send a message back in time, but not a person (or at least back in time since the invention of the machine).  However, don't all messages, be they molecular, subatomic, electronic, all contain mass, and therefore it would be impossilbe to send any message back in time at all.  Thats been my understanding.  I don't see how a worm hole would also make a difference.  AM I correct?  Thanks for the trouble.

Answer
Hi,
First of let me tell you that I know next to nothing about this subject!
And certainly not, the maths and physics of worm holes!

So what can I tell you that might interest you?

There is however an interesting thing about physics. Reality as we know it is multi-sided, of which we know just a few sides.

Time travel by "external means" is one side of the coin.
The other side of which I also know little, also exists.
This side does not require "externals" at all.
Time travel "just happens" for those who know that side.

I am not propagating this view to kill time or shy away from an answer.
I am just putting it across so you may "make space in your mind for "other possibilities".

coming to your question, Going back physically in time is meaningless because the moment one does that, one regresses to whatever state one was in at the moment in question, thought process and all.

One cant "go back" and say "hey! I will travel back one year but still retain my environment that is current! (unless you do such a thing how will you know you have travelled "back" in time?).
You would have to maintain the "current frame of reference in your mind in order to grasp the significance of the fact that you had indeed travelled backward or forward by so many years.

The problem is that that type of isolation is NOT possible. Your "environment variables" will change state as you go back, and you will embed yourself in the loacal "environment" you will become one with it and loose track of anything else!
Those past times will appear current to you!
This situation is inescapable. In fact you will go thru the same thoughts you had 1 year ago!
And appear in that reality at exactly the same spot where you were 1 year ago.

It would be a fruitless excercise of just re-living the timeline of a year till you reached "original current state.
Something like the push & pop that computers do when they switch subroutines.

Think about that.
Last of all, appearing in your past at any "other, forced" location will completely change the future of NOT only yourself, but the whole universe!
Simply because your time line will take you thru a parallel reality that you had not experienced earlier.

Read Asimov's Trilogy on Psycho-history & Hari seldon, the foundation series, to understand all about these issues.

Another book to read is the "end of eternity".
refer:- http://en.wikipedia.org/wiki/The_End_of_Eternity
It deals with all the paradoxes of time travel. I read it in 1975-1976 and marvelled at it.
Especially the character named 'Noÿs'!
You will too.

regards
Jayen