Existence Conditions for Time-Travel. Formulated on the Delhi Metro, documented on my terrace under the stars with my dog sleeping at my feet.

Some days ago the papers informed me that two German gentlemen had discovered photons that travelled faster than light. My memory tells me that time travel is possible if one could travel faster than light, ofcourse one might find that cosmic strings, black holes and/or warp drives might come in handy in one's endeavour.


What does it mean to travel in time? What would one do if it were posible to go into the future? Or the past?? I looked at my watch - it read 10.11 AM then; in about half an hour I'd be in Dwarka. Too little time to completely analyse questions of such importance, I thought.


But half an hour was sufficient to lay down the basic requirements essential for time travel. The rest I left to people on overnight train journeys.


Hmm - technically if time travel was possible then it means at this point of time, 11:18:37...38...39...PM I could travel to say 08:00 AM tomorrow morning or to 07:00 PM tonight. To travel to these two separate 'times' they must exist now ie 11:19:03...04...05...


So for time travel to exist there must exist all times - A separate parallel universe for every unit of time that has occurred or will occur.


But then what happens if I go into my past and kill myself? So travelling into the past could throw up a paradox that violates causality. In which case we do away with the possibility of travelling into the past. CAUSALITY CANNOT BE VIOLATED, EVER! Though certain experiments have proved otherwise.


So we are left with the possibility of travelling into the future.


I remember by the time I got off the Metro that day I had it all figured out in my head. I turn to Miles Davis as I try and recollect my mental work from that trip - my dog (Cookie) is having some sort of a dream. Her eyes are half open as she sleeps and every now and then she jerks her left leg and then draws an imaginary circle in the air with her paw. As you see, the setting is perfect for the following -


Now a basic requirement for travelling into the future would be that it should take lesser time than it would in reality ie I should travel from 2007 to 2010 in less than three years. Like all good economists im tackling the most basic requirement first.


So say Im on my way to Dwarka and am presently at Rajiv chowk - if I were to travel 15 mins. in the future, where would I be? You could say I would be near Rajouri Garden, still in the metro. But in the 15 mins. that elapsed I could have gotten off two station before Rajouri Garden and taken a train back to Rajiv Chowk, or I could have waited at that station staring at my feet or if I felt like I could have left the station all together and could be counting the no. of white cars that I saw pass by me, or maybe black. What I am attempting to say is that in 15 mins. time I could be at many different places doing many different things. So if I were to travel to 15 mins. in the future I could be at any such place doing any such thing.


So to begin with for each unit of time in the future there must exist as many parallel universes as there are possibilities. As time 'passes' these possibilities get narrowed down to what actually has occurred.


Coming back to me being in Rajiv Chowk in the Metro. Say travelling 15 minutes into the future I find myself still in the metro, at Rajouri Garden. Everyone who was with me in the Metro at Rajiv Chowk is still with me, Have they travelled time as well? I guess not. So basically im in another universe that always existed. The others are actually 15 minutes ago (it is getting difficult to maintain grammatical standards.) But actually only about 10 seconds have elapsed, so I can't be at a particular time - I am at a particular place that exists for a particular time. it is not the unique place for that time. As many places exist for that time as are required to accomodate every possibility in the universe, everybody else who could have travelled time and so on.


Miles Davis is getting groovier and Cookie's dream has turned more violent it seems.


Now that I am where I am. A place that is located 15 minutes into the future but is only 10 seconds away in real time. I wonder what could be done. technically 10 seconds have passed since the Metro left Rajiv Chowk. I am 15 minutes into the future, but even 10 minutes after the train pulled out of Rajiv Choek is 'future' for me because in reality only ten (okay 88) seconds have passed yet. So if my time travel gadget travelled with me I could go to ten minutes after the train left Rajiv Chowk from being present in some universe where 15 minutes had elapsed since the train left Rajiv Chowk.


But this doesnt mean I have travelled in the past. It only means I am travelling back in my available future. From 2007 I could go to 2100 spend a year with my great grand children and then go to 2010. The only year I can't go to is 2008 because it has passed. And I wasn't there. You could say that when I went to 2010 then I could kill myself and m visit to my great grandchildren in 2100 would violate causality. But that is an incorrect conclusion. Actually 2010 hadn't occured, when I was in 2100..........................
..................."The next station is Dwarka Sector ...." I remember. It was 11:07 then - surely it didnt seem like it had been 50 mins since I got on at Rajiv Chowk - certainly there are better ways of spending a long ardous Metro ride. Ways that might involve a pretty girl and a great conversation. This is one.


PS: But I promise as I got off the Metro that day, I had it all figured out, all the necessary conditions for time-travel. Just didnt put them together, saving it for another such ride.


******
Cookie is awake now. Both of us are staring at the sky, imagining the infinite possibilities that the universe holds. In another world Cookie could still be having a bad dream.