Subject: As far as i know, traveling back in time would defy the 2'd Law of Thermody

As far as i know, traveling BACK in time would defy the 2'd law of 
thermodynamics(Something traveling back in time would add energy to 
that universe) However, I have a friend who says this is not true 
because the past,present and future universes' are really a part of 
ONE big universe and that the total energy of THAT universe would be 
conserved even if we travelled back in time.  I understand this is a 
very hypothetical question, but I was wondering if there are any 
educated scientists out there who belive that it is possible to travel 
BACK in time, without violating the 2'd law of thermodynamics.

Re: As far as i know, traveling back in time would defy the 2'd Law of Thermody