Parallel and multiple universes

In response to my posting about parallel universes, here are a couple of very valid points of view and my responses.

My office roomie, Michael said, “If you take probability into account, 124 or billions of universes is possible. You can use mathematical probability to find out if other universes exist, but probability is still the art of assumption by deduction.”

I agree with this assessment. Perhaps there is a universe that has physics that only allows for 124 parallel universes? Oh yes, there is nothing from saying these other universes can or cannot have totally different physical properties. This is also a reason why we may not want to jump universes even if we could. It would be a rather short trip if you popped into a universe were physical energies were backwards from our own, an anti-matter universe. Or what if you jumped into one that only had 3 dimensions; two dimensions of space and one of time. Quantum theory allows pretty much for anything to happen, so who's to say it cannot. We are now beginning to see that our own universe has more than the four dimensions we currently know (X, Y, Z, time). One theory states there are 10! But the other 6 are “curled up” so small we cannot detect them. Sounds like science fiction I know, but if you read up on a little theoretical physics, suddenly you see that these guys are totally serious about this and have some very compelling evidence.

Ok back to the 124 parallel universes. Maybe in The One the 124 didn't represent all the accessible universes, but the ones that were similar enough to travel between. Or perhaps the ones where humanity evolved. Perhaps in the others the human race never existed or did not exist in a way in which we would recognize them as human. But I am digressing into debating the science fiction of the movie.

Melly brought up Hermann Minkowski, a Russian born German mathematician and physicist who taught in various Universities in Germany. He even taught Einstein! Minkowski was the first to come up with space-time. Stating that you cannot truly describe something without it's three spacial dimensions and time. Melly's contribution was Minkowski's “world-line”. According to the world-line theory everything has it own line through space and time, from the past into the future. The world-line is set, cannot be changed. Thus the time line could not branch.

This bothered me for a bit. This means no matter what happens, that was our destiny. We cannot change our world-line. But my tree still can exist. Rather than a solid line that splits and splits infinitely, it's a rope. This rope has an infinite number of stands. As time progresses further the rope unravels more and more and more. When I decide not to have that bagel for breakfast, that was my predetermined destiny, just as my parallel universes' selfs' destiny is to eat the bagel.

This has some interesting implications for time travel. I can travel back in time on my world-line but I cannot change anything. Or if I do, I was meant to do so. In either case, I cannot go back to change the results of an event. The way the future plays out will not change.
If we jumped to a different world-line in a different dimension, we couldn't change it, but our presence would be vital to that time line. So if we show up with a time machine and change the world, it'll be only in the time line because it was meant to happen. Don't forget, we have an infinite number of parallel universes so we can screw up the multiverse. For all we know an alien race some where has already gone through this, hopping from one parallel universe to the next spreading its technology and knowledge and basically mucking things up. How would we know? In our world-line we are not aware of this. It hasn't effected us, as far as we know.

The world line is interesting when you consider that we can no travel forward in time now. Since the future is already determined we could go see what we will become. If you go forward and read about your past and it says you never made it back, looks like you're stuck. Remember, you can't change the past.

Time travel is still in the realm of sci-fi, but it sure is fun to speculate on. I believe we will discover time-travel is possible, but it may not be possible in our universe. It may not be practical either. If you need a black-hole to go back for anthropological reasons I don't think many people will. It's just not that important. We don't NEED to travel through time. If anything we will want to control time so that we may be able to travel across the galaxy or to other galaxies quickly. But then we are breaking the physical laws that we know now. Oh how interesting.