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Thursday, May 03, 2007

for waswillbe reference

This is going to be a post about why time travel won't work in most cases, and it might touch on a cosmic substrate (Aether), so go to wikipedia and look at the Michaelson Morley experiment, or take your chances on reading it cold. I don't much care either way because this is more written to get it written down than to be read anyway.

Here's the scenario:
I went out for a run with some co-workers the other day. We went on an 8k loop from/to the office. In the last third of this loop there was a pond. We run once around the pond and then continue on our way. On this particular day one of my coworkers had a fire under his ass and was actually running at a pretty good pace. He was just far enough ahead of us that he could do a second lap of the pond, putting him just behind us on the straight home. Pretty soon after that he passed us again. At this point my competitive streak started to kick in. I thought, maybe I'll catch this guy. But then I thought, he's already done that extra loop, so in actuality I can't catch him. If we exclude the possibility of running back to the pond, my opportunity to actually catch him, to run that second loop of the pond had passed.

The options I had left to me were to

a. run up to him and be physically with him for the remainder of the run (although he's covered more ground)

b. run faster than him and pass him to compensate for that extra lap. This would physically separate me from him, might somehow compensate for the difference in "effort" we put in, but would do nothing to compensate for the difference in the amount of ground we'd covered, nor would it locate us physically in the same place at the same time.

I believe this is a good analogy for why time travel is mostly impossible, or at least only yields intuitive results. I say mostly because while my co-worker is on that second loop, and I'm just finishing my first, I still have an opportunity to follow him on that second loop. The constraint in "real life", at a particle/wave/wavicle level is that this cycle is either on the order of Planck time (Planck time: the time it takes light to traverse a Planck Length: diameter or a spherical black hole which has a Schwarzschild radius equal to it's Compton wavelength, or very small) , OR is only maintained as long as uncertainty can be preserved, which is to say, while the two things are not in causal "contact".

So, if you can imagine the duration of time while my coworker is running his extra lap until he catches us up. He has managed to stretch space, but not time. When he catches us up we're once again in causal contact, but the continuity of our shared topological history is broken. In real life this cycle takes place at least every Planck time for each Plank length, with the caveat that if the units are not in causal contact, the relationship becomes subject to the general constraints of relativity (or should I say the constraints of general relativity)

The implications (and none of them are new) are that:

a. There is an underlying substrate or Aether which I'll call here a cosmic spin network. (I don't see a need to peg this assumption to any/many/some of the results from the many many Michaelson-Morley experiments that have been run through the years. The observed digital nature of quanta of electrons which precludes an analog-continuous scale is proof enough for this laymen that there's an underlying structure. That this structure is in Planck units, a so called "natural scale" is very important to me and I think needs to be taken into consideration)

b. there's not one clock, but there are many. This dovetails nicely with Einstein's relativity. But deviates when we add the note "one at every node of the spin network" because that "spin network" assumes an underlying structure or substrate.

c. to the extent to which things are in a causal relationship, the network provides a location at a time. If you're not at this location at this time, you never will be.

d. in order for a "being" like a person to "be" they must be in causal contact with themselves and the universe around them (they're in their light cone). It's very difficult, if not impossible to alter the orientation of a light cone, so it's going to be very difficult if not impossible to get out of causal contact with something you're already in it with (i.e. to backtrack along your path to the point where you can re-run the extra loop around the pond).

e. we're doing "time travel" now, but it's a one way thing and we're in almost total lockstep with everyone and everything we can perceive (i.e. we share a light cone)

It's unfortunate, but at least credible, that using this metaphor doesn't much improve any understanding of time travel or suggest any new conclusions that can be drawn. In order to keep myself from stooping to writing pure science fiction, I'll stop now.

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