Friday, February 10, 2006

I'm No Physicist

But I think Louis Savian might be wrong about time travel.

His basic claim is that time travel is impossible. He proves this by flaunting the equation:

v = dx / dt
v = velocity
dx = change in distance
dt = change in time
Basically Velocity equals X miles per hour (or km per second, etc.).

He then "proves" that time travel is impossible with this equation:

v = dt / dt
Velocity equals hours per hour. And as we learned in middle school math, a unit of measure in both the numerator and denominator cancel each other out. So, then, Velocity would equal 1 (v = 1 / 1). "This is of course meaningless as far as velocity is concerned," Savian says. I agreed with him up to this point.

He said earlier, "When push comes to shove [proponents of time travel] will insist that physicists mean something different when they speak of motion in spacetime. Never mind that motion has always been defined as a change in position in a coordinate system. This definition of motion has not changed in millennia." I can agree that motion is defined as a "change in position." However, I believe that his assumption that motion is equal to velocity is false. To this humble layman, motion is the act of moving, while velocity is the measure of how speedy one moves. Simply, motion is a change, velocity is the rate of that change. Therefore, his equation does not disprove time travel. It only proves that a change in time cannot be measured relative to a change in time.

Let's say you get paid one dollar for every foot you walk. Your income would be measured in dollars per foot (i = d$ / dft). Now suppose someone says, "I want to measure your income in feet." (Why? Ask Mr. Savian.) So, he comes up with the equation i = dft / dft. Then he says, "It's impossible to measure your income in feet!" Duh! Because for every foot you walk, you've walked one foot. This has nothing to do with your income. Just as time travel has nothing to do with velocity.

What Mr. Savian fails to realize is that velocity is measured in dt (a change in time) because we're already time traveling (at one second per second) for whatever reason (Maybe chronologically is the only way the human mind can comprehend this "time" dimension of spacetime; but that is beyond the scope of this post.) So, in a sense, the conventional sense of time travel is actually accelerating in time (or reverse accelerating for going "back in time").

Now acceleration is probably not the best terminology because (if I remember Mr. Marley's physics class correctly) it is a function of velocity, and I've already said that velocity is not what we're measuring in time travel. However, I lack the proper terminology to deal with this concept, so I'll use "time acceleration unit" (tau) to mean the amount of time (relative to seconds) a time traveler experiences (as compared to the time that a normal, non time traveling person experiences). So, if we wanted to bring velocity back into this (a "temporal velocity" (tv)) we could say that tv = dtau / dt. A time traveler's temporal velocity equals his time acceleration units per second. So, if a time traveler wanted to experience time at five times the rate of a normal human his temporal velocity would be 5tau per second.

Therefore, time travel does not seem impossible, it just seems we lack a mathmatics for it (to my knowledge). Although, I do not agree with Savian when he says that time travel is impossible, I would say that time travel (as it is depicted in science fiction) is very improbable and impractical.

NOTE: With all that being said, am I just full of shit or what? Is there someone out there who knows a lot more about physics and mathematics than I do that could check this out. Because, while I'm confident with my own mad musings, I just kinda spouted all this b.s. out without too much thought or calculation. And I highly doubt that I could have casually thought up something that a real physicist would have over-looked.

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  1. awesome post. any time travel haikus in the works?

    I know this won't answer your question, but it is interesting nonetheless: read Light Of Other Days by Arthur C. Clarke. He posits using wormholes to see through time, even if outright time travel isn't "possible." It reminded me of Pastwatch by OSC at first but was much larger in scope. The 12,000 Days chapter and the very end were amazing.

  2. Uh...well...after reading your hypothesis, my hypothesis about a condition of considerable time is /vd = //std>.

  3. I think they're actually STIs now.

  4. in regards to looking into the future, i just watched Paycheck the other night. it was alright, i guess.


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