Thursday, September 20, 2007

How do I know time?

This puzzles me: If I place a treadmill in the back of a truck moving 25 mph and stand on it without turning it on, I and the treadmill would also be moving at 25 mph. Yet, if I turned the treadmill on at normal human gait (3 mph) and began walking, I would be moving at both 3 mph and 25 mph. Also, the structure of treadmill would be moving at 25 mph, but the tread would be moving at 3 mph in reverse and simultaneously 25 mph forward. I, the truck and the treadmill are also moving at the rate of the rotation of the Earth, which means we're moving at three different speeds. If I'm moving opposite of the rotation of the Earth, we're now moving at four different speeds. Thus, it seems I can arrive at my destination at four different times. I don't even want to contemplate what happens when I consider the expansion of the universe.

2 comments:

Magister P said...

My first thought is that these rates of speed are relative to some standard so that when you are referring to 3 mph or 25 mph or whatever, you are actually referring to speed within different systems. To ask the question "How fast am I going?" in scenario you imagined would produce a variety of accurate answers, each needing to be qualified. I am moving at 3 mph relative to the treadmill. I am moving at 25 mph relative to the truck, etc.

Of course, this seems like something best directed to Mr. Gibson.

Hannah said...

I agree with the above comment--time is objective and so must be treated accordingly. For example, while we have been in our "new millenium" for seven years now, Ethiopia has just entered theirs. This does not mean that Ehiopia is really further back in time than we are, but only that they recognize a different system than the Roman calander. So, in a short answer, yes you could arrive at your destination at four different times but it would be logicaly irrelevant because the true nature of the universe does not recognize time. It is only a human invention meant to aid in understanding. Ironic, since in situations like this it really complicates matters.