Re: Snatch the pebble from my hand, Grasshopper.

Posted by Dale on Mar 05, 2002 at 10:07

Re: The rock is younger , something permanent happened (dogrock)

They are both part of the same measurements.

Kind of. Both time dilation and shape change are related. You can use one to predict the other. The difference is that time dilation has a lasting effect on a clock while shape change does not. Neither, however, is detectable by an observer traveling at the same velocity. The electrons canít tell they are moving that fast. It is only the stationary observer who see the change.

The shape change is predicted by the time dilation. Assume a 1 foot ruler with a pen on each end traveling at speed with respect to a 2x2 foot piece of paper. If it is perpendicular to the direction of travel it makes two marks 1 foot apart. Now turn it parallel to the direction of travel and poke it down instantaneously to make two marks supposedly 1 foot apart. The stationary observer will see two marks closer than 1 foot apart because the ruler is shorter in that direction. An observer on the ruler, however, will see two marks a foot apart on a piece of paper that is less than 2 feet long because to the ruler, it is the paper that is moving. How do we get around this problem? The answer is that instantaneous isnít instantaneous to everyone.

To create an instantaneous marker first assume the ruler is back to perpendicular to the direction of travel. We set up a light source in the middle. We flash a light at the middle and when the light gets to each end we push the pen down. No problem. Since the direction of the light beams is perpendicular to the direction of the ruler, everyone sees both beams hitting the ends at the same time and the pens come down at the same time and everyone agrees they are 1 foot apart so the marks end up one foot apart.

Now turn the ruler parallel to the direction of travel. Repeat the ďsimultaneousĒ marking experiment. According to an observer on the ruler, the same thing happens. The light reaches each end at the same time and the pens mark the paper 1 foot apart. But the paper is shorter than 2 feet in that direction so the marks are closer to each edge than would be expected from a 1 foot ruler on a 2 foot paper. An observer on the paper, however, sees something very different. The light leaving the center of the ruler travels to the same speed in both directions but the rear of the ruler arrives long before the other beam reaches the front. The rear pen goes down first and then some time later (after the ruler has moved forward, the forward pen goes down. Of course the marks are closer to the edges than expected. The ruler is short but the marks arenít being made simultaneously.

I believe what I have described is far above where you were going. But that is why I have trouble with your intelligent electrons deciding on wave motions and such. Itís all relative and every electron sees what it expects to see. We are talking about a change that the stationary observer sees in a moving object but a moving observer doesnít see the same change. The poor electrons are ignorant of the situation.

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