MadSci Network: Physics |
This is a common misunderstanding. Special Relativity (SR) tells us how the measured "distance", both in space and time, between two events changes between inertial reference frames. An inertial reference frame is defined as one where the observer is moving with a constant velocity, not speeding up or slowing down. Observers moving at different velocites relative to one another will measure *different* space and time intervals between events. Let's examine the case relevant to your question. Here, we'll take the two events to be ticks on the second hand of a watch. If you are moving relative to me with uniform speed, by my watch it will take longer than 1 second for the two ticks to happen on your watch. However, this phenomenon is *relative*, and you will see the same thing, i.e., two ticks on my watch take longer than 1 second measured on your watch, by exactly the same amount. This may sound paradoxical, but given the assumptions of SR, it's the only way it can happen and make sense (for more info, see link below). Anyway, the point is that if you are moving relative to me, I see that all physical processes occur slower in your reference frame, and you see the same for me. Now, the amount by which one of us sees things slowed down in the other's frame has to do with the relative velocity. The closer our relative velocity is to the speed of light, the slower we see things happening for each other. If you take the relative velocity all the way to the speed of light, what you calculate is that it would take an INFINITE amount of time for anything to happen in the other guy's reference frame, relative to you. However, this limit is really only mathematical, since we can't ever actually travel at the speed of light relative to one another, etc. So, because an object is moving, it's "passage through time" is not increased. Rather, an observer moving relative to that object views physical processes related to the object as being slowed down. The object itself moves with some constant velocity, and for a given observer, takes the usual amount of time (distance/velocity) to get from point A to point B. This is true even for photons, moving at the speed of light. For more info, see the sci.physics.relativity FAQ, located at http://math.ucr.edu/home/baez/physics/relativity.html.
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