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jadrian
jadrian is offline
#12
Feb21-12, 07:54 PM
P: 143
Quote Quote by BruceW View Post
Yes, but this is not how time is defined in a frame of reference. When we imagine a frame of reference, we can think of an instantaneous moment in that frame of reference. And there are clocks with dials at each point in space. So the time at each of those locations is the instantaneous reading on each of the dials. It doesn't matter that an observer could not in practise know what all of these dials are saying at that instantaneous moment.

This is the idea in special relativity that we have a rigid spacetime coordinate system that extends throughout space. And we define far-away events by a time and position, even though we were not there when the event happened. How is this theory useful? Well, for example, if there was a solar flare on the sun, and we already knew the sun-earth distance, then we can calculate the time difference between when the solar flare happened and when we received the light from it. (By using the fact that light travels at c). So in this case, we have 2 events, event 1 is when the solar flare happened on the sun at time t1, and event 2 is when the light reaches us at time t2. So you can see that we define the time at which the solar flare happened on the sun, even though we were not actually there.
i have a deep problem with this. i believe the solar flare happened when you saw it.