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Spatial dependence of time 
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#1
Feb2112, 01:58 AM

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I heard that the lorentz transformation for time means that time depends on the space.(I'm only talking about special relativity)I wanna know is there a explicit relationship between time and space in special relativity?
thanks 


#2
Feb2112, 02:48 AM

P: 2,809

Yes the Spacetime interval dist^2  (ict)^2 a pythagorean distance for Spacetime measurement notice the ict term that coverts time in seconds to imaginary meters.



#3
Feb2112, 05:26 AM

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Under GR, time and space are interchangeable properties.



#4
Feb2112, 05:55 AM

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Spatial dependence of time
The version with "i" is the original one that Minkowski set forth in the early 1900s, but it's considered oldfashioned notation now. Practically all textbooks and researchers have used the version with the  sign and without the i, for fifty years or more. 


#6
Feb2112, 07:54 AM

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P: 16,983

It sounds like you want the Lorentz transform equation:
http://en.wikipedia.org/wiki/Lorentz_transformation [itex]t'=\gamma \; (tvx/c^2)[/itex] The spacetime interval and the Lorentz transform are very closely related so you can go from one to the other pretty easily. 


#7
Feb2112, 07:56 AM

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P: 3,443

In preEinstein physics, the time difference between two events would be the same for all observers, but the position difference would depend on the relative velocity of the observer. (This is the 'Newtonian relativity'). In special relativity, the time difference between two events also depends on the relative velocity of the observer. So this is why special relativity is said to bring time on an equal footing with the spatial dimensions. In your first post, you talked about the Lorentz transformation for time. Here are the Lorentz transformations (using only 1 spatial dimension, for simplicity): [tex]ct' = \gamma ( ct  \beta x) [/tex] [tex]x' = \gamma ( x  \beta ct) [/tex] where t and x are the spacetime coordinates of an event in one frame of reference and t' and x' are the spacetime coordinates according to another frame. You heard that "the lorentz transformation for time means that time depends on the space" But as you can see from the transformations, time depends on time and space of the same event in another frame. So this isn't giving an explicit relationship between t' and x'. (It just tells us how the coordinates transform when we choose a different frame of reference). 


#8
Feb2112, 10:39 AM

P: 771

No guys.I know these things.let me clarify more.
In some books,it is said that we should place a clock in every point of space.then we send light signals from one clock to others to synchronise them.but because it takes time for the light to reach other clocks,there would be difference between the time shown by clocks in different places.It suggests that the time in one reference frame is different in different places and if you think it explains why time dilation occurs.So Time in one frame should depend on the space in the same frame.But spacetime interval is just an invariant quantity not such a relationship. 


#9
Feb2112, 10:42 AM

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#10
Feb2112, 10:53 AM

P: 771

Not interchangeable nor the same thing.They are different dimensions of the manifold of our world.



#11
Feb2112, 02:17 PM

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This is the idea in special relativity that we have a rigid spacetime coordinate system that extends throughout space. And we define faraway 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 sunearth 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. 


#12
Feb2112, 07:54 PM

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#13
Feb2112, 08:06 PM

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#14
Feb2112, 08:09 PM

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#15
Feb2112, 11:30 PM

P: 771

Why do we need it to be transitive? And to you BruceW. If you study the train thought experiment(You sit somewhere near a railroad and two light signals are emmited simoultaneity from two windows of the train each one on a different side of yours and having equal distances to you.because the train is moving one reaches you sooner and so you don't say the distances are equal)I know this is not a proof or so but it suggests that It does matter that an observer could not in practise know what all of these dials are saying at that instantaneous moment. 


#16
Feb2212, 03:07 AM

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#17
Feb2212, 06:10 AM

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