frames of reference

[Guest mikaela]

Two events occurs at the space point in a particular frame of reference and are simultaneous in that frame. Is it possible that they may be simultaneous in another frame?

[timo]

Actually, they are simultaneous in any frame of reference.

Reason: If the two points have the same space and time coordinates, they are the same point in 4D. There´s only one tuple of coordinates for any one point in 4D in any coordinate system.

[Johnny5]

Two events occurs at the space point in a particular frame of reference and are simultaneous in that frame. Is it possible that they may be simultaneous in another frame?

 

I suppose you are treating events as four tuples. For the sake of simplicity, suppose you are using rectangular coordinates to describe points in this specific frame F. So, at moment in time T in frame F, a space point (X,Y,Z) is represented as a four tuple as follows:

 

Event: (X,Y,Z,T)

 

Suppose that an electron is located at (x1,y1,z1) at moment in time t1 in frame F, then it moves somplace else, and later returns to its starting point.

 

We have:

 

(x1,y1,z1,t1)

(x1,y1,z1,tn)

 

These 'events' are different simply because not (t1=tn), but they did have the same space-point as you called it.

 

But if TWO events are simultaneous in frame F, then regardless of their respective space-points, their time-points are identical. So in order for them to really be TWO, they must have different locations in the frame.

 

But I think what you have described is this:

 

Event1: (x1,y1,z1,tn)

Event2: (x1,y1,z1,tn)

 

Therefore, event 1 = event 2, they are not different.

 

You ask if it is possible that they may be simultaneous in another frame, but they are really just one, so I'm not sure what you are asking.

 

If indeed you mean two different events which are simultaneous in F, then I suppose your question is this:

Given two events which are simultaneous in frame F

 

Event1:(x1,y1,z1,t)

Event2:(x2,y2,z1,t)

 

Not (x1=x2 and y1=y2 and z1=z2)

 

Is there any reference frame other than F, in which these events are simultaneous?

 

I need to ask you a question. Do you assume that the speed of light is the same in all inertial reference frames?

[J.C.MacSwell]

Two events occurs at the space point in a particular frame of reference and are simultaneous in that frame. Is it possible that they may be simultaneous in another frame?

 

Only if the two frames are not moving wrt one another.

 

Edit: I already think this is wrong, it depends on the spatial alignment of events and the direction of relative movement of the frames also.