Question

Explain how two events can be simultaneous in one reference frame but not simultaneous in another frame.

Answer 1

Explain how two events can be simultaneous in one reference frame but not simultaneous in another frame.

Two events that are simultaneous in one reference frame (S) are not necessarily simultaneous in another reference frame (S’) moving with respect to the first frame.Whether or not two events in different places happen at the same time has no absolute meaning - it depends on the frame of reference in which the events are described.

If the two events occur at the same point, then the events will occur simultaneously in all frames of reference.

Two events that are spatially separated in one frame of reference

• will be co-located in another frame of reference and not simultaneous in any frame if the interval is time-like.
• will be simultaneous in another frame of reference and not co-located in any frame if the interval is space-like.
• will be neither co-located nor simultaneous in any other frame if the interval is light-like.

We know that, two events that are simultaneous in one reference frame are in general not simultaneous in a second frame moving relative to the first. "Simultaneity" is not an absolute concept but rather one that depends on the state of motion of the observer.