I think i get it. The difference come when they move relative to each other. This is why we can't have an absolute time ? Thanks for the response.Ibix said:You mean that A and B are at rest with respect to one another? In that case no, if the impacts are simultaneous for one then they are simultaneous for both (although strictly the presence of gravity makes this more complicated, we can easily arrange things so we can neglect that). B will certainly receive light from the impacts at different times, but relativity is about what happens after you correct for the travel time of light. Observers in relative motion turn out to get different results if they use the same procedure to correct for the travel time, but observers at relative rest (like your A and B) get the same result.
I assume you've heard of Einstein's train thought experiment? The point is not that the observers receive the light at different times, but that they put different interpretations on what they see.
Strictly, it's one way to show that a global notion of time is inconsistent with an invariant speed of light and the principle of relativity. You then need to go out and do an actual experiment to see if it's consistent with reality. Which we've done, and so far it is consistent.adosar said:This is why we can't have an absolute time ?
"Observers A & B: Rest & Simultaneity" is a thought experiment that explores the concept of relative motion and the relativity of time. It involves two observers, A and B, who are moving at different speeds and how they perceive the concept of simultaneity.
According to the theory of relativity, the speed of an observer affects their perception of time. The faster an observer moves, the slower time appears to pass for them. This is known as time dilation and is a fundamental principle of the theory of relativity.
Yes, two events can be considered simultaneous for one observer but not for another. This is because the perception of time is relative and can be affected by the speed of the observer. What may appear to happen at the same time for one observer may not be simultaneous for another.
The concept of simultaneity challenges our understanding of time by showing that it is not an absolute concept, but rather a relative one. The perception of time can be different for different observers, depending on their relative motion. This challenges the traditional notion of time as a universal constant.
The concept of "Observers A & B: Rest & Simultaneity" has many real-world applications, particularly in the fields of physics and engineering. It has been used to explain phenomena such as time dilation in space travel and the synchronization of clocks in GPS systems. It has also been applied in the development of technologies such as atomic clocks and satellite communication systems.