Question

If according to Einstein spacetime is relative & not absolute, and the order of events can change depending on the observer's frame of reference, does this contradict the idea of the Arrow of Time/2nd Law of Thermodynamics (that events must always be ordered in order of increasing entropy)?

For example, suppose from one frame of reference, there is increasing entropy in a sequence of events as time passes. But from another frame of reference, the same sequence of events is in order of decreasing entropy as time passes. Does this mean that from the second perspective, the Arrow of Time/2nd Law is violated?

Answer 1

According to Einstein's theory of relativity, the order of events can change depending on the observer's frame of reference. However, this does not contradict the Arrow of Time or the Second Law of Thermodynamics. While the perception of entropy order may change depending on the observer's frame of reference, the overall increase in entropy holds true.

Step-by-step explanation:

According to Einstein's theory of relativity, spacetime is relative and not absolute. This means that the order of events can change depending on the observer's frame of reference. However, this does not contradict the idea of the Arrow of Time or the Second Law of Thermodynamics.

The Arrow of Time and the Second Law of Thermodynamics state that entropy, or the measure of disorder, always increases in a closed system. This means that events are generally ordered in the direction of increasing entropy. From one frame of reference, a sequence of events may appear to have increasing entropy as time passes, while from another frame of reference, the same sequence of events may appear to have decreasing entropy as time passes.

This does not violate the Arrow of Time or the Second Law of Thermodynamics because the entropy of the entire system would still be increasing. The perception of entropy order may change depending on the observer's frame of reference, but the overall increase in entropy holds true in all frames of reference.