# What are causally disconnected events in special relativity?

I am learning that the order of causally disconnected events is the same for every observer regardless of your point of view, but it's beyond my comprehension what exactly it is? Are there real time examples? here is the diagram from the you tube video.

for observer A event order is 1,2,3 for observer B event order 2,1,3 but 2 is always happening before 3 for both observers because 2 is causally disconnected. In order to change the order of 2 we have to travel faster than speed of light.

• Possibly related: Why is causality preserved in special relativity? – Jonas Feb 5 at 15:21
• I think you are mistaken. The order of causally disconnected events may not be the same for two different observers. As they are causally disconnected, this is no paradox. The ones which are causally connected are the ones who preserve the order. Use the diagram in your picture and try to find a reference system in which 2 causally connected events A $\rightarrow$ B appear as B $\rightarrow$ A. You'll find that that observer must travel at $v>c$. – Pablo Feb 7 at 21:50