In Modern Physics class I remember it was said that two events can be simultaneous, but they might not be simultaneous to all observers (depending on their speed and possibly something else). It was my gut reaction to conclude that the events are either simultaneous or not, and that whether they
appear to be simultaneous is the thing that differs between observers. But it turns out that the
actual simultaneity of the events (not just the appearance of such) is what differs from observer to observer.
Wikipedia article on the topic. One of the weirdest physics concepts I've heard of.
So I wonder if this means what age you see someone link to depends on how fast you're traveling as you watch them link?
