I believe what he is getting at is that there is a limit on certain space times that are accessible to a given observer. Imagine an alien race (or a point in sp

I believe what he is getting at is that there is a limit on certain space times that are accessible to a given observer. Imagine an alien race (or a point in space) that is 10M light years away. We want to obtain information about the current state of that point in space. Unfortunately, the next X years of that section of space (I don't know enough relativity to calculate X) is totally inaccessible to us. There is absolutely nothing we can do to obtain information about the current state of that point until X years has passed.