It's like astronomy: you can look up and see it all at once, but what you see "now" is the just-arriving view of what happened minutes or billions of years ago.

It's like astronomy: you can look up and see it all at once, but what you see "now" is the just-arriving view of what happened minutes or billions of years ago. Getting a grasp on what constitutes "now" can be rather distressing when you really think about it.