Picture two events that took place two thousands years apart (say today and Jesus' fifth birthday). Now, remember that since God is eternal he experienced infinite periods of time both before Jesus' fifth birthday and after today.
Doesn't this already raise some questions? For example, what would it mean to say that "God experienced infinite periods of time"? If God is atemporal (outside of time), he doesn't experience anything (since to experience something is to have subjective awareness of it through some temporal span), let alone anything infintely long--but suppose we grant that he does (or at least can) experience things--how can anyone, whether or not he is God, experience something that is infinite in duration? It seems to me that to "experience" something is to have finished it. I can't really say that I've "experienced" Beethoven's Fifth Symphony until I've heard all of it, can I? If I fall asleep in the middle of the first movement, I have at best partly experienced it. But I have not experienced "the (entire) symphony" itself, and if the symphony is infinitely long then I don't see how I can ever claim to have experienced it.
In some sense, though, the temporal order is all eternally present to God all at once--not in a moment, but in something less than a moment, a point, if you will, or a singularity. He knows everything about the created order not as we know, say, the plot of a movie, but in the way that we know what the color red is like when someone utters the word "red"--it is automatic, total, and instantaneous. It's difficult--at least for me--to get one's mind around that kind of awareness, and more difficult still to imagine what it must be like to be in an atemporal state. It's tempting to wonder about it, though, because we believe that when we die we will enter into Eternity. Life may seem short to us now (especially if, like me, it's already half over for you), but we are all semi-atemporal beings in the sense that our souls are immortal--they had a beginning, but they have no end (unless you think that damnation consists in the obliteration of your soul, but that is not the orthodox view).
Does this mean that there will come a time, when we experience the Beatific Vision, in which all things will be present to our awareness all at once--or at least those things that are proper objects of our (as opposed to God's infinite) intelligence? It makes my head hurt just to think about it. But it's something to look forward to, if only because I'll finally understand why mayonnaise jars are made so deep yet with such narrow openings.
(The title, by the way, is from Blake's Songs of Innocence and Experience.)