From 'The Weight of Glory'

'...I am almost committing an indecency. I am trying to rip open the inconsolable secret in each one of you--the secret which hurts so much that you take your revenge on it by calling it names like Nostalgia and Romanticism and Adolescence; the secret which pierces with such sweetness that when, in very intimate conversation, the mention of it becomes imminent, we grow awkward and affect to laugh at ourselves; the secret we cannot hide and cannot tell, though we desire to do both. We cannot tell it because it is a desire for something that has never appeared in our experience. We cannot hide it because our experience is constantly suggesting it, and we betray ourselves like lovers at the mention of a name.....
.....we remain conscious of a desire which no natural happiness will satisfy. But is there any reason to suppose that reality offers any satisfaction to it? "Nor does the being hungry prove that we have bread.".....'
-C.S. Lewis

I love this quote from C.S. Lewis. Have you ever felt a swell of longing, the object of which is so elusive that you can't put your finger on it. Perhaps you feel it when you see the sun setting beyond the mountains. Or maybe it wells up when you see a child smile or hear her laugh. It comes knocking at unexpected moments when I'm driving through aspen groves or listening to a choir sing.

Carl Sagan once said something to effect of (forgive my paraphrasing), "...We get the sense that we have fallen from a great height."

Even someone who doesn't believe in God is well aquainted with that feeling. I believe it is at the core of who God made us to be. It's part of what draws us to him. He knit into the fabric of our hearts the capacity to feel overwhelming desire in order to demonstrate his glory and cause us to believe in perfection, eternity, fellowship with Christ, as John Eldredge would say, "man fully alive" and "the restored heart." As C.S. Lewis would say, it's "Heaven."