What surprised me was that with enough exposure time, the sky was blue, not black (I’d also note that this being 2008, the color change cannot be attributed to algorithmic processing of the image in camera).
If that was surprising to you, have you seen full moon long exposure images? It looks just like the day time. I have long exposures during a full moon, where at first glance it just looks like a random daytime shot, but when you look more closely, you can clearly make out the stars/milky way/etc. The water also has that telltale smoothing. I actually enjoy this style of photography, but it is so constrained by the short availability window. Essentially, it's a golden hour type thing. Once the moon gets too high, it's just overpowering. So just before/after moon rise is best.
This shouldn't be that big of a surprise. The atmosphere is still there, it does the same thing to incoming light that it always does, your eye normally can't see it because the total amount of light drops the color filtering below the detection threshold of a human eyeball.
It’s the sort of surprise that seems obvious once you see it, but isn’t so easy to predict. Without this experience, most people would guess that in a long exposure picture of the night, you would see a black sky with perhaps brighter luminaries and more easily seen objects on the ground, not a blue sky.
What surprised me was that with enough exposure time, the sky was blue, not black (I’d also note that this being 2008, the color change cannot be attributed to algorithmic processing of the image in camera).