JJ Naas is right. The sun's rays move more to the red end of the spectrum when it is closer to the horizon...the same happens with the moon. I've been on a plane and seen a moonrise before--it was practically blood-red, it was cool.
Which reminds me: technically, in Dragen's picture, it shouldn't appear to be the middle of the night. It should appear to be just after sunset. That's because in the picture, there's a full moon that has just risen. Full moons always appear directly opposite the sun, so that means that the sun should have just set.
[end astronomy rant]