Demonstrates the rules of perspective, shows footage of sunset taken by soldier in Afghanistan (over very dry desert) showing sun shrinking as it recedes (can't happen with 93-million-mile-away huge sun),
Unless viewed by a camera. It's an optical illusion. There's my hint, and since you are so smart, I'll leave the rest to you to figure out as to how the illusion works.
also shows the image of the apparent sunset zoomed in on to show that it's still well above the horizon line.
So? He couldn't wait for the sun to actually set? It plays out nicely as another illusion.