This is neat. It reminds me a bit of part of my Conky setup. It looks like this: https://imgur.com/zi1Ub. It's not as accurate, but it gives me an idea of what time of day it is everywhere.

I have a cron script that runs every hour that pulls in sat images of cloud cover, the earth, and then the daylight lines and composites them together with imagemagick. I got the script from a lifehacker article where they used it for wallpaper.