In the show, the way the sun and moon move are by Celestia and Luna moving it, but it still changes from day to night when the Princesses are turned to stone, unable to move. See more
'Scuse me! Dragon on the move! Important princess documents comin' through!
Female Pony 1
Whoa! Everypony from Manehattan to Saddle Arabia is here!
I know, filly! We almost couldn't book a stable!
Princess Twilight must have her hooves full with this giant Festival!
Female Pony 2
Are you kidding? She's smart and organized and cool under pressure! There's nothing she can't handle!
Ommmmm... Ohhhhhhh mmmmy goodness, I can't handle this! Ooh! Nothing is working! I just have to get it together! Just go in there! ...