How do astronomers explain the phenomenon of stars moving in a straight line across the night sky?

Well, honey, those stars ain't actually moving in a straight line across the sky – it's Earth's rotation making it seem that way. Astronomers call it apparent motion, 'cause it only looks like they're moving straight when really it's our little old planet spinning around like it's key lime pie at a bake-off. So next time you see those stars haulin' butt, just remember, it's Mother Earth putting on her own celestial show.