My Common Sense vs your science. Afternoon Session.

I’m curious to know why the thing that looks like the Sun, that seems to radiate heat like the Sun, that casts the Moon’s shadow onto Earth during an Eclipse like the Sun, that radiate light like the Sun, and it even has me fooled, as i on occasion have found myself thinking it’s the Sun (Silly. I know). Any ideas why that thingy stayed behind when the Sun moved?