Hard to explain question but, is it possible to have a code in PHP perhaps (or something different) for Flash that when it get's to a certain time the image will change?

For example I want to have a Flash movie on the side of my website with a sun shining when it's day-time, for ex. like 6 am - 7 pm, and change into a moon a star scene from 7 pm til 6 am.

I would really like to do this but no idea if it's possible tehe. Please help ;D <3