Bright green ball falling quickly from the sky.

We saw a large ball of light falling from the sky. It was much, much larger than a star and extremely bright. It was green, and then changed into a yellow color, then red, and back to green. It was heading straight down, so once it met the horizon we could not see it any longer. The sighting only lasted about 5 seconds.
We are both college students who have seen other unidentified objects in the sky before, but have not seen one that was this out of the ordinary, or this large and bright.