I was in my back yard smoking a cigarette when a glowing yellow sphere appeared suddenly and rapidly descended horizontally in a manner similar to a "shooting star". It was several times larger than any star, and left no trail. As it fell, it expanded to at least twice it's original size. This led me to believe that it was indeed no shooting star. It then disappeared as suddenly as it appeared. It made no audible sound and was presumably a considerable distance away from where I was standing. The whole event was less than 5 seconds in duration. My first impression after the event was that I had witnessed something other than a meteorite, comet, etc entering the atmosphere and being incinerated as it did so.