We heard a low intermittent unexplained rumble then a bright fireball took off headed away from us.

We heard a rumbling noise that we couldn't explain because the sound was not moving and was unlike anything we had heard before. It was an intermittent rumbling noise, almost like that of a rocket engine, but we checked, and there were no rocket launches today. Then a fireball-shaped bright light appeared over the horizon and took off, moving very quickly away from us over the horizon. The light then quickly either went out of view or turned off because just as quickly as it appeared, it went away. The rumbling noise then continued for a few seconds and then stopped.