@DirtySchizo even if it is merely dropped from great height and not propelled like a missile it would certainly be observed and captured on video. Maybe? Also if it were merely dropped from above the stratosphere - hell above 2,000 feet it would be extremely difficult if not impossible to do so with any degree of accuracy. A vertical drop - accelerated only by gravity itself it is not possible to guide the thing to its intended target. Even with highly sophisticated bomb sights it is for all practical purposes impossible to merely drop (and not use any laser guided system or some such) it with any assurance of strking the intended target and NOT some densely populated area. So to me "rod of god" sounds fictional.
I'm not arguing that the explosion in Beirut was accidental - I believe it was fully intentional and that we shall never know who did it or why.