Interestingly, I would wonder what scientific explanation could do first. Or if I were to see something like "God's hand coming from the sky", I'd think that I'd lost my mind or either had too much to drink.
Scripturally speaking: No one can see God and live.
So that means if a person/s really did see God's hand, one/s wouldn't live to tell about it. Or, the person/s that did see this shouldn't be able to tell about it, because then that bible statement would be a lie. Therefore, that would bring into question the whole validity of the bible.