"Combustible" doesn't matter. Nor, really, does "impact" in the sense of one objectively solid body striking another objectively solid body. Think Chelyabinsk -

"Combustible" doesn't matter. Nor, really, does "impact" in the sense of one objectively solid body striking another objectively solid body. Think Chelyabinsk - the actual "thing hitting the ground" impact was a relative nothingburger, and all of the excitement happened at altitude.