Let's Try Dropping a Bowling Ball Into the Mariana Trench

The latest hypothetical question for the What If? series by Randall Munroe and Henry Reich (previously at Neatorama) asks how long it would take a bowling ball to fall from the ocean surface to the bottom of the Mariana Trench. The trench is the deepest part of the world's oceans, and the point called Challenger Deep is around 11,000 meters or 36,000 feet deep. A bowling ball would take quite a while to sink that far. 

But wait- the real surprise here is that it might not sink at all. It might float! That depends on how heavy the ball is. Galileo told us that a hammer and a feather will drop at the same rate if you control for air resistance, like doing it on the moon or in a vacuum chamber. Apparently, physics doesn't work like that underwater, so we find out how objects of different weights would fall in the ocean. But let's don't do this, because that would be littering.