Wow, that’s incredible. I thought for sure it would be a difference of something like 2–5%. But to actually be barely one third of one percent‽

Out of curiosity, I looked it up. Officially a pool ball is 57 mm diameter ± 0.127 mm. If we add and subtract that to different axes of the ball, that’s actually surprisingly close, coming in at 0.44% bulge, not a whole lot more than Earth’s 0.34%. It’s actually closer than I expected.