I’m not sure how true that is. It’s smoother than anything else, but the degree to which it is oblate makes it less spherical than, say, a pool ball, doesn’t it?
The planet Earth has a rather slight equatorial bulge; its equatorial diameter is about 43 km (27 mi) greater than its polar diameter, with a difference of about 1⁄298 of the equatorial diameter.
It’s not something so outwordly small that people couldn’t do better, but it’s better than bearing balls or a spherographic pen tip. It’s way, way smaller than any deformation you will find in a game ball.
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.
I’m not sure how true that is. It’s smoother than anything else, but the degree to which it is oblate makes it less spherical than, say, a pool ball, doesn’t it?
It’s easy to check in Wikipedia https://en.wikipedia.org/wiki/Equatorial_bulge:
The planet Earth has a rather slight equatorial bulge; its equatorial diameter is about 43 km (27 mi) greater than its polar diameter, with a difference of about 1⁄298 of the equatorial diameter.
It’s not something so outwordly small that people couldn’t do better, but it’s better than bearing balls or a spherographic pen tip. It’s way, way smaller than any deformation you will find in a game ball.
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.