Neil deGrasse Tyson says that because the earth has been spinning (at 1000 mph for more than four billion years), the earth is not actually round but has become an oblate spheroid and, more accurately, is a pear shaped object.
Neil interview:
'The Science' says that even though the world looks round from all the photographs taken from space, if you zoom in real close - to the pixel level - you can show oblateness. My problem is that no actual photograph exists that isn't simply a composite. So using a fake image as a proof is just sad.
Also, if we are on a pear shaped object wouldn't that mean we're actually wobbling through space and not rotating? With that kind of never ending lopsided motion wouldn't we all be sick?