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The Earth is Smoother than a Snooker Ball

Yes, it's true, amazing as it may seem, that the planet Earth is smoother than a snooker ball. Indeed, even including the Himalayas, the surface of the Earth is smoother per scale than a snooker ball!

So, if you could make a perfect model of the earth the size of a snooker ball, it would be smoother than an actual snooker ball? Yes. It's true.

Well how can that be?

OK, the highest point on the Earth is Mount Everest, which is about 28,000 feet, or 5-6 miles. And the deepest part of the ocean is the Mariana Trench, which is about 7 miles deep. So, the biggest difference is at most 13 miles. On a sphere which is 8000 miles in diameter (24 thousand miles in circumference), that's about one part in 600.

Now, for a snooker ball to be smoother than that, at a couple of inches in diameter, it would have to have no craters, lumps, or scratches bigger than three thousandths of an inch.

On inspecting an average snooker ball, it's clearly got features on its surface bigger than 3 thou'!*

So, therefore, the Earth is (per scale) smoother than a snooker ball!

The next interesting question is, if you could magnify a snooker ball up to the size of the Earth, what would the geography and landscape of it look like?! It would surely have surface features more extreme than the Himalayas and the Mariana Trench!

* a thou' is a thousandth of an inch. Therefore 3 thou' means three times as big as one thousandth of an inch. (ie of the order of 1/300 inch). Although the thou' is an oldfashioned measurement, it's a convenient size for feeler gauges and other fine measurements in engines. Maybe we should have measured the snooker ball in metric.

Incidentally, Zyra.org.uk was the originator of this page, in the Truths section, so if you see a stolen version then that's a case of plagiarism. A while ago there was an incident of such plagiarism at Yahoo, but the good news on this is that Yahoo have finally got their act together and got this (and seven other cases) sorted out! Well done to Yahoo! Now we just need them to get the search sorted out and stop banning this, the original site!