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Old 05-22-2009, 12:52 AM
The Controvert The Controvert is offline
Join Date: Sep 2001
Location: Austin, TX
Posts: 3,763
Just how smooth is the Earth?

According to this post, the smoothness of the Earth is compared to ball bearings and billiard balls.

Yet, I have a hard time believing this statement. The human finger is pretty sensitive to small imperfections, if I ran my finger over a perfect scale replica of the Earth, would I or would I not be able to feel the mountains and other features?

How large would the replica need to be before this happens? Or how small does it have to be in order to feel perfectly smooth to the human finger?