On: The hairy ball theorem

[pixcavator]

>the earth would always have at least one circular wind pattern

Not necessarily. There may be two stationary points and all winds blowing from the first point to the second. Nothing circular...

[DougBTX → pixcavator]

Hopefully that won't last too long, or all the air on the planet will end up at point two! (A constant amount of non-compressible air was assumed in the example.)