4 ms·
This reminds me of the proof that there is always a point on the earth where there is no wind. This is a property of spherical surfaces: http://en.wikipedia.or
by nextstep 15y ago
This reminds me of the proof that there is always a point on the earth where there is no wind. This is a property of spherical surfaces: http://en.wikipedia.org/wiki/Hairy_ball_theorem http://en.wikipedia.org/wiki/Hairy_ball_theorem
- crazygringo 15y agoAnd some people think mathematicians have no sense of humor!
- cbr 15y agoThere is only a windless spot on earth if you take wind to mean air moving horizontal to the earth's surface. Otherwise imagine that we have wind that points north along the ground, with wind pointing up at the north pole and down at the south pole (and higher up wind comes back south).
- nextstep 15y agoThat's a good point. I think the surface you are describing (that the wind would sweep out) would be a torus. The 2-torus is "combable."