Here's another visualization based on this one:
https://www.windyty.com
This is also a cool demonstration of the Poincare-Hopf theorem (the "hairy ball theorem", more colloquially), which states that the sum of the indices of a vector field equals the Euler characteristic of the surface the field is defined on. In this case, with a sphere, that Euler characteristic is 2 (it's the same as for a cube, where you can use Euler's formula V - E + F), which means the sum of indices is nonvacuous, i.e., there is at least one zero point of the vector field.
