........But when the particles move in parallel with the field lines, they behave very differently, with the turbulence evenly spread, like crinkly mountains that extend as far as the eye can see (see diagram). "It's a different kind of physics," says Chapman.

What's more, that crinkliness is constant, no matter how much you zoom in or out on a patch of wind, making its behaviour fractal (The Astrophysical Journal Letters, doi.org/skf). Snowflakes, shorelines and most recently black holes (see "Turbulent black holes grow fractal skins as they feed") also exhibit such fractal behaviour.....