There's something immensely satisfying about seeing the world distorted by reflection in a sphere. All the angles seem wrong - straight becomes curved, and our perspective is skewed so that up and down become hugely important, while the centre, where we are, our usual focus, is reduced to a pinprick. But perhaps strangest of all, the horizon curls up like a grin, and that feels strange and unbalanced. We like our flat earth. When it bends, we feel small and a bit odd and out of proportion with our surroundings. But although it makes us feel a bit dizzy, we kind of like it.