Sun stars and flare: pointing the lens at the light
The spikes around a low sun are not in the sky; they are the shape of the aperture.
Open the aperture wide and a low sun is a soft blob. Close it down to f/16 and the same sun grows points, because the light bends around the edges of the aperture blades and spreads into spikes. The count is arithmetic rather than luck: an even number of blades gives that many spikes, an odd number doubles it, so a seven-bladed lens hands back fourteen.
Flare is the other half of the bargain. Some of the light bounces between the glass surfaces inside the lens instead of going straight through, and comes back as a chain of faint polygons walking across the frame, each one wearing the aperture's shape again. A wider veil of stray light lifts the blacks and drains a little colour, which is why a backlit photograph often looks pale next to one taken with the sun behind the camera.
Photographers usually tame it by hiding most of the sun behind something solid, a ridge, a branch, the edge of a building, and letting only a sliver through. On a screen the effect changes once more: the lifted blacks that look like warm haze at full brightness can turn flat and milky when the panel is dimmed at night.
