Is light from the sky polarized?

Yes, light from the sky is partially polarized due to scattering by atmospheric particles. When sunlight interacts with molecules and small particles in the atmosphere, it becomes polarized at certain angles. This effect is most noticeable when the sun is at a low angle in the sky, such as during sunrise or sunset, and can be observed using polarizing filters. The polarization is also responsible for certain visual phenomena, such as the blueness of the sky and the appearance of glare.