Red is the rarest hair color, but to understand why that’s the case, you need a basic grasp of the science. There’s a lot ...

Nocturnal animals tend to have proportionally bigger eyes than humans do. They also tend to have pupils that open more widely in low light. So, at the outset, nocturnal eyes gather more light than ...

WE have shown 1 that the impression of brightness produced by a light ray which forms an image on a fixed area of the retina depends in high degree on the position of entry of the ray in the eye ...