The studies of the evolution of the eye have shown that the eye has independently evolved in other species over 40 times(ga68)
The studies of the evolution of the eye have shown that the eye has independently evolved in other species over 40 times(ga68)
Your eyes do emit photons, as part of an exchange with the photons radiated by a source of light; but like the paths involving photons bouncing at crazy angles off a mirror, they do not show up in the everyday world because of the way the probabilities cancel out(sk107)
In some animals a layer of connective tissue so dense and shiny bounces photons right back through the retina a second time, doubling their rate of capture (a useful trick for night vision)(sod8)