Light on clouds

The other day I saw a book which S has got to help her with her thesis. The title is "Catching the light". I read the first chapter which is a sort of introduction. The author introduced some interesting concepts, not the least being that light needs to hit something for light to be seen. I guess that what this means is that we see the light of day because photons of light from the sun hit particles in our atmosphere, and that is what we see; the particles, even though we say that we see light. 

Further on in his introduction the author writes about the difficulty seeing experienced by those who have had their sight restored (e.g. by way of removal of congenital cataracts) after years of blindness. Because the optic cortex has not been stimulated by input from functional eyes at the right time, it has not developed and the person cannot "see", despite fully functional eyes, optic nerves and optic cortex.

I did see the light show created by the sun interacting with the clouds, and stimulating my cortex. It was typically grand.