Why we can see the sunlight for over 20 minutes even after sunset?
Asked by: Joy Wing-kai Lam
For the same reason that when the sun is overhead, you can see the sky: refraction.
When passing through mixtures, light is scattered in various directions. After the
light from the sun no longer directly meets your eyes, it is still passing through
miles of atmosphere over your head, and being scattered all around. It is indirect
Answered by: Steve Story
'The mathematician's patterns, like the painter's or the poets, must be beautiful; the ideas, like the colours or the words, must fit together in a harmonious way. Beauty is the first test: there is no permanent place in the world for ugly mathematics.'