QUESTION #74

Why we can see the sunlight for over 20 minutes even after sunset?

Asked by: Joy Wing-kai Lam

Answer

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 lighting.
Answered by: Steve Story

'There must be no barriers for freedom of inquiry. There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors.'

J. Robert Oppenheimer
(1904-1966)