It's not another photon created, it bounces off the side of the wall and reaches our eyes. So a reflection. It's the same light from the sun it's just that it's been mirrored and reflected a lot of times thus it reaches everywhere. But didn't AsiJu already determine that photon is a sort of energy but with no mass. It's an energy of its own? Damn I love physics, The explanation of the universe (in our own limited understanding). XD http://en.wikipedia.org/wiki/Andromeda_Galaxy#mediaviewer/File:WISE-_Andromeda.jpg Look at the picture guys and think of all the civilizations there.