Another way to think of it is this: When you put your eye somewhere, you can see everything around you: houses, trees, cars, people. Why? Because of the light that’s coming right here into your eye. Now if I move out of the way, there’s still light going through this little area in space, right there.
And it must contain all the information of the scene - the complete detail and color and everything - because otherwise I wouldn’t be able to see it when I put my eye there. So that means that here, and here, and here - every little area in space - there is in the light all the information about the complete scene of where the light is coming from, whether it’s being reflected or emitted from a lightbulb or whatever, even from behind you. If I turn 180 degrees around, I can see all the scene that’s over there, too. And it’s all contained in the light. The light that’s invisible. you can’t see it as it passes through this little area in space. All that information is encoded in the light, in the frequency - the different colors - in the brightness and in the direction it’s traveling. And it’s moving through there pretty fast - at 186,230 miles per second, in fact.
bob miller’s light walk