Eli5: why are the light waves bouncing off an object, allowing us to see what and where it is, only seen “directly” but aren’t seen going in every direction away from the object?

Question

Tough question to articulate, but hopefully very answerable.

Presumably, from whatever angle imaginable away from your hand, as an example, there is information in the form of [light waves?] about the shape and color of your hand, but that information only becomes relevant from your unique perspective. “Directly” let’s say. You can’t see the “data”/lightwaves being sent in every other possible direction away from the hand, even though no matter where you are in the room, assuming nothing obscures your view, you could see the hand.

In: Physics

Answer 1

Because our eye can only see light that hits it.

Saw this comparison in a similar thread and it makes a lot of sense:

Imagine you have food in front of you. Now pick it up and move it into your mouth so you can eat it – do you gain nutrition from that food that *entered your mouth*? Yes (assuming it had nutrition to offer).

Now take that same food, and move it past your head without letting it into your mouth – do you gain nutrition from that food *not* entering your mouth? No.

Your eyes work similarly, they only react to light that enters the eye and do not react to light traveling on a path that doesn’t enter your eye. A glowing object is different in that it continuously emits light that *does* hit your eye as it travels…but individual light photons do not emit more light photons in all directions.