Even if the object does not shine by itself, why can we see it?
Eye is the organ that feels light. Even if the object does not shine by itself, why can we see it?
Most objects can reflect light without emitting light themselves. Light reflected from rough surfaces such as paper or wood is scattered in many directions. The eyes recognize this diffuse light. Therefore, people can see objects with a little light.
To view objects in detail, the light originating from one point on the object must be accurately gathered at one point on the retina. If the lights are scattered all over the retina, we will lost the focus.
In order to gather the emitted light into one point of the retina, there must be a device that acts as a convex lens. This is the cornea and lens of the eye.