The reflection of light is responsible for how we see the entire world.
But, the way we think we see the world is not the way the world really is.
We see objects because light reflects from them and then enters our eyes.
But then, why don’t all objects look like mirrors?
An object does not necessarily have to be flat to be a mirror.
Nor does an object have to reflect all the visible colors of light to be a mirror.
Red mirrors reflect red light,
yellow mirrors reflect yellow light,
and violet mirrors reflect violet light.
But how is this different from red, yellow, and violet objects
that do not behave as mirrors?
White objects reflect all the visible colors of light,
but we don’t see reflections even in white objects.
What is it that makes mirrors special?
To begin, let us recall that with the exception of the second law of thermodynamics,
almost all of the laws of physics work the same way backwards in time
as they do forwards in time.
This means that a beam of light reflects from a mirror
at the exact same angle that it comes in.
This is because if the two angles were not equal,
it would not work the same way backwards in time as it does forwards in time.
When rays of light from an object reflect from a mirror,
the image in the mirror is where the light rays appear to be coming from.
If we have two mirrors, we will have a reflection of the reflection,
and the images are again where the light rays appear to be coming from.
There is no limit to the number of reflections we can have,
and this is why finding the exit in a maze of mirrors can be difficult.
For flat mirrors, the reflections appear to be
the same size and the same distance from the mirror as the original objects.
For curved mirrors, this is no longer true.
Mirrors can produce many optical illusions.
For a curved mirror like this one,
the images can be made to appear in front of the mirror and inverted upside down.
But what is it that makes normal objects different from mirrors?
All mirrors, both curved and flat, have a smooth surface.
So far, we have only seen examples of how light reflects from smooth surfaces.
Most objects, even if they appear smooth to us,
do not actually have a smooth surface when viewed on the microscopic scale.
In these cases, the light rays reflect in random directions,
and no reflected image can be formed.
In other words, most objects behave like shattered mirrors.
When the pieces of a shattered mirror are very tiny
and all oriented in random directions,
we are unable to see an overall reflected image.
This is a good thing, because if everything behaved like a mirror,
it would be very difficult for us to see the world around us.