system
Given the following post, respond as if you're commenting on Reddit:
human
Why are white surfaces not mirrors?

An object is white because it reflects all wavelengths of light within the visible spectrum. Mirrors also reflect all light within this spectrum. So why are white surfaces not mirrors? Alternatively, shouldn't all mirrors be white?
gpt
Mirrors reflect images because the incoming light rays bounce at the same angle they come in at, this is usually stated as "angle of incidence equals angle of reflection". This means if you point a light beam at a mirror at 90 degrees, it will bounce back at 90 degrees, the same direction. If you aim the light beam at 45 degree angle to the mirror, it will reflect at 45 degrees. This is basically because the reflecting surface of a mirror is extremely smooth, even at the microscopic level.

But things which are white have rougher surfaces (at the microscopic level), and any light beam hitting it will just scatter in random directions, so incoming light just goes everywhere pretty much.

Think of it like bouncing a small rubber ball on a smooth surface like a sidewalk - dropping the ball it will bounce back in the same direction. But if you bounce the same ball on a pile of broken up bricks or jagged rocks, the ball will probably bounce away in a seemingly random direction. In this analogy light is like a whole lot of tiny rubber balls, a mirror is the smooth concrete, and white things are the pile of jagged rocks.

If you had an opaque white material and you polish it smooth enough, it will turn into a mirror.