If you’ve ever found yourself surrounded by numerous mirrors, most likely in an elevator or bathroom, the effect is that your reflection appears multiplied onto each opposing mirror. If you peer into one, it seems as if you can see yourself reflected on and on and on, until the image is too distant to see unaided. This effect is known as the infinity mirror, caused by a beam of light bouncing back between two parallel reflective surfaces.
But do these reflections actually go on forever? Technically, if the mirrors were entirely perfect and reflected all of the light that reached them without absorbing any of it, they would theoretically produce an infinite number of reflections – though you’d need specialist telescopic equipment to help your eyes resolve the ever-diminishing images.
In the real world, however, all mirrors have tiny imperfections in their silver and aluminum coatings. This results in a small amount of the light's energy getting absorbed with every reflection (sometimes as much as 10%), darkening the image over time. Eventually, the remaining light is absorbed and the repeating reflections become too dim to see, ultimately fading into invisibility.
Gazing into infinity:
- No mirror is able to reflect 100% of the visible light that strikes it. Even the very best mirrors will absorb a tiny amount of visible light, though they may be able to create thousands of reflections before becoming too dark.
- High-quality mirrors with minimal imperfections have numerous scientific applications, including helping the cells in solar panels absorb light and generate electricity.
- Iron oxide is a common impurity in mirror surfaces. This gives the image a very slight green tinge, which gradually darkens across multiple reflections.
