LIGHT PASSES THROUGH OPAQUE MATTER

Omar A Piazza Hernandez

It has long been believed that rays of light bend around objects and, of course, pass through them if they are clear, but new research has proven that when it comes to opaque surfaces, light can indeed pass through. Most people learned this in high school and assumed that that was the main difference between clear and opaque surfaces, but now that notion is starting to get heavy scrutiny.

When light passes through an opaque object, most of the energy usually bounces around the surface of the object or is scattered back to the source, while very few light particles actually make their way through. It is kind of like putting grains of rice through a strainer, where few grains make it to the other side and most of them get stuck in the strainer. Using special filters in a new experiment carried out in the Netherlands by two scientists named Ivo Vellekoop and Allard Mosk, most of the radiation actually passed through a layer of milk, illuminating the other side.

Scientists used cow’s milk for example because it had been thought that when light strikes an opaque substance like milk, it scatters around instead of penetrating it completely. In new studies, that has not been the case. The filters they used make the light particles behave differently, whereas in a normal, controlled scenario light would strike opaque matter in an orderly fashion, these new filters actually disorganize the ray of light and distribute it unevenly across the surface. The randomly distributed particles then propagate through the object at a higher rate than orderly rays, although some still bounce back to the source. This new technique, although very rarely seen in nature, questions the modern definition of opaque substances.

The experiment had been years in the making, but now these remarkable conclusions have been confirmed. Although further optical experiments are underway for theorists to find a catalyst for these studies, the base work is mostly done. Scientists believe that they could apply these new findings to technology. Whether it is sunglasses or paint primer, the immediate benefits of such every day applications is obvious. Imagine a greenhouse built with opaque panels, something like wood or concrete, but as you open the door you find plants growing in its seemingly dark interior.

I found this story interesting because it directly challenged my knowledge of light as I know it. In high school, “clear” meant “transparent”, which would allow light to easily penetrate it, and “opaque” meant “not transparent”, which obviously would have the opposite effect. I find it amazing that such a theory had not been developed before. I would also love to find out if there is one true opaque substance, which would be 100% impenetrable to light even under the toughest experiments. Such a material could really have its uses in technology, although none pop into my mind at the moment. Still, this news attracted my attention because of how simple it sound, yet how significant the discovery is.