And There Was (Something We Call) Light

courtesy wallpoper.com

Ages and ages ago ~ I must have been about 10 ~ I read a book in which I came across a question that really intrigued me: How do you explain light to a blind person? I don't remember whether there was an answer, or even an attempt at one, but that question has stayed with me and resurfaces occasionally. Most recently, it did so when I saw this incredible article on the subject, on the occasion of the International Year of Light, as 2015 has been designated by the U.N. Long story short, it's a form of radiation, specifically, electromagnetic radiation, and it is carried by electromagnetic waves (it was James Clerk Maxwell's calculations that showed this). In this way, light is very similar to X-rays and radio waves ~ it's just a matter of the wavelength. But here's the interesting part. Within these waves, light travels in little energy bundles (which Einstein called photons), and this means that light is actually a particle. It behaves as both a wave and a particle at the same time. While this may sound confusing, it's actually quite a useful discovery, as we can ~ and do ~ take advantage of its duality in the ways we harness it. As explained by the Max Planck Institute's Eleftherios Goulielmakis, "We can control the light, and through it we can control matter": http://www.bbc.com/earth/story/20150731-what-is-a-ray-of-light-made-of