New Criticals

A high energy photon, say with an ultraviolet wavelength that is energetic enough to cause a genetic mutation, can be thought of as a concentration of energy in space relative to lower frequency, thermal radiation. When it hits the earth’s atmosphere, it suddenly encounters a dense fluid (air is a fluid--you spend every moment of your life immersed in a fluid) compared to the relative emptiness of space and it collides with the molecules in the air. Of course, the photon is really a wave being scattered but to intuit the statistical counting process involved I think it’s easier to visualize a “packet of energy.” Each random interaction diminishes in some way the energy of the “packet,” but energy is not lost--it is merely spread out, becoming less concentrated. When radiation is diffuse enough that it can no longer excite electrons in the bonds of organic molecules we call it heat instead of light, but these words are defined relative to the bond energy of organic molecules. However, electromagnetic radiation is an expression of the same fundamental interaction whether or not it is concentrated enough to excite the pigments in your eyeball and thus be “seen.”

So the more the wave is scattered the less energetic “it” becomes, or using the particle metaphor, the more the photon bounces into molecules, the more it is broken up into smaller “pieces.” This “increase in the number of pieces” is my loose, everyday rendering of the increase in entropy due to increasing available quantum microstates. If “quantum microstates” sounds like mumbo-jumbo then I promise you that nothing essential is missing from your statistical understanding of what’s happening if you simply imagine a solid chunk of energy breaking into small bits of energy and thus increasing the number of ways to arrange the pieces. This may, however, be very misleading when trying to understand the wave nature of nature but that’s language for you, no single metaphor lets you tell it all.