So I’m standing in a field just north of Taos, New Mexico taking my umpteenth sunset shot and I finally get to wondering – beyond the smoke or dust in the air, what is it that causes these red sunsets?
What makes a sunset?
A little online reading and I come up with the simple explanation that the red hues we get in these dramatic New Mexico sunsets are caused by the scattering of light by air atoms and molecules (yes, I’m vastly over simplifying it, otherwise I wouldn’t understand it myself).
This is called Mie Scattering
“Mie scattering occurs when the particles in the atmosphere are the same size as the wavelengths being scattered. Dust, pollen, smoke and water vapour are common causes of Mie scattering which tends to affect longer wavelengths. Mie scattering occurs mostly in the lower portions of the atmosphere where larger particles are more abundant, and dominates when cloud conditions are overcast.”
The blues and violets in the sky however is caused by Rayleigh Scattering. Now that is:
“the elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the light. The particles may be individual atoms or molecules. It can occur when light travels through transparent solids and liquids, but is most prominently seen in gases. Rayleigh scattering is a function of the electric polarizability of the particles.
Rayleigh scattering of sunlight in the atmosphere causes diffuse sky radiation, which is the reason for the blue color of the sky and the yellow tone of the sun itself.
Scattering by particles similar to or larger than the wavelength of light is typically treated by the Mie theory, the discrete dipole approximation and other computational techniques. Rayleigh scattering applies to particles that are small with respect to wavelengths of light, and that are optically “soft” (i.e. with a refractive index close to 1). On the other hand, Anomalous Diffraction Theory applies to optically soft but larger particles.”
So there you go. Something to think about when you’re photographing (or just plain enjoying) an awesome sunset on your travels.
Now that summer is coming to an end and these amazing August sunsets are at their best, I’m thinking about winter. No, I’m dreading winter. It is the one season I can’t stand.
The thought of the cold and dark have me thinking back to the winters (and sunsets!!) I’ve spent on a Mediterranean beach and it has me thinking again that a mid-winter Mediterranean beach could be just what I need to look forward to. And yes….it even has me looking at hotels….