What's 10 Microns?

Ten microns refers to the wavelength of light at which the picture was taken. The human eye is sensitive to light in a very small wavelength band from around 0.4 microns (which we see as blue) to 0.7 microns (which we see as red), so we're in the dark as to a lot of light around us. A micron is 1 millionth of a meter, so there are 25,400 microns to the inch.

We perceive other wavelengths of light in other ways -- we feel infrared light (those are wavelengths longer than red) as heat and we get sunburnt by ultraviolet light (those are wavelengths shorter than blue).

Every warm body "glows" at a wavelength characteristic of its temperature, and the hotter something is, the more it radiates at shorter wavelengths. So, the sun, with a temperature of several thousand degrees Kelvin, gives off light in our visual range. We humans, at about 99 degrees Farenheit, give off light too, primarily around a wavelength of 10 microns

In the picture of me taken at 10 microns, the color indicates how much light there was, with white showing the most light and dark red the least. The whiter parts of my face, like my eyes, are hotter, so they give off more light at 10 microns than the cool parts like my hair.

This picture was taken in the dome of the Hale 200-inch telescope on Palomar Mountain with a science camera called MIRLIN just before it was commissioned on the telescope in 1995. Luckily, infrared images are ageless.