Look Up In the Sky…!

graduate_electromagnetism_class_sky_watchingYesterday’s graduate class in electromagnetism had a bit of extra fun. We did a particular computation in some detail, and arrived at a pair of results. We thought about the main features of the equations we’d derived and I then asked the class if they could think of an example. An example with those equations essentially written all over it. It was the sky. Not just the blueness of the sky (for which the result supplies a partial answer) but the pattern of blueness on the sky, especially when looking through your polarised sunglasses. (You know how you tilt your head when wearing them and you can darken or lighten the sky a bit? Well, that effect is way more effective if you are looking in a direction at right angles to the sun as opposed to either toward or away from the sun.)

So I took the class outside to gaze upon the sky in person, rather than just sit and talk about it. Actually, a little bit of knowledge about the pattern of blue in the sky is useful in a lot of ways. For example it is amusing to me to see how often architects and their artist collaborators get the sky wrong in renderings of […] Click to continue reading this post