Burn, Baby, Burn!

After my weights routine, I've had time to walk around the outdoor track.  I take off my shirt, so that I won't be as pasty white as usual.  Even after just one hour in the late afternoon sun, I started turning rosy pink on the first day I tried it.

It's interesting that my back got sunburned but my chest didn't.  I mean, I can understand that my abs didn't burn because of the shade cast by my mountainous pectoral muscles (especially in the deep valleys between each abdominal muscle, where it's always shaded, like crevasses on the moon), but why didn't my pecs burn?  (Maybe it's because my big head got in the way.)

My legs didn't burn, either.  Of course, that could be due to the hair on them, which diffuses or blocks the sunlight.  (I guess I wouldn't have burned at all, if I had hair on my back.)