The author, Randall Munroe, is a NASA scientist who has a keen sense of humor (and is apparently deathly afraid of raptors) and publishes a new comic a few times a week. The comic above is one of his most popular, and even graces one of his T-Shirts (I also like the "Science. It works, bitches." shirt)
I'm sure I'll be able to wrangle some internet access during the week, but chances are that it will be limited (I need to get me a laptop at some point). I'll be back late Thursday night, so posting will probably resume next Sunday.