Drake Equation T-shirt - alien civilizations tee Solid colors: 100% Cotton; Heather Grey: 90% Cotton, 10% Polyester; All Other Heathers: 50% Cotton, 50% Polyester Imported Machine wash cold with like colors, dry low heat Here's a t-shirt of the famous DRAKE equation which is a "probabilistic argument used to arrive at an estimate of the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy." Perfect for mathematicians, scientists, engineers, college students, professors, sci-fi fans, and ironic supermodels! Lightweight, Classic fit, Double-needle sleeve and bottom hem