Information is Beautiful has an excellent interactive chart up at the BBC covering the Drake Equation. I remember studying the equation, which estimates the number of civilizations that might exist in our galaxy, in an astronomy class called “The Search for Extraterrestrial Life” at the University of Texas. Why wouldn’t I take that elective? It was actually less fun than I thought it would be, but it was still very interesting. Apparently they no longer offer the course, or at least not this semester.
The Drake Equation