I first learned

of the Drake equation back in school during a delightful class on extraterrestrial life that blended biology and astronomy under the tutelage of Moshe Elitzur, a wonderful professor. Now there's this:

Are we alone in the universe? Not likely, according to the maths

By flipping the question of possible alien life to a question of whether we are unique, researchers find it much more likely the universe has seen many civilisations come and go.