An anonymous reader writes: An equation, which calculates the probability of the evolution of other technological civilizations, has found that it's wildly unlikely we're the only time advanced society in the universe. Adam Frank from the University of Rochester and Woodruff Sullivan from the University of Washington base their new equation on the Drake equation, used for calculating the probability of extraterrestrial civilisation, written by astronomer and astrophysicist Frank Drake in 1961. The scientists also take into account Kepler, which suggests that one in five stars have planets in the habitable zone. Frank and Sullivan calculated that human civilisation is only unique if the odds of a civilisation developing on a habitable planet are less than one in 10 billion trillion. "One in 10 billion trillion is incredibly small. To me, this implies that other intelligent, technology producing species very likely have evolved before us," Frank said. Frank said: "Of course, we have no idea how likely it is that an intelligent technological species will evolve on a given habitable planet. But using our method we can tell exactly how low that probability would have to be for us to be the ONLY civilization the Universe has produced. We call that the pessimism line. If the actual probability is greater than the pessimism line, then a technological species and civilization has likely happened before."