The Drake Equation Estimates How Many Alien Civilizations Are Out There
Dr. Frank Drake presented the Drake Equation in 1961, not as a definitive way of determining the number of extraterrestrial civilizations in our galaxy, but as a theoretical tool for estimating how many may exist. It takes into account factors such as the number of percentage of stars that have planets, the chances of a plant developing life, and average life-span of intelligent civilizations. The equation is not foolproof, and can result in a broad range of answers depending on how optimistic or informed the user is. However, many scientists look at the equation as a useful and interactive symbol for the probability of life on other worlds.