How many intelligent civilizations are there

Are we alone? It is a question that has occupied mankind for centuries. Around the BBC. The only way to truly find out is to communicate with them. Until the s, however, no one had even thought about how many intelligent civilization might be out there. It took the innovative mind of Frank Drake, an astronomer and early pioneer in the search for extraterrestrial life, to find a way to answer this question.

His simple, yet comprehensive, equation that he developed in is named the Drake Equation in his honor. The Drake Equation is intended to help clarify the kinds of things we would need to know to figure out how many intelligent civilizations like ours exist in our galaxy. It estimates the number of intelligent civilizations that we could detect or communicate with in our galaxy based on seven parameters.

That's a big pile of symbols, but when you break it down into individual components, it's more clear and comprehensible:. The next three components f l f i f c tell us how likely it is that an advanced civilization like humans would evolve on an earthlike planet.

Unfortunately, exact values for each of these components, especially the last four that involve life and intelligent civilizations, are not known. We can only make logical guesstimates. While planet detection projects like the Kepler space telescope have given us a better understanding of the number of planets in our galaxy, we know very little about the origins of life and the evolution of intelligent life, since we only have a single example.

And this plague of not knowing is a big problem when it comes to using the Drake Equation. This is because putting different values into the equation can lead to dramatically different results. If we consider "optimistic" values, in which it's fairly common for life to arise and somewhat similar to those used by Drake and his associates at the conference where the equation was first described, we would expect a huge number of civilizations in our galaxy.

On the other hand, if the Universe makes it hard for intelligent life to emerge, as the advocates of the "Rare Earth Hypothesis" sugges t, we might be alone in the universe:. The total number of civilizations that we calculate relies very heavily on our assumptions.

If other civilizations don't exist at the same time we do in the Milky Way, then maybe our time is rather short lived. The Solar System formed around 4. However, the first signs of microbial life appeared on Earth around 3. And it then took much longer for modern humans to evolve, dating back around , years, and for modern civilization to begin around 6, years ago.

Following all those years, human beings became an intelligent, communicating civilization around years ago. Considering that it took nearly 5 billion years for a technological civilization to exist on a planet, and assuming that life evolved on other planets the same way it did on Earth, the team of researchers behind the new study estimate that there could be 36 other alien civilizations or more in the Milky Way alone. The criteria for these civilizations is based on how long they have been actively sending out signals of their existence out into the universe, such as radio transmissions, the same way that Earthlings have.