A famous physicist by the name of Enrico Fermi once was discussing the vastness of the universe with fellow physicists. He was also thinking on the potential likelihood of there being other intelligent life out there in space when he asked the question:
where are they?!
Let’s see how he came to ask this question. Fermi assumes that humans are typical intelligent lifeforms. No other life (multi-cellular, UFOs or otherwise) has even been found so life on Earth is all we have as an example. He defines intelligent life in a certain way.
It can be argued that cave dwellers dating back 10,000 years should already have had the mental capacity and physical dexterity to pilot an airplane. This is not the definition of intelligence that Fermi had in mind. By intelligence, Fermi instead meant any lifeform that has the potential to transmit and/or receive signals over interstellar distances.
Humans fit the profile (whew!) but only just. We do not transmit signals. Even TV/radio programs are not broadcast into space as the popular media/science fiction film would have us believe. We sometimes receive signals from outer space, although we do not do so 24 hours per day seven days per werk with the specific goal of detecting signals from extraterrestrials. What is important is that we have the potential to transmit/receive signals. We have thus satisfied the criterion of being ‘intelligent.’
Now then, if life on other planets follows a similar pattern to life on Earth, then it will take 5 billions years for the first intelligent lifeforms to arise from primitive single-celled bacteria. As the Milky Way is roughly 12 billion years old, this means that the first stars turned on that could have given risen to planets and life that was intelligent as early as 7 billion years ago.
According to this model, and our best guesses for how many planets may harbor intelligent lifeforms, intelligent lifeforms ought to emerge approximately every 70,000 years. At 70 years old we are newborns. At an imagined ‘Galactic Summit’ we would be the youngest representatives by a large margin. Would other aliens listen to what we have to say or instead direct us to the daycare?!
Stay tuned for part two on colonization and the conclusion to our story. In the meanwhile, imagine what we humans will be like in another 7 billion years, that is if we can only manage to establish peace in the world in the interum?
