During breaks while working on the construction of the first atomic bomb in 1943, Enrico Fermi and his colleagues talked of many things. One of which was alien intelligence.
The Milky Way galaxy that we live in is easily large enough to house millions of civilizations and is certainly old enough (about 13.5 billion years old) so that one of them should have colonized the galaxy by now, so Enrico asked, “Where are they?” This questions is now known as the Fermi Paradox.
There are about 100 billion stars in the galaxy, and even if the chances of life are like winning the lottery (say about 10 million to one), there should still be 10,000 winners! In order to apply a more scientific analysis to Fermi’s Paradox, Frank Drake devised what is now known as the Drake Equation in 1961 at a conference in Virginia that would lead to the beginnings of SETI (The Search for Extraterrestrial Intelligence).
The Drake equation can produce many results based upon whether the user is optimistic (10,000) or pessimistic (exactly 1 – us); Drake himself came up with a value that is equal to the number years an intelligence civilization survives. Since we have survived a little more than 100 years as an intelligent civilization, there are about 100 alien civilizations in the galaxy.
Whenever I am asked whether I believe there are aliens out there, I always respond “yes,” but I also quickly follow that up by saying that the likelihood of us actually contacting them anytime soon is extremely remote. The reason for both answers is the same – the galaxy is too big!
Follow your curiousity to the Fred G. Dale Planetarium at Wayne State College.