# So Where Are All Those ETs?

Fermi’s Paradox is a theory named after Italian physicist Enrico Fermi (1901-1954) who, during lunch with a fellow scientist, posed a question kind of like this, “Where the heck are the aliens if they are supposed to exist?” The premise of his theory goes something like this:

• Billions of stars similar to our Sun exist with many of them billions of years older than our own planet.
• It is highly probable that some of these stars would be orbited by Earth-like planets with conditions that could lead to the development of intelligent life.
• If intelligent life developed on these older “Earths” their respective civilizations might have developed interstellar travel and have already begun investigating Earth.

Combine all these facts and you come up with the conclusion that Earth should have already been visited by ETs. So, like Fermi said, “Where is everybody?” Despite mankind’s best efforts Fermi could not find any credible evidence of alien visitation. The conclusion then must become that the existence of intelligent life is:

• Extremely rare, or…
• Alien intelligent civilizations have not contacted Earth.

In 1961 a scientist by the name of Frank Drake took Fermi’s 1950 theory and applied a mathematical formula to the probabilities. It is called the “Drake Equation”. The formula is expressed as:

N = R* · fp  · ne · fl  · fi  · fc · L

The variables are defined as follows:

N = The number of civilizations in The Milky Way Galaxy whose electromagnetic emissions are detectable.

R* = The rate of formation of stars suitable for the development of intelligent life.

fp = The fraction of those stars with planetary systems.

ne = The number of planets, per solar system, with an environment suitable for life.

fl = The fraction of suitable planets on which life actually appears.

fi = The fraction of life bearing planets on which intelligent life emerges.

fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.

L = The length of time such civilizations release detectable signals into space.

But what does the formula mean to scientists? Well, that depends on who you talk to. Some scientists translate the results to be wildly optimistic that there is, indeed, intelligent life out there. Others feel quite the opposite. When Frank Drake met with Carl Sagan to speculate on the calculations, they estimated the existence of 1,000 (on the low end) to 100 million (on the high end) possible intelligent civilizations in our Milky Way galaxy. To counter their claims, scientists Frank Tipler and John D. Barrow put forth that the average number of intelligent life civilizations in our galaxy would be much less than one. Seeing as how human civilization exists, that would consequently, then, rule out the possibility of any other intelligent civilization existing at the same time.

The Search For Extraterrestrial Intelligence Institute (SETI) sees the Fermi’s paradox and accepts the reality that either interpretation of the possibility of the existence of intelligence life has a chance of being true. Thus, they continue their efforts, erring on the side of optimism. And the gringa likes that. Why not hold out hope? Why not be curious? And why not exercise such curiosity with a healthy dose of skepticism to balance out the equation and prevent a full-scale pre-disposition to crazy alien conspiracy theory by maintaining strict scientific standards?

SETI continues exploration and research as they search for others out there in the galaxy. They believe in the possibility that if a suitable environment was allowed enough time, that it is possible for intelligent life to develop. By using all sorts of science and technology (satellite arrays, chemistry, optical telescopes, and sophisticated radio signaling devices) SETI not only searches for signals from other civilizations but reaches out with messages of our own to anyone who may be listening. And with their Education and Public Outreach program (EPO), humans of all ages and walks of life can be a part of their endeavor. For educators there is nothing more exciting than to introduce to a classroom of elementary and middle school students SETI’s “Life in the Universe” curriculum. So log on and order your first package today and get students engaged with a lesson plan that is certain to pique their curiosity and hopefully inspire them to be the future of our world’s STEM programs, because we need them.

Sources:

www.seti.org

www.yahoo.news

wikipedia.org

Image Credit:  bing.net