Back to Contents
Some time in 1945, so the story goes, Enrico Fermi approached several of his colleagues gathered in the cafeteria at Los Alamos and, as if delivering a lightning bolt out of a clear blue sky, asked, "So where is everybody?" The scientists sitting at the table understood that Fermiís Question, as we now call it, referred to alien civilizations.
In 1961, for a meeting of astronomers who had used radio telescopes to make a preliminary search for alien radio signals, Frank Drake devised an equation that would enable him to estimate the number of alien civilizations available for radio contact.
The Drake equation tells us that we can estimate the number of civilizations in our galaxy with which we might possibly communicate by multiplying together all of the following factors:
1. The number of stars that give us the right conditions for the evolution of intelligent life. Those stars must lie on the Main Sequence of the Hertzsprung-Russell diagram and must have the Harvard classification codes of F, G, and K. Such stars live long enough to develop intelligent life and are neither too hot (producing too much ultraviolet radiation) nor too cold (putting the life-bearing planets too close to the star).
2. The fraction of those stars that have planets. Given the discoveries of extrasolar planets in recent years, we may say that the fraction comes close to 100%.
3. For each of those stars, the average number of planets per star that has the potential to support life. Based on the one example that we know for certain, that number is one, possibly two.
4. The fraction of those planets that do actually produce life. Based on the success of experiments aimed at producing the chemical precursors of life, we can estimate that fraction at close to 100%.
5. The fraction of life-bearing planets that evolve sentient life. With only one example known to us and the evolution of that example still not fully understood, we can say that this fraction is anybodyís guess.
6. The fraction of intelligent species that develop civilizations that emit detectable signs of their existence into space. Again the fraction is anybodyís guess. Looking at our own world, we can see civilizations that likely would never have made themselves detectable by aliens, no matter how much time they had to develop.
7. And the length of time in which those civilizations emit detectable signs of their existence into space. Those signs might be electromagnetic radiation (television and radar are two examples), neutrinos from nuclear reactors, or other things yet unknown to us. So far we have been making ourselves detectable for less than a century.
Drakeís equation relates to Fermiís question by raising our expectation that a certain number of alien civilizations would form in our galaxy and, depending on their number at any given time, would give us neighbors with whom we might communicate. However, as Fermi tacitly noted in his question, we lack any evidence that such civilizations exist. We thus obtain an implication that life rarely produces a sentient species or that a technologically advanced civilization either does not arise or has a very short lifespan. With that implication in mind along with the fact that sentient life and a technological civilization exist on Earth, we want to think about what might shorten the lifespan of that civilization.
One answer that came quickly to the front of the conversation suggests that all-out nuclear war wipes out any civilization before it can spread off its home planet. Such an event would reduce any survivors to the conditions of hunter-gatherer groups of the Early Stone Age. Further, any civilization capable of such self-injury will have used up its planetís resources in a way that precludes the second rise of an industrial civilization. The best that we could hope for our descendants in such a scenario is that they would eventually create a civilization at the technological level of our civilization prior to 1800, maybe 1850, essentially a civilization not significantly different from that of the Romans, but with railroads and the telegraph.
But we seem to have avoided that particular catastrophe. The people who control nuclear weapons have displayed remarkable sanity, even to the extent of talking about eventually eliminating all nuclear weapons from this planet.
No, thereís an even greater threat to Humanity, one that can easily extinguish us all. And its all the more dangerous because so many more people can carry it out.
On my computer my security system tells me that it now protects me from over one million threats (as of 2009 May 05). That fact means that thousands of people of malicious intent have created electronic diseases and released them onto the Internet to infect other peopleís computers. How long will we have to wait before bio-technology advances to the stage at which hobbyists can create their own micro-organisms? What then will stop some self-pitying psychotic, like the typical mass-murdering gunputz that has plagued our world for years, from creating a virus that will wipe out Humanity? Contemplating those questions gives us an answer to Fermiís Question more compelling than the nuclear war scenario, if only because so many more people can, in concept, carry out such plans.
But the devastation of Humanity doesnít even require malice: sheer, utter stupidity will do the job quite nicely.
I can recall easily two incidents in which coworkers came to work sick, coughing a tainted mist throughout the office (one giving me near-fatal pneumonia and the other a cold). Or consider the implications of a woman handling food in a buffet line, using her bare, unwashed hands, and then tossing it back, an event that one of my friends witnessed. In both examples we have people who either donít know the fundamentals of basic hygiene or they donít care. In those examples we see how disease spreads. But we have bigger examples as well.
In the late 1340's a disease that originated in Central Asia came to Europe on a single ship and devastated the continent. The Bubonic Plague, also known as the Black Death, killed between thirty and fifty percent of the population in towns and cities across the continent before it burned itself out.
And think of cholera, which originated in India. It might have stayed there and eventually gone extinct, except that the British came, took over the subcontinent, and then spread the disease around their world-spanning empire. And they did it with the transportation technology of the 1700's.
We might also note the devastation of the Native Americans in the Sixteenth Century by European diseases, such as flu brought by the Spanish in their pigs. In the 1500's Europeans had only a few small settlements in North America: there were just too many people already here for new colonists to move in. But by 1600 the native population had been so decimated by disease that European settlers found large areas of essentially vacant land on which to build their towns. So devastated were those native cultures that scientists in the Nineteenth Century couldnít believe that Cahokia had been built by the ancestors of the people still living in the area.
And we have the Spanish flu epidemic that followed World War I and killed millions of people. Between January 1918 and December 1920 an especially deadly strain of influenza swept the world, killing between three and five percent of the population. Now imagine a scenario in which a much deadlier disease, such as Ebola fever, spreads as quickly and as widely (and given modern transportation technology, even more effective than what was available in 1918, it certainly could).
So here we have the engineering challenge. We have before us the goal of creating an infrastructural element that will identify, attack, and destroy diseases before they kill enough people to bring down civilization. And as with any good engineering solution, this one will have a social dimension to augment the mechanical and chemical dimensions. That social dimension will include improvements in health education, provision of health services, and alterations in law and custom. And just for practice we need to improve our ability to hunt down and destroy existing diseases, as we did with smallpox.
We may not live in the first civilization to evolve in our galaxy, but we apparently face the challenge of being the first to survive its infancy. Meeting that challenge successfully will involve fully taming our animal nature and developing true intelligence. We will have to develop improved knowledge and the intelligence to apply it. A brief glance at our mass culture offers little hope.
Back to Contents