The year was 1950, the place was the Los Alamos National Laboratory. Over lunch, several prominent scientists were discussing the recent spate of UFO reports. The discussing that was spurred by a cartoon published in the newspaper that day that humorously mocked the UFO sightings by blaming the recent disappearance of municipal trashcans on marauding aliens.
During the conversation, allegedly apropos of nothing, the prominent scientist Enrico Fermi suddenly exclaimed, “Where is everybody?” For some reason, all of his colleagues understood what he meant right away. Fermi was asking a deep question: Where are the aliens? Why haven’t we seen them yet?
Because of his famous question, Enrico Fermi lent his name to the now famous paradox that is at the heart of the search for intelligent life elsewhere in the universe. The Fermi paradox is the apparent contradiction between the high estimates for the chances of intelligent life and the lack of evidence for such life.
The Fermi paradox can be stated in this way. The universe is billions of years old. It contains countless numbers galaxies, each galaxy containing hundreds of billions of stars. Even if only a small fraction of those stars have planets, and even if only a small fraction of those planets are capable of harboring life, there should still be enough opportunity for many forms of intelligent life to arise in the universe. However, despite this abundance of opportunity for life to arise, we still have not seen any evidence of extraterrestrial intelligence.
This apparent contradiction is made more extreme when the progress of technology is taken into consideration. After all, based on our experience here on Earth, once a technological civilization has appeared, its advancement, it seems, starts accelerating at breakneck speed.
Humans have existed for less than 1 percent of the Earth’s history. Majority of that 1 percent was spent in the stone ages. However, ever since the Industrial Revolution, the march of human progress seems to have gotten exponentially faster. The Wright Brothers achieved flight in 1909. Less than 50 years after that, the Soviets sent the first artificial satellite into orbit in 1957. Then in 1969, only 12 years after the first artificial satellite was sent into orbit, humans have set foot on the Moon.
The speed of technological advancement in information technology in the Internet is even more impressive. If, in the few years since the birth of the Internet and the World Wide Web we have gotten to where we are, image where we will be 100 years from now.
The suggestion, therefore, is not only that there has been enough time for at least a few alien civilizations to arise. It seems that there has been more than enough time for civilizations significantly more advanced than ours to develop and leave traces of their activity in the galaxy.
And so Fermi’s paradox haunts us: Where is everybody? Why haven’t we found signs of advanced civilizations scattered everywhere in the galaxy?
Because of the implications of the Fermi paradox on the possible trajectories of life not only on other planets, but also here on Earth, scientists have always been fascinated with this puzzle.
One implication of the Fermi paradox is that technological civilizations don’t last very long. There might be something about civilizations that just spell disaster. Maybe civilizations tend to destroy themselves after some time.
There are many ways civilizations can do this. Just our own civilization presents many examples. There’s the threat of nuclear armageddon, destruction of the global environment, global pandemic, or the creation of a technology that will result in our species’ demise.
Another possibility that scientists entertain is that once a civilization has become dominant, they might feel threatened by the rise of other civilizations and they eliminate these threats as soon as they discover them. Such scientists, such as the late Stephen Hawking, usually suggest that we do not try to contact other civilizations because they might be more technologically advance and view us as threats to be eliminated.
Another option is that technological civilizations are exceedingly rare. Perhaps most of life in the universe is non-intelligent, or perhaps most intelligent beings are not interested in exploring the universe and contacting others.
These are but a few of the speculations that some people have put forward to try to address the Fermi paradox. As science progresses and we discover more about the nature of life and the universe, as we discover more planets and the ways they can be, we’ll come closer to answering one of humanity’s most perennial questions—are we alone in the universe? And if we’re not, where is everybody?