It IS rocket science! But fortunately we do not need to be conversant with the technical specifications of spacecraft propulsion systems to understand the rationale behind Enrico Fermi’s (1901-1954) question “Don’t you ever wonder where everybody is?” The question is generally stated as “Where is everybody?” or “Where are they?” these days, but Herbert York (1921-2009), who was present at the lunch, at the Fuller Lodge in Los Alamos, back in the summer of 1950 when Fermi asked it, recalls the longer version.
York recollects that Fermi enjoyed asking rhetorical questions at these lunches and then offering possible answers. Fermi was the builder of the first nuclear reactor in 1942 and a leading light of the Manhattan Project, which produced the atomic bombs that forced Japan’s surrender to end World War II. When he posed this seemingly simple question everyone at the table knew he was referring to extraterrestrials. His fellow “rocket” scientists also understood what lay behind it. That basis and the question itself have come to be known as the Fermi Paradox.
Essentially, Fermi was asking why we do not already know of extraterrestrial civilizations if they exist. Why we haven’t been visited by automated or “manned” spacecraft, or have evidence of them. Remember that this conversation took place just at the start of the whole modern UFO debate. What is now referred to as the Roswell UFO Incident occurred in 1947, but may have been unknown to them; it didn’t really become prominent and controversial until the late 1970s. The basis for the question has to do with the physics and structure of the Universe, the Fermi Paradox might be phrased as “If the age and size of the Universe is as it seems, then there should be many extraterrestrial civilizations. So why do we have no evidence supporting this hypothesis?” But let’s just consider our galaxy, the Milky Way.
The Milky Way galaxy consists of between 80 and 400 billion stars, with 250 billion the generally accepted consensus. These stars are spread through all stages of their lifespans. While many may be younger than our star Sol’s 4.6 billion years, many are much older. The Universe is estimated at 13.7 billion years old, and the oldest star found so far within the Milky Way, HE 1523-0901, is 13.2 billion years old. From the center of our galaxy to the outer rim is between 50,000 and 60,000 light years; the Solar System is in the Orion Arm, about 28,000 light years from the center. We need to use light years as the measurement unit for distance because in miles or kilometers the numbers would become meaningless to us. One light year is the distance that light will travel in one year. Light travels approximately 186,000 miles or 300,000 kilometers in just one second.
The argument goes that if extraterrestrial civilizations arose in just a minuscule percentage of stellar systems within the Milky Way, it would still amount to a large number of such civilizations. It is suggested that even with technology not too far advanced from what we could produce now and traveling at speeds well under the speed of light, one such civilization could explore the galaxy using self-replicating robot probes within 4 million years and spread throughout the galaxy in a few million more. Thus the question: where is everybody?
The Fermi Paradox has generated much debate and many possible answers, in both scientific and religious circles as well as the general public. There has been a range of possible answers including:
* God created life on the Earth alone.
* Doomsday suggestions that civilizations self-destruct before they can develop the will or technology to spread out from their birth star systems. Many countries today have arsenals of nuclear, chemical and biological weapons that could knock us back to the Stone Age if they didn’t wipe us out completely. The deprivations of our technology and the exponential increase of our population in the last 100 years could lead to our extinction without needing a Third World War.
* Earth is deliberately left in isolation, with reasons ranging from benign to uncaring to fearful containment. Our brief history of near continuous warfare among ourselves over comparatively slight differences would give few aliens the expectation of a friendly reception. Our entertainment media of the last few decades have us dominating alien species even when we are not blatantly aggressive towards them. The Star Trek movies posit an interstellar civilization including many friendly extraterrestrials, but it is called the Terran Federation and dominated by humans.
* They are already here. There are two main aspects to this hypothesis, either they use their advanced technology to hide their presence or their presence is being deliberately hidden and evidence obfuscated by ultra-secret governmental agencies such as the “Men in Black”. Considering the advances made in our own spy and anti-spy technology in just the last 50 years, a civilization one million years in advance of ourselves should be able to disguise or hide their presence with very little effort.
* They have been and gone. The suggestion is that many of the myths and legends that have come down to us from ancient civilizations and some of the physical evidence found by archaeologists shows visitations by extraterrestrials in ages past. Perhaps they tried to help us, but gave us up as a lost cause because of our warlike natures.
In the June of 2009 there is no knowledge of which of these possibilities, if any, might be true. At least, none known to the general public. If the conspiracy claims of some in the UFO debate are true, then someone will actually know more than the rest of us. If an extraterrestrial spacecraft openly arrives in orbit around our planet, we will know we are not alone and might find out the answers from its occupants, if there are any. Otherwise we are going to have to wait; wait and see if we can find evidence through SETI (Search for ExtraTerrestrial Intelligence), by scanning our skies for communications across the enormous voids of space, or even until the time when we can voyage across those voids and find out by up close examination, if we ever can.