Where is Everybody?
Humans have been asking the question “Are we alone universe?” probably as far back as we had languages. We still don’t have an answer, but a great deal of work has been done and published. I’m going to review what we know and what’s been published and then put my conclusions out for you to ponder.
“Where is everybody?” was a question asked by Dr. Enrico Fermi during a lunch with Dr. Edward Teller, Herbert York, and Emil Konopinski at the Fuller Lodge at Los Alamos. For full disclosure they had previously talked about the flying saucer reports just published in the May 20, 1950 New Yorker magazine, and the possibility of someday exceeding the speed of light, which Fermi thought was one in ten. In addition, these men were probably aware of classified reports published by Stanislaw Ulam at Los Alamos in 1946 and 1947 showing how nuclear bombs could be used for orders of magnitude improvement in rocket propulsion.
Dr. Fermi was famous for doing order of magnitude trades and analyses in his head and evidently, he had determined that once a civilization could perform successful interstellar missions, they could literally colonize the entire galaxy in a few million years. The universe is 13.5 billion years old whereas the solar system is just over five billion years old and Earth formed about 4.5 billion years ago, so other civilizations could be billions of years older than us and if interstellar travel is possible, they should have been here millions of years ago. Hence his question.
In the seventy years since Fermi asked his question much has been written about the “Fermi Paradox” as it now is called. I recently read a book by Stephen Webb titled “If the Universe Is Teaming with Aliens … Where is Everybody?” in which he covers 75 possible answers to the Fermi Paradox. Most of them are whimsical, but a few are worth mentioning here. The solutions fall into three basic categories: 1) they are here, or have been here, but we haven’t found the evidence, 2) they exist but they haven’t visited yet and we haven’t made contact yet, and 3) they don’t exist. We are alone in the galaxy (I don’t use universe because the closest large galaxy is 70,000 light years away and it could be teaming with life and we will never know).
They visited early and left clues
This option assumes intelligent life developed elsewhere in the Galaxy, developed interstellar travel, visited Earth, but decided not to stay. There are two more possibilities inherent in this option. First, they found the planet already inhabited and after interacting with the population left for greener pastures (i.e. the Van Danken hypothesis). Unfortunately, everything Van Danken has described as evidence of ancient aliens has another human-driven answer, and we are gradually learning that ancient humans were much cleverer than we have been giving them credit for. I just watched a PBS special on construction of the great pyramid at Gisa where they showed archeological proof how the stones were moved to the site by boats in specially flooded canals and how rubble ramps were constructed to allow the stones to be dragged to the top using sledges (ancient Egyptians did not have the wheel yet).
The other hypothesis in this option is that they arrived when life was present in quantity but before intelligent life was present. They determined that the existing life had promise, rebuilt their starship and moved on. This is sometimes called the “Zoo Hypothesis”. Having participated in Interstellar systems design I know that it takes the resources of an entire solar system to build, fuel, and power an interstellar vehicle using the physics we currently understand. Unless we’re talking Faster than Light (FTL) propulsion systems, it is inconceivable that any alien would visit the Earth in the last four billion years and depart without at least leaving a colony. This includes the periods called snowball Earth when ice and snow covered the entire planet. We have never found any clue of prehistory visitation, so I have to reject this option. There is a chance that an alien civilization sent a robotic probe into the solar system, it found life on Earth, transmitted the news back home, and then backed off to observe and report. This is quite possible, but until we run across that probe, we are back where we started.
They exist, but they haven’t visited yet
This option implies that intelligent life is rare in the galaxy, and/or that interstellar travel is impossible, or at least very difficult. Webb’s book gives literally dozens of reasons why alien species might not have visited Earth yet. The most convincing is that stellar expeditions are expensive and would only be funded if the target was significantly lucrative. Right now, we know of no lucrative targets within range of our first-generation starships (whenever they might be possible). Hence, the settling of Stars will not be a dense coverage but in lines travelling from one high-value star system to the next, leaving wide swaths of the galaxy empty of settlements. Earth could well be in one of those empty spaces, which is why we hear nothing and have never been visited.
Another reason that kind of makes sense is that an alien species that has been around for billions of years has most likely reached the “Singularity Point” as described by Verner Vinge.
This is the point where their computers become intelligent and suddenly artificial intelligence takes over running of society. This could offer virtual worlds without limits and a society with that option might forget about pushing to explore space.
Finally, there is timing. The Universe is 13.799 billion years old and Sol, our star, is 4.6 billion years old. The first-generation stars in the Universe burned hydrogen and helium because that was all there was from the big Bang. After hundreds to billions of years the larger of those first stars supernovaed and the first metals were formed. Billions of years later next generation stars agglomerated out nearby gases in a solar nebula and the cycle repeated. The point is that it could easily take eight billion years for a 2nd or 3rd generation star capable of supporting life as we know it, to be formed. Hence, we might not be all that behind the aliens in development, and they have not had the time to reach us yet.
They don’t exist and we are the first intelligent creatures in the Galaxy
I’m running out of time this week and I have a lot to say about this option so I’m going to sign off and finish this up next week.
Thanks for your attention.