The Fermi Paradox (after the physicist Enrico Fermi) is briefly as follows. There are extraterrestrial intelligences with advanced technology and interstellar spaceflight capabilities. Interstellar space flight under light does not violate any laws of physics. Adopting the mantra of quantum physics, ‘everything that is not forbidden is mandatory’. The time it takes to explore every nook and cranny of our Milky Way galaxy via low-light interstellar spaceflight is a small fraction of the age of the galaxy. There is at least one universally valid reason to go bold: the survival of the species. No star, no solar system lives forever. We (planet Earth) cannot hide from extraterrestrial exploration and/or colonization. So where is everyone? [By analogy, terrestrial life forms like bacteria, ants and cockroaches, birds, and of course humans, have explored and colonized Planet Earth in tiny fractions of the time that Earth itself has existed.] So again, where is everyone?
I can hear cries of ‘quibble, quibble’ now. It’s obviously too far away and it takes too long to get from there (wherever it is) to here. Well, life wasn’t meant to be easy! Seriously, if you think about it for a while, it seems to me that you protest too much!
First of all, aliens might have a very long natural lifespan compared to us carbon-based terrestrial bipeds. There is no natural law that limits intelligent life forms to an existence of only three score and ten.
Second, advanced aliens may have perfected various hibernation techniques. Put your spaceship on autopilot and sleep through the long journey.
Third is the old sci-fi, multi-generational interstellar spaceship. While I think that’s an unlikely concept, especially for exploration, it might not be that far off if interstellar colonization is the goal.
Then there’s bioengineering, which turns an organic body into something that’s more machine than flesh and blood, perhaps similar to the Daleks from Doctor Who. Given the advances in artificial parts of the human body, be it hip replacements or dentures or even mundane tooth fillings, that’s certainly a valid possibility.
Fifth, why stop there? Ship 100% machines: artificial intelligences in the form of cybernetic ‘organisms’ or robots or androids or small nanotech machines. Obviously a ‘Star Trek: The Next Generation’ data thing, or something along the lines of the original Cylons from ‘Battlestar Galactica’. Think of the savings from not having to provide life support and other life essentials for biological organisms. We have already started down this path. There is nothing different in principle between a Cylon and our Pioneer 10 & 11; our Voyager space probes. It’s just that a Cylon is much more sophisticated. The day will come when our Pioneers and Voyagers will transform into something resembling a Cylon, or any of the many dozen similar ‘beings’ in science fiction literature. Since the AI is near-immortal (relative to flesh and blood), that takes care of the time-travel arguments, and the possible environments suitable for relatively easy exploration (colonization?) are vastly expanded.
Lastly, maybe, just maybe, a warp drive of sorts, a faster-than-light ship, is possible. Aliens whose science is thousands of years more advanced than ours could have exceeded Einstein’s speed limit. I wouldn’t want to bet money on it, but I’d be less than open-minded not to admit the possibility, however remote. Add to that, theoretical but permitted ‘gateways’ between distant points in our Universe, perhaps even to other universes: wormholes and black holes. Maybe, just maybe, an advanced alien civilization has the ways and means to manipulate said objects and forces to facilitate space (and time, too) travel. An excellent sci-fi novel based on hardcore science that doesn’t rely on pseudo-technological mumbo-jumbo that illustrates this is Carl Sagan’s “Contact.”
So once again, where is everyone?
Answers include (but are not really limited to) general concepts that suggest that…
They don’t exist; I never have and I never will. What’s wrong with that? Well, given the vastness (100,000 light-years across) and timelessness (more than 12 billion years minimum) of the full extent of our Milky Way, the odds of us being the proverbial IT, the only one, is extremely unlikely. . It is a massive violation of the Principle of Mediocrity or Copernican Principle.
We are the first kids on the block, not the new kids on the block. What’s wrong with that? Once again, the chances that in all the vastness of our Milky Way we will be the first are extremely unlikely. Our Solar System is only 4.5 billion years old; our galaxy is much, much, much, much older than that.
They exist but they don’t care about exploring space, looking for new life and new civilizations. They do not want to go boldly or seek communications. They want to be left alone: isolationists. What’s wrong with that? That could be true for one or more extraterrestrial civilizations, but to extrapolate and suggest that that applies across the board to any and all extraterrestrial civilizations is illogical.
They go boldly, but they have not crossed our path yet. What’s wrong with that? Again, it doesn’t take that long to explore the entire Galaxy. It would be a fluke if we had not been noticed and registered in the database of some other civilization.
They’re here, but leave us alone. What’s wrong with that? Again, that could be true for one or several alien civilizations, but extrapolating and suggesting that that applies across the board again seems illogical to me. There is something called the Zoo Hypothesis to explain the Fermi Paradox. It’s a Star Trek ‘Main Directive’ concept combined with that of a zoo. Aliens (zookeepers) do not interfere with us (although of course zookeepers have to interact with the animals (humans) in the zoo from time to time), they do not allow others to interfere with us, although they probably they would. it will not allow us to escape from the cage (probably referring to the far reaches of our solar system, I mean that we have been allowed to travel to the Moon).
They are here and they interact with us and our environment: UFOs, anyone? What’s wrong with that? Absolutely nothing!
UFOs are a perfect answer to the Fermi paradox!
Some recommended reading on the Fermi Paradox:
Hart, Michael H. & Zuckerman, Ben (Eds.); Aliens: Where are they?; Pergamon Press, New York; 1982:
Hart, Michael H. & Zuckerman, Ben (Eds.); Aliens: Where are they? [2nd edition]; Cambridge University Press, Cambridge; nineteen ninety five:
Verma, Surendra; Why aren’t they here? The question of life on other worlds; Icon Books, Cambridge; 2007:
Webb, Stephen; Where is everybody? Fifty Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life; Copernicus Books, New York; 2002: