The universe is a big place. It seems arrogant to think there isn't anyone else out there. Well, that's not what I believe. There may be intelligent life in the universe, but there is none in our galaxy. That leaves hundreds of billions of other galaxies for extra terrestrials to reside in, but not this one. I also believe there is plenty of opportunity for biologically advanced (multicellular) life to exist in our galaxy, just not technologically intelligent life. My argument is grounded on a conjunction of the Fermi paradox and the present state of human technological evolution. Either one of these things alone makes a good argument against ET in our galaxy. When put together, the evidence is overwhelming and the conclusion is undeniable.
Seems kind of out of place doesn't it? Here I am writing articles about how much I love science and technology. I've written about futuristic robots and such. I seem like the kind of person who would embrace exterrestrial life, don't I? Many other scientists seem to take that view. I used to believe the universe, including our galaxy, must be teeming with life. It seemed so obvious, basically for the same reasons that Carl Sagan was so popular for advocating. There is so much room out there for life to evolve and it seems to have occurred so easily on our own planet. It seems inevitable that there must be life out there, just waiting for us. It's exciting to think about for one thing, imagining a world inhabited not only by living beings, not only basic plants and animals, but thinking cognitive beings who we could communicate with. They might be far more advanced than us and could teach us incredible things about the universe. It would be like meeting God.
The problem is it's not going to happen. We aren't going to meet anyone. Space is a desolate place for sure, and we will discover no enlightened beings that can tell us the universe's secrets. This is an old debate and I don't believe I have anything too new to contribute (except in the afterthought section), but many people just don't seem to get it, so I feel it is necessary to repeat the good arguments for why this is the case.
The main argument supporting a plethora of life in the universe, including our galaxy, is the Drake equation, created by Dr. Frank Drake in 1961. This is a very simple equation that yields the number of technologically advanced civilizations existing in our galaxy right now. It's really easy to understand. Here's how it works. You take a number of independent values that ET is dependent on and multiply them. The result is the number of planets with ET on them. The Drake equation looks like this (ripped from http://www.seti-inst.edu/science/drake-bg.html without permission):
N = R* x Fp x Ne x Fl x Fi x Fc x L
where,
| N = | The number of communicative civilizations The number of civilizations in the Milky Way Galaxy whose radio emissions are detectable. |
| R* = | The rate of formation of suitable stars (per year) The rate of formation of stars with a large enough "habitable zone" and long enough lifetime to be suitable for the development of intelligent life. |
| Fp = | The fraction of those stars with planets The fraction of Sun-like stars with planets is currently unknown, but evidence indicates that planetary systems may be common for stars like the Sun. |
| Ne = | The number of "earths" per planetary system All stars have a habitable zone where a planet would be able to maintain a temperature that would allow liquid water. A planet in the habitable zone could have the basic conditions for life as we know it. |
| Fl = | The fraction of those planets where life develops Although a planet orbits in the habitable zone of a suitable star, other factors are necessary for life to arise. Thus, only a fraction of suitable planets will actually develop life. |
| Fi = | The fraction life sites where intelligence develops Life on Earth began over 3.5 billion years ago. Intelligence took a long time to develop. On other life-bearing planets it may happen faster, it may take longer, or it may not develop at all. |
| Fc = | The fraction of planets where technology develops The fraction of planets with intelligent life that develop technological civilizations, i.e., technology that releases detectable signs of their existence into space. |
| L = | The "Lifetime" of communicating civilizations (years) The length of time such civilizations release detectable signals into space. |
Don't be daunted by all those terms. Read it one by one and it is easy to understand. The terms become more specific from left to right. For example, R* is the prerequisite for all terms to the right of it, and fp is the prerequisite for all terms to its right, and so on.
I have no argument with the Drake equation in that I believe it correctly represents the problem. However, people have to make educated guesses about the values in the Drake equation in order to derive the final product, that being the number of technologically advanced civilizations existing in our galaxy, and I believe that people have absolutely no clue what values to plug in for these internal fractions and this can lead such a wide variety of values for the final outcome of the equation that the equation becomes utterly useless for finding anything useful out about the question it is attempting to answer. Notice that since the Drake equation is a product, if just one of these values is nearly zero, then it doesn't matter how high the rest of the values are, the final product will still have a value of nearly zero. That's how multiplication works. The parameter that I believe is practically zero is Fi, but that's just my personal opinion. It doesn't matter which value is near zero. I am sure at least of them must be, and the end result is the same. So why am I so sure one of these values must be nearly zero then?
Enter the Fermi Paradox. Physicist Enrico Fermi was actually a believer in ET and it is ironic that his question has become a primary argument against ET. He worked at Los Alamos and one day he just threw out the question, "Where are they?" The basis of this exclamation was that people had been toting the obvious existence of ET but that there was no sign of them. The reason this seemed so strange was that it is easy to calculate that if intelligent life did exist, it should most certainly be here by now.
Here's one way of breaking it down. The galaxy is approximately 100,000 light-years in diameter. Let's assume it takes ET the longest possible time to reach us, say from the opposite side of the galaxy. Let's assume that once ET started exploring the galaxy they expanded at a rate of approximately one percent the speed of light. Assuming they have the means to travel faster than this allows them time to stop along the way, settle down, and root at new worlds before setting off again. If you are going to argue that this is far too fast and that I should slow it down considerably, you should be aware that I am not envisioning air-filled balloon like starships lumbering their way through space by the most inefficient means possible. By the time we are expanding outward, we will not be humans in our present form. We will be much more efficient robotic beings. The same logic applies to an advanced ET civilization. For more information on what I believe we will become in the near future, I refer you to my other mind ramblings topic, Robots and Mind Uploading.
So this means the travel time across the galaxy is ten million years. The universe is around 13 billion years old and the Milky Way has been in full swing for some considerable fraction of that time, say 10 billion years. So, take the travel time, 10 million years, and divide it into the galaxy's age, 10 billion years. You get 1/1000th. Now, assuming ET does exist, we presently live in one of three time periods: ET has not yet arrived, ET is in transit (in the process of expanding into the galaxy), or ET has already arrived (has already finished expanding and is essentially everywhere in the galaxy). The odds of us being in the in transit time period are one out of a thousand. We can assume we don't live in the post-transit time period because there don't appear to be any signs of ET. So that would mean we are in the pre-transit time period. In other words, they have not yet reached the point in their evolution where they become technologically advanced enough to explore space. That means we are alone as a technological civilization since the original question was, how many are there, and I have just concluded that there are none besides ourselves.
There are many counterarguments to the Fermi Paradox. For example, one factor in the Drake equation involves how long a technological civilization lasts. The point this factor is making is that advanced civilizations may destroy themselves. This possibility was probably raised because our own nuclear standoff seems to have come so close to eradicating us. The conclusion is that there may be many civilizations out there but they don't last long enough take over the galaxy. Maybe, if we can avoid destroying ourselves, we can go out there and meet them someday. It does give you some hope doesn't it?
Unfortunately, it is false hope. For example, a civilization will have a much harder time destroying itself once it lives on multiple worlds or lives in space itself. A simple asteroid impact or large-scale war may wipe out one planet, but the civilization will survive because its members continue to exist elsewhere. Perhaps in the nascent stages of such an expansion, longevity isn't guaranteed, such as an Earth/Mars civilization, because a relatively nearby Mars society could be drawn into the civil strife caused by a war back on Earth, but as the global civilization continues to expand, it becomes infinitesimally unlikely that every single society in a civilization would be drawn into a conflict and be destroyed. If we inhabited hundreds of nearby solar systems for example, it would be difficult for a single conflict to erupt that would encompass and destroy everyone. The distance is just too great.
Perhaps these civilizations are wiped out by a plague that spreads throughout its distributed populations. Again, I argue that a civilization will spread in an increasingly disparate manner. The number of distinct locales of life in an expanding civilization will rise exponentially over time. Start on one planet, then two or three, very quickly several solar systems, and subsequently large fractions of the local galactic neighborhood. A plague would have to catch up with and overtake every single exanding population faster than the populations expand themselves. This seems practically inconceivable to me. Besides, life appears to get along just fine on our plunky little planet with all kinds of plagues. What sense does it make to assume that a superplague capable of destroying all life exists in the first place? The suggestion has been made that this plague may be memetic in form. In other words, it may be an idea that spreads and somehow infects and destroys populations. This seems kind of silly to me. It suggests that there some sort of perfect idea, that once conceived, convinces everyone to partake in his or her own demise and species extinction.
Another counterargument against the Fermi Paradox is that all the ET civilizations may purposefully be hiding themselves from us. For one thing, if they are bent on hiding themselves and they are vastly superior to us, then SETI is surely promised a dismal failure because they will succeed in hiding themselves. Regardless, I still doubt this is the case. Of the multitude of civilizations out there, only one would have to express an interest in contacting us and we would know about it.
Perhaps they don't specifically hide, but they just xenophobically stay at home, maybe living in their solar system and a few nearby solar systems. I say the same thing I just did. It would only take one civilization to reach out, and we would be shaking their hands as we speak.
It is possible that the various arguments against the Fermi Paradox are valid. For one thing, my counter arguments are generally of the style that it would take only one civilization in a sea of civilizations. This is arguing the odds and statistics as a method doesn't work very well with low numbers. For example, if there are only two or three civilizations, then maybe they really did all choose to stay at home. That is why it is necessary for me to bring up a different issue altogether: Earth's history. Earth is the only example we have of life and humanity is the only example we have of intelligent life. While it is difficult to predict patterns from a sample size of one, I believe our own history offers some powerful insight into the notion of ET. Once humans emerged on the scene, it took us a scant 50,000 - 80,000 years to develop into our present technological form. It would appear that once an evolving species breaks a certain barrier, it practically explodes with ingenuity. Homo erectus didn't quite make it to this barrier. These hominids were some of our direct predecessors and were the most intelligent organisms to ever evolve on Earth prior to Homo sapiens and possibly Neandertals. Homo erectus could build simple tools, suggesting an inkling for technological prowess, yet they stagnated for almost a million years with their basic stone tools and never developed further.
However, when we showed up, the pattern is undeniable. Our technological evolution followed a standard exponential curve which means it started pretty slow, but it rose steadily, and as with all exponential curves it has a break-point, in front of which development is still rather slow, and behind which development takes off in an almost incomprehensible fashion. Humans appears to have approached and just passed through that point in the last one or two centuries and we are poised to go ballistic in the near future. Our technological prowess seems untamable. There is a force behind it that appears to propel it by fact of its sheer existence. For further details of what I believe is going to happen in the next century, I refer you to my other mind ramblings topic, Robots and Mind Uploading. For now, let me just say, the real show is about to begin.
The point I am making is that I believe humanity is about to take over the galaxy. We are at the very beginning of that ten million year expansion I mentioned earlier, and humans in particular seem to be so utterly efficient about territorial expansion (for better of worse), we may take over the entire galaxy in a fraction of that time, possibly just one million years. If human history is any indication, there is a drive for technological civilizations to spread.
It may very well be totally illogical to suggest the idea of an advanced civilization that chooses not to expand. This is akin to choosing to stop further technological, exploratory, and scientific advancement while it was such drives that made a technologically advanced civilization in the first place. A civilization that is prone to not expand is likely not to have become advanced to begin with. There seems to be something of an oxymoron in the suggestion that a tremendously poweful civilization with all kinds of technological and scientific knowledge would choose to suddently halt its own advancement, its own evolution, its own development. There have been a few examples of this in Earth's history however, ancient China being one. The Chinese were the most powerful society on Earth but suddenly chose to turn their ocean-sailing junks around and stop exploring. Did humanity as a whole stop expanding? Not in the least. The Europeans took over and became the dominant power in the world as a result. The same would be true of ET civilizations. Those that don't expand will by definition be the weaker civilizations. Evolutionary pressure will thus drive most if not all technological civilizations to expand as quickly and thoroughly as possible, but nare a peep has been heard so far.
Another interesting point is that from the onset of intelligent life to the breakout into the galaxy appears to have taken us less than 100,000 years total. If there were ET on other planets that were still evolving technologically, the logical conclusion is that they wouldn't take much longer than us. This would mean to suggest that we live in a microscopic 100,000 year window in which another civilization exists but has not broken out yet. 100,000 divided into 10 billion is 1/100,000. That is the chance that we coexist with another presently evolving technological civilization. In other words, not only are there no technological civilizations presently here, and no technological civilizations presently expanding into the galaxy, but there are also no presently evolving technological civilizations that we might meet after we both begin to expand outward.
What does this contribute to the Fermi Paradox? It argues that once a technologically advanced civilization emerges, it is practically inevitable that the civilization is, at that moment of its emergence, only ten million years away from completely saturating the galaxy with its presence, and yet we see nothing.
Perhaps you buy my arguments, perhaps you just think I'm a pessimist. I am certainly not a pessimist. The idea of what I believe humanity is going to become and will accomplish in the near future energizes me. This is not a pessimistic attitude to say the least. It does sound kind of pompous to suggest that we are totally alone though doesn't it? Well, that's not what I'm saying at all. I believe quite thoroughly that we are alone as an intelligent technological species in the Milky Way galaxy.
However, I do believe that it is quite likely that our galaxy is running amok with interesting biology. Discovering life on other worlds, be it micro-scopic, single-cellular, multi-cellular, plant-like, or even animal-like, will be one of the most exciting endeavors of our existence. The idea of seeing and learning about how life works on other planets and moons sends shivers up my spine. I cannot imagine a more exciting way to spend my time.
At the same time, I allow plenty of room elsewhere in the universe for intelligent life. There are literally hundreds of billions of galaxies in our universe, far far far greater than the number of stars in our galaxy. I permit for intelligent life to have evolved in practically all of those galaxies. I am allowing many billions of super-advanced civilizations to exist. The reason for this is that while the universe and our galaxy are old enough that it is inevitable for ET in our galaxy to have visited us, the universe is not so old that the same inevitability applies to distant galaxies. It is questionable whether it is even possible to travel between galaxies. The distances are just so immense. Perhaps nearly adjacent galaxies can be visited, but the idea of expanding into the universe is quite different from the idea of expanding into a galaxy. Maybe such a mission is possible, but it would require so much time that it is entirely probable that we live in a time and place that has not yet been reached by those civilizations.
Now that I have thoroughly defended my opinion that there is no intelligent life in our galaxy, I will propose one theoretical scenario in which I may be wrong. In other words, I can conceive of a realistic and possible scenario in which there are ET in our galaxy and yet there is a logical explanation for why we have not seen them yet and may never see any evidence that they exist. I will first refer you to my other mind ramblings topic, Robots and mind uploading for an explanation of where I believe we are headed in the future. There are two main points to be made here. One, we will be, for all intent and purposes, immortal. Our "bodies", which will be robotic, will last for extremely long periods of time and will be fully replaceable. Two, we will be robotic, not just our bodies, but our minds as well. This will allow perfect virtual reality. No heavy goggles and headphones, no computerized gloves. We will simply plug virtual reality into our senses and experience an alternate physical existence that will be totally real to us despite its absolute artificiality. It is possible that, as technological species gain this ability, they retreat from true physical reality into a much more pleasing virtual reality.
On the individual level this virtual reality would be more appealing because it could be forged to our will. The argument that we prefer true reality because it surprises us doesn't hold either. Virtual reality can easily be programmed to produce "places" that we don't know about in advance that we can then explore. We might even be able to program our minds to temporarily forget they have an alternate truer physical existence, just for the sake of experiencing the virtual reality from within. We might even be in that state right now, waiting to wake up when the alarm goes off. Pretty wild, huh?
On a larger civilization level, it should be possible to network everyone's minds together in any way that is desired. This allows more versatile communication, and in the end, more personal relationships.
It is possible that the allure of such an existence, when compared to static and unimprovable real reality, is a completely totally all-superior force. It may be true that no advanced species can resist this temptation (and why not, it doesn't sound bad does it?) and that consequently all the advanced ET civilizations out there consist of permanantly hibernating minds. Perhaps the planets that these beings live on are protected by ever-evolving, ever-improving robotic sentinal armies that ward off invaders and keep every individual's mind humming along nicely by replacing computer components whenever necessary. Maybe all we would find in exploring the galaxy is planets like this, hidden under unpenetrable defense systems with no interest in meeting us because they have created a replacement reality that suits every conceivable need, including curiousity, that they could ever have. Perhaps we are destined for the same fate. Perhaps we won't venture out in the universe because we too, in the very near future, will attain phenomenal virtual reality and will consequently simply shut our doors and go to sleep literally forever.
Whether this scenario counts as pro or con ET depends on your point of view. Strictly speaking in such a scenario ET exists, right? However, these beings will definitely live an extremely xenophobic and harshly defended solitary existance. It will be dangerous to exit conscious oversight of the present universe because invaders could arrive anytime and these beings will literally be asleep at the wheel. It is possible that confronting such beings would not only be dangerous (because their defensive systems may defend very very harshly) but might also be entirely futile. With a perfect fantasy existence at their beck and call, they may have no interest in interacting with us. Picture someone high on the most pleasing drugs we have, drugs like heroin. While under the influence of such euphoria, the only thing a person wants is to be left alone to enjoy the sensation. Nothing in dismal grayscale reality can compare to the wild appeal of drugspace. So do these ET count? We can't communicate with them, we can't learn from them, we can't trade cultural or technological currency with them. Plus it is possible we are on the same path and will become sleeping beauties ourselves, in which case we will close ourselves off and consequently never meet them, isolated islands of dreaming minds. Does this count as a galaxy populated with life that is waiting for us to explore and meet it that we will eventually explore ourselves? Not really.
I would really like to hear what people think of this. Feedback is not only welcome, but desired and appreciated. Keith Wiley, kwiley@cs.unm.edu