Not long ago I wrote a post in which I compared the traditional characteristics of angels with the characteristics attributed to aliens in pop-culture. I was discussing it with a friend who’d read it, and he initially misinterpreted what I’d written. He took me to be describing what I thought aliens were actually like, as opposed to how they’re described in literature, movies, and so on. I clarified what I meant; but it occurred to me that maybe I should discuss my thoughts on aliens in real life. Onward, then!
The logical starting point in discussing aliens is clarifying our terminology. What most people take “alien” to mean, without explicitly saying it (or perhaps not even explicitly realizing it), is “intelligent life forms originating elsewhere in the cosmos”. In short, alien intelligence is automatically assumed without even taking into the account the probability of alien life. If there is no life in space at all, though, there can certainly be no intelligent alien life. Thus, we have to start at the beginning and ask, “Is there life in space at all?”
Even that question makes unstated assumption, to wit: Are we talking about any life, or only, to use the cliche, “life as we know it”? Life as we know it–that which we see on Earth, including ourselves–is based on carbon. Carbon is the building block of the amino acids that form the proteins out of which life is made, as well as of the RNA and DNA by which genetic information is passed from generation to generation. Things could, however, have turned out differently.
Without going too deeply into the chemistry involved, the reason carbon is so well-suited for life is that the number of valence electrons (electrons in the outermost orbital) in the carbon atom is four. This makes it ideally suited to combining with other carbon atoms and atoms of other elements, forming complex compounds, including the double helix of DNA. Carbon is not the only such element, though–all elements in the same column of the Periodic Table of Elements as carbon have the same number of valence electrons. Elements such as silicon, germanium, tin, and lead, for example, also have atoms with four valence electrons. Thus, any of these could hypothetically serve as a basis for life.
Of course, these elements are still different, and though they combine in similar ways because of their valence electrons, the compounds behave differently. One atom of carbon can combine with two atoms of oxygen to form CO2–carbon dioxide, the gas that we exhale every time we breathe. Like a carbon atom, a silicon atom can also bond with two oxygen atoms, forming SiO2–silicon dioxide. Silicon dioxide is what is more popularly known as “sand”. Same valence electrons, same molecular structure, but quite different results!
Thus, while the elements below carbon in the Periodic Table could hypothetically combine in ways conducive to life, the differences in how they behave and the conditions under which they make compounds make it unclear whether they could, in actuality, be the basis of living things. The only such element, as far as I know, that has been suggested as a basis for life, is silicon. The classic example of this in science fiction is the episode of Star Trek, “The Devil in the Dark“.
My point is that in discussions of alien life, we’re always talking about carbon-based life. That is actually OK. With what we currently know, it is impossible to say whether or not silicon-based life (or life based on other elements) does, or even can, exist. Without knowing what such life would look like, or the types of planets or environments in which such life would be found, there is no reasonable way to seek such life. The same is true for life based on other elements, energy beings, and other such exotic creatures.
Another possibility with regard to extraterrestrial life, assuming it is carbon-based, is its chirality. Chirality is the “handedness” of molecules. Just as my right and left hands are identical, but mirror images of each other, so some molecules are mirror images–right or left-handed version of each other. Just as you can’t put a left hand into a right glove, or a right foot into a left shoe, so molecules of opposite chirality, though composed of the exact same constituent elements, do not combine or interact with other chemicals in the same way.
As it happens, all life on Earth exhibits homochirality. That is, all the molecules of living things have the same “handedness”. Amino acids are always and exclusively left-handed, and sugars are always and exclusively right-handed. No one knows why this is so. It has been speculated that had things been differently, life could have evolved with the different chirality. Perhaps life elsewhere did evolve otherwise. Maybe E. T. has right-handed amino acids and left-handed sugars. This is an interesting possibility, and actually featured in James Blish’s novel Spock Must Die. Be that as it may, the issue here is much like the issue with silicon-based life forms. We simply don’t know if life with opposite chirality from ours exists; and if it does, we don’t know under what conditions it exists. Lacking this knowledge, we have no way of even beginning to look for such life.
Thus, in summary, before we even begin searching for life out there, we have to specify “life as we know it”–carbon-based life with the same chirality as our own. Hortas or creatures with right-handed amino acids may exist; but at the present, there’s no point in wasting our time looking for them.
Having specified all this, let’s proceed to look at the issues involved with aliens, which I will number.
1. Does life exist elsewehre in the cosmos?
Before we get to Vulcans or Klingons or UFO’s, we have to ask whether life of any sort exists outside Earth. As I’ve noted in previous posts, there is evidence, though inconclusive and controversial, for bacterial life on Mars. Amino acids, the building blocks of proteins, and thus of life as we know it, have been found in comets. This indicates that the chemical constituents of life are not rare. Finally, over the last couple of decades, earthlike planets have been discovered orbiting other stars (these are known as “exoplanets”; and the study of life that may exist on them is called “xenobiology”, just to get the terminology down). All of this, in my opinion, indicates a high likelihood of life, at least on the single-celled level, on other planets. If I were to give odds, I’d say the chances of microbioal extraterrestrial life are 90% or higher. Many would say 95% or even 99%, but I’m being conservative. The discovery of even bacterial extraterrestrial life would be momentous, but it would not interest most of us. That brings us to the next question, to wit:
2. Does multi-cellular life exist on other planets?
This is our first step into speculation. Multi-cellular life evolved fairly rapidly on Earth; but Earth is a single data point. I sometimes use this analogy: Suppose no one had ever seen an automobile of any kind, and then one day a ’68 Volkswagen Beetle is discovered. Everything we’d then know about autos would be based on that bug. Some information would be quite accurate–we’d learn all about internal combustion engines. On the other hand, we’d come to some very inaccurate conclusions, e.g. that cars have trunks in the front and engines in the back, that cars are small and have only two doors, and so on. If our only knowledge of cars came from a Beetle, in short, we’d have no way of distinguishing essential attributes (internal combustion engines) from attributes specific to the particular car in question (trunk in front).
Similarly, our temptation is to say that life “must” do such-and-such because it did so on Earth. Some aspects of life–carbon, proteins, DNA, RNA, and such–are doubtlessly essential. With other things, though, it’s less clear. Do microbes inevitably evolve into multi-cellular organisms, or is that just a quirk of how life went on Earth–the trunk in the front of the VW? The same is true for conditions on Earth–which are essential for life, and which are not? It has been speculated, for example, that the moon, being a far larger satellite with respect to its planet than seems to be the norm, is responsible for complex life on Earth. The idea is that by acting as a shield against asteroids and meteors that would otherwise hit Earth, the moon prevented more frequent extinction events, such as the one that killed off the dinosaurs, from occurring. It thus may be the case that on most earthlike planets, complex life tends to get eliminated before it can develop and that we just lucked out. We simply have no way of knowing.
Thus, in giving odds here, I’m going out on a limb. Granted the numerous factors of which we have no knowledge, it still seems to me that the forces driving evolution on other planets would be similar to those at work here. Thus, and admittedly arbitrarily, I’ll lay odds of 75% that multi-cellular life exists elsewhere. Yes, I’m pulling the figure out of my hat–or posterior, if you prefer–but I don’t think it’s unreasonable. That said, while the discovery of the extraterrestrial equivalent of a rose bush or a squirrel would be the most momentous discovery of the century, it wouldn’t really interest most people more than exo-bacteria would. What most people really mean when they ask about life in space is…
3. Does intelligent life exist elsewhere in the cosmos?
The first problem here is that we don’t even have a clear definition of what we mean by “intelligent life”. Some dolphins and whales are highly intelligent, and there are reasons to believe they may possibly be as intelligent as humans, though in a different way. That is, while they lack technology–for obvious reasons, given their aquatic environment–they may well tell tales, recite poetry, compose great oral epics. Given the radical differences between their sensory apparatuses and ours, and the difficulty in figuring out how to communicate with them, it may never be possible for us to know. The point is that if we can’t even be sure if animals with which we share this planet are intelligent, how will we recognize extraterrestrial intelligence when and if we encounter it?*
Of necessity, then, we must adjust the question to, “Does recognizably intelligent life exist elsewhere?” The answer, alas, is, “We have no way of knowing.” After all, we still have the problem that we are once more working from a single data point. Worse, as far as we know, no other Earthly species† ever developed recognizable intelligence besides us, so even on our own planet we’re a single data point. While we have some reasonable ideas as to why multi-cellular life developed, there is still no generally accepted explanation for the evolution of intelligence. We thus have no idea whether the forces that led to our intelligence would be common, or even operative at all on other planets. Given the uncertainties and lack of information, I would say the chances of extraterrestrial intelligence on other planets is 50-50–literally a coin toss.
Even if recognizable intelligence exists elsewhere, most people aren’t very much taken with the idea of extraterrestrial cavemen, or little green men in horse (or thark or bantha) drawn carriages. I said before that what people really want to know is whether intelligent life exists elsewhere. To nuance that, what they really, really, REEEEEALLY want to know is…
4. Do intelligent extraterrestrials with advanced technology equal to or superior to our own exist?
Of all the questions we’ll look at here, this is the most difficult to answer. Even if we specify not only recognizable intelligence, but intelligence that develops an industrial-technological civilization much like our own–perhaps more advanced than our own–the simple fact remains that the variables are so many and the information we have so sparse that there is no way we can even make a coin-toss estimate of the odds.
Being rather full of ourselves, we tend to assume that intelligence is such an evolutionary advantage that it surely must develop wherever life is, and that, having developed, it must inevitably progress to civilization, from there to high technology, and from there, to the stars. It is not, in fact, clear that intelligence is even a long-term advantage for a given species, though, let alone that it leads to space exploration. Homo sapiens has been a phenomenally successful species, spreading to all parts of the planet and making incredible achievements in science and technology. On the other hand, as is evident to anyone with eyes to see, pollution, anthropogenic climate change, war, increasing population, and any number of other factors make our prospects of long-term existence questionable, at the very least.
It has been hypothesized, in fact, that for intelligent species there is a so-called “Great Filter“. The theory is that intelligent species inevitably come up against some challenge or set of challenges in their transition to technology–nuclear war, overpopulation, environmental destruction–and that few, if any, such civilizations are able to rise to these challenges. Thus, they either become extinct, or are reduced to a state of pre-industrial technology. If this hypothesis is correct, we would expect there to be few, if any, intelligent species, at a level of technology similar to our own. This would also throw into question the likelihood of our own continued existence, let alone the chance of our reaching the stars.
Of course, as with most of the other factors we’ve been looking at here, this is pure speculation. It’s reasonable to assume that intelligent life forms similar to us would meet similar challenges; but based on the single data point that is our own planet, we simply can’t generalize. Perhaps most technological civilizations fail; perhaps many or most succeed; perhaps high tech is an aberration, and most societies stabilize at an agrarian level, never progressing beyond a Medieval level of technology. Who knows? Unlike the case with the previous questions, I have no percent to give, even as the wildest possible guess. We have one more question to go, though:
5. Have aliens achieved interstellar travel, and if so, have they (or will they) ever come here?
This question is one on which I can be much more confident in giving an answer. Back here I explained why it is almost certain that humans will never attain interstellar travel. The same reasons would be applicable to alien species, too. The difficulties inherent in interstellar travel are, in my judgement, too great to overcome. Thus, I think that, with the possible exception of unmanned (unaliened?) probes, no extraterrestrial civilization that may have existed in the past or that may exist now, ever has achieved interstellar travel, or ever will. The obvious corollary to this is that they have not and do not come here, and never will in the future; nor will we travel to their worlds, either.
Obviously, not all would agree. Some would point to many anomalies observed over the years, of which the UFO phenomena is only one. Others would argue that advanced civilizations might discover ways of interacting with matter and energy beyond anything we can now even conceive of. I would partially agree with these notions.
As I noted in the earlier post on angels and aliens, there are striking similarities between premodern accounts of encounters with deities, fairies, angels, devils, and such, and modern accounts of alien encounters and other paranormal phenomena. Writers such as Jacques Valée, John Keel, and J. Allen Hynek have postulated that some sort of non-human intelligence inhabiting a realm not quite mental, not quite physical, and transcending physics as we know it, are behind the UFO phenomena (and perhaps other anomalous things as well, such as some accounts of cryptids). Such a concept is obviously highly speculative. Equally obviously, there’s no way even to begin to assign a probability to it. Still, it strikes me as much likelier than actual spaceflight in nuts-and-bolts ships through interstellar space.
Whether such intelligences should be considered “aliens” or not is unanswerable. We don’t even know whether ordinary, run-of-the-mill biological intelligent aliens have evolved or might evolve. We certainly have no way of determining if such life forms might somehow eventually transcend flesh and blood altogether. In any case, if they did originate elsewhere than on Earth, they are still no aliens of the sort we usually envision and they did not come here on starships such as the U.S.S. Enterprise. It would be equally useful–and equally in line with the very little we know–to assume such beings to be angels or demons, or for that matter, fairies. At this point, we are far beyond even the point of speculation.
So, in short: Alien life? Almost certainly. Intelligent aliens? Maybe. Aliens coming here? No, unless they’re so advanced as to be literally indistinguishable from gods and angels. On that note, let me leave you with some psytrance music inspired by…ALIENS!!! Enjoy!
*A good treatment of this problem in science fiction occurs in Terry Carr’s short story “The Dance of the Changer and the Three“.
†Neanderthal Man is usually considered to be a separate species from modern man–Homo neanderthalensis, as opposed to Home sapiens; and Neanderthal man was almost without doubt recognizably intelligent. The same may be true of various other species of early hominids–Homo habilis, whatever species the Denisovans were, and perhaps others. These species were all closely related, however, and for the purposes at hand here, I’m lumping all intelligent hominids together. It is also conceivably possible that some of of the ornithomimid dinosaurs may have developed near-human intelligence. If any such intelligent dinosaurs existed, they evidently didn’t develop industrial technology–after all, no one has dug up pieces of factories from dinosaur-level strata yet (though there have been some interesting suggestions)–and there’s no way we can tell their intelligence from the fossil record. Therefore, all speculations aside, we are the only known species which is intelligent in the way we understand intelligence.
Part of the series “Science and Technology“.
Posted on 09/06/2019, in science, science fiction, space and tagged aliens, biology, exobilogy, J. Allen Hynek, Jacques Vallée, John Keel, psytrance music, science, science fiction, space, space exploration. Bookmark the permalink. 1 Comment.