One of the relatively minor annoyances of the 21st Century is the devolution of the Discovery group of cable channels into a horror show of pseudo-science and assorted other disinformation. Prominent among these offerings are “documentaries” of visits, ancient or contemporary, to the Earth by “aliens,” short-hand for super-intelligent extra-terrestrial creatures. Sorry, but to put it delicately, I must call bovine manure.
Not that I don't, now and then, enjoy a good fantasy as much as the next guy, but these lamentable productions distort what real science is, and worse, distract from real challenges facing us, such as climate change, resource depletion, and overpopulation.
However, I suppose that believers in the alien fantasies, and their enablers, may have gathered comfort from recent news stories to the effect that astronomers have calculated that there are hundreds of billions of Earth-like, and hence life-hospitable, planets in our galaxy alone. While this may well bolster the case for extra-terrestrial life, it doesn't do much for the notion of alien visits.
There are a number of reasons for my skepticism, but one of the major ones is Einstein's theory of relativity. According to the theory, the speed of light limits the velocity with which we can travel. This may or may not apply at the quantum (unimaginably tiny) level, but in the context of our own activities, it appears to be well-proven. This means that even if we could drive a space vehicle at the speed of light, it could consume lifetimes to reach the nearest habitable planet. (Yes, it might not appear so to the travelers, but that effect isn't relevant to the discussion.) For those mounting (and financing) such an inter-stellar expedition, there would be no discernible return, not even a report of success or failure, in their lifetimes – if ever. I'd love to see NASA try to get funding for such a project. I can't see even Richard Branson touching it.
Another important aspect of the theory of relativity is the not-so-small matter of the amount of energy needed to propel such a vehicle close to the speed of light. The higher the velocity, the more energy needed to kick it along. And, of course, it would take an equal amount of energy for the deceleration at destination. At a time when our energy resources are becoming increasingly costly and difficult to find, it would be absolute folly to commit any significant proportion to so dubious an enterprise as an inter-stellar expedition.
But that's us. Isn't it possible some stupifyingly advanced civilization could overcome these difficulties? After all, there's been some serious speculation that with ion (or anti-matter – Thor save us) drives, the use of so-called worm holes in the universe, or the use of curvature in space, inter-stellar travel might be possible. Our sun is a comparative late-comer to the universe's party, so there's been time for such a civilization to emerge.
Possibly reasonable points (OK, I'm being generous), but in assessing the likelihood of visits from representatives of such a civilization, there are several aspects to consider.
A major consideration is how much of a fluke humankind is. For hundreds of millions of years, life on Earth flourished nicely, thank you very much, without some creature with a hypertrophied brain to screw with every part of the biosphere. For most creatures, a brain is a necessary evil – an energy-consuming organ which should be as large and complicated as consistent with survival but no larger.
So how did ours get so freakishly big?
There are a large number of probably unprovable hypotheses floating around, but the more plausible ones posit that it has something to do with walking on two legs and fluctuating climate change, which in turn has something to do with the current configuration of the continents. So an improbably lucky concatenation of circumstances enabled our ancestors, and latterly us, to become major players in the evolutionary drama.
Well, how likely is it that a similar concatenation could lead to similarly sentient beings on other planets? On the face of it, it would seem to be an unlikely event. But given the apparently huge number of life-hospitable planets available throughout our own galaxy, and the bazillion galaxies extant in the universe, what is unlikely becomes pretty much a dead certainty – perhaps many times over. Our own existence is proof it can happen.
So it seems quite possible, maybe even probable, that E.T. Is out there somewhere. But how likely is it he has come, or is now, calling on us? To answer that question, we would need to have some notion as to E.T.'s nature. But how could we possibly inform ourselves of that?
Well, given the lack of any reliable direct evidence, any assertion about E.T., even the most tentative, would be speculation. But perhaps we could indulge in somewhat informed speculation. After all, we do have an example of an intelligent life form with which we are well acquainted – ourselves. Now it may seem questionable, not to mention arrogant, to attempt to generalize from that one example. Nevertheless, there do appear to be certain imperatives to the operations of life which can point to E.T.'s probable nature.
The first is the defining characteristic of life – a self-replicating complex molecule with enough wiggle room in the replication to enable viable variation. The second is the necessity for raw materials to provide the wherewithal for the replication and energy to enable the replication. Given those conditions, life is off to the races.
And a race it is. Unfortunately, the finish line is death. Put a strain of yeast into a vat of grape juice, at a reasonable temperature, and the little buggers will replicate (reproduce) like mad, right up to the point where the alcohol they excrete as waste kills them all.
So it turns out no organism we know of can keep its numbers down to a sustainable level without outside “help.” Which brings us to a third defining characteristic of life – life lives at the expense of life. In a finite world, there is never enough material and energy to enable unlimited reproduction. So the various life forms compete for these necessities, and one form the competition takes is the predation of some forms on others.
Actually, we could say the entire animal kingdom preys, directly or indirectly, on the plant kingdom, since only the latter, by virtue of photosynthesis, holds the key to storing solar energy directly as usable, energy-yielding, chemicals. Not that plants don't compete, they do – for space and access to light and nutrients – and the competition is just as vicious and lethal as any in the animal kingdom, even if plant competition occurs in silence and slow motion. But I digress.
The animal kingdom raises predation to a fine art. Big 'uns eat little 'uns all the way up the food chain, although, as far as land animals are concerned, there are large, in fact very large, herbivores. And, to keep their numbers in check, there are also large carnivores to prey on them.
Now it doesn't seem to take much brain power to be an herbivore – since you've got to spend most of your time grazing (your food yields low amounts of energy, so you've got to eat lots of it), you just need enough smarts to stay with your herd (if you don't have a herd, you're toast), join in defense when threatened, and mate if you can. Not much potential there for developing a super-brained, technologically-sophisticated, star-hopping species.
Of course, it doesn't necessarily take a lot of brain power to be a successful predator either. Alligators and Crocodiles aren't noted for their smarts, and they've been around since the dinosaurs' heyday. But, if you're going to get into the predation game in a major way as a latecomer and as a relatively puny and poorly-armed player, enhanced brain power may be your only option. You can't outfight 'em, but you can outwit 'em.
It would be a good idea to develop weapons to compensate for your lack of innate armament. A rather nasty, aggressive, grasping, and paranoid nature wouldn't hurt either, as long as its tempered by some benevolence for your in-group. And your prowess can be enhanced further if you can master the use of some external energy source. Like fire, for instance. It can make your food more digestible, allowing you to operate with a smaller, more energy-efficient gut. It can frighten off bigger, better-armed predators. It can warm you, allowing you to spread into more cold, hostile areas.
In fact, once you've reached that plateau, pretty much ain't no other species, herbivore or carnivore, gonna mess with you. Well, maybe sporadically in self-defense or desperation, but by and large, you've got it made. The only things keeping your numbers in check are disease and your propensity to let out your aggression by murdering your out-group fellows.
But in our case, that wasn't enough – we became too numerous for hunting and gathering to support all of us. So we had to figure out a more efficient way to get our food – agriculture and animal husbandry. Only trouble is, over the long haul they're not sustainable. Soil depletion, salinization, deforestation, desertification – they all take their toll. So it didn't take all that long until once again we were bumping up against the limits on the capacity of the Earth to sustain us.
Until we discovered a cache of external energy that surpassed anything we'd known before – coal, oil, and gas – you could say our real holy trinity. And that's the final improbable stroke of luck enabling our civilization. For hundreds of millions of years, various life forms lived, died, and laid down their carcasses to be worked on by heat and pressure to yield burnable and otherwise useful organic compounds. Without fossil fuels our technology couldn't have advanced beyond that of the 17th Century. Harnessing the power in these fossil fuels has enabled us to breed way, way past the natural carrying capacity of the entire planet. At least in the developed countries, every mouthful of food is eaten courtesy of a prodigious expenditure of fossil fuel – chiefly oil. And even in the underdeveloped world, fossil fuels play a major role by way of fertilizers and cooking fuel.
So, enabled by the cheap and abundant energy provided by fossil fuels, we have achieved a civilization so technologically-sophisticated that we can start thinking about inter-stellar travel, even though we haven't figured out a feasible method of accomplishing it.
And, of course, we never will.
Whoa, big fella – isn't that a pretty bold statement? Are you really putting a limit on human ingenuity?
Not exactly. I'm putting a limit on the time and resources requisite to effectively exercise that ingenuity. (For the grammar purists, yeah, I split the infinitive. Tough.) The unfortunate fact is that fossil fuels are a finite resource, and there is no viable substitute. All the cheap, easy sources are gone or are in decline, and we are figuratively close to scraping the bottom of the barrel – if we are not already there. The same may be said of most of the materials, metals, minerals, soil – even water, crucial to maintaining the industrial way of life.
So in all likelihood, industrial civilization is going to collapse, and humanity is going to go through a monumentally catastrophic die-off, which will put paid to any notion of a junket to the stars. Stone age technology, which is what we will be left with, just won't cut it.
Well, what does that have to do with E.T.?
Let's review the bidding. Unless super-intelligent E.T. Sprang into existence full-blown, like Athena from Zeus' headache, an extremely improbable event to understate things, E.T. Would have had to emerge from a long process of evolution similar to that which produced us. Which means he would be far more likely to be bellicose than benevolent, and short-sighted rather than a long-view thinker.
Why the latter you may ask? Well, evolution proceeds by baby steps. There is no over-all goal, and any slight genetic survival advantage accruing to an individual will be passed on to his/her/its offspring. Until changed circumstances render it no longer useful.
In other words, evolutionarily speaking, Yogi Berra's adage applies: “When you come to a fork in the road, take it.” And, by and large, clever as we may be, we don't operate much differently. We use what works and advantages us now, and let the future look out for itself. Long-range wisdom is not in our nature. Just consider how, in the period of a couple of centuries, we have burned through our endowment of fossil fuels, one built up over an unimaginably long period. Not to mention all the waste we have created in the process. But that's another story (hint: think of yeast, alcohol, and a vat of grape juice).
Is there any reason to suppose a clever alien species, enjoying our extremely improbable advantages (including a huge cache of fossil fuels), would be any wiser? Well, given the evolutionary imperatives we've outlined, as the Brits would say – Not bloody likely.
Enrico Fermi once asked, apropos of alien visitors, “Where is everybody?” I submit the answer is they're stay-at-homes because: 1. They never advanced beyond the stone age because they never possessed an abundant and cheap source of energy, or 2. they did, but they burned through it quickly and stifled themselves on their own waste and are now extinct, or 3. they managed to avoid extinction but never figured out a way around the limits set by the theory of Relativity, or 4. they did figure out a way, but they couldn't figure out a way to make it pay, or 5. they could make it pay on some pristine planets, but a plundered, depleted, and polluted planet like Earth simply isn't worth the effort.
As an addendum, Stephen Hawking is probably right – if E.T. did show up, the results would likely be as unpleasant for us as it was for the natives of Hispaniola when they encountered Columbus. Good thing we'll likely be gone if it ever happens.