The Indigestible

As both a consumer and producer of SF, I confess to being enamored of the idea that there is extraterrestrial life out there. I get a kick out of the idea of Little Green Men in small, disc-shaped craft flitting happily from star to star, and I like the way SF permits us to question ourselves in ways that many other entertainment genres do not.

Films such as The Day the Earth Stood Still — and television shows such as the Twilight Zone episode “The Monsters are Due at Maple Street” — served an extraordinarily crucial social need, questioning the wisdom of belligerence, the merits of clannish tendencies, the value of naked aggression in the face of the unknown.

The original Star Trek series served the dual purpose of being American democratic/progressivist propaganda and showing us a future, suggesting that humanity had a future — and in the late 1960s, that was not a given.

Movies such as E.T. can reach deeply into the compassion of the human, letting us see as beloved that which is least human — yet, graced with intelligence, still recognizably kin to us.

Nevertheless, as much as I enjoy such fare, I have to recognize at the end of the day that it is not, strictly, science fiction; it’s closer to fantasy. Even my belief in extraterrestrial life is merely that; it’s a confession of faith, not anything I can rationally ground in the plausible.

I’m introducing a new category of post at TI with this writing: UFnO. It’s going to deal exclusively with why I’m essentially certain that Earth never has been visited by extraterrestrial life, is not now being visited by extraterrestrial life, and — here’s the kicker — never will be visited by extraterrestrial life. Along the way I’ll be going into why, exactly, I don’t believe we will ever encounter intelligence in the universe, regardless of how advanced we become.

I don’t currently have any plans to actively pursue claims on an individual basis. I don’t really think it’s necessary. For instance, showing how at least some “crop circles” have been made by very human pranksters, I believe, effectively casts doubt on the nonhuman origins of all “crop circles” by raising the parsimonious likelihood that any one “crop circle” might have been produced by a human agent.

That is, it’s much more likely that any one “crop circle” was made by a human or group of humans than that it was made by aliens or spooky supernatural forces that we have yet to discover, since we know for a certainty that humans make “crop circles”, but we have yet to confirm that aliens have ever made one.

Thus debunking “crop circles” individually becomes a waste, and could become obsessive. And, as anyone who pays attention to the net knows, the last damned thing we need is another obsessive Web site.

I’ll begin by playing fair and debunking my own faith in life off of Earth — or, more accurately, showing exactly why it’s faith, not a sensible or defensible perspective to believe that there may be life out there somewhere.

The First Problem: Paucity

Let’s start with what we know, what we can be totally certain of: Life exists here, and doesn’t seem to exist anywhere else on any of the planets or moons within our reach in this solar system. There may be some places in Sol’s demesne where life could have gained a toehold once (Mars); there may be places where some form of life — as we’d recognize it — may be eking out an existence now (Europa); however, there is only one world within our detection radius that inarguably is teeming, and we’re currently on it.

(I’m aware that there are some who would argue that life could take forms other than the carbon-based that we recognize, but until someone with the appropriate degrees in the appropriate sciences can clearly demonstrate how such non-carbon-based human-recognizable life could exist, let alone what it would resemble, I’ll relegate such objections to the realm of the sufficiently improbable to ignore. This could be arrogance, but to me it’s simply practical. As soon as we open the door to, say, “sentient energy”, we quickly find ourselves bogged down in all sorts of silly ideas.)

This doesn’t tell us as much as would be desirable. We really can’t infer a damned thing from the apparent relative sterility of our solar system, but we can infer that there must be at least some conditions in place before life can really be expected to appear.

The first is some kind of stability, but it doesn’t have to be overdone. Life is astonishingly robust, surviving in conditions here that are, in some cases, incredible. There are bacteria that live near suboceanic volcanic vents, thriving in the darkness in water that would poach any fish — or human — that got close. This suggests that conditions for the development and persistence of life might not be particularly fragile, which could give us reason to hope that, eventually, we’ll find traces on Mars which suggest life did exist there, at least for a while.

What can’t happen is total environmental collapse, which absolutely did happen on Mars. The atmosphere leached away, and along with that went liquid water and, if they ever existed, anything that had been able to develop and evolve in the early morning of our solar system. Take away water and (possibly) some kind of air, and you’ve basically guaranteed extinction.

The second prerequisite for life appears to be water. There isn’t a hell of a lot of that in liquid form anywhere but on Earth; it’s feasible that Europa may have liquid water somewhere under its layers of ice, and possibly enough raw materials to even sustain life, assuming it got started there.

But that leads to a first major question about life. We have an idea what conditions it needs to survive — liquid water seems to be the bare minimum, plus of course nutrients and such — but we don’t know exactly what it needs to get started. Did life begin with RNA? Or with RNA-like proteins moiling about in some rich primordial broth? Well, how, exactly?

Crystaline lattices in clay, for example, are interesting to discuss, but if they were what taught RNA how to be RNA, what does that say about the likelihood of life elsewhere in this solar system? Does Europa have clay deposits? Did Mars?

Life appears to be robust — but there are some pretty good circumstantial reasons to think it might be rare.

The Second Problem: Scale

What does rarity mean, though, in a galaxy as large as (for instance) the one we inhabit? The Milky Way contains something between 200 to 400 billion stars, of which perhaps 60 to 120 billion are sufficiently like our own to produce conditions similar to what we find in our solar system. (Yes, I realize that second link is to an analysis of the Drake Equation, which I’m presenting here in a less numbers-intensive way.) We have to take into account that our solar system might lie in a habitable galactic zone — if so, we may be left with a paltry 20 to 40 billion stars that could have life-sustaining planets orbiting them.

That’s a huge number, though, of stars like our own that may have worlds like our own orbiting them. An absolutely huge number, which would make it seem almost certain that millions, perhaps billions, of them have terrestrial planets — on which one, surely, life may be found. Right?

Guardedly, yes … or at least maybe. It’s plausible, it’s not infeasible, that life exists somewhere, but it is absolutely not certain.

And this is where the real problem of scale rears its head.

There’s a star very similar to our own in local space; it’s called 18 Scorpii, so named because it’s the 18th brightest star (by visual magnitude) in the constellation of Scorpio. It has nearly the same mass, brightness and spectrum as our own star, and is almost certainly the same age. It’s not quite Sol’s twin, but it’s close enough.

It is also about 30 light-years away.

That means that if we were to send a message to a planet orbiting 18 Scorpii, it would take 30 years for that message to arrive, assuming (1) a terrestrial planet orbiting it; and (2) life on that planet capable of intercepting and comprehending our message attempt, whch would almost certainly take the form of radio. So we’d have to wait 60 years, at least, before we even got a reply.

Well, we’ve waited at least that long — and heard nothing.

Wait, you may be thinking; we sent a message already? In 1945 or so?

We have indeed been sending messages out to space, and we began well before 1945. Actually we’ve been sending messages since 1897. This means that our self-possessed monologues and dialogues have been pouring more or less continually out into space for nearly 110 years in an ever-expanding sphere that, by definition, is now 220 light-years in diameter.

If we follow our pattern with 18 Scorpii and give our Little Green Men the chance to respond to our message, we have a sphere approximately 100 light-years in diameter from which we could expect to hear a reply any time — and that sphere contains more than 500 stars similar enough to our own to satisfy our life-nurturing requirements.

To date, we have heard nothing.

Radio and similar communications channels are probably all we’ll ever have for talking to the neighbors, because of the absolutely insane distances between stars. (I’ll go more into that in another post.) The point here is that it seems reasonable to presume that the 500 or so stars like our own which might have intelligent life as we know it don’t appear to, at least not yet.

(And yes, the stars in question should be like our own. Larger stars put out a lot of radiation and don’t survive very long; smaller stars are low-radiation and might not even have planets.)

The Third Problem: Intelligence is Not the Goal

Where we get our teeth kicked in is when we realize that there is nothing, absolutely nothing, in the process of evolution that guarantees intelligence (though several cetacean, cephalopod and primate species here seem to have acquired quite a lot of it), and even given the presence of intelligence, there’s no further guarantee of technology.

Of the current intelligent species on Earth, only two are observed to be tool-making animals. Of those two species, only one has developed radio. This means that we, though we imagine ourselves to be the pinnacle of nature’s design, don’t really need to be here; intelligence simply isn’t part of any grand scheme, whether goddish or evolutionary in nature.

From the standpoint of most other species, we were objects of indifference for millennia, though lately of course we’ve become rather dangerous. But the way we view the world — indeed, evolution itself — we have a bias that all the mutation, natural selection and speciation has led to us, took place in order that we might be, when in fact no such thing has occurred.

If technology-bearing animals — one of one hundred million or so species — arrived here on Earth as an unexpected byproduct of results of a stochastic process, how likely is it that such creatures have evolved elsewhere? (We aren’t the only intelligent, tool-making species ever to have lived here; we’re just the most recent, but all the tool-wielders are on the hominid line with us.) The odds against our brand of intelligence arising again here, given identical initial conditions, seem to be at least 100,000,000:1.

We can’t meaningfully measure the odds of intelligence on other worlds, with unknown initial conditions and developmental features. It might be more likely; it might be less. The safest bet is to assume it’s about the same as here, and what we must continually remind ourselves — what hurts our ego most — is that evolution is not a process that moves toward a goal such as intelligence; there is absolutely no inevitability in the arising of self-awareness or technology on any species track anywhere.

So the presence of life on a world — any world — even this world — is not an automatic sign that intelligence has, does, or ever will exist there.

Too Few Facts

Let’s revisit our modified Drake, using what we understand now about the odds against intelligence arising on Earth. Say we have reason to be very optimistic and can definitely put life on one planet orbiting each of 120 billion sun-like stars.

We’re left with just 120 worlds that could arguably have animals like us on them, animals with internets and telephones and radio and annoying political debates. (Of course, this assumes evolution’s timescale is the same on each world — a topic for yet another discussion.)

120 worlds is not very many.

It’s so few, in fact, that the only word to express the idea of extraterrestrial intelligence is faith.

Do I believe?

In life out there, yes. In extraterrestrial intelligence? There, I’m a bit more like Fox Mulder. I want to believe, but right now, I can’t. I’d need to see some real evidence first, and in later posts I’ll detail why I conclude that we have yet to find any.