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It is 50/50: Either they do or they dont
July 28, 2011 5:49 PM   Subscribe

Are We Alone In the Universe? New Analysis Says Maybe. In a new paper published on arXiv.org, astrophysicist David Spiegel at Princeton University and physicist Edwin Turner at the University of Tokyo argue...using a statistical method called Bayesian reasoning...that the life here on Earth could be common, or it could be extremely rare — there's no reason to prefer one conclusion over the other.

Salient quote from the article:
While it's true that life arose quickly on Earth (within the planet's first few hundred million years), the researchers point out that if it hadn't done so, there wouldn't have been enough time for intelligent life — humans — to have evolved. So, in effect, we're biased. It took at least 3.5 billion years for intelligent life to evolve on Earth, and the only reason we're able to contemplate the likelihood of life today is that its evolution happened to get started early. This requisite good luck is entirely independent of the actual probability of life emerging on a habitable planet.

"Although life began on this planet fairly soon after the Earth became habitable, this fact is consistent with … life being arbitrarily rare in the Universe," the authors state. In the paper, they prove this statement mathematically.

Their result doesn't mean we're alone — only that there's no reason to think otherwise. "[A] Bayesian enthusiast of extraterrestrial life should be significantly encouraged by the rapid appearance of life on the early Earth but cannot be highly confident on that basis," the authors conclude. Our own existence implies very little about how many other times life has arisen.


from the paper:

By constructing a simple model of the probability of abiogenesis, we calculate a Bayesian estimate of its posterior probability, given the data that life emerged fairly early in Earth’s history and that, billions of years later, sentient creatures noted this fact and considered its implications. We find that, given only this very limited empirical information, the choice of Bayesian prior for the abiogenesis proba- bility parameter has a dominant influence on the computed posterior probability. Thus, although life began on this planet fairly soon after the Earth became habitable, this fact is consistent with an arbitrarily low intrinsic probability of abiogenesis for plausible uninformative priors, and therefore with life being arbitrarily rare in the Univers

Some criticism of the analysis already emerging.
posted by Potomac Avenue (111 comments total) 18 users marked this as a favorite

 
tl;dr version: Yeah, we're still totally guessing about all of this.
posted by cmoj at 5:54 PM on July 28, 2011 [14 favorites]


In other words: We have no idea whether or not there is life and we do not have sufficient evidence or knowledge to make an educated guess as to one way or the other.
posted by Malice at 5:54 PM on July 28, 2011 [2 favorites]


We have a whole bunch of places in the solar system that seem like they could support life-as-we-know-it. One (Sol III) has it for sure. One (Sol IV) almost certainly did and maybe still does but we're working on narrowing that down. And a bunch of others (Europa, Enceladus, etc.) we have very little info on, but none of the very circumstantial chemical, etc investigations we've done have been inconsistent with it.

And whenever we look at trying to mimic the individual steps in the lab, it's always surprisingly easy, even if we haven't gone a->z yet, and likely won't for a long time.

While almost all of this is speculation and circumstantial, what we DO know sure does make it look like you get the basic pieces together and life is the default.
posted by John Kenneth Fisher at 5:56 PM on July 28, 2011 [5 favorites]


Their result doesn't mean we're alone — only that there's no reason to think otherwise.

I don't think this idea is as novel as they think. Only because we haven't seen evidence of it, which is pretty much how science works, you know, evidence based. Solid evidence.

I just find the idea of no other intelligent life totally improbable. The numbers are just too huge. Planets around stars. Stars in the galaxy. Galaxies in the universe. If there is no one else, what an incredible playground we have, and also, wtf?
posted by IvoShandor at 5:56 PM on July 28, 2011 [6 favorites]


What are the statistical chances of two intelligent lifeforms independently concluding that there's only a 50/50 chance that the other exists?
posted by odinsdream at 5:57 PM on July 28, 2011 [7 favorites]


Assuming the conditions under which life can arise are not unique to our solar system, and assuming another species capable of comprehending us as sentient exists at this time, and assuming this species exists within a distance from which they can detect us, and assuming this species possesses the capability of contacting us...

...we've certainly given them plenty of bloody good reasons not to want to, haven't we?
posted by Faint of Butt at 5:58 PM on July 28, 2011


What are the statistical chances of two intelligent lifeforms independently concluding that there's only a 50/50 chance that the other exists?

50/50?
posted by philip-random at 6:03 PM on July 28, 2011 [1 favorite]


Appropriate musical accompaniment.
posted by Joey Michaels at 6:04 PM on July 28, 2011 [1 favorite]


50/50?

1 in 42.
posted by IvoShandor at 6:04 PM on July 28, 2011 [5 favorites]


One (Sol IV) almost certainly did and maybe still does but we're working on narrowing that down.

Really? That's the consensus these days?
posted by auto-correct at 6:09 PM on July 28, 2011


So much science fiction involves elder, godlike extraterrestrial races looking down on Johnny-come-lately earthlings or guiding humanity. How bizarre that it could end up the other way around!
posted by kimota at 6:10 PM on July 28, 2011 [1 favorite]


No way we are the only ones.

As to why they aren't talking to us nobody knows. My preference is we are not too interesting to the ones who know about us. My worst nightmare is that it is a law of nature that right after an ecology makes nukes the whole thing almost always goes ka Boom.
posted by bukvich at 6:13 PM on July 28, 2011 [1 favorite]


I'm not ready to give up yet, but yeah, in spite of the fact that there's never been any evidence of extra-terrestrial intelligence, the thought of the alternative strikes me as, well, alien.

How crazy it could be that Earth not only sustains life, but is where all life in the Universe begins.

Or, you know, would have if not for budgetary shortfalls.
posted by Navelgazer at 6:13 PM on July 28, 2011 [6 favorites]


Really? That's the consensus these days?

I dunno about that, I haven't read all the research. But we do know that much of Mars was once covered with water. Everywhere on Earth that there is water there is life. The deduction isn't difficult from there.

Also wouldn't earth be Sol d, and Mars Sol e based upon the current naming scheme endorsed by the IAU?
posted by IvoShandor at 6:20 PM on July 28, 2011 [1 favorite]


Did it ever occur to these scientists that everyone else in the universe is fucking with us?
posted by digsrus at 6:21 PM on July 28, 2011 [11 favorites]


"Maybe we're alone" is not the same thing as "We don't know".

Also, what does "its evolution happened to get started early." even mean?
posted by benito.strauss at 6:22 PM on July 28, 2011


There's either a philosophical or a technological hitch that stops civilizations from expanding and/or surviving. A little over a hundred years after steam engine we had Cuban missile crisis and a near miss with erroneous detection of missile attack in the 80s.

There could easily be a scientific experiment that looks incredibly tempting but, in a way that's impossible to foresee, creates a bubble of true vacuum or something of the sort.

Or it could be that any sufficiently advanced philosophical system develops to the point where expansion or even survival itself are seen as barbaric and crude as cannibalism seems to us.

Otherwise it's hard to see how any civilization that must have appeared in the last few billion years failed to expand at near light speeds.
posted by rainy at 6:25 PM on July 28, 2011 [7 favorites]


Did anyone think of just sending out a message that says "MARCO"?
posted by tumid dahlia at 6:26 PM on July 28, 2011 [8 favorites]


Did it ever occur to these scientists that everyone else in the universe is fucking with us?

I like this. Like there are a bunch of sentient species out there but they treat Homo sapiens like the guy at the party who is largely ignored and then passes out first and wakes up to find a bunch of Sharpie-drawn penises on our collective foreheads.

Beats being alone. I guess.

Except for the penises.
posted by joe lisboa at 6:27 PM on July 28, 2011 [3 favorites]


Any sufficiently complex system is indistingushable from being fucked with
posted by The Whelk at 6:27 PM on July 28, 2011 [43 favorites]



Beats being alone. I guess.

Except for the penises.


Spreak for yourself
posted by The Whelk at 6:28 PM on July 28, 2011 [3 favorites]


I find it funny that so many prefer being fucked with as opposed to there not being anyone to fuck with us in the first place.

I also count myself among those who would prefer there are folks out there fucking with us. But consider Earth: we could be the first. JTB reference.
posted by joe lisboa at 6:30 PM on July 28, 2011


As to why they aren't talking to us nobody knows.

My favorite theory is bandwidth. Imagine an asteroid belt converted to computronium, populated by uploaded consciousnesses. If you head out to the stars, you'd lose your 100 PB/s connection to your culture. Who'd want to have to funnel all they have to say through a comparatively narrow bandwidth laser comm channel. And think of the latency! By the time you get to the gas giants it's already taking minutes to get a return message. If even talking to a Pluto explorer would be dreadfully dull, why on earth would waste power signalling some primitives who live light years away?
posted by justsomebodythatyouusedtoknow at 6:32 PM on July 28, 2011 [4 favorites]


Alone + penises + something beating something = joke that writes itself.
posted by joe lisboa at 6:32 PM on July 28, 2011


"Are We Alone In the Universe?"

I prefer the question by The Fixx: Are We Ourselves?
posted by bwg at 6:32 PM on July 28, 2011


Perhaps there exist more complex and recondite forms of organization than life, and we lack the perspective to perceive them.
posted by clockzero at 6:33 PM on July 28, 2011


I just find the idea of no other intelligent life totally improbable. The numbers are just too huge. Planets around stars. Stars in the galaxy. Galaxies in the universe. If there is no one else, what an incredible playground we have, and also, wtf?

No one else... yet.

It sounds like their point is that the possibility that we're the first is higher than we intuitively feel it is when we assume without evidence that we're an average example of life - which we do because we're working from a sample size of one.
posted by anonymisc at 6:34 PM on July 28, 2011


The thought that keeps me up at night is "what if we're currently the most advanced species in the universe?"
posted by Joey Michaels at 6:34 PM on July 28, 2011 [2 favorites]


That's awful
posted by The Whelk at 6:35 PM on July 28, 2011


Humans are so impatient. What's a couple hundred years?
posted by seanmpuckett at 6:35 PM on July 28, 2011


"We are a way for the cosmos to know itself" :)
posted by anonymisc at 6:37 PM on July 28, 2011 [1 favorite]


tl;dr version: Yeah, we're still totally guessing about all of this.

It was the Drake equation which convinced me of that.

R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = don't know yet, but we may find out some day
fℓ = nobody has the slightest idea
fi = nobody could possibly know that
fc = some poorly-defined number we might guess at
L = well it's probably more than zero, but that's about all we know
posted by sfenders at 6:37 PM on July 28, 2011 [5 favorites]


"All I know is my gut says: 'maybe.'"
posted by Eideteker at 6:41 PM on July 28, 2011 [1 favorite]


Billions and billions. That is all.
posted by chmmr at 6:42 PM on July 28, 2011 [3 favorites]


My favorite obligatory YouTube musical accompaniment on this topic: Vlad the Astrophysicist. (Sorry Joey, this one is directly related to astrophysics, other civilizations, the probability that they exist, and drinking beer. I will give you this, Monty Python rocks. I spent many a rainy Saturday listening to this song, drinking orange soda and playing video games at a friends house in the 80s...)
posted by Nanukthedog at 6:42 PM on July 28, 2011 [1 favorite]


The title of this post is from one of my favorite poker jokes by pro player Kenny Tran: "All poker is 50/50 baby. Either you win, or you lose. So, 50/50."

I find that very profound on the subject of probability.
posted by Potomac Avenue at 6:43 PM on July 28, 2011 [1 favorite]


Mathematical masturbation: easier to get published than just masturbating the old fashion way.

The argument boils down to:

Let's assume that Earth-like planets that are habitable have X% of forming life "rapidly". By the way, we won't specify Earth-Like, or "rapidly". We'll also assume X is really, really low.
Now, let's assume that X% actually differs between these planet.
Let's assume our planet had a high X%.
Therefore other planets have a low X%.
Therefore life isn't likely on other planets.
posted by kithrater at 6:47 PM on July 28, 2011 [4 favorites]


As a frequentist I hail this latest triumph of Bayesian analysis.
posted by docgonzo at 6:47 PM on July 28, 2011 [8 favorites]


My gut feeling is that there are two reasons life hasn't contacted us:

A. Temporal separation. If you look at the Earth, it's had intelligent life and civilization for a tiny percentage of its lifespan. Unless civilization survives for a really long time (and it's hard to see how that would work with resource depletion, ecological damage, etc.), even the Earth may only have intelligent life for a millionth of its lifespan. Even if intelligent life is ultimately pretty common, it's easy to see how this might result in it never really contacting other civilizations.

B. Physical separation. The theory of relativity really makes it sound like there just isn't going to be any way to send information faster than light, and thermodynamics suggests that space travel isn't ever going to be cheap, either. Maybe rockets and radio really are the best the universe has to offer. This would limit most civilizations to the scale of their planetary economy, which means very few species are going to spend the absolute fortunes that the slow methods of travel cost or waste the tons of energy on the extremely slim chance that anyone might be listening.
posted by Mitrovarr at 7:05 PM on July 28, 2011 [7 favorites]


Between this and the news that FTL travel is impossible, it's a bad week to be a SF fan.
posted by briank at 7:11 PM on July 28, 2011 [3 favorites]


While I concede that it seems incredibly unlikely that we will ever come into contact with other sentient lifeforms, I find the possibility of being completely alone in such an incomprehensibly large universe to be appalling. Somehow the idea that the universe in all its vastness only contains one species sentient enough to explore and understand it seems like a hideous waste to me.
posted by yasaman at 7:13 PM on July 28, 2011 [4 favorites]


What's "other intelligent life"? What's the significance of other intelligent life? What if there's intelligent life, but we're completely unable to communicate with it? What if we just never run into each other? I would find that shit hilarious.
posted by Eideteker at 7:16 PM on July 28, 2011 [1 favorite]


Here is the Jets to Brazil reference I was alluding to: http://www.youtube.com/watch?v=8g2p00k_ZgU

There is something quite powerful about the line: Consider Earth / we could be the first whenever discussion of sentience in the Universe comes up. Maybe it is just me.

Meaning: maybe it is just us.
posted by joe lisboa at 7:17 PM on July 28, 2011


It's a good thing that the universe doesn't care about its facts hurting people's feelings otherwise it would be really bummed out all the time.

Either that or it does care but there are so few creatures with feelings that it can successfully ignore those twinges while it goes about expanding or cooling or making pretty nebulae or whatever it is up to these days.
posted by Potomac Avenue at 7:17 PM on July 28, 2011 [1 favorite]


My favorite theory is bandwidth.

That was the Accelerando idea, as I recall -- which is an attractive solution, but I think it suffers the same flaw as a lot of other theories, which is that it assumes that these societies are unreasonably (IMO) monolithic.

You can have the most aloof, or introspective, or incurious, or carefully silenced interstellar civilizations you want, but if they really are interstellar civilizations they surely constitute trillions of individuals, and all it takes is one who doesn't follow the pattern. I just don't find it plausible that everyone out there is so universally in agreement.

I tend to buy two (unrelated) factors:

1. Life is easy, intelligence is rare. I think analyses like the one in the article put way too much emphasis on the initial spark of life and too little on the series of events that push it toward intelligence. Life on Earth started very quickly, but it was 3 billion years until the Cambrian explosion. Likewise, if the K-T event hadn't happened, is there any reason the Earth couldn't have gone another 100 million years with Paleozoic life?

2. It costs money to advertise. Already we've replaced a lot of wasteful omnidirectional broadcasts with direct communication channels that produce much less leakage, and compressed what we do send. (Perfect compression should be indistinguishable from random noise.) We look for other civilizations by looking for energy they're wasting, but an arbitrarily advanced civilization would waste almost none and would thus be nearly invisible. I think we would have to notice them by the entropy they create -- something in a star's brightness, or a planet's orbit, indicating energy being drawn out of the system. A tall order, to say the least.
posted by bjrubble at 7:21 PM on July 28, 2011 [6 favorites]


Space is so big we might as well be alone.
posted by humanfont at 7:25 PM on July 28, 2011 [6 favorites]


I'm not sure which idea is sadder, but these seem like two of the three most likely hypotheses:

1) We're alone.

2) All the other sentient species live too damn far and we'll never be able to contact each other.

Luckily the third is:

3) We just invented the radio a couple of centuries ago, people! We've only started to look. In a couple of decades or centuries we're gonna find out that the universe is TEEMING with intelligent life.

I'm really hoping for #3.
posted by callmejay at 7:27 PM on July 28, 2011 [3 favorites]


Here's something I've never heard discussed before: why are we looking for signs of life when we should be looking for signs of intelligence? Could there be such a thing as intelligence without life involved? How would that even work?

No I don't mean space terminators. Well maybe I do a little.
posted by Potomac Avenue at 7:27 PM on July 28, 2011 [1 favorite]


Seems highly unintelligent to be inviting unknown space critters to our neck of the woods.
posted by dave78981 at 7:28 PM on July 28, 2011 [1 favorite]


What are the statistical chances of two intelligent lifeforms independently concluding that there's only a 50/50 chance that the other exists?
posted by odinsdream at 5:57 PM on July 28 [1 favorite +] [!]

1 in 42.
posted by IvoShandor at 6:04 PM on July 28 [2 favorites +] [!]

Probably closer to two to the power of two hundred and seventy-six thousand to one against, and falling.
posted by FatherDagon at 7:29 PM on July 28, 2011 [3 favorites]


I can't recommend enough Paul Davie's excellent little book on this very topic.
posted by Bromius at 7:33 PM on July 28, 2011


If I understand this (and statistics and probability have always boggled me a bit, I must admit, even though I have a math degree), the idea is that with a sample of precisely one known case of life arising, we can't say much about it arising elsewhere. With each new case we find, even of microscopic life forms, on, say Mars or the jovian satellites, we would be able to make better predictions about how often it might arise else-elsewhere.

Which seems reasonable.
posted by stavrosthewonderchicken at 7:35 PM on July 28, 2011


While logically I know the chances of finding another intelligent ( whatever that means, for values of, using very specific technologies) civilization out there are so slim as to be NIH, the teenager who hitchhiked to Princeton To hear Dr. Tarter give a speech says KEEP LOOKING DAMN YOU I NEED THIS
posted by The Whelk at 7:37 PM on July 28, 2011 [1 favorite]


It's a good thing that the universe doesn't care about its facts hurting people's feelings otherwise it would be really bummed out all the time.

Either that or it does care but there are so few creatures with feelings that it can successfully ignore those twinges


Either that or it does care, but it's also malicious and an asshole.
:)
posted by anonymisc at 7:38 PM on July 28, 2011 [1 favorite]


Where Is Everybody? is the plate-of-beans approach to the question.
posted by neuron at 7:47 PM on July 28, 2011


My favorite scifi novel in my head is that humans are either lowly animals or food of the universe. If the aliens ever need cannon fodder for a war or an emergency food source, they know where to find us. Then they'll come for us. In the meantime, who wants to deal with such an ignorant, backwards race. We're like a planet of carrot tops.

But really, we don't know anything. We've only been around for a blink of eye, barely have a grasp on the planets and moons in our own solar system and just managed to send some tiny craft outside of it. We've only been exploring space for 50 years, less than human life span. Meanwhile light from stars and galaxies that we can see is millions or billions of years old. There's probably intelligent life form around one of those stars, casting one of it's 4 imaging tentacles to the sky, wondering if it's all only. Millions of years from, an image of Adolph Hitler will finally reach their sensors and man are they going to be disappointed.
posted by Brandon Blatcher at 7:48 PM on July 28, 2011 [1 favorite]


My favorite theory is bandwidth...And think of the latency!

So the latency is too prohibitive for ChatRouletteUniverse? Damn!
posted by troll at 7:48 PM on July 28, 2011


"While logically I know the chances of finding another intelligent civilization out there are so slim as to be NIH"

The National Institute of Health?
posted by Eideteker at 7:50 PM on July 28, 2011


Nil, but with extra typo flavor.
posted by The Whelk at 7:51 PM on July 28, 2011


LOL Bayesians - the hammer is so awesome, all the problems must be nails. They're like the furries of the math world. Weird, shunned, probably wrong, oddly arousing.
posted by Slap*Happy at 8:14 PM on July 28, 2011 [10 favorites]


Life is probably common. Intelligent life that is recognizable to humans, has as at least radio technology, is close enough to interact with and will exist long enough for communication to take place? Probably not. There are probably extraterrestrial dolphins twice as smart as us who can't make radios because they don't have hands.

Jared Diamond's output for the Drake Equation is 1-2 civilizations per galaxy at any given time at best.
posted by spaltavian at 8:25 PM on July 28, 2011 [1 favorite]


In particular, if we knew the probability per unit time
and per unit volume of abiogenesis in a pre-biotic environ-
ment as a function of its physical and chemical conditions
and if we could determine or estimate the prevalence of such
environments in the Universe, we could make a statistical esti-
mate of the abundance of extraterrestrial life. This relatively
straightforward approach is, of course, thwarted by our great
ignorance regarding both inputs to the argument at present.


Douglas Adams, is that you?
posted by dsword at 8:28 PM on July 28, 2011


Haven't they found some ancient dna on asteroids? Given that water bears can survive in space, I'm willing to bet that at least a few extremophiles have occupied the niche of "desolate space rock". Hasn't Penelope Boston found life in hermetically sealed caves, so subterranean that life could not have migrated? The notion of 'intelligence' in this debate seems like more of a philosophical concept than a biological characteristic. Cetaceans have been conjectured to have spoken language, ants practice agriculture, and chimps make spears.
I'm fond of Gaia theory, the notion that the planet can be considered as a single organism. That theory's flaw is that we have not seen the earth reproduce. I like to think that we are the planet's gonads, intended to terraform other planets into earth-like copies, in a process similar to bacterial conjugation.
posted by MisplaceDisgrace at 8:41 PM on July 28, 2011 [2 favorites]


Time is the major factor. The galaxy may be teeming with intelligent life, but most likely we'll never see it because our (and their) time window of existence is so fleeting. If we could find that radio waves from space left some sort of permanent imprint in the geologic record (not sure how - rocks? carbon? ice?), it might be possible to look back over the past few billion years for evidence of intelligent signals that passed by Earth.
posted by stbalbach at 8:41 PM on July 28, 2011


spaltavian: "Jared Diamond's output for the Drake Equation is 1-2 civilizations per galaxy at any given time at best."

I wasn't aware that Diamond had dipped his toes into speculative astrobiology. I thought he was strictly a history/anthropology/resource-studies academic. Do you have a link for the work you mentioned? GG&S and Collapse were great reads, I'd love to check out his take on Drake. (If it's in either of those books I'll eat my foot).
posted by troll at 8:49 PM on July 28, 2011


On the plus side, if we are alone, then all these worlds are ours... including Europa! Who's up for attempting a landing there?
posted by No-sword at 8:49 PM on July 28, 2011 [2 favorites]


Might we say that we're part of an intelligent universe, and that we're one of many ideas/memes generated by that universe? If we're alive, we have to be a part of something that sustains life, right? We're a subset of the universe, no? Would "discovering" another life form really mean discovering something discrete from ourselves, or seen as a part of ourselves>

Another strange thing that is that posing these questions puts us in a place where we're trying to figure ourselves out. Is that even possible? Every time we pose a question we impact the thing that we are trying to analyze; it's like a cat chasing its tail. The very quest begs all kinds of questions. (Wittgenstein claimed that an entire philosophy could be built from the interrogative, from questions. We can't get outside of ourselves, or the universe (at quantum levels). We're "stuck" with what we perceive ourselves to be (accepting the fact that our perceptions evolve - conceptually and physically - maintaining multifarious diversity at all times).
posted by Vibrissae at 8:51 PM on July 28, 2011 [1 favorite]


Assuming the conditions under which life can arise are not unique to our solar system....

Well that's the problem. Previous attempts to estimate the probability of extraterrestrial life relied on the idea that our solar system was typical. But as we have found out, there is a huge diversity in the way planetary systems can evolve, none of which inherently involve a planet that has conditions similar to Earth. Add to that limited galactic zones for habitable planet creation, gamma ray bursters and other threats, and it begins to look like planets continually having conditions favorable to life must be extremely rare.

Add to that the fact that we don't know how difficult it is to go from life to intelligence, but bear in mind that for nearly all of the history of life on Earth, life merely consisted of bacteria, and while there's been a number of near misses, technological intelligence has evolved only once. That doesn't give much confidence in it's inevitability.

Not depressed enough yet? Well let's note that even if we do find a technological civilization out there, we won't actually be seeing them, but their past. If they are 10,000 light-years away, a trivial distance by astronomical standards, we would be seeing 10,000 years into their past, a time longer than recorded civilization here. There could be an advanced civilization in a nearby galaxy right now, one that's been around for tens of thousands of years, and even if we could detect them, we couldn't possibly know about them for hundreds of thousands of years.

Even if there's billions of civilizations in the universe, distance and time mean that detection is unlikely, and communication merely a fantasy. Effectively we are alone, and always will be.
posted by happyroach at 8:52 PM on July 28, 2011 [2 favorites]


In the last few years we have found radically different forms of life on Earth. Bacteria deep in African mines, that live on radiation, that new big black fungus, living on radiation at Chernobyl, arsenic eating bacteria. We are designed to see our food, our mega predators, we are not designed to see energy, or anything really different from our current situation. The idea that we think, we can out think the cunning of awareness, and its proclivity for inhabiting chemically active systems, is charmingly innocent. Humans want to see life, as if they were looking in a mirror. Humans want to know intelligence, that is intelligible, pinned to what we know. We should definitely be more appreciative and nurturing of what we have here, and the intellectual luxury we enjoy. Navel gazing is not for the starving, or for the immediate victims of war, or for the cunning who view life and intellect as an economic resource to be exploited. These talking heads do have some cush jobs, and keep yer danged hands off the other planets in our solar system, they belong to themselves. "I wonder, wonder, wonder,wonder, who, who wrote the book of love?" The Monotones.

Well, and then views of space show what look to be horrible catastrophes, galactic collisions, taking place in some indescribably slow dance, the chaos of crashing stars, and giant clouds of ripped apart reality, and again I think our navel gazing must be a luxurious state. The universe can look back upon its doings through us and this is quite possibly why we are in existence.

"Somebody get me a cheeseburger!" Steve Miller
posted by Oyéah at 9:34 PM on July 28, 2011 [3 favorites]


The scientists seem to argue that because it took billions of years for live to evolve a species with sufficient intelligence to have space-faring technology that there's on reason to believe that it happened anywhere else any faster. The idea being that "life started really fast on Earth but intelligence took billions of years more."

That's specious argument. They're putting their thumbs on the scale against abiogenesis and saying life is arbitrarily rare.

This is like saying that because Earth flipped a coin 5 times and got 4 tails before it got a heads that you have no reason to expect that anyplace ELSE would get a heads in any fewer flips.

I will not accept that 3.5 Billion years from Life to Technology-using intelligence is normative, and I will accordingly not accept the notion that panspermia is impossible at the same time that abiogenesis is arbitrarily rare.

I will assert without any fear of contradiction that, on the various planets in the universe that outnumber the grains of sand on Earth, there were plenty where the window between life starting and technology using intelligence is measured in millions of years, not billions.

Methinks that either this is really horribly shitty science journalism, or the scientists who published this arxiv paper have an insufficient grasp of the law of large numbers.

When you're talking about the universe, those numbers are really REALLY large, and when you say that something is "arbitrarily rare" in a universe as big as it is, you're actually saying its existence is "a veritable certainty, in abundance."
posted by chimaera at 9:59 PM on July 28, 2011


Now don't get me wrong, we very well may be "alone" in our light cone (Fermi paradox style), but to steal their usage, our light cone is arbitrarily small compared to the size of the galaxy, and our galaxy is arbitrarily small compared to the rest of the universe.
posted by chimaera at 10:05 PM on July 28, 2011


Seems like an awful waste of space.
posted by fungible at 10:13 PM on July 28, 2011 [2 favorites]


On the plus side, if we are alone, then all these worlds are ours... including Europa! Who's up for attempting a landing there?

f*** that. let's invade Europe.
posted by philip-random at 10:32 PM on July 28, 2011


chimaera: "I will assert without any fear of contradiction that, on the various planets in the universe that outnumber the grains of sand on Earth, there were plenty where the window between life starting and technology using intelligence is measured in millions of years, not billions. "

Out of curiosity, what (besides the number of planets) makes you so sure of this? Without another evolutionary path to compare, how can we assume that evolution could be sped up by several factors?
posted by Hardcore Poser at 10:45 PM on July 28, 2011 [1 favorite]


What if intelligence is entirely anthropomorphic? What if other sufficiently advanced lifeforms where grey eel-like blobs floating in water using electrical pulses to create patterns devoid of any meaning other than to make interesting geometric electrical waveforms interesting to nothing but itself?

The universe could be filled with wild-assed lifeforms that don't lend themselves to reaching humans. Maybe they did the math and decided, ahh fuck it?
posted by roboton666 at 12:53 AM on July 29, 2011


Somewhere in a distant part of the universe, over the span of tens of millions of years, sentient life forms on two planets separated by less than ten light years. They broadcast, and discover each other. Eventually, they meet.

That doesn't happen to us.

fin
posted by eddydamascene at 1:01 AM on July 29, 2011 [12 favorites]


Out of curiosity, what (besides the number of planets) makes you so sure of this? Without another evolutionary path to compare, how can we assume that evolution could be sped up by several factors?

I think it helpful not to think that evolution has a specific point or direction. Life on Earth didn't change much from the very first multicellular organisms until the Cambrian explosion. If the circumstances were right at any time, that massive expansion and variegation of life could have happened far sooner (or far later). Evolution isn't something that requires minimum lengths of time to happen -- just the proper circumstances.

It took a meteor to finish off the dinosaurs and let the little furry mammals flourish and expand into all those evacuated niches. But mammals had been around since the Triassic. Had the mammals had the upper hand in the Triassic (for whatever reason), it's well within the realm of possibility that something like humans could have evolved nearly 250 million years ago. And this is if I assume that mammals are a "necessary" path to technology-using intelligence. If the circumstances were right for us, why could they not have been right for any animal with a brain at any point in the last billion years?

Literally at any time during the period of complex animal life, any animal with the proper selection pressures could have developed higher intelligence. Evolution has a very, very low "minimum" speed -- many bacteria and even animals are minimally changed in hundreds of millions of years. However, evolution doesn't really have (much of) a "maximum" speed. Under the right circumstances, in just a couple dozen million years you can go from a mammal that is basically a shrew to a human. There's no clear reason why one couldn't start from *any* land animal with a brain to technology-using intelligence in that period of time.

So, with some very plausible premises:

1) The Cambrian explosion could have happened 500M years earlier (plausible if oxygen-creating organisms had been much more plentiful and successful).

2) Land animals evolved ~100M years after that (this is basically what happened, land vertebrates came along about 150M years after the Cambrian explosion during the Carboniferous)

3) One of those land mammals evolved intelligence over the course of 50M years (the timeline that takes us basically from shrews/lemurs to humans).

... you can end up with tool-using intelligent creatures 800 million years ago, without even resorting to massively unlikely (on Earth) circumstances. The only real "long pole" in the evolutionary tent that sets the timeline is an atmosphere gaining critical oxygen levels by cyanobacteria/algae/etc. And on a planet where oxygen might have been more plentiful in the atmosphere to start with, who is to say that it could not have been merely millions of years from the first complex animal life (animals with specialized organs including a brain) to tool users?
posted by chimaera at 1:33 AM on July 29, 2011 [6 favorites]


That was all rather long-winded, but when talking about the realm of evolutionary possibilities, and I know this is skirting dangerously close to a tautology, but if an animal has selective pressure that massively rewards intelligence and technology use, that animal can very easily go go from tooth and claw to simple tools to flying in cans in space after just tens or hundreds of thousands of years.

And that's just a blink of time, universe-wise.
posted by chimaera at 1:43 AM on July 29, 2011


Intelligent life will never contact us until we lose our religion
posted by rh2 at 3:26 AM on July 29, 2011


Somewhere in a distant part of the universe, over the span of tens of millions of years, sentient life forms on two planets separated by less than ten light years. They broadcast, and discover each other. Eventually, they meet.

I think this could be very close to the truth. What if first contact is generally disastrous or alternatively a non-event, in that life forms are too different to communicate, or lack sufficient interest in each other, or are openly hostile or at least resource-starved, or too outright alien in terms of ethics... If this were generally true, those civilizations who are inclined to vast exploratory journeys (which may be a small fraction of total intelligent life, that which is land-based and fortunately located on relatively small gravity wells) might intentionally stop looking after engaging in the massive technical challenge that was discovering one, and turn inward. This would narrow the communications window even further, as the chance of finding an amicable alien civilization in a relevant timeframe would be much smaller, and finding certain unfriendly types might bring further attempts to a halt. (Other random thoughts of mine include the necessity of ocular vision for astronomy, another quirk of evolution which didn't turn up until the Cambrian explosion. Different paths to intelligence could potentially not involve it at all, and lack our fascination with the sky.)

A final thought is that intelligence and tool-using do not necessarily go hand in hand with the rapid capitalist technological innovation which enabled EM broadcast technology, among other goodies. We have been toolmaking and practicing basic agriculture for at least 10 000 years, but we didn't really pick up the pace until the last couple hundred, due to very specific social pressures. Even amongst human societies pre-globalization, that kind of instability and associated rapid change was anomalous. What if there was no New World and associated colonization rush? That was just a fluke of geography, but essential to getting to where we are today, for good or ill.

It's possible that intelligent creatures with different reproductive strategies and social structures would find a stable state and not have space races or world wars or any of that other human stuff. We can see plenty of examples of this on Earth already, as we are not unique as intelligent tool-using animals.
posted by mek at 3:42 AM on July 29, 2011 [2 favorites]


Intelligent life will never contact us until we lose our religion

That's me in outskirts
That's me in Sol System
Losing my religion
Trying to keep up with you
And I don't know if I can do it
Oh no I've transmitted
Broken broadcast silence
I thought that I saw you drooling
I thought that I heard hunger
I think I'm scared we'll be entreés
posted by stavrosthewonderchicken at 3:45 AM on July 29, 2011


Fly me to the moon
Let me sing among those stars
Let me see what spring is like
On Jupiter and Mars

In other words, hold my hand
In other words, baby kiss me

Fill my heart with song
Let me sing for ever more
You are all I long for
All I worship and adore

In other words, please be true
In other words, I love you
posted by stavrosthewonderchicken at 4:34 AM on July 29, 2011


Let's assume we are alone.

Then maybe we won't be so Hell-bent on exterminating ourselves.
posted by bwg at 5:41 AM on July 29, 2011


What if peaceful intelligence = non-expansion. And warlike = expansionist.

Then the intelligences that we want to meet don't care to meet us. And the ones that we'd hate to meet are actively looking for us. As well, since we have already started expanding via probes and rockets. doesn't that make us the people we'd hate to meet?
posted by Splunge at 5:58 AM on July 29, 2011


Then the intelligences that we want to meet don't care to meet us. And the ones that we'd hate to meet are actively looking for us.

It's just like online dating.
posted by Nixy at 6:19 AM on July 29, 2011 [4 favorites]


3) We just invented the radio a couple of centuries ago, people! We've only started to look. In a couple of decades or centuries we're gonna find out that the universe is TEEMING with intelligent life.

Interestingly, the first sentence leads to your conclusion being invalid. Consider this graphic depicting the sphere of our electromagnetic transmissions.

Any intelligent life outside of that sphere cannot know we exist, even if it was right next door. That's only our galaxy, of which there are billions.

The reverse is obviously true as well. Look at that little group of three stars just above and to the right of our sphere. Even life right there wouldn't be obvious to us for at least a thousand more years.

Couple this with the reality that we don't even observe a small fraction of the sky 100% of the time. Life indeed could be everywhere and we'll never, ever notice it.
posted by odinsdream at 6:22 AM on July 29, 2011


I'm fond of Gaia theory, the notion that the planet can be considered as a single organism. That theory's flaw is that we have not seen the earth reproduce. I like to think that we are the planet's gonads, intended to terraform other planets into earth-like copies, in a process similar to bacterial conjugation.

There is a particularly sad James Tiptree story A Momentary Taste of Being, which is sort of on this theme. Admittedly, I'm not sure there's any such thing as a not particularly sad Jame Tiptree story.

Although in Kim Stanley Robinson's Mars books, there's a sort of mystical idea that "greening", spreading life, is the underlying force that drives everything.

Me? I've been sad for years, ever since I realized in the nineties that space travel was almost certainly too expensive and too resource-intense to ever become widespread. I would go to Mars with the First Hundred, I would leave with the aliens like in "The Women Men Don't See", I would sell my people out to the Culture - just show me the way.
posted by Frowner at 7:13 AM on July 29, 2011 [3 favorites]


The reverse is obviously true as well. Look at that little group of three stars just above and to the right of our sphere. Even life right there wouldn't be obvious to us for at least a thousand more years.
This is not entirely correct. If they start broadcasting today, then yes, it's correct, but if they've been broadcasting for a thousand years (or whatever), there's nothing stopping us from detecting them today except ourselves.
posted by Flunkie at 7:14 AM on July 29, 2011


As is often the case, Randall Munroe puts the matter rather concisely: http://xkcd.com/638/
posted by sotonohito at 7:21 AM on July 29, 2011 [1 favorite]


@Flunkie There's good reasons to suspect that omnidirectional radio broadcasts are only a very briefly used technology. We've declined from our peak use ourselves.

Worse, they tend to be relatively low powered and would probably be stopped by the sun's ionosphere. You'd need a receiver array out around Saturn to really have any hope of picking up random omnidirectional radio.
posted by sotonohito at 7:25 AM on July 29, 2011 [1 favorite]


"Absence of evidence is not evidence of absence." - Carl Sagan
posted by tommasz at 7:33 AM on July 29, 2011


If you consider that spacetime is a continuum, there is life all over the universe, whether it starts here or not. Eventually, life will be spread throughout the universe, and in that sense it already has happened.
posted by chaz at 7:40 AM on July 29, 2011


Are We Alone In the Universe? New Analysis Says Maybe.

- The Onion
posted by mrgrimm at 8:22 AM on July 29, 2011


We're almost certainly not alone in the universe, but just as almost certainly, we might as well be. Whoever else is out there, we'll never reach them and vice versa.
posted by rusty at 8:26 AM on July 29, 2011


I'm fond of Gaia theory, the notion that the planet can be considered as a single organism.

If you're going to go that far, you might as go all the way and include the universe as a single organism. I'm not sure what it will get you, though.
posted by mrgrimm at 8:26 AM on July 29, 2011 [1 favorite]


A lot fewer organisms?
posted by rusty at 8:27 AM on July 29, 2011


We're almost certainly not alone in the universe, but just as almost certainly, we might as well be. Whoever else is out there, we'll never reach them and vice versa.

That kinda seems like the takeaway here. After all, the visible universe is 28 billion light years in diameter, which might only be the beginning. That seems really big to me.

Did it ever occur to these scientists that everyone else in the universe is fucking with us?

I think more likely is that our instruments (and/or perceptions) are too limited to make accurate assessments of almost anything on a universal scale.

As is often the case, Randall Munroe puts the matter rather concisely:

I like Randall, but that's stupid. It's a decent analogy *if* the universe were the size of ... Angel Falls?

In the grand scheme of things Us:Universe::Ants:Universe. Using the link above, ants are 4mm long and humans are 1.7m long. Ignoring whatever the actual size of the total universe is, the visible universe is 8.24x10^25 bigger than us and 3.5x10^28 bigger than an ant. The kitchen:ant analogy is just stupid.
posted by mrgrimm at 8:53 AM on July 29, 2011


When you consider the truly incomprehensible number of galaxies, stars, planets etc. out there, you have to go with the odds. I mean, here we are, and that can't just be a huge cosmic crap shoot. But then again, Sagan made a great point when he said that no matter how long it takes or under what conditions, Somebody has to be the First. Maybe us?
posted by TDavis at 8:57 AM on July 29, 2011


One of the reasons why I'm a skeptic WRT aliens and SETI is that we really have little comprehension of the vastness of deep time. Even if we optimistically say that a civilization is sending out EM signals for about a million years (which is a time frame that can only be understood abstractly), that's less than 1% of the age of the universe. That other civilization may have peaked and died in the Jurassic, or may only develop the first radio telescope after Homo sapiens becomes extinct.
posted by KirkJobSluder at 9:28 AM on July 29, 2011


In the grand scheme of things Us:Universe::Ants:Universe. Using the link above, ants are 4mm long and humans are 1.7m long. Ignoring whatever the actual size of the total universe is, the visible universe is 8.24x10^25 bigger than us and 3.5x10^28 bigger than an ant. The kitchen:ant analogy is just stupid.


....I kind of think you missed the point Randall was trying to make.
posted by EmpressCallipygos at 9:51 AM on July 29, 2011


I like Randall, but that's stupid. It's a decent analogy *if* the universe were the size of ...

I laughed but then I didn't read the analogy as being about size. I read it as looking for the wrong kind of evidence. That is, an ant being ant-centric is going to look for the kind evidence an ant would leave (pheromone trails). Humans being human-centric tend to make the same mistake (ie: we're looking for radio waves whereas the alien may be the size of a planet, it may be a planet the size of Jupiter, it may be Jupiter, an nth dimensional entity that reveals itself via all encompassing psychedelic impression that, to our sensory mechanism, is indistinguishable from a dream, the alien may be a dream).

And so on. This is why we will always need new and improved sci-fi.
posted by philip-random at 9:55 AM on July 29, 2011 [1 favorite]


So here we sit, in our cozy simulation, and y'all are debating about "life" in the "universe". LOL! The question is really, is there a universe still out there? And is there still any life in it? Could our simulation continue in the abscence of the builders?
posted by Goofyy at 10:09 AM on July 29, 2011


I laughed but then I didn't read the analogy as being about size.

I thought it was about both - wrong evidence, lack of perception of scale. He specifically mentions "dozens of kitchen tiles" - but the scale thing is ridiculous.
posted by mrgrimm at 11:06 AM on July 29, 2011


I would sell my people out to the Culture - just show me the way.

Oh hell yes.

This is not entirely correct. If they start broadcasting today, then yes, it's correct, but if they've been broadcasting for a thousand years (or whatever), there's nothing stopping us from detecting them today except ourselves.

I'm imagining a lovely little Processing example using random ripples in a field. The field represents the galaxy or universe. Ripples start at the point civilizations reach the technical capability to transmit signals, expand at the speed of light, and stop when the civilization dies or discontinues use of omnidirectional signaling.

Consider that a ripple must intersect a currently-active civilization for there to be contact. It's not enough for the ripple to pass through the point where a civilization was, unless, as discussed above, there were a way to detect past presence of radio transmissions in physical matter.

You can probably imagine that you could radically bump up the life density in such a simulation while still having very minimal or absolutely no contact between civilizations.
posted by odinsdream at 11:40 AM on July 29, 2011


I find it deeply gratifying that anyone makes pronouncements of any kind about what we know to be true. It demonstrates tremendous optimism and a really touching earnestness and "if we all work together, we can be the BEST, SMARTEST HUMANS EVER, guys" attitude.

As nearly as I can tell, we think we know some things about the universe and how it works. But the problem is that what we think we know is, well, predicated upon our understanding of how the universe works. And there is a mind-blowing shit-ton of stuff we don't understand about how the universe works.

So, yes, for now we're pretty confident that Einsteinian relativity works. We have empirical evidence that seems to tell us, yes, this is a thing that happens. Which is great. But we have not the first goddamned clue what we don't know.

Considering the amount of time humanity has been capable of doing science, and the constantly revelatory nature of what we've learned just in that short time, my money is on us being just flat-out wrong about almost everything. We can't go faster than light? Okay, I'll accept that for exactly as long as it takes us to discover that thing we didn't know about that permits us to go faster than light.

The numbers are completely stacked against us being the only form of life in the universe. It's a common-sense conclusion that's also backed up by the fact that we can't even begin to approximate a tentative guess at how many stars or planets there are. Shit, we don't even know how big the universe is.

Speculating on this stuff is awesome and it's nice someone's trying to quantify things, but it's a little bit like a housefly going "Guys, I'm pretty sure I'm the only form of intelligent life in this Large Hadron Collider, because nothing ever happens heeeEEEEEEEEEEEEEEEE HOLY SHIT AAAAAAAA"
posted by scrump at 11:46 AM on July 29, 2011


Well, hence my question. Sure, there's life out there, but what's the chance we'll be able to meaningfully interact with it, given distance, timescales, and exotic forms of intelligence? Because some people are looking for "life." Others are looking for "intelligent life." And I'd bet a large percentage are looking for "life that's like us." By virtue of being self-organizing, life is bound to happen wherever it can, but will it be like Star Trek, or like Lem?
posted by Eideteker at 12:02 PM on July 29, 2011


Are We Alone In the Universe? New Analysis Says Maybe.

I hate these filthy neutrals.
posted by ROU_Xenophobe at 12:21 PM on July 29, 2011


I hate these filthy neutrals.

Bizarre. I saw that episode just last night.
posted by cmoj at 1:55 PM on July 29, 2011


Hmm. Reading the thread, I don't think there's an adequate understanding of Bayesian thinking... or of Bayesian thinkers.

OK. You have a way of thinking about the universe that is solely dictated by probability calculated on the fly. No, really, you do.

The Bayesians take this, and put real probability math behind it. The type of math that really lends itself to computational proof. To the point where most of them are busy beavering away at software to bring about singularity eschaton... a computer program that can predict its own outcome. It's not AI research as we know it, it's dangerous punk-rock, cut-yourself-goth AI research.

Every now and again, they stumble out from behind thick velvet curtains on blood-stained platform heels with a shockingly accurate prediction that can be used to meet real-world goals.

This is not one of those times. They got caught up in reality as it applies to Bayesians, which is generally profoundly uninteresting angels-on-the-head-of-a-pin bullshit.

If they said, "Other life in the universe is unlikely", that would be something. Instead they said "Life in the universe being likely and life in the universe being unlikely, are equally likely!"

Only in Bayesworld is that even a remotely interesting conclusion, mostly because it means they can use it to live forever in Singularity-land, somehow.
posted by Slap*Happy at 9:20 PM on July 29, 2011 [1 favorite]


So the latency is too prohibitive for ChatRouletteUniverse?


All those guys jerking off... All turned to dust....
posted by Trochanter at 8:13 PM on July 30, 2011


Like wanks ....in the rain
posted by The Whelk at 9:53 PM on July 30, 2011


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