"There may be no signals from space, yet those with their antennas tuned to more anthropomorphic wavelengths are sure to pick up a buzz of social signaling in people’s attitudes towards the search for extraterrestrial beings. Such social background noise might in fact be one of the main obstacles to intellectual progress on many big picture topics."
I first apologize for being an obstacle to intellectual progress.
I then pose the question:
Is it impossible for Venus to have harboured some form of life (sentient or not) involved in a carbon cycle not unlike ours, hundreds of billion years ago, except (or perhaps similarly...) due to one of the "Great Filter" probability barriers, the life on the planet eventually produced a runaway greenhouse effect, which leads to the current state of Venus today (and over hundreds of millions of years, wiping all obvious traces of life)?
Summary: Author hopes we don't find life on Mars because if it's dead that provides an ill omen for the human race. He thinks if life on Mars wasn't sustainable then he repeats the whole argument that there must be some reason why advanced civilizations can't manage to get off the original rock they're assigned to and that's why we haven't seen any other intelligent life.
Nick Bostrom's reasoning is more complex, but yes, you nailed the summary perfectly. Even shorter: The more complex life on Mars we are going to find, the more we as human race are doomed, says Bostrom. Because as Bostrom wrote in TimGebhardt words: "there must be some reason why advanced civilizations can't manage to get off the original rock they're assigned to" and if there is life on Mars, it could be everywhere in the universe. Nick Bostrom's reasoning: If life could start everywhere else, why haven't we detected it, yet. I think Nick Bostrom should have focused more on the time and randomness factor. Maybe there was life in our galaxy, but they visited us before humans have lived. Or we have been visited (think peruvian desert drawings), but before we as human race were as advanced as we are today and they left our boring planet to visit another galaxy. There are probably more than 170 billion (1.7 × 1011) galaxies...
If the Orion project in the 1960s hadn't been stopped, we might have viable interplanetary colonies already. Also, if NASA hadn't poured most money into the shuttle (and hence had a reason to kill competing projects, for job security) the space exploration/colonization would be much further along.
Even now, we might be less than 50 years from independent colonies, if lower costs for space launch finally "take off" with Musk.
This implies that if there is some common reason (e.g. a physics experiment with unexpected outcome) that exterminates budding civilizations, it ought to have already happened (and we were lucky) -- or it is something big enough to blast a whole solar system.
Edit: It would be interesting with percentage chance evaluation of the possibility that the Shuttle project doomed humanity to extinction...?
Which in itself is a bit weird. Mars and Earth formed in the same solar system, from an orbital disk around the same sun. Similar conditions and building blocks.
Surely whatever improbability would be diminished because of this?
The probabilistic evidence is a bit more indirect, and depends on anthropics:
Since we don't see galaxy-spanning, highly advanced civilizations, there seems to be some combination of factors that prevents planet-bound dirt from turning into them. If those factors are primarily after our stage of development between dirt and galactic civilization, that's Very Bad News, because we shouldn't expect to get extraordinarily lucky. If those factors are primarily before our stage of development, that's reasonably good news, because we've already made it past the hard part.
Seeing bacteria isn't as bad as seeing the ruins of a civilization just past our stage of development. But it does move the probability-mass forward more than if we just found dirt.
There's so many things that can go wrong, during the period needed for advanced intelligent life to evolve. Add to that the inherent difficulty of moving between solar systems. Space is vast, and we're not really making that much noise. I don't see a big paradox here?
It may be a slight cause for concern if we find extinct life on Mars, but for it to be too much of a worry, you have to make quite a lot of assumptions. There are plenty of other explanations for the Fermi paradox that don't include a great filter, and this argument only applies if the life we found was dead rather than possibly still present microbiological life. And it's also assuming the life here and on Mars wasn't seeded from the same place, but Earth was the only hospitable planet.
My view is that it's likely/possible the universe is has quite a lot of life. However, since all evidence suggests the universe had a beginning, between abiogenesis, evolution, and the universe/galaxy/planet being in a state hospitable to life, it might always take a very long time to get the state we're in now, just as it did on this planet. It's quite possible that there are billions of planets with life in some stage of evolution, but few of them are significantly more advanced than our planet's life. Even if there are a smaller number of super-advanced civilisations, they may only have been broadcasting for a few hundred thousand years, and we may not be in range of that, or pointing our antennae at the right place to pick up the very weak signals. Even if they have discovered FTL travel, it would conceivably still take an extremely long time for them to visit every planet in the universe. Even if they have visited Earth in our historically documented timeline, they may not have been interested enough in what they saw to stop by and have a chat. Worse, if they have discovered FTL, they're probably not using radio broadcasts any more.
But that doesn't mean that life is uncommon, or even that there isn't some intergalactic federation of civilisations, just that any given civilisation being significant enough to notice or be noticed happens rarely. I would be far more worried about extra-terrestrials being hostile than non-existent (see Stephen Hawking's views on the matter).
Really, most of these sort of arguments feel quite similar to a bunch of humans sitting around a hundred thousand years ago, discussing with their tribe that they are probably the only humans on the planet, since no other more advanced cultures have communicated with them yet. Even though they haven't discovered any efficient means of transport to actually explore the Earth yet...
I'm really paranoid about loading unfamiliar websites up (I've got a version of Chrome with js and plugins disabled that I use for random links), and pdfs are still a bit of a concern as an attack vector. It looks like this viewtext.org will come in handy.
It's hardly a surprise, though. There's organic compounds everywhere in the solar system. If they found amino-acids it would be a totally different story, but just organic compounds is really rubbish information.
Just to clarify.
This guy -> http://en.wikipedia.org/wiki/Charles_Elachi
in a conference in Rome today said that what they found in Mars was organic molecules. He said it was a "perhaps" because they still have to check the data. He also said that Curiosity can not say if an organic molecule is biological or not, so all they can say is that there are organic molecules. Again, perhaps, until the data checking ends and full data is presented.
All this reported by ANSA.
PD: it was in a conference in La Sapienza, in Rome, hardly a remote and/or obscure university/place.
This news was anticipated by an article in The Guardian as the speculation was building up, "Whatever the Curiosity rover has found, it's not evidence of life on Mars."
The author's evidence for that bold headline claim was earlier reporting on the issue as the speculation built up.
"Whatever Curiosity has found, it is not evidence for life on Mars. It can't be. Curiosity is not designed to look for life. Grotzinger has stated this himself. In a Nasa video about the mission, he says, 'Curiosity is not a life detection mission. We're not actually looking for life; we don't have the ability to detect life if it was there.'
"Following up the internet speculation, Jeffrey Kluger of Time talked to Nasa's Jet Propulsion Laboratory spokesperson Guy Webster and was told, 'It won't be earthshaking, but it will be interesting.'"
Organic molecules (molecules containing carbon) are commonplace in many lifeless places around the Solar system, so this is hardly surprising. It is moderately interesting, but certainly not earthshaking, as previously reported.
AFTER EDIT: Replying to the first reply kindly posted to my comment,
I'm not arguing whether Curiosity has found evidence for life on Mars or not but I would like to point out a logical fallacy in the cited argument; in particular, the statement "device X wasn't designed to do Y" does not imply "device X can't do Y".
I take the statement made by the NASA planners at face value for a simple reason. While the Curiosity rover, with its cameras, would surely be able to detect Martian megafauna, if there were such a thing, for example a Martian elephant, I trust the statement that Curiosity is incapable of providing unambiguous evidence of microorganisms on Mars. I cited the Guardian article in my first posting of this comment. The issue of detecting life, or not, was surely discussed by the NASA mission planners, who included astute exobiologists. The mission profile of Curiosity does not include a task of detecting life on Mars, and the instruments on Curiosity are not reliable for distinguishing organic molecules made by living microorganisms from organic molecules made by purely physical processes. Whatever Curiosity detects with its molecular analysis instruments, it cannot be taken as evidence for life on Mars. That is the statement of the article, based on interviews with people knowledgeable about the planning of the mission, and that is a credible statement, given the amount of thought the mission planners must have devoted to this issue.
They detected organic molecules on Mars decades ago, and we are now seeing proof that those who refused to accept the evidence were wrong. I wish I recalled the name of the scientist that designed the test done in the late 80s. He was far more polite and gracious than he should have been. He detected signs that were EXACTLY what they went in looking for in the first place, no one else even proposed an alternative explanation, they just decided to ignore it with pigheaded stubbornness. I hope news agencies dig up the man (I believe he is still alive, he is mentioned in the fairly recent book '13 Things That Don't Make Sense') and they have some of his contemporaries apologizing for going with their hearts instead of their brains.
I'm not arguing whether Curiosity has found evidence for life on Mars or not but I would like to point out a logical fallacy in the cited argument; in particular, the statement "device X wasn't designed to do Y" does not imply "device X can't do Y".
I think what he(?) was pointing out simply that the lack of design intention doesn't mean lack of functional capability. Certainly my fingers weren't designed to type, yet there it goes. The other side of such a fallacy would be akin to stating that because I can type with my fingers, they must have been "designed" (intelligently?) to type. So abstractly, I have to agree (since it was posed in an abstract variable replaceable way).
In this case, however, since the scientists know what they'd need to "prove" life, they can state that Curiosity doesn't have enough sensor capability to gather such evidence. Rather than stating that Curiosity was not designed to detect life, it would be more appropriate to state that Curiosity is incapable of providing rigorous proof of life.
Now, back to the evidence. Stating that what Curiosity has found is not evidence, may be taken at face value only if we narrow the definition of "whatever Curiosity has found" to the information capable of being gathered and returned, as opposed to the sources of the exhibits under observation (which may or may not have a biological origin, or may or may not be a precursor to biologic functions). A thin metaphysical/epistemological distinction to be sure, but one that is relevant because when we need to trust our senses, we need to know our sensor limits, and when we need to trust remote sensors, extra-terrestrial remoteness is as remote as it gets, and its hard limits cannot be easily overcome once deployed.
Curiosity is loaded with sensors, these can be used to draw conclusions they weren't designed for. Here's an admittedly absurd example: if Curiosity's cameras recorded a Martian puppy running around it, scientists would almost certainly consider that conclusive evidence for life.
It would be evidence but not conclusive evidence. In this case, we might think it was some sort of horrible prank played by a disgruntled scientist who hacked the instruments. But it might be enough for a second mission designed to conclusively verify the existence of life.
What if the Martian puppy started licking Curiosity and started to reprogram the cameras and antennas to communicate with us like an interplanetary telephone system?
That would be a pretty conclusive proof of live even though Curiosity wasn't designed to work in that way.
The ability of a device to detect "life" depends on the assumptions about what types of life one expects to find and what level of certainty is required.
Curiosity could certainly detect certain kinds of life... but not the types of life astrobiologists are guessing might exist near the surface. Curiosity definitely can detect active chemical processes for which there would be few if any non-biological explanations... but after so many false positives in the past the science community has decided that alone would not be definitive proof.
Curiosity was not built to detect life, but it can. However scientific conservatism would likely mean any “yes” result would be interpreted as a ”maybe.”
Organic molecules on mars are nothing new. Methane had been shown in very low concentrations using remote sensing (spectral) methods, but had not been detected directly on Mars so far by Curiosity. This might mean that it has now detected methane after all.
The reason why methane would be exciting is that it is broken down by UV radiation, so there must be some persistent source of it on the planet for a sustained presence.
Does anyone know how this jives with Slate and The Atlantic reporting yesterday that the whole thing was a big misunderstanding and that no big discovery had been made?
Please keep in mind that Curiosity has not the capability to recognize biological molecules, only organic ones. That means that even if it finds current life, it will only be able to recognize the presence of organic compounds. That is why the "organic, not biological"; it may well be biological, but Curiosity cannot know.
Sigh. There is no difference between "organic" and "biological" molecules chemically. There is no "vitalism" force which makes a biological molecule special.
Also, Curiosity is quite capable of unambiguously detecting life on Mars, the question is just a matter of how likely it would be. Curiosity can detect a wide array of organic compounds, and if a sufficient quantity of the right variety of compounds were detected it could be near incontrovertible proof of life. For example, if you fed a pile of fine wood shavings into Curiosity's SAM instrument you would be able to look at the data and go "yup, this is absolutely, definitely, wood, it couldn't be anything else".
The difficulty is that realistically the amount of organic matter from some life form that is sampled by Curiosity could be fairly small and very difficult for the rover to get any useful data out of. That's why Curiosity was not designed as a "life detection mission", which would require other instruments. However, that doesn't mean Curiosity is incapable of detecting life, just that it would likely have to get fairly lucky to do so, and most of the evidence it would gather would likely be fairly circumstantial rather than definitive.
This is all rather speculative though as there has been no information provided on Curiosity's new findings, merely more speculation from people who don't know the findings (in this case the manager of JPL).
"Curiosity - ha spiegato Elachi oggi - non è dotato di strumenti per trovare tracce biologiche", ossia molecole necessarie o prodotte da forme di vita, "ma ha la capacità di riconoscere molecole organiche". Già questa sarebbe una novità importante: tali molecole, composti a base di carbonio, non provano di per sé la presenza di vita, ma senza di loro la vita non può svilupparsi.
If Curiosity founds "formic acid", that is a simple 5 atom molecule, then it is not a proof of life, because there are some non-byological process that create that molecule, so it is distributed everywhere in the universe. (I'm not sure that "formic acid" is the best example, but probably any small organic molecule is a good enough example.)
If Curiosity founds "celulose", that is a very complex ~20000 atom molecules, with the atoms arranged in a very special scheme, then it is almost almost almost sure that it was created by some kind of life, because we don't know any non-biological process that can make it.
The main problem is that there is no distinction between organic and biological molecules, so you can't make a sensor that distinguishes them.
The very simple molecules (formic acid) are expected to be found even in places without life. The intermediate molecules (some sugars, aminoacids, even some nucleotides) are more rare, but not unexpected. The big complex molecules are unexpected, so after discarding everything else, the conclusion would be that in that place there is something living.
A similar problem is "How many grains of rice is a lot of rice?": One is not enough, one million is enough, but there is no a clear border. There is not a clear border between organic and biological molecules; the question is "Is the probability that a molecule like this was created by a life form greater than the probability that a molecule like this was created by an inorganic process?"
> The main problem is that there is no distinction between organic and biological molecules, so you can't make a sensor that distinguishes them.
For a given molecule, life tends to strongly prefer either the left-handed or right-handed version.
Curiosity's gas chromatograph can tell them apart. If it finds a strong handedness preference for several chemicals, then Mars almost certainly has life.
I think you may be confusing liquid chromatography and gas chromatography, gas chromatography afaik can't distinguish between the left handed and the right handed form of a molecule but liquid chromatography mass spectrometry can (and that's not the most sensitive / efficient way to do it either).
One of the GC columns has a chiral stationary phase. Chromotography works whether the carrier fluid is a liquid or a gas. The real problem with gas chromotography is that amino acids have a low vapor pressure. They seem to be chemically functionalizing them to improve the volatility.
What they're talking about is the difference between measuring a dead organism (looking at organic molecules, something Curiosity is capable of doing) on the one hand and performing experiments to detect active biological activity of a live organism on the other hand. Look at the experiments that the Viking Landers carried for examples of this: http://en.wikipedia.org/wiki/Viking_biological_experiments
Is this some kind of job security on NASA's part? The unspoken goal of these mars missions has always been to find life, so why not make sure the rover has every possible piece of equipment to do so. Unless they want to send another one. They certainly have good arguments for the pitch now.
If only it were that easy. Curiosity already is a $2.5 billion roving science lab, quite literally. However, it's necessary to have a guiding principle for what you set out to investigate when you decide what equipment to bring to Mars, and in the case of Curiosity that principle has been mineralogy and chemical composition. Overwhelmingly, Curiosity's instruments are designed to be able to determine the mineral makeup of rocks and the chemical makeup of samples. This gives it the possibility of discovering hints of life if it gets lucky, but overall it's not very good at that role.
Partly this is because we still need to know about the mineralogy of Mars, there is a ton we don't know. Improving on that knowledge will mean that we are all that much more able to target the regions of Mars that are more likely to harbor or have harbored life. And then we can send a "life detection" class mission.
However, such missions aren't easy. Consider a few of the challenges. In order to determine the composition of a rock you really don't care about the extreme minority constituents of that rock. If you can figure out what the elemental composition of the rock is within, say, 1% that can be a good day. However, if you want to determine whether or not a sample of dirt contains living or formerly living microbes then you are talking about a teeny, tiny fraction of a fraction of a percent of the material. Which means that you don't just need to break down the material into its major parts, you need to figure out how to focus in your studies to just that small bit of biological material. Which could mean extremely high magnification microscopes, for example, though that has a throughput problem. Or it could mean making use of various experiments to prove the existence of running metabolic activities within living organisms, such as using radiologically tagged nutrients, for example. But these sorts of things are pretty much a crap-shoot, and wouldn't help if the biological samples are no longer living.
Also, a NASA life detection mission requires much higher standards of clean-room assembly and pre-launch sterilization, which add expense and complication to the mission.
This is the sort of question that keeps NASA scientists up at nights. It's a fundamentally tough problem to tackle, especially with just a rover full of instruments and experiments. You can try to design the experiment such that you can show that it's the presence of external samples which show signs of biological activity and not the parts of the machinery itself (e.g. comparing results with and without an external sample present, comparing different samples, etc.) but even that isn't foolproof.
Keep in mind that for unmanned "life detection" missions a spacecraft would not just be constructed in a clean-room but all of its components (as well as the whole vehicle) would be extensively sterilized (at 112 deg. C for about 30 hours, for example). Additionally, the vehicle would be extensively swabbed throughout assembly to search for any amount of biological contamination.
However, more than likely the focus will not be on an unmanned life detection mission but rather on a sample return mission (which would be optimized to try to find samples containing life) or on a manned mission (which would also likely entail sample return). In either case there would be a considerable amount of research resources available to study any samples of Martian life, should it be found, and bring to bear instruments or tests which would unambiguously show it to be of a different origin to Earth life.
Perhaps every possible equipment is not possible given current funding; It could be a trade-off between probability of detecting possible indicators of life (organic compounds) and ability to detect more certain indicators of life (actual examples of life).
Imagine if you were only allowed to purchase $100 of equipment - it could either be a digital camera that can take pictures of fossils and definitively prove life exists on Mars once and for all, which is less likely than, a piece of equipment that detects the presence of methane in the atmosphere. (more likely but less definitive proof).
I think to the lay public, it feels like an excruciating process to announce that there is life on Mars.
The way NASA communicates to the public makes it tough. If a troupe of green martians wearing tophats and kilts started doing the "Lord of the Dance" routine in front of the rover, NASA would announce "We are still awaiting test results, but we believe that the Curiosity rover may have discovered organic materials that resemble felt that resembles something that could potentially be a hat."
This brings to mind an old adage about eggs and baskets.
More seriously, adding extra components to a mission means many more man-hours designing, testing and vetting the extra functionality, and also adds a boatload of extra weight, which makes the entire thing massively more risky and expensive (especially with the rover's at-the-time-unproven landing mechanism). There's no real need to send everything at once, especially if a lot of what you're sending could be ruled out as entirely unnecessary depending on the results of other tests you're carrying out.
So, finding some organic molecules in Mars is totally expected. On the other hand, finding a any proof of life in Mars would be amazing, but as far as I understand this "report" is only an uniformed speculation.
Organic chemistry technically just means carbon chemistry.
In biology carbon is the backbone molecule for all life/biological chemistry, although there are theories that on other planets/ecosystems other similar chemicals, such as silicon or germanium (both able to form 4 bonds, like carbon - same column of the periodic table) may be able to fill the same role.
From the scientists perspective discovering 'organic molecules' is important because basically when you get down to the nuts and bolts of what carbon molecules are, the point is that on a planet with an environment such as mars', without 'biology' as an underlying mechanism for the generation of these molecules, there shouldn't be any, I.e. they will all get degraded by the environment without some process churning them out.
That doesn't mean it's the only way that they can be made, just a theory that we have for their source.
The presence of methane (organic and usually biological in origin) in the Martian atmosphere has long been suspected of being persistent (ir should otherwise escape/be broken down) because of renewal due to biological activity however that is far from clear and more likely scenarios put the gas escaping from geological processes under the surface as the cause.
The long and short is thus that the discovery of organic molecules may be a tantalising clue to the presence of biological processes, either now or at some time in the past, however there would likely remain many alternative hypotheses to rule out and it would be (extremely) unlikely that any announcement could point to the existence of a form of 'life' on mars due to the equipment they have available.
Organic compounds and organic chemistry are thus named for historical reasons, not that they necessarily have anything to do with organisms (although they can). Generally it's carbon-hydrogen based molecules, for example, methane (CH4) is the simplest organic molecule.
As to what is a biological molecule, well, that's a harder question. In a somewhat tautological way I'd probably say that's something coming from a biological organism.
Gasoline is an organic molecule. (Quoth wikipedia: An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon.)
DNA is a biological molecule - a molecule used more or less exclusively in biology and not spontaneously occurring outside the context of life.
That's all true, but gasoline is actually a biological derivative as it's formed from the remains of living things. So your two examples actually both occur within the context of life.
We do know that organic molecules with non-biological origins do exist on other planets and even on asteroids. Titan has large quantities of organic compounds on it's surface that have non-biological origins, for example. It is believed that at one time Mars had a much thicker atmosphere and active geology which may have lead to the formation of organic compounds.
Right, I was actually thinking of synthetic hydrocarbons (for example motor oil), and thought gasoline was something people could relate to.
Methane on Titan would be a better example, and I actually initially used methane - but most people have experience with methane in the context of biology, too.
I think that if something like this comes from a NASA director, it is not made up or speculative. A speculation like that not being true would mean the end of his career.
It's not a NASA director, it's the head of JPL. And it was abundantly clear from his comment of "perhaps Curiosity has found simple organic molecules" that he does not actually have any firm knowledge of what Curiosity has or has not found and is merely speculating along just like every other armchair scientist has been. And because that is abundantly clear to everyone with a gram of common sense, notably excluding those who want to hype this speculation into something it's not, whether or not it's actually an accurate prediction has about as much impact on his career at JPL as him speculating about whether or not it will rain in Pasadena tomorrow.
I'm not sure why you're focusing on Charles Elachi or his job title (properly, "Director of JPL") here.
Charles Elachi (http://www.nasa.gov/about/highlights/elachi_biography.html) is an eminent scientist in his own right (follow the link to see) and you can bet he's very well-informed about MSL, which is JPL's biggest mission right now. This is because Charles has been running JPL ever since MSL was in the planning stage. His job would include briefing all interested parties about the progress of the mission and its instruments for about 8 years now.
In no sense is Charles Elachi "just like every other armchair scientist".
Besides this side show (I work at JPL so it's bothersome to read mischaracterizations of Charles), I agree with you that this story has been shifted beyond what it actually means. If I read you right, that's what caused you to comment. "Organic" has been changed from its chemistry meaning ("containing carbon") to its lay meaning ("coming from something living"). And "perhaps" has been left out completely.
Charles is a careful speaker and a veteran at communicating results to the public. This is why his statement contains a specific disclaimer ("not biological"). You have to give the article credit for getting this right.
The question is whether or not he's speaking from having some insight into Curiosity's findings or if he's merely engaging in speculation, which I think is ambiguous given his statements so far. Until he's made a more clear-cut statement I don't think it's helpful to read too deeply into what he's said and assume that he has some special knowledge of the mission findings.
And he said, in fact, that that was what they found, but that it's still a "perhaps" because they have to check the data very very thoroughly. Read the news, and get your informations right.
Please stop trolling all over the thread, thanks :)
The wikipedia article supports InclinedPlane. And the title of your submission doesn't include "Perhaps", so it is quite misleading. I think maybe you need to check your information first.
?? I say he is a Director, InclinedPlane says he is only the "Head". The wikipedia article states without doubt that he is a Director. How is that supporting InclinedPlane? Pfff....
I really doubt that a speculation made on some remote conference, containing the words "perhaps" could mean the end of his career if it doesn't come true.
NASA is the agency that made a big prime time press conference for their "arsenic DNA" discovery not so long ago, which proved to be BS (and not well researched at that).
Edit: It seems more Italian newspapers are reporting this quote than just this one site, but for an announcement of this importance, I'm still not going to believe it until we get some more confirmation.
Slate specializes in punditry rather than reportage, I wouldn't worry too much about it. If it's BS NASA will clarify or deny within a few hours, but there have been hints leaking from several sources about some exciting news that was still under embargo while they continue testing. I think it's OK to post since it includes a legit source/scientific forum.
"La Gazzetta del Mezzogiorno" is not a blog, it's a newspaper. The news was reported by other Italian newspapers too, quoting Charles Elachi's words during a speech held in Rome.
I want to summarize and add some commentary to the article[1] posted by macu as a reply to another comment.
It's amazingly interesting and well argued. In short, the author says first that any sufficiently advanced civilization will at one point send self-replicating probes that will eventually colonize all of the galaxy and even universe. And it takes only one match to light a fire, and this is important--that is, for a sufficiently advanced planet, it would take only one rebel, one mad scientist, to set the colonization, by robots, of every habitable body in motion.
Assuming the above is true, then why do we not see any sign of these probes? It follows that there must be a Great Filter that prevented them from ever being created. Things that qualify as such a filter are not plenty, and include the original formation of life and the transition from procaryotic to eucaryotic (taking a couple billion years).
Thus if we find life so easily formed on Mars or anywhere else (especially eucaryotic cells), we can assume these past events are not really Great Filters. Then, the only reason we haven't found a single probe is that any sufficiently advanced civilization destroys itself before it ever gets to that point. If it's not nuclear weapons, then there must exist technologies that are sure on our path to discovery while at the same time guaranteeing our extinction--again, think in terms of things that only need one outlier to use it in a way that compromises the existence of all on Earth for good.
So he concludes that we must pray that we never find life anywhere else, because it would in turn give us hope (but not assure us) that there might exist no Great Filter ahead of us, and the Great Filter was indeed in our conception as life--thus we are the one single unfathomably lucky planet to ever have harbored life. If nothing potentially impedes our expansion, we will be the one sending probes and expanding to everywhere.
Adding my own expansion on this, I believe it's extremely unlikely that there is some irrevocably cataclysmical tech to be discovered before ever we are able to send self-replicating probes--ones who can mine the raw materials needed for unbounded expansion.
I don't think we're that far from that point, and taking from our own anecdotal existence since it's the only one there is, even if we do annihilate ourselves before sending them out by chance, other civilizations might not have done so, if they existed. Thus indeed the only tech that would assure a Great Filter is the self-replicating technology itself. And that is a strong point--the author seems to ignore the fact that these probes wouldn't really be the expansion of humanity, it would be the expansion of drones. And what might the precursor techs for such a replicating machine look like? If superior AI is needed at any rate, we could think that the tech leading to sure extinction is indeed robots who decimate us humans. And since they would do this as early as chance would afford it, the robots eliminating us would be as dumb as possible--thus we can assume they would be incapable of advancing technology on their own; or of coordinating an event like launching themselves into space, and thus would never leave Earth. In this scenario, we can assume every civilization that ever got a shot in going to space ended up extinct, their planet ridden with dumb self-replicating robots who can never launch themselves into space.
Since self-replicating robots are the hypothesis of the author's argument, then indeed it makes sense that every potential civilization either never reached this tech (the Great Filter is in life's conception, or otherwise somehow denies the existence of self-replicating robots), or it must absolutely reach it, in order to colonize space, but in doing so it declares it's extinction.
So, like the author, I also hope[2] that we never find life elsewhere, that we might put our tiny hopes in thriving as a race, the only one that ever existed.
It's an interesting thought experiment, but not too meaningful. The universe is still young; it's been around for 13 billion years, the Earth for 6. Given the immense distances involved, and the complexity and resources required for interstellar travel, it's not surprising we wouldn't have seen life.
And, for a moment, let's suppose your thought experiment is true, and there's an alien probe somewhere in our solar system. Would you be surprised we haven't found it yet? There're an awful lot of places left to look.
1. I was wondering if we could apply an anthropic type of argument here? We are having this argument at this time and place because we predate the colonization by self-replicating bots / other end-of-world scenarios. Multiverse version: any time we're having this discussion, we are on the surviving branch predating self-replicating bot colonization that renders the planet unlivable. I realize this type of argument can be extended to reach absurd conclusions, but nonetheless it's an entertaining thought.
2. What is life? What is civilization? What are their goals? Why do we assume a society of relatively independent individuals? Is it even a sustainable model for a post-human level civilization? Aren't we anthropomorphizing aliens a bit too much? What if a civilization either dies out at human-level stage or necessarily reaches a mental unification point and all its further activity is inward focused? I think we're on the first stages of self-awareness compared to rocks and jellyfish, imagine the level of self-awareness experienced by a far more advanced civilization. Would it necessarily be resource and space-greedy and try to colonize the galaxy? At least it's not immediately obvious to me why it would.
3. Another point is, what scales are we looking for? Doesn't our scale essentially depend on the planet / star system we evolved in, and the scale at which original life started? What basic building blocks / resources does alien life use? Maybe they rely on physical resources we haven't yet explored (dark matter, etc). Essentially I'm agreeing with the people saying "we don't know what we're looking for".
I really liked point 2. It seems to be the default assumption that we as a species should seek to increase our chances of survival by looking to colonize other planets. However it is entirely possible that our mindset may change in the future and we come to the conclusion that, even with capable technology, it is better for us to live out our existence on this planet.
"Assuming the above is true, then why do we not see any sign of these probes?" Because for example these probes are as tiny as a nano-meter? Hey it is the year 2012 here on earth. In the last decades we have already shrunk computers from the size of a entire room to fit in our pockets and soon our blood. And we ourselves can already build nano-technology, despite not being able to travel around our galaxy. What tells us that intelligent life has to build "probes" so big that we are able to detect them. Maybe these probes are just as large a nanometer and are already flying towards us or were near us or are already on Pluto. Or maybe other life forms shrink themselves to fit into a trillionth of a trillionth of the diameter large spaceship to be able to travel around space faster than light. All of the theories are just expanding from current knowledge as of today, not factoring in any stunning surprises of how the universe might really work :)
This seems like a good point on the surface, but since it takes only one outlier to dominate the universe (by Bostrom's train of thought), then it would have happened anyway. It's the law of smart for one, dumb for all. Assuming most life forms would decide to live minified, any life form not deciding so would have immense advantage to consume all untapped resources. Following this logic, and since any sufficiently advanced replicators would all be competing for the same space, the most overwhelming kind would take over all others.
Suppose that we start near the edge with a self-replicating probe that can spread outwards no faster than Voyager 1. In 2 billion years, every solar system in the Milky Way would be chock full of factories trying to expand.
And there is no need to assume that it is so slow. We have already designed technologies to send probes to stars much, much faster than Voyager 1. Here is one. Put a bunch of solar panels on Mercury, and use the power to shine a laser into space. That can push on a light sail, pushing the probe outwards at something like 1% of the speed of light. Then as it nears its star, let the sail fly away, shine the laser again, and have its reflected light brake the probe.
With this level of technology, which may be feasible for us in just a few hundred years, the colonization of an entire galaxy can be reduced to tens of millions of years.
If technological life is out there in our galaxy, in the blink of cosmic time finding evidence of it will not be a search for a needle in a haystack - it will be closer to finding a piece of straw in a haystack.
I find much confused logic in Nick Bostrom's argument, and huge assumptions:
"I will return to this scenario shortly, but first I shall say a few words about another theoretical possibility: that the extraterrestrials are out there, in abundance but hidden from our view. I think this is unlikely, because if extraterrestrials do exist in any numbers, it’s reasonable to think at least one species would have already expanded throughout the galaxy, or beyond. Yet we have met no one."
Sorry mate, but it's not reasonable to think that at all. The galaxy is colossal. We have exactly zilch insight into how even a two-star civilization might work, and the kind of problems it would have - and he's saying it's reasonable to assume the existence of a civilization with dozens of thousands, or hundreds of thousands, of millions of stars?
It's possible, maybe, but it's not reasonable, and it doesn't disprove the idea that we simply haven't looked deeply enough for ET yet. As Jill Tarter of the SETI Institute once remarked [1], it's like asking if there are any fish in the ocean, filling a cup with ocean water, and upon discovering that it has no fish in it, you conclude that all the world's oceans don't, either.
In short, we haven't done the experiment yet - we may as well refrain from making conclusions. Our galaxy could house a million times the diversity of species in Star Trek, Star Wars, Battlestar Galactica and Mass Effect combined, but it may take a while to find evidence of any of that.
A basic nuclear rocket—the kind we could build today—can reach 10 kilometers per second. That's gets a robotic factory across the galaxy in 1.5 billion years. The oldest habitable stars are considerably older than that.
Top quality propulsion can shrink the time to 50 million years, which means somebody can colonize the galaxy faster than dinosaurs can evolve into talking monkeys.
So there has been plenty of time for robotic probes to colonize the galaxy. So where are they?
The time between dinosaurs and talking monkeys is basically irrelevant. The important figure is the time between the formation of the sun and talking monkeys - 4.5 billion years. You're also making some assumptions about how easy it is to build a ship capable of crossing interstellar distances and also reproducing itself.
In fact, using current technology, we actually could build a "self-replicating probe" loaded with algae and other photosynthetic single-celled organisms. So we really can't rule out ourselves as the evidence we're looking for. We might even be evidence that such probes usually malfunction.
Minor nit: is there evidence that dinosaurs evolved into monkeys? didn't they all get wiped out by an asteroid?
AFAIK, mammals existed during the dinosaur era. But they occupied a tiny ecological niche and were physically tiny. They survived the asteroid hit because they were tiny.
The absence of dinos enabled them to eventually occupy niches occupied by dinos.
My hunch is that it's true: that when we get better at detecting it, we'll discover bacteria/viruses/spores of various kinds all over the place (including Mars and other solar system locales).
I heard recently that if the earth was 3 times larger, the most advanced chemical rocket would not have the energy density to leave the atmosphere.
Scientists now know that with out a Jupiter, the asteroid belt might not form in such a way to deliver 'water' and protect us from large comets roaming the galaxy.
Even now it may not be possible to leave our solar system without a significantly different understanding of physics. Voyager is just no leaving our solar system, and it will take decades for it to actually leave the effect of our sun. Today if we launched a craft it probably would get just about as far as Voyager in just about the same amount of time, but maybe our power source could power a more efficient version for a decade longer, getting us just a bit further than voyager will, but still no where near Alpha Centauri.
For us to explore the depths of space, it would need to be much easier and cheaper than it is today.
For it to even be plausible a DIY Scientist as you suggest would need to create energy density so powerful, it would be hard to imagine a world where that sort of thing is not regulated.
For us to study sub atomic physics, we have a structure that is 20 miles in length, this is not the research of... a DIY community.
Today we argue about Iran getting enriched plutonium for nuclear research, when some think they want to build a bomb and others think they want to build a power plant. I really can't imagine a neighbor of mine being able to ... take that step without raising some alarms.
Your mad scientist would have to be on a far off island/ comet/ moonbase with all of the resources and man power required without interference from others, but still have access to raw materials.
I am just not sure we will find other worlds in humanity's lifetime.
We may be able to colonize mars and a few other large bodies in our solar system, but leaving it is a different story.
> Your mad scientist would have to be on a far off island/ comet/ moonbase with all of the resources and man power required without interference from others, but still have access to raw materials.
well unless he, or his supporters, are also granted dictatorial control over a significant portion of the planet.
Well let's not get ahead too much. Suppose such a civilization has existed in another galaxy, there is probably very little chance that they would be able to jump to another galaxy. The distances are huge.
And there is also the possibility of having intelligent civilizations never reaching the space age for one reason or another.
We have only ONE specie on Earth among billions which reached this point, it is not like we have much of a sample to make any rule.
All this is just assumptions based on very small data pool. Meaningless.
What if we are the replicated life sent out to colonise the universe. It would be hard to self-replicate knowledge and especially knowledge of our own origins over such distances and tiny cracks.
#justsayin
I am also not too sure the maths adds up either.
Lets assume that this "spread everywhere" civilisation does exist, and it fortuitously started evolving just after the Big Bang, and neatly at the "centre" of the universe (i.e. somewhere that is not next door to us, nor the furthest point possible from us)
Lets also assume it took them roughly 4Bn years to evolve to the Promethean level (age of the Earth) and so have been spreading for past 10 BN years.
And (yet) another assumption - they spread uniformly outwards, travelling at speed of light (!) but taking a recharge period to, I don't know, consume the resources of a planet, build a few houses, before spreading again.
So, with a observable bubble of 46 bn light years, and 10^^23 stars in it, I think the following calculation works
* there are 10^^23 stars [1], spread evenly over 46 bn light year diameter bubble
* they atarted their migration to us (to everywhere really) 10bn years ago
* between the "them" and us there should therefore be a even distribution over 23 bn light years or ~ 10^^23 - 10^^9 = 10^^14 stars.
* given a "pause" of 100 years at each star system and light speed travel in between that is still 23 bn years plus (100 x 10^^14) 10^^16 years or a ridiculous number that I have probably got wrong but is clearly older than the age of the universe many times over.
I know this can be tweaked any which way, but if we are looking at the pan-dispersal approach, even simple lower bound cases make it highly unlikely that a civilisation spreading enormously fast and comprehensicvely throughout the universe will still "never" get here for any value of "never"
"In short, the author says first that any sufficiently advanced civilization will at one point send self-replicating probes that will eventually colonize all of the galaxy and even universe."
That's the mistake. Its an extension of cultural / religious / philosophical values of the European colonial era. Not politically correct in this era or likely any point in the future.
Its the "star wars" effect applied to SETI. The "star wars" effect is we used to have emperors and knights in shining armor and mage/paladin wannabe types and castles and long choreographed sword fights so I'm sure the future will have them too. However good a hollywood movie plot, that's not realistic.
Repeating Earth's 1492 is dramatically less likely than ... a gray goo accident. Look for one of those. Or evidence of an unfortunate accident involving using black holes/singularities as a power source.
You're missing the point that it takes only one sufficiently equipped human being to set the whole colonization in motion. Given appropriate technology, it doesn't require any concerted effort or grand scheme. Just a single match lights the fire. Think of the DIY folks in 500 years. Given the size of the human population, it's a given that it will happen at some point, if the technology becomes available.
Yes, which 'rock' (point of origin) did the first human-scale single-celled organism on earth launch from? In this line of thought, the fact that we got off of that rock, grew into the ecosystem that we are today, and are now well on our way to doing it again is hopeful in itself.
Also, when thinking about this, i don't think we should discount the possibility that we have already discovered and merged with other forms of life, especially during explosive growth periods over previously uncharted territory. Maybe some forms of life we know of today were actually independent in origin.
But i definitely like this kind of intelligent design by self angle more than any other.
I agree. Like with investments in startups there could be a "spray and pray" strategy. Maybe "they" are just happy to spray very basic life forms like DNA around the universe and watch evolution happen, like how we in our labs like to watch experiments develop.
It's amazing how little we know--it might just be that an organic, living, genetically engineered being can sustain the pressure and vacuum of space (though how about propulsion?) and hostile planets, and consume raw resources out of soil and atmosphere to reproduce. That's a scary thought.
I think Nick Bostrom should have focused more on the time and randomness factor. Maybe there was life in our galaxy, but they visited us before humans have lived. Or we have been visited (think peruvian desert drawings [1]), but before we as human race were as advanced as we are today and they left our boring planet to visit another galaxy. There are probably more than 170 billion (1.7 × 1011) galaxies...
The point is, well before folks who could feel "boredom" passed by us, their self-replicating probes would have landed here, many thousand, million or billion years prior. And they would have harassed our planet to depletion, since they are dumb and drone-like. Even if a meteor somehow extinguished them, by then they would have launched themselves into all of the solar system, and by chance would land here again. Given time and randomness, these probes are like radio waves; they get everywhere once set in motion. Thus we can assume they were never set in motion.
When I'm visiting Japan I don't have to "probe" them. It es enough to take some pictures and leave. Like Star Trek, maybe they had some guidelines on their journey to us that stopped them from interfering with the history of our planet. And maybe they didn't even need our resources or "probe" the entire universe in the first place, because they invented a new way to create materials directly out of matter and anti-matter, without the hassle of mining the universe. The 'self-replicating probe' factor is just a theory by a human scientist from earth. Just because evolution may happen someplace else, that doesn't have to imply that all intelligent life ticks and reasons ultimately the same. Everything is just a big 'if this than that' logic, where every part of the theory can be trashed. Until now the human race can only reason with our own brain. More advanced life forms could reason with endlessly intelligent A.I. and could come to completely different conclusions. For example if it is a good strategy to visit or be detected by primitive animal life forms like us. Maybe they want just obverse us, like Bostrom mentioned.
> When I'm visiting Japan I don't have to "probe" them. It es enough to take some pictures and leave.
Using a transport infrastructure whose effects can be seen across the galaxy.
A theory of advanced races who have different sensibilities misses the point. What matters are the ones that have a growth and expansion sensibility. The first one of them to arise will conquer the galaxy.
The problem with the original argument (if I read it correctly) is that Bostrom assumes that the "growth and expansion sensibility" is a near certainty and that lack of evidence of this type of civilization, and the fact that we exist (as compared to having previously been 'harvested'), means that life does not exist elsewhere.
However, what everyone else in this thread has been saying, is that his conclusion (that no life exists elsewhere) is wrong because there are number of other possible explanations as to why we don't see evidence of this civilization. A quick summary of some of those arguments:
1. The expansion that Bostrom assumes is inevitable is actually physically impossible at the scale he describes.
2. It is possible that we are actually a by product of that expansion (DNA being the 'self-replicating' robot).
3. The expansion is happening, but hasn't reached us yet.
4. No other civilization has reached such an advanced stage yet (it is entirely possible that our 4.5 billion years was an extremely and uniquely fast time for evolution to intelligent life)
5. Super-intelligent civilizations come to conclusions that expansion is not a productive or useful undertaking.
While it is possible that life doesn't exist elsewhere (or at least intelligent life), it is by no means the natural conclusion to Bostrom's hypothesis.
6. The expansion is complete, and they are conservationists with an eye for subtlety.
I favor this possibility. Fledgling expansionists cannot know if they are wards of conservationists who have spent the past billion years developing spying technology and culling weapons. On a game theoretic basis, every sensible fledgling expanionist, even the first one in the universe, should reasonably act as if a living god is judging them.
It's also possible (more likely?) that life on any nearby planet discovered would just be a failed attempt of our own. If this is the case, then its discovery would actually be good news, it would mean we can continue in the face of catastrophe. I don't think the author touches on that.
We already know of at least one catastrophe we are rebuilding from, there's also no reason to think we weren't already rebuilding from earlier (possibly much larger) catastrophes.
Following this, there's nothing to say that we haven't already had some major effect on our surroundings (intentional or not) in some previous, possibly more complex or larger-scale growth. Our influence on our surroundings could be huge. Lack of life or anything that seems anomalous in our immediate vicinity could be our own doing. A seeming lack of evidence for this might be explained by scale, or the nature of the catastrophe, or (if it was intentional) by design.
It's been said by others HNers, but I want to stress the point further with a reformulation.
We have great difficulties to find foreign planets. We barely know what's beyond Pluto. Heck, we probably have a couple of surprises waiting for us in the solar system.
One cannot expect us to be able to detect alien probes, operating with engines and communication capabilities beyond our understanding, probably only few meters wide (if not much smaller!) and operating somewhere near our star, probes we don't even attempt to detect in the first place.
Plus there is a bias toward colonization. I agree that an advanced civilization, except if it becomes extremely xenophobic, would probably want to explore the universe, but colonize? If you have the technology, it's possible you don't need to spread physically that much.
It's a compelling point, albeit in many ways very short-sighted. Though I really do believe we're headed to a full virtual reality. Why live life--the hard, cold future life as depicted in Matrix--when you can be a millionaire in the 20s one day and a pillaging crusader on the next?
We have cultural fantasies and biases that will be hard to break free (or do we want it?), and the possibility of fully reliving those as we please will be a Great Temptation as the writer puts it.
Still I think it's short-sighted in that the people who can be as powerful in real life as everyone else can in the virtual will take advantage of it and control the masses with infinite happiness. So I don't think it's ultimately a good point to stand for the Great Filter.
> And what might the precursor techs for such a replicating machine look like?
I would wager, attempted mischief, that words themselves are the self-replicating machine, to the Universe..
Think about it. These very characters, here on this page .. motivate the pro-creation of yet more, and so much the human organism is designed exclusively for the propagation and 'existence' of these words, that eventually, to the Universe, it must look like each letter is but a sperm, off to meet some fertile substance designed to fuse another font of near endless replication, reproduction, duplication, consumption ..
If it's not nuclear weapons, then there must exist technologies that are sure on our path to discovery while at the same time guaranteeing our extinction--again, think in terms of things that only need one outlier to use it in a way that compromises the existence of all on Earth for good.
How about hydrocarbon fuels? They don't need one outlier. They seem to have chemistry and physics resulting in an economic trap for t heir use.
1. The worst-case "predictions" of the doomiest environmentalists are that the shoreline will move in a bit, and the tropics will get a bit iffy.
2. Hydrocarbons are a temporary religious dogma, not a trap. There are collosal amounts of thorium waiting to be tapped when the energy religion is reformed.
... and that large swaths of the Earth receive new weather patterns completely disrupting nearly every ecosystem, with cascading effects including no food for us
I am quite annoyed with the shield of political correctness that the scientific community has to wield w.r.t the "life on Mars" issues in order to preempt yellow journalists who will, without a doubt, use any turn of phrase to rile up the various factions for and against to generate clicks, sales, and burnings-at-stakes.
As if our opinions change the chemistry of a planet none of us have ever been to.
Guy Webster, a spokesman for NASA’s Jet Propulsion Laboratory in Pasadena, Calif., which operates Curiosity, said the findings would be “interesting” rather than “earthshaking.”
That is from yesterday, and was trying to calm down expectations after the first famous “This data is going to be one for the history books. It’s looking really good.”.
Today, the Director of the JPL (and so also Webster's) is the one saying that what they found are organic molecules. And he said it, by the way, as a way to calm down people, because what he was trying to explain was that it was not biological molecules, only organic ones. Of course, it's still a great deal, but it's not fossils or green little men.
You are right. But this "perhaps" is not the kind of "Perhaps it's that, perhaps it's something else". He is saying "perhaps" because they are still checking, double checking and extra checking the data. He says "It's preliminary data that must be checked (on) organic, not biological, molecules"
None. The life on earth as we know it in a traditional sense is based on carbon-based compounds. You can use anything else that forms polymers essentially, but carbon happened to happen.
Carbon is not just a little bit better than other elements at forming polymers and complex molecules it is many orders of magnitude better, and it's hugely abundant. Many complex carbon-based molecules are even formed in entirely non-biological processes in significant quantities. Ethanol, ribose, glycine, adenine, and others, for example. The overall nature of life in the Universe may prove to be quite a surprise to us humans but for now the overwhelming scientific consensus is that carbon based chemistry is by far the most likely route for life to develop anywhere.
It is safer to be a carbon chauvinist if you accept that ancient Mars was covered with oceans. A silicon-based microbe would be hard pressed to explain its distaste for water to its carbon-based neighbor.
This has become an example of an organization losing control of it's PR when it goes viral. This is damaging to the credibility of those involved. If / when the details are given they will be "historic" either for their scientific importance or the hit it has done to NASA.
You are right. But this "perhaps" is not the kind of "Perhaps it's that, perhaps it's something else". He is saying "perhaps" because they are still checking, double checking and extra checking the data. He says "It's preliminary data that must be checked (on) organic, not biological, molecules"
http://en.wikipedia.org/wiki/Organic_chemistry