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Drake on Drake: ET Life A Certainty
astro writes "Frank Drake, Chairman of the Board of Trustees of the SETI Institute applies Occam's Razor to his own Drake equation: 'Life should appear very frequently on other Earth-like planets. There will be microbial life nearby the solar system.' The simplest scenario is that 'Not Life' has a nearly identical number of assumptions as 'Life.' The contrasting view is that experimentation can prove it--but how many times did life independently create itself while the Earth changed through the whole spectrum of what biological forces might conjure up elsewhere. A sample size of 1 is in fact an experimental sample size of many--just here during Earth's climatic history."
I'm always leery of the term "Certain" when a key premise is time on the order of billions of years.
The assumptions presented in the article cannot be proved or disproved. What does it help us to state "Not Life has as much chance as life" or "Consider our existence as proof".
Although I tend to believe there is intelligent life in the universe outside of Earth, I'm not sure this argument serves as proof or even a good starting point for a proof.
I think we ought to just be content saying there might be a chance that other intelligent life exists and we'll get to proving it through empirical data. Then if everything checks out we can go applying theory, probability, and predictions. Until then, this stuff is simply philosophy - the earth was flat until we found out it was not.
If you play it by the numbers, then yes, life should occur frequently. By even the paltry data we've already collected, life should be abundant and soon even reachable.
This has a unintended but frightening implication, however.
Humans have existed as a sapient, technological species for approximately 30000 years (and that's generous, really). That means that in the cosmic equivalent of a the beginnings of a heartbeat, we've gone from caves to extraplanetary exploration, and our technology curve will only accelerate from here on out.
Considering that it took almost no time to get here, it will take even less time to get to point where we would be leapfrogging across the galaxy, colonizing everywhere. Within the next 30,000 years we'll have had more than enough time to have distributed explorers to every inhabitable/explorable planet in the galaxy.
The question, then, is why hasn't anyone found Earth yet, if the probability for life is so high? Either every civilization gets wiped out long before they can begin galactic exploration (without exception--a pretty difficult thing to imagine, unless you're an apocalyptic environmentalist), or, perhaps more frightening in an indirect sense, there simply aren't any other intelligent civilizations in the galaxy.
You'd think that even if ancient astronauts had found Earth, we would have uncovered at least SOME sort of artifact. After all, playing the probabilities, if one civilization found us, it would be overwhelmingly likely that many, many others would be able to, and would. So far we've got nothing.
It's a difficult reality to accept, but it may very well be that we're alone in the galaxy, and perhaps even in the universe.
I am always amazed at the extent of humanity's arrogance, or at least our blind optimism, when I read about the logical arguments about the likelihood of intelligent life outside the solar system.
Perhaps there is, but I can't imagine limiting ourselves to looking for multicellular, carbon-based, or RNA-based life, or for that matter any form of life patterned upon that on Earth. It seems to me astronomically more likely that highly organized or self-conscious matter found elsewhere would not be recognizable to us as what we would call "life".
I have slowed down my participation in the SETI@home project because I have become increasingly skeptical that other life forms would happen to care enough about radio frequency communications to build a transmitter. I consider it at least equally likely that extraterrestrial life forms are more interested in gazing at their own navels than evolving the means for the complex physical arrangements of materials necessary for instrumentalities designed to emit radio signals.
The yearning to communicate with other beings is both honored as a deeply "human" characteristic, and asserted as a likely goal of extraterrestrial life, but I think we have to choose one or the other, and get realistic about the chances of finding other societies sufficiently similar to us that we could detect each other.
That either FTL (faster then Light) travel is utterly impossibly, or that civilations that discover FTL are few and far between.
Lawyers, MBA's, RIAA? A jedi fears not these things!
When it comes to Drake related wonderings.
There's the thought that its almost an absolute certainty that intellegent life has evolved elsewhere, and probably in vast numbers of individual civilizations.
On the other hand, the theory goes that within a few hundred years, we'll have the ability to (and therefore probably will) send generation ships to other solar systems. If we are to assume that 500 years after each colony is settled, it launches its own generation ship to the next solar system, the entire galaxy could be colonized in a matter of a few million years. This is of course assuming that most of the colonies don't manage to kill themselves off.
The point being, since a few million years is a cosmic blink of the eye, if any intellegent life DID exist, either it should be everywhere already, or all previous incarnations have wiped themselves out before they've had a chance to travel beyond their home world. Either that, or they're leaving us alone. After all, we ARE rather far away from anything. Its possible that a 4.3 lightyear stretch is too far to consider useful. And its also possible that we're the result of such a colonization project and everyone forgot about it, or were dumped here without knowing to begin with. Or maybe they knew and simply never passed it on. Its not like a lot of folklore has lasted for 30K years.
So, to recap this rant. Assuming there IS intellegent life, its already everywhere it wants to be, and either we're a part of it, or it's decided to completely leave us alone.
-Restil
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Personally, I find it hard to get worked up about ET algae or whatever. I mean, it's a good thing in terms of implications for habitability of other worlds, terraforming, etc. But every time someone trots out an argument about how easy it is for life to arise in the universe, people assume that once you have life at all, you have intelligent life.
If life has arisen independently on Earth multiple times, how many times has it produced humans? And by this I mean, how many times did humans evolve, from scratch, our of distinct gene pools? I would have a hard time believing any answer greater than 1 (or less than 1, for that matter). So the more times life has formed and *not* evolved into sentience, the worse the odds are that it will have done so in other environments.
And even if sentient life has evolved on some reasonably nearby planet, what are the odds that we'll inhabit the same slice of time as them? Human beings have been a technological species for an infinitesimal time slice compared to the age of the galaxy, and at the rate we're going that time slice may not last much longer. If this is representative of sentient species in general, it would be very rare for two species to chance upon the necessary coincidence of space and time to actually meet each other. Sad but true.
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When these discussions about probability of life come up, I always think of the massive amount of parallel processing that is provided by the surface area of an entire planet, and the large amount of processing time that is available for the task.
Especially regarding the probability that life will start in a puddle... Or in some wet clay, just as well... but taking puddles as an example:
Take a square mile of earth. Picture a kind of primordial earth, the surface seething with puddles. Maybe, say, one square foot of puddle for every four square foot of earth. That's
6,969,600 puddles per square mile. There are 197,000,000 square miles on earth; assume 1/10 of these are land, so multiply 6.9 million by 1.97 million: 13,730,112,000,000 puddles. Oh, then multiply that by 365 billion or so days, to yield the number of daily heating/cooling cycles provided by the rising and setting of the sun. That's 5,011,490,880,000,000,000,000,000, right? So maybe I've overestimated the surface area, or the number of viable puddles. OK, divide that by 10 to the third or fourth; it's still a pretty darn big number.
Next time some Creationist lectures you about how improbable it is that life started in a puddle, be sure to multiply whatever probability they provide by that number.
Of course there's that detail about cells, and multiple cells, and the "sudden" leap to intelligence (forgetting a few billion years here and there). Well, that would require... evolution! But then, this is starting to look like a troll, and I didn't mean it that way.
Yours isn't a silly explanation for the great silence, but consider this. Several proposed solutions to the Fermi paradox assume that the aliens build utopias, or destroy themselves, or have a 'prime directive' preventing them from contacting our primitive world. The problem is, any one civilization could sweep through the entire galaxy on a time scale of millions of years. So any behavioral explaination of the aliens' absence requires that ALL the alien civilizations in the galaxy have one of these reasons for not spreading through the rest of the galaxy. If there are hundreds of thousands of other civilizations in the galaxy (which some 'optimistic' Drake followers have calculated) then the odds that NONE of them had the drive to have colonized, explored, or, heck, even eaten Earth (for you Greg Bear fans out there) Earth is very very low.
I personally believe that the development of tool-using, communicative intelligence is very difficult in evolutionary terms, and is thus exceedingly rare. Remember how quickly unicellular life developed on earth, and how late intelligent life arose. At most, there may be only a few civilizations scattered through our galaxy; but it is very possible that we are the first, the only technical civilization in the galaxy.
Look, this is an old argument that has the informational gene for immortality -- it just won't die, but it should (or at least hibernate until truly new data shows up).
... perhaps our philosophy about the SETI will also change.
The Earth radiates like a small star in the radio region, from our civilization's emissions. Yet we don't hear a peep of anything like that out of the rest of the universe, and there's no obvious evidence of stellar engineering to be seen either. Where are other forms of intelligent, information-exchanging, perhaps macro-engineering life? Well, it could be they aren't macro-engineers, or that they don't pass information like we expect them to.
But it could also be that there isn't any other life at all, or just low-level forms that we won't be talking to.
We only have one assured point of data to answer the Life question, and that's not good enough. One point doesn't "trend"; it has an infinite number of slopes; you can fit any curve to it. You can hardly expect to win your case for universal life without evidence of detecting anything outside of the Earth. Even other planets in the same system show no evidence of engineering or biochemical activity, and we've been looking at them for decades with some pretty good instruments.
We must keep looking, sure, but the evidence is pretty well on the side of a lifeless galaxy. Be scientists for once, and ditch that superstitious need for alien races and galactic empires. The facts are overwhelmingly against alien life, and until we expand our methods of searching, that's how we must judge it if we are to pay any due respect to logic.
On the hope side of things, our methods and assumptions can change with more data. For instance, it was taken for granted (although well-enough thought out) that if aliens existed, biochemistries between two such races would almost always be dissimilar. One race might settle on carbon, oxygen and sunlight, and another on silicon, hydrogen and geothermal energy. But recent theories and observations suggest that cosmic gas clouds harbor molecules that can start biochemistry upon planets. Since such clouds are large, it could be that this seeding process could produce similar biochemisty across different star systems. Hence, across the lightyears, biochemically-similar lifeforms might be able to arise if the seeding process has the potential we theorize. So the basic philosophy about alien differences has changed
Myself, personally, I figure we will need Jodie Foster {tm} to take up radio astronomy before we get the signals we are looking for.
[also misbehaves on Kuro5hin as Peahippo]
No, you just didn't understand Fermi's paradox. Nowhere does it say that the species in question has to travel in their own person. You can send unmanned probes, spanning the entire galaxy in a network that would report on life it it were there or if it later appeared.
And who is talking about mortal beings?
FTL is also a bogus argumant and Fermi did not need it. You just need 10 million years.
Oh, and if a catastrophe vipes out all technology, how come then someone will survive to become a cave man??
All in all you have made it painfully clear you have not bothered to read nor understand Fermi's paradox.