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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."
A sample size of 1 is in fact an experimental sample size of many--just here during Earth's climatic history
Ummm....Im sorry, but I thought that there was, perhaps many singular events where life was formed billions of years ago, but simple evolution and extinction dont "scale" to be equivalent to non-life becoming life.
Furthermore, I recall reading a book..."Probability 1", that spend several chapters mucking around before submitting a "proof" that there must be intelligent life elsewhere...As I recall, it hinged on one instance of life, which is us.
William of Ockham - "One should not increase, beyond what is necessary, the number of entities required to explain anything."
Francis Drake - "My whole life's work, from SETI to the Drake equation to the 1970's Arecibo radio transmission, depends on their being aliens somewhere in the Universe, so I'll pop up every year or so and assert that ET does exist so I won't be a failure.
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I'm just an ordinary man with nothing to lose.
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!
We have a sample size of only one, and that this sample resulted in intelligent life is a given (else we wouldn't be here to make observations on it.) We do however have some timing information. From this we see:
1) Life evolved on Earth pretty much as soon as conditions were stable enough to allow it. This suggests that bacterial life is highly likely.
2) It took at least hundreds of millions of years to develop Eukariotic life (big cells with a nucleus, such as we are made of, as opposed to bacteria.) This means that this step might be rare.
3) It took about 3 billion years to evolve differentiated multicellular life. This means that this step could be exceedingly rare.
4) Multicellular life evolved into a vast array of designs in a just a few million years (the 'Cambrian explosion'.) This means that once multicellular life starts, it will quickly produce complex forms.
5) From the Cambrian explosion to us is something like 500 million years. This is an intermediate time scale that makes it hard to judge how likely intelligent life is.
Disclaimer: I'm not 100% sure of some of the timescales above. It is all from memory.
Disclaimer 2: The Edicara fauna complicate the picture above on the origin of multicellular life, depending on how you interpret them.
Disclaimer 3: All the above is merely probabilistic. E.g. if the evolution of bacterial life is very rare, there is still a 5% chance that it will have occurred during the first 5% of the available time. Therefore we can't strongly exclude the possiblity that the evolution of bacterial life is hard.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Why would intelligent life want to talk to earth? Indeed, why would it want to talk to anyone? If there is other intelligent life out there that managed to survive more than a few thousand years, maybe they just figured out that staying home taking care of their own planet is a lot more pleasant than traveling around the universe in tin cans or holding conversations with hundreds of years of lag.
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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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.
I recently rewatched "V - the series" and "V - the final battle". For those few here that haven't seen it, a bunch of seemingly humanoid aliens come to earth. However, these aliens end up being lizards who wear human skin to disguise themselves. A group of partisans realize the intent behind these aliens (to steal our water and use us for food).
One of the partisans makes what I consider a pretty good point (and makes this whole post on-topic). He notions the idea that unlike Earth, where some sort of disaster (meteor) wipes out many of the reptile species, the alien planet had no such disruption and the reptiles were free to evolve into sentient human-like beings.
Perhaps this is far-fetched. However, it is possible given our current idea of evolution. Why couldn't reptiles evolve into conscious beings? I'm not very knowledgable about the physiology of the human brain, but I do remember that temperature may have been a big factor in our evolution. The again, the word may implies that no one really knows exactly how evolution occured, and until we do I would say it is possible that reptiles may very well have been a predominent life on this planet if not for the meteor or whatever that wiped out all the dinosaurs.
Is in Toolmaker Koan. Lousy book, interesting premise. The premise is that progress comes through conflict, and that any society with the social drive to achieve the technology necessary for space travel is - axiomatically - so conflicted that it always bombs itself back to the stone age.
It's hard to argue against. We haven't destroyed ourselves - yet - but then again, we haven't achieved space travel either. I don't count holding our breath while we dash out, touch the moon, and dash back. That's proof of concept. When we get a self sufficient and growing colony on another planet, get back to me.
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