The Drake Equation Revisited

[Moontanman]

[quote]

Originally Posted by Larv

This is my first exposure to the Drake equation. At first blush, it appears to me to be a logical extension of Isaac Asimov’s “Extraterrestrial Civilizations” (1979), in which he is makes one critically false assumption: biological life leads improbabilistically but nevertheless stochastically to intelligent life and civilization as if there were a natural driving force toward higher complexity. No such driving force exists in natural that I know of.

This is thought to be true.

What I think is wrong with the Drake Equation is the absence of what I will call the “one-off factor.” The one-off factor would allow for the assumption that nature often produces just single events—ones arising from an infinitely rare set of circumstances—that produces a completely unpredictable emergent property. As such, the one-off factor would render the Drake Equation all but useless. So far as we know, abiogenesis was such an event. Add to that the improbably emergence of intelligence humans and eventually civilization on Earth, which seems to me to be much more one-off-ish than statistically predictable.

I'm not sure why you can say abiogenisis is a one off deal, most schools of thought think that abiogenisis will occur naturally when ever conditions allow it. Some even think it occurs on almost all planets as they form only later becoming extinct as conditions change. See the book "Rare Earth"

Like Asimov’s speculation, the Drake equation relies on large numbers of event opportunities that have no statistical basis for validity. They are simply saying that because there are so many planet-bearing star systems—“billions and billions and billions” (Carl Sagan)—that it is fair to expect that what happened on this planet will likely happen somewhere else.

I happen to agree it makes little sense until we can actually nail down more of the variables, so far we are trying to plot a trend with one point.

Hasn’t the SETI experiments already proven one thing? If there were other civilized planets with our level of technology then we should be hearing from them by now. Where are the messages from space that beckon us to communicate with them? We seem to be awfully alone, don’t we?

Actually no, SETI pretty much depends on a signal intentionally being beamed to get our attention, when it comes to accidentally detecting an Earth like civilization SETI comes up very short. There is some doubt if we could detect accidental signals from a close as Alpha Centari much less hundreds if not thousands of light years away. Our own radio leakage is now thought to be completely swamped by interstellar static with in just a few light years of the earth.

Do all life-bearing planets eventually go through a transition from prokaryotes to eukaryotes? Do they eventually have their own versions of the Cambrian Explosion? Do they have the same kinds of environmental stresses and mass extinctions that we have had here on earth? And will they eventually adopt civilizations to cope with their vicissitudes?

Very good question, the Rare Earth theory would suggest no they do not and that single celled prokaryotes may be the main life form in the universe.

Frankly, I don’t think we know nearly enough about the course of biological evolution from abiogenesis to civilization to make any judgments on the likelihood of extraterrestrial civilizations. I think the safest assumption is that we are uniquely intelligent and uniquely civilized, no matter how many “billions and billions and billions” of stars are out there.

I agree with the first point but assumptions are always a bad idea.

[TheBigDog]

Originally Posted by Moon

Actually no, SETI pretty much depends on a signal intentionally being beamed to get our attention, when it comes to accidentally detecting an Earth like civilization SETI comes up very short. There is some doubt if we could detect accidental signals from a close as Alpha Centari much less hundreds if not thousands of light years away. Our own radio leakage is now thought to be completely swamped by interstellar static with in just a few light years of the earth.

This is an interesting point. It is even possible that transmissions which make perfect sense to an alien communication system would only look like random static to us. Who's to say that they don't encrypt their messages for privacy, or they use digital encoding in such a fashion that without the knowledge of the protocol it is meaningless. Someone receiving signals from earth, even without distortion, may only be able to read them as random static.

Imagine you are sending a picture. Not so long ago the only way to do that was to deliver a hard copy of the picture. Then we got television and we broadcast pictures, but without a technical understanding of the broadcast protocol it would be a huge challenge to turn those radio signals back into a picture. Now we are in the digital age. We send a JPEG into space. Who do we expect to take those ones and zeros and turn them into coordinates and colors unless they know the protocol ahead of time.

We are also biased to sight and sound. Other life may have sensory bias that is totally out of context with what we are communicating.

But lets throw all that out and look at math. The concepts of math and counting are universal. We often see examples of prime numbers being used to indicate that a civilization has a concept of math. This is logically sound to me. What I don't know is the frequency that we expect to receive these signals. There are algorithms used by SETI which look for patterns, but we are looking for patterns that necessarily make sense to us. If someone was tapping out a series of prime numbers to us what is our realistic expectation of the interval that we receive those signals? We could be throwing out alien communications simply because our cultural assumptions dictate a specific range of time to receive information.

And that brings us to the types of waves used for the communications. On earth we still have AM and FM for radio. Amplitude modulation and Frequency modulation are two different beasts when if comes to how you read them. Now digital is taking over and it gets even more complicated as we are not interpreting analog streams anymore, but taking packets of compressed data and expanding them into information. And we have hundreds or thousands of these data streams intermingled in the same range with protocols used for sifting one out from all the rest. I can't imagine trying to make sense of them without prior knowledge of the system.

Originally Posted by Larv

Do all life-bearing planets eventually go through a transition from prokaryotes to eukaryotes? Do they eventually have their own versions of the Cambrian Explosion? Do they have the same kinds of environmental stresses and mass extinctions that we have had here on earth? And will they eventually adopt civilizations to cope with their vicissitudes?

Frankly, I don’t think we know nearly enough about the course of biological evolution from abiogenesis to civilization to make any judgments on the likelihood of extraterrestrial civilizations. I think the safest assumption is that we are uniquely intelligent and uniquely civilized, no matter how many “billions and billions and billions” of stars are out there.

As for development of life. I think that our one point of reference makes a strong argument for the likelihood of life being pretty much anyplace capable of supporting it. Everywhere we go on earth we find life. In the heights of the atmosphere we find life. In the depths of the sea we find life. In boiling water around volcanic vents we find life. In caves without sunshine or circulating air we find life. In the driest desert we find life. In the coldest winters at the poles of the earth we find life. Where the oceans batter the shores we find life. After nuclear explosions and irradiation we find life. After the most cataclysmic global disasters we find life. Life as we know it finds a way to survive and to thrive. There is no reason to believe that this is a unique phenomena to our planet.

Each individual life form is unique and leads a unique existence. While they may be from a macro perspective very similar to all the others of their species, they are still unique and represent a potential new path for genetic adaptation and diversity. Even something like a horseshoe crab, which appears to have been essentially stable for hundreds of millions of years still has the potential to adapt and evolve given the proper circumstances to drive that happening. The only one-offs are the individuals. It is a statistical impossibility that parallel paths of development do not happen given enough time and opportunity. That is the purpose of the Drake Equation. To try and figure out the odds of parallel development. If you want Earth to be a one off, then simply rationalize the variables to come up with an answer of near zero. But even then all you are doing is satisfying your own preconceptions rather than following a more investigative route.

Then there is the practical side of things. What if we found out today that there was life on another planet. It is likely that nobody alive today would live to experience an encounter with that life other than something as simple as tapping out number sequences and then waiting decades for a response of the same or the next numbers. Actually visiting would take centuries even for the closest stars unless there is a fictional leap to faster than light travel in our future. Should we come up with an equation to predict the likelihood of that?

Bill

[Larv]

Originally Posted by Moontanman

I'm not sure why you can say abiogenisis is a one off deal, most schools of thought think that abiogenisis will occur naturally when ever conditions allow it. Some even think it occurs on almost all planets as they form only later becoming extinct as conditions change. See the book "Rare Earth."

Moontan, I happen to be impressed by the fact that abiogensis remains only an untested theory. I would expect abiogenesis to be high-school lab experiment by now, for the hoopla made over it. This makes me suspicious that abiogenesis did not happen on Earth, but instead in some other place of unknown character. Panspermia offers a vehicular theory for Earth habitation, but it does not account for the original event. I would regard such an occurrence as a one-off event…if we actually knew anything important about it. We certainly do NOT know enough about it to call it a recurring event.

And yet there are renowned scientists who make very bold assumptions, such as Stuart Kauffman (in “At Home In The Universe,” 1995, p. 45). I call it his “order-for free-miracle-garden assumption”:

There are compelling reasons to believe that whenever a collection of chemicals contains enough different kinds of molecules, a metabolism will crystallize from the broth. If this argument is correct, metabolic networks need not be built one component as a time; the can spring up full-grown from a primordial soup. Order for free, I call it. If I am right, the motto of life is not We the improbable, but We the expected.

Peter Ward (“Rare Earth”) ostensibly makes the same assumption. But I’m not ready yet to make it, not until we learn how abiogenesis actually occurred and reproduce it in the laboratory.

[Moontanman]

Reproducing abiogenisis in the lab will only be practical when we have a lab as big as a planet and millions of years of lab time.....

[Larv]

Originally Posted by Moontanman

Reproducing abiogenisis in the lab will only be practical when we have a lab as big as a planet and millions of years of lab time.....

If that is what you think will be required to produce an artificial abiogenesis then you are admitting that abiogenesis cannot be effectively understood.

[Moontanman]

Originally Posted by Larv

If that is what you think will be required to produce an artificial abiogenesis then you are admitting that abiogenesis cannot be effectively understood.

Just because something cannot be reproduced in a test tube doesn't mean it cannot be understood. We have a pretty good handle on star formation and evolution but we cannot make a star in a test tube. Abiogenesis is a complex process, we understand many parts of it, have theories about some of it and small bits of it are still undetermined. You have an unreasonable desire for cut and dried answers, yes/no, right/wrong, white/black, man/eunuch, a great many people think this way, they are called fundamentalists, possibly you should join them for your answers.....

[Larv]

Originally Posted by Moontanman

Just because something cannot be reproduced in a test tube doesn't mean it cannot be understood. We have a pretty good handle on star formation and evolution but we cannot make a star in a test tube. Abiogenesis is a complex process, we understand many parts of it, have theories about some of it and small bits of it are still undetermined. You have an unreasonable desire for cut and dried answers, yes/no, right/wrong, white/black, man/eunuch, a great many people think this way, they are called fundamentalists, possibly you should join them for your answers.....

Stars are big and hot and dangerous. Life is small and cool and molecular. You ought be able to do abiogenesis in any pot, once you have the right recipe. After all, it’s only the basic primordial soup you’re brewing there, waiting for those metabolisms to crystallize. I’ll very interested when you get to the part where your molecules invent the genetic alphabet.

What does this have to do with the Drake equation? The Drake equation assumes necessarily that abiogenesis is a ubiquitous process. I question that assumption.

[Moontanman]

Originally Posted by Larv

Stars are big and hot and dangerous. Life is small and cool and molecular. You ought be able to do abiogenesis in any pot, once you have the right recipe. After all, it’s only the basic primordial soup you’re brewing there, waiting for those metabolisms to crystallize. I’ll very interested when you get to the part where your molecules invent the genetic alphabet.

What does this have to do with the Drake equation? The Drake equation assumes necessarily that abiogenesis is a ubiquitous process. I question that assumption.

You obviously do not have a clue as to what abiogenesis is or how it it thought to work. Again you are talking like a fundamentalist who thinks life is a on/off yes/no thing. I suggest reading a few recent books on the subject, "Life as We Do Not Know It" by Peter Ward would be a good place to start. You are the one harping on abiogenesis in the drake equation, to question that assumption you need more information than the average creationist web site provides.

[Larv]

Originally Posted by Moontanman

You obviously do not have a clue as to what abiogenesis is or how it it thought to work.

Oh, I might have at least a clue.

Again you are talking like a fundamentalist who thinks life is a on/off yes/no thing. I suggest reading a few recent books on the subject, "Life as We Do Not Know It" by Peter Ward would be a good place to start. You are the one harping on abiogenesis in the drake equation, to question that assumption you need more information than the average creationist web site provides.

Yes, I have read Ward’s books. I noticed that in “Life as We Do Not Know It” he makes a key omission on page 96 when he explains away the emergence of a genetic code in “bag life” as merely perfunctory: “Eventually, a genetic code using nucleic acids comes from within the cells.” That’s it? My gosh, it’s that simple?

Then he goes on to speculate that genes came first, protein (enzymes) second, and cells third. That’s interesting. The only thing, though, is where the hell did those genes come from? Just out of nowhere? Just a happy coincidence of an emergent property that arrives pre-coded for instant application?

And, moontanman, you can dispense with those condescending remarks, and that creationist crap, too. I’m an untheist, through and through. (An untheist believes that it doesn’t matter if there is or isn’t a god.)

[Moontanman]

I am going to assume you really want to understand what abiogeneis is larv. If you read this link and all the side links it should give you some idea of why is it so unreasonable to think you should be able to pour ingredients into a pot and get life. More than likely several different processes came to gether at various times to produce the first self replicating molecules that lead to the first things that could be called alive.


Abiogenesis - Wikipedia, the free encyclopedia