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One of the things I love so much about the Drake equation is how it's all so much bullshit. Before you downvote me, I think it's a great equation and I don't h

One of the things I love so much about the Drake equation is how it's all so much bullshit. Before you downvote me, I think it's a great equation and I don't have problems with folks using it. As long as you know what you are doing. really, think about it, all it actually says is that there is this list of things that we feel have to happen in order to determine communicating civilizations, and given any random set of probabilities for a list of things, you multiply them together to get an aggregate answer. It doesn't address whether the list is complete, or overly complex, or mis-stated. The numbers provided are juts best guesses. It's just "multiply a bunch of numbers together and get a new number" I love it. It's definitely not science -- yet it has this cool-looking formula involved. It also has a powerful impact on folks who use it. Drake is really cool in that it gets people thinking about how likely ET is. For that, it's a wonderful tool. But at its heart there's really not much there. At least yet. Perhaps in the future we'll have some solid survey results to put in, especially with Kepler online. Can't wait to start seeing those results coming in.

dantheman 16y ago
I really dislike the drake equation because it's the epitome of bad science -- when someone enters value for the variables they have no idea what is reasonable, absolutely no idea -- is it 0.1 or 0.0000000000000000000000000000001 we have no way of knowing. Though I do like how it gets people to realize how small and insignificant we are in the grand scale that is the solar system, the reasoning we take to get there is fundamentally flawed. We use numbers that have everyday meaning to us, and of course it spits out nice results; this is flawed reasoning since we have no basis to think those numbers are even remotely correct. In general, I just think it's sloppy thinking that takes advantage of deficiencies in human thinking -- it's a magic trick.
- DanielBMarkham 16y ago
  I really tried to be even-handed with my comment -- I didn't want to sound like a troll -- but you are completely correct. In fact, the Drake Equation is a religious statement. That is, it is a creative speculation using commonly understood symbols to that which are completely unknown to us. It's the same as a couple of cavemen sitting on a hill talking about thunder as being large rocks falling from a cliff in a faraway valley. It makes sense, it fits in with what we know, but it's really just a bunch of guesses connected with symbols that, based on context, we feel social approval towards. It's a mind-hack. And a very nicely executed one at that. The reason I didn't use the "R" word, religion, is that folks see that word and stop thinking. They give you an instinctual answer. No way! I'm not religious! etc. The Drake equation basically says what anybody who has looked up at the night sky knows intuitively: there are a lot of stars out there, and it's extremely unlikely that we're all by ourselves. It just does it in a way that makes us feel like we're receiving some sort of imparted scientific wisdom, instead of what it really is: creative speculation. In that sense the formula itself may be total bullshit scientifically, but what it tells us about how science and religion play with each other is very important. People look at it and just feel that there is some truth there, and there is, but it's not the same kind of truth as f=ma, although both statements are expressed mathematically and have the same air of seriousness around them.
  - jerf 16y ago
    "The Drake equation basically says what anybody who has looked up at the night sky knows intuitively: there are a lot of stars out there, and it's extremely unlikely that we're all by ourselves." Further reinforcing your core point, it can also tell you that we are. You don't have to be that painfully conservative with the numbers to come with one or fewer per galaxy. For instance, 50% of stars having planets may be a brutal overestimate, a lot of stars are in multi-star systems or other situations in which there are no stable orbits, resulting in any initial planets getting ejected very quickly if they form at all. 2 Earth-like planets per star is a bold statement, depending on the exact definition of "Earth-like", we only have one in our system and if you read past the propaganda in the planet finding press releases they aren't coming up with all that many other "Earth like" planets yet. Yes, that's because they still can't see them, but the press releases convey a false sense of how the search is going when they do things like call a planet with a surface gravity of 3 or 4 G and a surface temperature beyond rock's liquification point a "Super-Earth". 10000 years is a bold estimate for how long a civ will be around and communicating, certainly. I actually am against the self-loathing that some circles find fashionable but 10,000 years is a long time. I consider these numbers generous and it still only comes up with 10. It's missing some terms, too. Irregular galaxies [1], approximately 25% of the galaxies out there, are thought to be entirely unable to support complex life because basically all the stars in such galaxies will take a system through a region of the galaxy with too much radiation and sterilize the planets every few tens of millions of years. I mean this only as an example, you can go on naming more fairly reasonable criteria that eliminate half or more stars from contention for quite a while (star types, star galactic orbits, other galaxy attributes, even before we get to planets we can eliminate a lot). To brutally abuse notation, the night sky is O(n^3) in size, if the probabilities of developing civilization are O(2^n)-type it doesn't matter how large the sky is. Big numbers fall fast when you multiply independent probabilities together, and it's not sophistication to just give up and declare there must be a lot of other civilizations out there; it's still a mathematical copout. We don't know. [1]: http://en.wikipedia.org/wiki/Irregular_galaxy http://en.wikipedia.org/wiki/Irregular_galaxy
    - bad_user 16y ago
      I agree with your poing, but Mars is earth-like and it could have carried life ... There is evidence that Mars once carried liquid water on its surface, it's formed out of the same materials (carbon, hydrogen, water) and had all the elements needed for life. Mars lost its liquid water because (contrary to earth) it lost its atmosphere because it also lacks active plate tectonics (also, contrary to earth). So our solar system has 2 earth-like planets ... with one that became a desert and died, but that was once very much like Earth, with some people still hoping to find microscopic life at the poles. That's not too shabby. Basically it is considered that if a planet holds liquid water, then it can carry life (liquid water implies other things, like the presence of an atmosphere). Bigger solar systems may contain even more earth-like planets, but I agree: an average of 2 is way too high. EDIT: Also, one other thing: if Mars wouldn't have lost its atmosphere, then oxygen would have spread faster than on earth, because the planet is smaller, which means the transition from microscopic life to macro would have been faster.
- nollidge 16y ago
  It's not bad science, though, because it's not science. It's not meant to be science. All Drake set out to do was establish an agenda for an NAS meeting in 1961 regarding extraterrestrial intelligence. It's a list of known unknowns. It was not arrived at via scientific experimentation, and was never claimed to have, so anyone calling it "science", even "bad science", is mislabeling it.
  - jdp23 16y ago
    seems to me that an agenda for a major scientific meeting falls into the category of "science".
jsomers 16y ago
There is a wonderful book edited by Carl Sagan called Communication With Extraterrestrial Intelligence (CETI), Proceedings of a conference held at the Byurakan Astrophysical Observatory, Yerevan, USSR, 5-11 September 1971. The chief aims of the conference were, first, to estimate values for terms of the Drake equation, and second, to devise strategies for contact. So all these top American and Soviet scientists had to discuss a remarkable range of topics—everything from the chemical origins of life, to the anthropology of early civilizations, to the problem of encoding messages in a form comprehensible to intelligences vastly unlike ourselves. It's possibly the most interesting thing I've ever read.
- jdp23 16y ago
  sounds like science to me...
rue 16y ago
So the solution is to add a variable for confidence in the completeness of the equation. Perhaps range 0.5..1.5. And then another for confidence in the confidence.
- dantheman 16y ago
  The problem is that we don't know what the confidence should be, and as of right now we don't have anyway to tell. In the future hopefully we'll know enough to use the equation but right now we just don't know.
kmfrk 16y ago
Michael Crichton had a great lecture/essay about this (which, for some reason, is no longer available on the original website). Originally, it was available at http://www.michaelcrichton.net/speech-alienscauseglobalwarming.html http://www.michaelcrichton.net/speech-alienscauseglobalwarmi..., but I've ViewText-formatted a mirror on http://viewtext.org/article?url=http://climaterealists.com/index.php?id=2097 http://viewtext.org/article?url=http://climaterealists.com/i.... It's one of my pieces of writing available online.
jdp23 16y ago
> It's definitely not science Why not? It's proposing an underlying model, which in turn provides a framework for investgation as well as a way reasoning about things in the absence of harder data as. Sounds like science to me. What would you propose as a more scientific approach to estimating the number of communicating civilizations in the galaxy?
thret 16y ago
Obligatory XKCD: http://xkcd.com/384/ http://xkcd.com/384/ http://xkcd.com/718/ http://xkcd.com/718/
guscost 16y ago
Haha, this was the subject of my first blog post. It's pretty ridiculous. Here's a link actually, should be doing this more. http://guscost.com/2010/12/23/science-where-are-the-aliens/ http://guscost.com/2010/12/23/science-where-are-the-aliens/
russell 16y ago
The Drake Equation has so many fuzzy unknowns that you cant get meaningful information out of it, if rephrased right we could get some meaning variables to play with. If we want to know if there are possible communication partners right now, we can figure out some of the unknowns. First the definition of an earth like planet. It has liquid water and dry land. Liquid water, because the only kind of life we know of developed in liquid water. Dry land because developing a communicating technology requires an abiulity to isolate your experiments. I believe there are so many impediments under water that a technological civilization would never develop. So a technological civilization requires 4B years to develop from the birth of a star. The habitable zone of a star is where water is liquid roughly. An earth-like planet must have inhabited a continuously habitable zone for 4B years. A flare star may not have a continuously habitable zone. An M star's habitable zone may be so close to the start that the planet is in a tidal lock with the star. An enterprising astrophysist can probably estimate the probability of a sufficently large stable habital zone for a given class of stars. We dont have enough data for estimating the probability of a water/dry land world being there. Given life and enough time, what is the probability of a technological civilization arising. 1.0 or so small that we are alone. We are probably at the age and interconnectedness that we will survive a very long time. I dont wory about nuclear war, but I do worry about bio-terror and nut cases. I think the big constraint is patience. I dont think any civilization is ready to invest the time and energy to wait 1000 years for a reply. I think the potential partners will be limited to a volume of 100 light years. Maybe 5000 stars, not all that many.
InclinedPlane 16y ago
The Drake equation is a lot like the Fermi paradox. They are not revelations of some truth about the nature of intelligent life in the Universe (or even our galaxy), they are merely reflections of our utter ignorance of the subject. Where do these figures come from? For fully 5 out of the 7 parameters to the Drake equation we have extraordinarily limited data. How common are Earth-like planets? Call back in about 5-10 years when we'll have some solid data from the Kepler mission. How common is life on Earth-like planets? Who knows? We aren't even close to being able to get solid figures on that. If we can find life on Mars or rule life out of ever having existed there then we'll have a teeny tiny bit of data. But even then such an estimate will be biased by the anthropic principle and at best only accurate to perhaps a single order of magnitude (if that). Even then that leaves half of the parameters as wild ass guesses. Not to mention that the parameters aren't independent. If we find life on Mars existed or still exists that would make f-sub-l higher, but it would probably make f-sub-i correspondingly lower. Worse yet, the very premise of the Drake equation is at odds with the premise behind the Fermi paradox. If even a single, slow colonizing intelligent civilization ever existed in our galaxy it would make the number of possible communicative worlds differ by perhaps even 6 or 9 orders of magnitude. The exercise is only worthwhile when it is not taken seriously, which is a bit of a catch-22.

dantheman 16y ago

I really dislike the drake equation because it's the epitome of bad science -- when someone enters value for the variables they have no idea what is reasonable, absolutely no idea -- is it 0.1 or 0.0000000000000000000000000000001 we have no way of knowing. Though I do like how it gets people to realize how small and insignificant we are in the grand scale that is the solar system, the reasoning we take to get there is fundamentally flawed. We use numbers that have everyday meaning to us, and of course it spits out nice results; this is flawed reasoning since we have no basis to think those numbers are even remotely correct. In general, I just think it's sloppy thinking that takes advantage of deficiencies in human thinking -- it's a magic trick.

DanielBMarkham 16y ago
I really tried to be even-handed with my comment -- I didn't want to sound like a troll -- but you are completely correct. In fact, the Drake Equation is a religious statement. That is, it is a creative speculation using commonly understood symbols to that which are completely unknown to us. It's the same as a couple of cavemen sitting on a hill talking about thunder as being large rocks falling from a cliff in a faraway valley. It makes sense, it fits in with what we know, but it's really just a bunch of guesses connected with symbols that, based on context, we feel social approval towards. It's a mind-hack. And a very nicely executed one at that. The reason I didn't use the "R" word, religion, is that folks see that word and stop thinking. They give you an instinctual answer. No way! I'm not religious! etc. The Drake equation basically says what anybody who has looked up at the night sky knows intuitively: there are a lot of stars out there, and it's extremely unlikely that we're all by ourselves. It just does it in a way that makes us feel like we're receiving some sort of imparted scientific wisdom, instead of what it really is: creative speculation. In that sense the formula itself may be total bullshit scientifically, but what it tells us about how science and religion play with each other is very important. People look at it and just feel that there is some truth there, and there is, but it's not the same kind of truth as f=ma, although both statements are expressed mathematically and have the same air of seriousness around them.
- jerf 16y ago
  "The Drake equation basically says what anybody who has looked up at the night sky knows intuitively: there are a lot of stars out there, and it's extremely unlikely that we're all by ourselves." Further reinforcing your core point, it can also tell you that we are. You don't have to be that painfully conservative with the numbers to come with one or fewer per galaxy. For instance, 50% of stars having planets may be a brutal overestimate, a lot of stars are in multi-star systems or other situations in which there are no stable orbits, resulting in any initial planets getting ejected very quickly if they form at all. 2 Earth-like planets per star is a bold statement, depending on the exact definition of "Earth-like", we only have one in our system and if you read past the propaganda in the planet finding press releases they aren't coming up with all that many other "Earth like" planets yet. Yes, that's because they still can't see them, but the press releases convey a false sense of how the search is going when they do things like call a planet with a surface gravity of 3 or 4 G and a surface temperature beyond rock's liquification point a "Super-Earth". 10000 years is a bold estimate for how long a civ will be around and communicating, certainly. I actually am against the self-loathing that some circles find fashionable but 10,000 years is a long time. I consider these numbers generous and it still only comes up with 10. It's missing some terms, too. Irregular galaxies [1], approximately 25% of the galaxies out there, are thought to be entirely unable to support complex life because basically all the stars in such galaxies will take a system through a region of the galaxy with too much radiation and sterilize the planets every few tens of millions of years. I mean this only as an example, you can go on naming more fairly reasonable criteria that eliminate half or more stars from contention for quite a while (star types, star galactic orbits, other galaxy attributes, even before we get to planets we can eliminate a lot). To brutally abuse notation, the night sky is O(n^3) in size, if the probabilities of developing civilization are O(2^n)-type it doesn't matter how large the sky is. Big numbers fall fast when you multiply independent probabilities together, and it's not sophistication to just give up and declare there must be a lot of other civilizations out there; it's still a mathematical copout. We don't know. [1]: http://en.wikipedia.org/wiki/Irregular_galaxy http://en.wikipedia.org/wiki/Irregular_galaxy
  - bad_user 16y ago
    I agree with your poing, but Mars is earth-like and it could have carried life ... There is evidence that Mars once carried liquid water on its surface, it's formed out of the same materials (carbon, hydrogen, water) and had all the elements needed for life. Mars lost its liquid water because (contrary to earth) it lost its atmosphere because it also lacks active plate tectonics (also, contrary to earth). So our solar system has 2 earth-like planets ... with one that became a desert and died, but that was once very much like Earth, with some people still hoping to find microscopic life at the poles. That's not too shabby. Basically it is considered that if a planet holds liquid water, then it can carry life (liquid water implies other things, like the presence of an atmosphere). Bigger solar systems may contain even more earth-like planets, but I agree: an average of 2 is way too high. EDIT: Also, one other thing: if Mars wouldn't have lost its atmosphere, then oxygen would have spread faster than on earth, because the planet is smaller, which means the transition from microscopic life to macro would have been faster.
nollidge 16y ago
It's not bad science, though, because it's not science. It's not meant to be science. All Drake set out to do was establish an agenda for an NAS meeting in 1961 regarding extraterrestrial intelligence. It's a list of known unknowns. It was not arrived at via scientific experimentation, and was never claimed to have, so anyone calling it "science", even "bad science", is mislabeling it.
- jdp23 16y ago
  seems to me that an agenda for a major scientific meeting falls into the category of "science".

jsomers 16y ago

There is a wonderful book edited by Carl Sagan called Communication With Extraterrestrial Intelligence (CETI), Proceedings of a conference held at the Byurakan Astrophysical Observatory, Yerevan, USSR, 5-11 September 1971. The chief aims of the conference were, first, to estimate values for terms of the Drake equation, and second, to devise strategies for contact. So all these top American and Soviet scientists had to discuss a remarkable range of topics—everything from the chemical origins of life, to the anthropology of early civilizations, to the problem of encoding messages in a form comprehensible to intelligences vastly unlike ourselves. It's possibly the most interesting thing I've ever read.

jdp23 16y ago
sounds like science to me...

rue 16y ago

So the solution is to add a variable for confidence in the completeness of the equation. Perhaps range 0.5..1.5. And then another for confidence in the confidence.

dantheman 16y ago
The problem is that we don't know what the confidence should be, and as of right now we don't have anyway to tell. In the future hopefully we'll know enough to use the equation but right now we just don't know.

kmfrk 16y ago

Michael Crichton had a great lecture/essay about this (which, for some reason, is no longer available on the original website). Originally, it was available at http://www.michaelcrichton.net/speech-alienscauseglobalwarming.html http://www.michaelcrichton.net/speech-alienscauseglobalwarmi..., but I've ViewText-formatted a mirror on http://viewtext.org/article?url=http://climaterealists.com/index.php?id=2097 http://viewtext.org/article?url=http://climaterealists.com/i.... It's one of my pieces of writing available online.

jdp23 16y ago

> It's definitely not science Why not? It's proposing an underlying model, which in turn provides a framework for investgation as well as a way reasoning about things in the absence of harder data as. Sounds like science to me. What would you propose as a more scientific approach to estimating the number of communicating civilizations in the galaxy?

thret 16y ago

Obligatory XKCD: http://xkcd.com/384/ http://xkcd.com/384/ http://xkcd.com/718/ http://xkcd.com/718/

guscost 16y ago

Haha, this was the subject of my first blog post. It's pretty ridiculous. Here's a link actually, should be doing this more. http://guscost.com/2010/12/23/science-where-are-the-aliens/ http://guscost.com/2010/12/23/science-where-are-the-aliens/

russell 16y ago

The Drake Equation has so many fuzzy unknowns that you cant get meaningful information out of it, if rephrased right we could get some meaning variables to play with. If we want to know if there are possible communication partners right now, we can figure out some of the unknowns. First the definition of an earth like planet. It has liquid water and dry land. Liquid water, because the only kind of life we know of developed in liquid water. Dry land because developing a communicating technology requires an abiulity to isolate your experiments. I believe there are so many impediments under water that a technological civilization would never develop. So a technological civilization requires 4B years to develop from the birth of a star. The habitable zone of a star is where water is liquid roughly. An earth-like planet must have inhabited a continuously habitable zone for 4B years. A flare star may not have a continuously habitable zone. An M star's habitable zone may be so close to the start that the planet is in a tidal lock with the star. An enterprising astrophysist can probably estimate the probability of a sufficently large stable habital zone for a given class of stars. We dont have enough data for estimating the probability of a water/dry land world being there. Given life and enough time, what is the probability of a technological civilization arising. 1.0 or so small that we are alone. We are probably at the age and interconnectedness that we will survive a very long time. I dont wory about nuclear war, but I do worry about bio-terror and nut cases. I think the big constraint is patience. I dont think any civilization is ready to invest the time and energy to wait 1000 years for a reply. I think the potential partners will be limited to a volume of 100 light years. Maybe 5000 stars, not all that many.

InclinedPlane 16y ago

The Drake equation is a lot like the Fermi paradox. They are not revelations of some truth about the nature of intelligent life in the Universe (or even our galaxy), they are merely reflections of our utter ignorance of the subject. Where do these figures come from? For fully 5 out of the 7 parameters to the Drake equation we have extraordinarily limited data. How common are Earth-like planets? Call back in about 5-10 years when we'll have some solid data from the Kepler mission. How common is life on Earth-like planets? Who knows? We aren't even close to being able to get solid figures on that. If we can find life on Mars or rule life out of ever having existed there then we'll have a teeny tiny bit of data. But even then such an estimate will be biased by the anthropic principle and at best only accurate to perhaps a single order of magnitude (if that). Even then that leaves half of the parameters as wild ass guesses. Not to mention that the parameters aren't independent. If we find life on Mars existed or still exists that would make f-sub-l higher, but it would probably make f-sub-i correspondingly lower. Worse yet, the very premise of the Drake equation is at odds with the premise behind the Fermi paradox. If even a single, slow colonizing intelligent civilization ever existed in our galaxy it would make the number of possible communicative worlds differ by perhaps even 6 or 9 orders of magnitude. The exercise is only worthwhile when it is not taken seriously, which is a bit of a catch-22.