Talk:Drake equation

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Drake equation example of Fermi problem[edit]

Just added a note to say that the Drake equation is an example of a Fermi problem and so more accurate than you would expect, was surprised no-one has mentioned it yet :). It is mentioned on the Fermi problem page, so it's just a case of linking the information both ways between the pages. Robert Walker (talk) 08:48, 21 April 2013 (UTC)

1961 esitmate[edit]

I've altered the figures to agree with those used in the BBC program (currently on iPlayer) "The Search for Life: The Drake Equation". Since Drake himself is on film performing the calculations, and since there is no references at all as to where the numbers came from, I think I've legimate in doing so. APL92 (talk) 01:44, 19 January 2011 (UTC)

I tried to watch this, but got "Not available in your area". Did he explicitly say these were the figures he used in 1961? Or could they be the figures he now believes? LouScheffer (talk) 02:05, 19 January 2011 (UTC)

The values on the page today are not the same as those given in the original interview which I have just watched. The following are the values said by Drake to have been the original ones together with a brief note on his justification: No of of stars formed per year 10 well known; Proportion of stars with planets 0.5 based on indirect evidence from binary stars; No of planets that are habitable 2 Earth and Mars (later he said this would should now be 4 to include the satellites of Jupiter and Saturn); Fraction of planets that would develop life 1 chemical experiments showed that life would eventually appear; Fraction that would develop intelligent life 0.5 a big guess but the fossil record shows brain size continues to increase; Fraction that would communicate 1 based on our history; Time for which communications would take place 10,000 years a conservative guess; and this gives 50,000 as a result. Ted (talk) 17:03, 5 May 2012 (UTC)

Qwantz vandalism[edit]

Just a heads up - this article has been linked to from Dinosaur Comics ( with predictable consequences. Looks like a people will be trying to sneak in Green Lantern or T-rex references for a few days. —Preceding unsigned comment added by (talk) 11:11, 7 January 2011 (UTC)

This article in the press[edit]

This article is linked to in this press article: Man Uses Math to Explain Girlfriend Woes Samboy (talk) 05:22, 14 January 2010 (UTC)

So this is just a guess? —Preceding unsigned comment added by AdbMonkey (talkcontribs) 13:22, 26 October 2010 (UTC)

Wrong equation for R*[edit]

The equation

 N^{\ast} = \int_0^{T_g} R^{\ast}(t) dt , \,\!

ignores the fact that all stars have a finite lifespan, as they will either undergo a supernova or become a white dwarf. In fact, our Galaxy is known to have multiple generations of stars, and not a single "first-generation" star (i.e. population III) has yet been discovered. Furthermore, assigning an age to a galaxy is rather ambiguous, since it is now known that galaxies (especially large ones) have undergone many mergers with other galaxies. Thus it can said that the age of all galaxies is (nearly) the age of the Universe. In the general case we might put

  N^{\ast} = \int_0^{T_g}( R^{\ast}- R^{D}) (t) dt , \,\!



is the rate at which stars are destroyed, by going (super)nova or becoming white dwarfs or being torn apart by gravitational forces during galactic collisions. — Preceding unsigned comment added by Cato9 (talkcontribs) 05:46, 28 February 2013 (UTC)

Wrong statement for L[edit]

RM below about L to talk. If L is the length of time such civilizations release detectable signals into space then Grote Reber and radio astronomy have nothing to do with this value, his antenna was a receiver, not a transmitter. Maybe the example should date back to the Invention of radio. Fountains of Bryn Mawr (talk) 00:23, 4 March 2010 (UTC)

The value of L can be estimated from the lifetime of our current civilization from the advent of radio astronomy in 1938 (dated from Grote Reber's parabolic dish radio telescope) to the current date. In 2009, this gives an L of 7300 years. However such an assumption would be erroneous. 71 for the value of L would be an artificial minimum based on Earth's broadcasting history to date and would make likely the possibility of other civilizations existing. 10,000 for L is still the most popular estimate.

Current estimate of fl[edit]

In the "Current estimates of the parameters" section, it says that Drake estimated fl to be 1, whereas a couple other guys more recently estimated it to be 0.13. However, in the two sections that calculate N based on the current estimates (both at the bottom of the "Historical estimates" section and the bottom of the "Current estimates" section), a value of 0.33 is used for fl. Where did 0.33 come from? Should an explanation should be added regarding how 0.33 was derived, or should we be using 0.13 in our current estimate calculation of N? SnottyWong talk 21:29, 19 April 2010 (UTC)

Using the following document as a source: [[1]] more than 50% of solar-type stars harbor at least one planet of any mass and with period up to 100 days. (Easy to detect, relatively) About 14% of solar-type stars have a planetary companion more massive than 50M-Earth

solar-type stars are important because they are the easiest to work with, so using these as a sampling we can extrapolate probabilities of non solar-type systems should be relatively similar.

Take a couple of facts from this page. 50% solar-type stars harbor a planet we can detect (Massive and fast orbiting). Jupiter has a period of over 3000 days, 30 times more than we are detecting. This means we are talking about massive planets as close to their star as Mercury is to the Sun.

[[2]] Talks about detecting a planet in a binary star system, a major breakthrough.

If you add up all of the data presented on these page, and include our observations of Sol with 8 planets (Not currently detectable by our technology), the logical conclusion is that almost no star system would be without planets. So a more educated estimate should be closer to 1.0, or at least 0.9. We are likely in the 96% statical range for the number of planets at least, and our system is likely not a freak or very special, it is far more likely it is common. — Preceding unsigned comment added by (talk) 22:10, 12 June 2012 (UTC)

Isn't fl an fraction of the occurrence of life? (Looks like you are debating fp.) Then why isn't Extraterrestrial organic molecules cited here? Kortoso (talk)

Mayr vs Sagan out? Michael Crichton in?[edit]


The late Ernst Mayr was the most famous biologist at our times, especially in the theory of evolution which is most relevant here, and he criticised the SETI project in various occasions. I find the discussion he had with Carl Sagan, one of the fathers of SETI especially enlightening and that is why I added it. Now the current section about critics of the SETI project contains a cite of Michael Crichton, a science fiction writer and removed the Mayr link. With all due respect to Mr. Crichton but I think the critics of Ernst Mayr is far more relevant. One of his arguments, which he clearly emphasised as being speculative is based on the fact that of the many species on earth, which might be in the billions, only one developed intelligence. Now the wording of the paragraph I added can be changed of course and rephrased, but leaving Crichton in and Mayr out, seems to me sort of ridiculous. Oub (talk) 12:52, 28 April 2010 (UTC):

Mayr's argument is actually fallacious. The reason only one species on Earth developed a technological intelligence is that there is only one niche per planet for such a species. Reflect on the fate of the Neanderthals. WolfmanSF (talk) 22:57, 2 October 2010 (UTC)
You're loading a lot of weight onto a highly speculative claim. What is your evidence for this conclusion? What peer-reviewed journals has this been published in?Dogface (talk) 17:37, 18 February 2011 (UTC)
Hi! The recent edits include a rather non-NPOV view in my opinion, saying the numbers are manipulated, and so on. This strongly implies that the editor knows what the true answer is, whereas no-body does. Also, there's no inconsistency in assuming life is very likely (it arose quickly on earth) but communicative life is rare. We don't communicate yet, there are lots of reasons a society might believe it unsafe (see Fermi paradox, and possible reasons for it), and there's a pretty strong bias in published literature about listening first before we transmit. Please provide a reference stating these are inconsistent since many sources find them reasonable (as much as any assumption can be reasonable in a field like this.) Other's views are of course welcomed on this topic. LouScheffer (talk) 18:11, 18 February 2011 (UTC)
In that case, all the parameters should just honestly be called wild ass guesses pulled out of someone's backside. As for "many sources" finding a particular wild ass guess to be reasonable, that's the logical fallacy of argumentum ad populum. What is the evidence to back up the specific numbers and reject other numbers. Where is the hard evidence. Please point out where this evidence is published in peer reviewed professional journals.Dogface (talk) 18:13, 21 February 2011 (UTC)

factor missing in the equation?[edit]

In the equation appear the factors

:fc = the fraction of civilizations that develop a technology that releases detectable signs 
of their existence  into space
:L = the length of time such civilizations release detectable signals into space.

It might be, that such civilization existed for 1 million years, that would produce a good result of calculation for N.

But if that happened 100 million years ago, and 99 million years ago that civilization disappeared, we cannot communicate. Should a "factor of same time" be added to the equation? Is there anything in the literature? --Hans W (talk) 15:14, 14 August 2010 (UTC)

εEarth is not obtainable from Drake equation parameters[edit]

It is not true that εEarth = fp x ne (where εEarth is the the fraction of stars with Earth-like planets). Consider an extreme but illustrative example. If fp = 0.01 (only 1% of stars have planets) and ne = 100 (each of those stars has 100 Earthlike planets), then εEarth = 0.01, but fp x ne = 1.0. You need to know the statistical distribution of ne to calculate εEarth. WolfmanSF (talk) 23:13, 2 October 2010 (UTC)

R* is the number of stars in the galaxy?[edit]

I'm not sure why this article emphasizes the number of stars formed per year, without multiplying that number by the number of years the galaxy has been forming stars! This matter is explained somewhat in the subsection "Alternative expression" but later ignored in the "Current estimates of the parameters" section. The result is that the first three terms of the right hand side give the number of earth-like planets formed per year. The end result, 2.31 civilizations, is an absurdly low estimate. The original Drake equation was: N = N_g \times f_p \times n_e \times f_{\ell} \times f_i \times f_c \times L \! where the first term on the right-hand side is the number of stars in the galaxy.  N_g is on the order of 200 to 400 billion, not 7. I have edited the "Current estimates" section with the estimates made by James Kasting in his book "How To Find A Habitable Planet". (talk) 03:23, 10 October 2010 (UTC) Eric

offensive anthropocentrism[edit]

I'm taking issue with the text

  • fi = the fraction of the above that actually go on to develop intelligent life. Estimated by Drake as 0.01 based on little or no evidence. This value remains particularly controversial. Pessimists such as Ernst Mayr point out that of the billions of species that have existed on Earth, only one has become intelligent[18] and infer a tiny value for fi.

the view that Earth has only one intelligent species is ridiculous and offensive. in fact it harbours several very intelligent species. this aspect of the controversy has not been exposed in the article. some versions of the drake equation, however, do make the distinction between intelligence and technological advancement as different factors. -- (talk) 01:43, 13 November 2010 (UTC)

Hm, please name another intelligence species on this planet! In order to prevent a fight over the word intelligence, the basic motivation of the Drake equations is to communicate. So instead of looking for an intelligent species one could say a species which posses a language with a full developed grammar, so I am curious which species do you have in mind? Oub (talk) 17:45, 16 November 2010 (UTC)
Not just communicate with each other. A species would have to be intelligent enough to develop long range inter-stellar communication. Something the neanderthals and chimpanzees never accomplished.-- (talk) 04:13, 12 January 2012 (UTC)

There is an issue here on whether you take the factor to be developed intelligent life which has survived or developed intelligent life. Neanderthals were capable of speech, as were other Hominids (I think), but are of course extinct. Since the article simply mentions developing intelligent life, and not the added clause of survival, I'm (in my view) rectifying this. APL92 (talk) 01:44, 19 January 2011 (UTC)

Current estimates of the parameters: Mayr (POV)[edit]

The actual subsection the fraction of the above that actually go on to develop intelligent life reads

Estimated by Drake as 0.01 based on little or no evidence. This value remains particularly controversial. Pessimists such as Ernst Mayr point out that of the billions of species that have existed on Earth, only one has become intelligent[18] and infer a tiny value for fi. Optimists note the generally increasing complexity of life and conclude that the eventual appearance of intelligence might be inevitable, meaning fi=1.[19]

several remarks:

  1. Mayr was a very famous biologist that should be mentioned.
  2. He is denoted as a pessimist, that is clearly POV , it would be more accurate to call him realist but I think it is best to drop any label.
  3. Now [19] is cited presenting a counterargument. first of all it is written by enrico , is this any known or even famous biologist? Besides in this article it not claimed that fi=1.

Given all that I suggest to drop pessimist for Mayr and drop the link to enrico. Oub (talk) 22:01, 18 November 2010 (UTC):

Famous is true, but irrelevant. Especially in this field, where little is known for sure, famous does not guarantee anything. (Einstein, clearly a famous physicist, said God does not play games with dice, but the consensus now is that he was wrong...).
Also, I provided a very solid reference to "Generally increasing complexity of life". Even if you object to some other reference, please do not remove this one. There is no doubt that many SETI folks have set the probability to 1 (that's what Meyr is objecting to....), based on (among others) this argument. So adding a "citation needed" is as far as you should go in this area.
Finally, it's not POV to summarize the two conclusions and the arguments behind them. Even though you, personally, may feel one is much stronger than the other, both have been used in the field, so they should remain. Removing, or minimizing, one of them only, is quite POV by itself. LouScheffer (talk) 19:14, 21 November 2010 (UTC)
Re: LouScheffer thanks for your answer. To make this clear: Both estimates about the value of fi should be mentioned. I only objected to the version Mayr vs Enrico. The second reference you inserted is solid enough, however I would prefer to leave out the first one, but I don' want to make a war about it. The formulation which I feel uneasy about it, is the word pessimist, that in my opinion is too strong and too biased, what's about skeptic instead of pessimist. Oub (talk) 11:24, 22 November 2010 (UTC):
The current meaning of 'pessimist' is someone who is pessimistic about making contact (for any one of a number of reasons). In this sense Mayr is definitely a pessimist, as I think he would agree. Similarly, 'optimists' are those who are optimistic about the chances of making contact, or at least about intelligence evolving. I personally think 'skeptic' is better reserved for those who believe all such calculations are unreliable at best, as opposed to those who are skeptical of making contact. Maybe we could say 'Contact pessimists' and 'contact optimists' or just replace it with the more bland 'some' and 'others'. LouScheffer (talk) 03:22, 23 November 2010 (UTC)
Re: LouScheffer hm Mayr is dead, so we can't ask him. I strongly recommend not to use pessimist or optimist but some and others. Oub (talk) 14:21, 23 November 2010 (UTC):

Two issues with the L value.[edit]

In the section "The Equation", we have: L = the length of time for which such civilizations release detectable signals into space.

Then in the section: "Historical estimates of the parameters", we have: L = ... (which will last .... years)

Now how long a civilisation lasts, versus how long it releases detectable signals, are VASTLY different things.

Expanding from that, I also have difficulties with these very large values of L. Look at what's happened here on planet earth, in terms of "unintended" signals: that is, signals that might be detected by an ETI even though that is not their target audience. For example, in terms of broadcast radio, over the last 40 years, we have gone from relatively small numbers of very powerful AM and shortwave radio stations, which are quite wasteful, to a relatively huge number of far less powerful and less wasteful FM and digital stations. But due to the very fact that they are more efficient and less wasteful, they are therefore far more difficult for an ETI to receive.

We could reasonably anticipate/extrapolate that this would not be a Sol-centric phenomenon: that as a civilisation becomes more advanced it develops more complex and efficient communication methods that by definition are more difficult to detect unintentionally. This has to have some effect on the value of L. Old_Wombat (talk) 09:20, 2 July 2011 (UTC)

I'd agree we need a more consistent use of L. The argument you are making about radio signals is covered in more detail in Fermi paradox#Civilizations only broadcast detectable radio signals for a brief period of time. On the other hand, other technologies that we are starting to use (such as large scale solar power) might also signal our presence. See, for example, "Large Scale Use of Solar Power May be Visible Across Interstellar Distances". . LouScheffer (talk) 13:56, 3 July 2011 (UTC)
I agree with both comments above. How long a civilization releases detectable signals is clearly what matters, but popular media always seems to define L as the lifetime of a civilization after it achieves the (radio) technology that distant others (we) can detect, which may greatly exceed the length of time they emit detectable radio. Given our developments of alternative forms of communication (fiber optic cable and satellites having transmitters directed toward the ground) it seems naive to assume we will continue to transmit detectable radio into space as long as our civilization continues to exist. Modifications of the Drake Equation to account for colonization of other planets need to consider this too, since colonies won't necessarily revert to detectable radio after their parent civilization has advanced beyond detectable radio. Lou Scheffer's comment about detectable solar power is relevant, but solar power may be a temporary technology too; would a civilization powered by nuclear fusion reactors be detectable? SEppley (talk) 14:40, 5 March 2012 (UTC)

Another factor relevant to the calculation of L is the length of time once a civilization begins to emit detectable signals after which they are detected and destroyed by another more advanced civilization (perhaps using Von Neumann spacecraft) that's wise enough not to emit detectable signals and doesn't want competitors increasing the galaxy's entropy. ;-) SEppley (talk) 14:40, 5 March 2012 (UTC)

T.J. Nelson[edit]

The link to the source for the T.J. Nelson quotation in the Criticism section is dead. Moreover, I can't find any information online that would establish his authority on this or any related topic. I suggest removing the quotation and reference. Schomerus (talk) 18:29, 7 November 2011 (UTC)

OK, I replaced the link with one that works. I did not look at his credentials, but think the criticism is worth including. LouScheffer (talk) 15:35, 9 November 2011 (UTC)
I removed it, because I think the author is not notable enough. I searched for how Nelson relates to Drake equation via google and found a lot of forums/blogs including this citation (most of them probably copied from the wiki article, since artifacts, such as [24] are present), but no WP:RS. One thing is that he's neuroscientist, not cosmologist or astronomer, so if we don't have reliable sources to establish notability of his citation, we probably shouldn't include it. 1exec1 (talk) 19:09, 10 November 2011 (UTC)
Hey, watch it! I'm a neuroscientist myself.[3] Seriously, there are very few folks who can list Drake Equation specialist as their day job, and the ideas are simple enough that anyone with a scientific background is on roughly equal footing. And if you want to keep one criticism, I'd prefer one from a real working scientist to one from a science fiction author. (Though any decent science fiction author could comment intelligibly as well.) LouScheffer (talk) 03:10, 11 November 2011 (UTC)
I did not have anything about neuroscientists. I just couldn't find any information about the author to verify his credibility. If we could find at least one WP:RS that talks about his quotation then we can keep it. Regarding that fiction author, there are some solid sources that think he's qualified to talk about Drake equation, e.g. Wall Street Journal 1exec1 (talk) 17:45, 11 November 2011 (UTC)

Current estimate of fP[edit]

Shouldn't this section use stronger language here? "It is known from modern planet searches that at least 40% of sun-like stars have planets" "However, a new study[12] suggests that fp may approach 1" I would say that the first sentence should read "It is known from modern planet searches that each star in the milky way has 1.6 planets" Lansey (talk) 18:30, 12 January 2012 (UTC)

I went with the more cautious language because there are such widely varying estimates; '40% of sun-like stars' to '100% of stars' is a pretty wide spread, so I didn't feel comfortable with going stronger than the reference to the new study. I think the new numbers are probably good, but given the early stage we're at in the science, and the wide range of estimates to date, that a little caution is warranted pending further data. The Rev (talk) 16:53, 15 January 2012 (UTC)

The latest Kepler results summarized in the Grauniad and presumably elsewhere say "We find that 22% of Sun-like stars harbor Earth-size planets orbiting in their habitable zones. The nearest such planet may be within 12 light-years." I'm not sure how that maps back into the individual parameters

R* = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets

2 billion total, right now. Alanf777 (talk) 02:49, 5 November 2013 (UTC)

Read the fine print in the paper. Although Kepler estimates an amount of Earth-sized planets, they are not Earth-like: There are several caveats. Although these planets are Earth-size, nobody knows what their masses are and thus whether they are rocky like the Earth, or balls of ice or gas, let alone whether anything can, or does — or ever will — live on them. The estimate cannot offer data on habitability, other than being in "Goldilock zones". Cheers, BatteryIncluded (talk) 02:21, 8 November 2013 (UTC)
Read the fine-print of the definitions =8-) fp is the TOTAL number of planets, including gas giants, and too-close or too-far orbits. Even this number is bumped up by the new number of earth-SIZED planets. ne -- habitability -- must surely be refined by the fact that they are earth-sized (not gas giants) AND the fact that they are Goldilockily potentially habitable. I put in the comment to alert editors to the fact there is new data, but that the impact on these two parameters is not clear. It is quite likely that both parameters must be increased significantly. Alanf777 (talk) 00:24, 10 November 2013 (UTC)
Point taken. Lets hope a researcher will soon publish a new "Drake equation estimate" using this value, so we can add it to the article with a reference. However, the more common Earth-like planets the worse the Fermi Paradox becomes. Cheers, BatteryIncluded (talk) 01:49, 10 November 2013 (UTC)
Phew! You missed my mistake : fp is the TOTAL number fraction .. Alanf777 (talk) 03:00, 10 November 2013 (UTC)

Assuming 0 and/or 1[edit]

We need to be careful to avoid original research. For the Equation results section, do any reliable sources explicitly advocate the "assume 0 for parameters that have no backup for any estimate" and "assume 1" approaches respectively? This was just added. I haven't checked all the sources, but there is no footnote for the "assume" part itself. Superm401 - Talk 21:02, 13 February 2012 (UTC)

I agree, both 'assume 0' and 'assume 1' need to go. 'Assume 0' leads to the only answer to this equation that we can factually say is false (that of none at all) so it's not possible to assume 0 for any factor. Regardless of one's opinion of how intelligent Earthpeople are, we still count as an intelligent species in this galaxy, and the Drake equation is how many civilizations total, not how many other than us. I'll do a little digging and see if I can find a generally accepted range anywhere. The Rev (talk) 03:45, 24 March 2012 (UTC)
Agreed; it makes no sense to assume any term is zero (we exist), nor is it mathematically or scientifically useful as a lower limit--any product of a series of terms containing a zero will of course be zero. Duckyphysics (talk) 21:44, 19 April 2012 (UTC)

Numbers for Fc?[edit]

Currently, there are no proposed numbers for Fc. For our only example, Earth, our planetary radar is easily detectable, so you could say our detectability is at least (fraction of the time it/they are on) x (fraction of sky covered). This will be a tiny number, since the beams are so narrow, but at least it's > 0. On the upper end, we may already be "communicating" (remember this is really "releases signs of existence into space", not necessarily deliberate communication). I've included some references to this, including one of my own (feel free to remove if you think it inappropriate). This could potentially be a quite large number, but depends on exactly how good you think alien astronomers are. Does anyone know of any published references or calculations along these lines? LouScheffer (talk) 17:33, 28 March 2012 (UTC)

Life on earth was formed more than once[edit]

I believe this phrase on this article is now inaccurate: "Also countering this argument is that there is no evidence for abiogenesis occurring more than once on the Earth—that is, all terrestrial life stems from a common origin. If abiogenesis were more common it would be speculated to have occurred more than once on the Earth." According to this link, NASA found a life form on earth based on arsenic instead of phosphorus and therefore being considered alien and proving that life on earth happened at least twice.

That's old news and it's nothing special as far as the origin of life is concerned. The bacteria is a type of Gammaproteobacteria, which are part of the bacteria domain (aka it shares a common ancestor with apple tree, humans, trouts, E. coli, etc...). Headbomb {talk / contribs / physics / books} 21:55, 15 April 2012 (UTC)

"If abiogenesis were more common it would be speculated to have occurred more than once on the Earth" -- this mostly goes to show that people shouldn't just use Wikipedia to argue off the tops of their heads. It is a common mistake to implicitly assume probabilities are uncorrelated even in cases where they are most probably extremely correlated, but it is a mistake nevertheless. I would go as far as to claim the world would be a better place if at least the people who bother to consider probabilities at all would all bother to think about correlation (in other words, to consider "Bayesian" arguments, as this is known these days) , or at least to make it explicit when they make bold assumptions about absence of correlations. --dab (𒁳) 08:21, 9 November 2012 (UTC)

The sentence as written is certainly true - it has been speculated. See for example Are Aliens Among Us?. However, there are lots of other reasons that the absence now does not mean it did not happen. It could be
  • Life only arose once
  • More than one arose, but all be one were out-competed
  • More than one arose, but earlier ones were wiped out by extinction events
  • And so on.
A discussion, or at least a reference to this, would make sense. LouScheffer (talk) 15:17, 9 November 2012 (UTC)

Math problem with the Historical Estimate section[edit]

Fl (sorry no subscript) is being given as 1 rather than 0.5, although it's clearly supposed to be a fraction (0.5). Since this changes the outcome value of N from 10 to 5, and I've always heard that the original value of N was 10, I don't want to change this myself. But the numbers we have there right now don't make sense. Ethan Mitchell (talk) 12:17, 17 April 2012 (UTC)

A value of 1 is OK; it's the fraction 1/1. I double checked this with Drake's book and it's what he intended. LouScheffer (talk) 12:50, 12 April 2013 (UTC)


This artical says that Drake equation "is used in the fields of exobiology". This has no base. It is more a "internal tool" of the SETI, not a theory or concept in the fields of exobiology. Is there reference that is is being used in exobiology outside of seti. Srinivasasha (talk) 07:28, 5 May 2012 (UTC)

It's a thought experiment, of course.

22:42, 20 November 2013 (UTC)

Generalized Copernican Principle[edit]

One thing that isn't in the article at the moment and I often harp on, is the fact that there is a known lower limit for the Drake Equation N, namely 1. With (at least) many 10s of billions of galaxies and (in time) empirical evidence for the frequency of planets that could produce life, it is more or less certain that on a universal scale that there are others. I know that Drake only addresses this galaxy, but there was a parenthetical comment with universal scope which I redacted for this reason. Lycurgus (talk) 12:41, 2 April 2013 (UTC)

If it was up to me, I would re-write the entire article as it has been taken out of context - either by its main editors or by the popular interpretation. The "equation" is NOT a hypothesis, a theory or a mathematical representation of a physical fact, as in E=mc2 , V=d/t , F= G*((m1*m2)/r2, etc. Drake originally formulated the equation merely as an agenda for discussion at the Green Bank conference. Just take a look at the actual requirements for planetary habitability and think if this equation addresses any of those factors. You may spend considerable effort invoking values and splitting hairs, but it is not a mathematical tool "used by SETI" or astrobiology. Again, it was meant merely as an agenda for discussion at a conference; it was a rhetorical question — if you will. Cheers, BatteryIncluded (talk) 21:22, 1 April 2013 (UTC)
Thanks BatteryIncluded, the above needed saying. As far as, albeit, my personal experience is concerned the Drake equation was never meant as a hypothesis, but purely as a discussion paper. I regret that I do not have the time to re-write the entire article. Regards and thanks, David J Johnson (talk) 22:26, 1 April 2013 (UTC)
Don't mind me if I do in the next few weeks. I will leave the calculations intact, but will refocus on its usefulness. CHeers, BatteryIncluded (talk) 14:02, 12 April 2013 (UTC)
I created this thread yesterday. Signing now with my named account. Moved illiterate comment from last year out of it. Lycurgus (talk) 12:40, 2 April 2013 (UTC)

Malware Link Removal[edit]

--Gary Dee 18:37, 21 July 2013 (UTC)

Drake equation fails to take 'Young' Universe into account[edit]

I am trying to find any reference to the fact that the Drake equation assumes a steady state for most of its factors. But given that the universe is only 13.8 Gy old but some of the factors that would be important like how long life takes to evolve from simple forms to complex forms would be on the order of 1 or 10 Gy (given that we only have one case we can't really be certain if the average value would be anywhere near the value for Earth of ~4Gy) it is unlikely that a steady state has been reached. This would mean that Earth life is among the first to arise (not the first just among the first). For SETI this has the effect that looking in other galaxies is likely to be less productive in that we see other galaxies at a significantly earlier time. Anyway, this is original thought, it just seems so obvious that I thought someone of significance must have already made the comment and so a reference could be found for it but I can't find one. Anyone know of such a reference.Bluetetrahedron (talk) 16:54, 14 October 2013 (UTC)

In brief, it is not a valid, scientific, mathematical equation, but a conversation catalyst. Cheers, BatteryIncluded (talk) 00:18, 21 November 2013 (UTC)

Hi BatteryIncluded: This blog: implicitly addresses the mismatch between the Drake equation's underlying assumption of a steady-state theory universe and the big-bang universe we observe. It has still not shaken loose of all the steady-state baggage, however, since it assumes that the first stars would have had planets similar to our own (Whereas the low metallicity of the population II stars argues that decent-sized planets would be significantly less likely to form.). This makes the rest of the entry pretty valueless - but the key point that the leftmost three terms of the equation rely on steady-state cosmology and are thus no longer helpful, remains valid. (To be fair the blog recognises it's own shortcomings in this matter.) A similar view is given in this:, so there are enough independent sources to justify adding a note to the main article, I believe. Less clear is if references to attempts to repair these deficiencies can be included. Articles like this: are attempting to replace Drake with something more closely tied to observable factors - but I doubt if Wikipedia is ready for that yet. By the way, I believe the idea that you state above, viz: "If it takes something like 12 or 13 GY to generate intelligent life, Earth life would be amongst the first on the scene" (Paraphrasing, sorry), does not hold. I'd guess there'd be enough random variation in the process to move any given star/planet a gigayear or two either side of the average, and there is nothing beyond the Great Silence to indicate we are on the leading edge of that 2-gigayear window. And there are other possible explanations for the Great Silence. Cheers, Nimrod54 (talk) 01:00, 10 May 2014 (UTC)

Hello Nimrod54, I am not against including the equation's assumptions and limits. In fact, I remark that the "equation" is more of a statement than a calculation. Please feel free to edit the article and add the pertinent references. Also please note that the comment above stating that Earth life was among the first to arise in the universe was not written by me but by Bluetetrahedron. CHeers, -BatteryIncluded (talk) 06:13, 10 May 2014 (UTC)

Conceptual, not mathematical[edit]

1) Dear user Headcomb, please read the introduction, and the reference you want to delete while you are at it. Even the SETI League states that its usefulness is not in the solving, but the ideas or concepts to contemplate. Conference hosted by NASA: [4]

"So that's the equation. But before we move on, I'll offer a few comments that are evident but somehow not really seen. One is that every factor in the equation appears to the first power. There are no exponentials, no powers, no power laws, no logarithms. Every one is equally important."

You don't need a Ph.D. in physics, mathematics or biology to understand the cited reference and realize the absurdity of all elements being exactly equally important and held in the exact same mathematical relationship e.g.: a simple product of factors.

2) My mentioning -and referencing- the actual mathematical usefulness of the equation is very relevant, especially in the section entitled Usefulness. If you want to argue the mathematical value of specific "factors" please do so in their own sections. Please discuss instead or reverting again.

3) The rules in the world of biology and rules in the world of physics are different. Biology and chemistry, as opposed to physics, do not admit ideological contexts: either the biological phenomena are real, or they are abstract. Biologists cannot say that a process or phenomenon, by being mathematically possible, have to exist forcibly in the real nature. For biologists, the ground of speculations is well noticeable, and biologists specify what is speculative and what is not. Thank you, BatteryIncluded (talk) 01:23, 21 November 2013 (UTC)

Thought experiment. Kortoso (talk) 17:19, 21 November 2013 (UTC)

Asteroid Mining[edit]

I put in a very brief entry of Martin Elvis's variation of the Drake equation, as a modification. It didn't seem to merit a section. I put a wiki link to Asteroid mining in the title -- I'm not sure if that's the right way to do it. Also, I put in a quote from NS -- but I didn't put it in quote MARKS, because it's NS paraphrasing what Elvis said. Alanf777 (talk) 21:40, 4 December 2013 (UTC)

His Master's Voice: Stanislaw Lem[edit]

Can't stop thinking about His Master's Voice by Stanislaw Lem. How do we know if a signal of extra terrestrial life is a signal of extra terrestrial life or not? What would consist of a signal? Would "life" be as "antropocentric" as we are thinking? How can we even think we can make a guess about how would "life" develop in another planet, never the less, think we could know what it is from a distance? -- (talk) 01:12, 13 April 2014 (UTC)

Electromagnetic modulation of signals (using technology) is not something that happens spontaneously in nature. BatteryIncluded (talk) 01:21, 13 April 2014 (UTC)

The form of the Drake equation[edit]

I have removed the following sentence from the section "Usefulness".

The equation assumes that every factor is equally important; there are no exponentials, no powers, no power laws, no logarithms, etc.[1]

The reason is that it was inserted in a way that suggested these facts about the Drake equation were things that affected its usefulness, and perhaps it should be more complicated. The truth is that it has to have this form, because of the rules of probability. It is essentially a long chain of conditional probabilities which arrives at an unconditional probability. As such it cannot contain anything but products of conditional probabilities, as it does. Elroch (talk) 22:54, 23 July 2014 (UTC)

"SETI" or "search for extraterrestrial life"?[edit]

The lead of this article contains a link to "search for extraterrestrial life." At present, that phase is linked to the "search for extraterrestrial life" article with only the acronym ("SETI") appearing in the text. It seems to me that all readers may not know what "SETI" is so I proposed to remove the acronym from the link while leaving it in the text (see this version). Another editor reverted that change, suggesting that readers could click on the link if they didn't know the acronym. True enough, but why not spell out the phrase and avoid the inconvenience? Butwhatdoiknow (talk) 12:19, 15 August 2014 (UTC)

Frankly, I do not see any problem with the original version with the acronym ("SETI") appearing in the text and is properly linked and is no inconvenience. The end use of this type of change is that every link in Wikipedia requires editing to "avoid the inconvenience". This is my final comment on this trivial matter. Butwhatdoiknow please keep comments on article Talk page and not individual editors Talk page. Thank you, David J Johnson (talk) 10:25, 17 August 2014 (UTC)
Since you are a SETI maven it is not surprising that you would not see a problem. But consider this: "It is possible that the reader knows nothing about the subject. so the article needs to explain the subject fully." Thus, editors should "State facts that may be obvious to you, but are not necessarily obvious to the reader. Usually, such a statement will be in the first sentence or two of the article." If you truly believe this change is trivial then why not simply yield to my request to make the change? - Butwhatdoiknow (talk) 16:30, 17 August 2014 (UTC)
No one seems to fault this reasoning so far. I'll give it one more day and then make the change. Butwhatdoiknow (talk) 12:27, 25 August 2014 (UTC)


  1. ^ "The Drake Equation Revisited: Part I", The Drake Equation Revisited, Palo Alto,CA: Astrobiology Magazine, August 26, 2003, retrieved 2013-11-21