# "SETI will find extraterrestrial life in 25 years". Yeah right. **URL:** \ **Category:** The BBQ Pit\ **Created:** [August 20, 2010, 9:52pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919 "2010-08-20T21:52:39Z")\ **Posts on this page:** 18\ **Page:** 3
**Author:** ![Hampshire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hampshire/32/4887_2.png) [@Hampshire](https://boards.straightdope.com/u/Hampshire)\ **Post date:** [August 23, 2010, 4:19pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/41 "2010-08-23T16:19:36Z")
> [@tagos](#): > > Is there any particular reason you haven’t changed ‘will’ to ‘could’ in this thread heading? > > Any particular reason you keep on replying to posts as if it hasn’t already repeatedly being pointed out to you that ‘could’ and ‘will’ are probabilities of a completely different order? Quote from the article: “I actually think the chances that we’ll find ET are pretty good,” The guy quoted actually said “chances that we **will** find ET are pretty good”. Sounds overly optimistic to me. He could have been a bit more conservative by saying “chances that we **could** find ET are pretty good” but he didn’t. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [August 23, 2010, 4:27pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/42 "2010-08-23T16:27:59Z")
[QUOTE=Hampshire] He could have been a bit more conservative by saying “chances that we could find ET are pretty good” but he didn’t. [/QUOTE] He could have, but the point is the OP is mis-characterizing what the guy actually said. The OP’s title is ‘“SETI will find extraterrestrial life in 25 years”’ and it’s in quotes. SETI isn’t saying it WILL find anything…one guy from SETI is saying that the CHANCES that they will find something are ‘good’. Those are completely different. As for the optimism of the guy quoted in the linked article, as Stranger says, he almost has to say stuff like that (funding and all), plus, being on such a project he probably really believes that. I remember a quote from a scientist concerning the Higgs Boson saying they would surly find evidence of it within 5 years. Or the guys looking for evidence of dark matter in mine shafts. If they didn’t believe they would find something they probably wouldn’t doing those projects…and if they couldn’t convince others that they could or would find anything, they wouldn’t convince anyone (including the public) to fund their research. -XT ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 23, 2010, 5:18pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/43 "2010-08-23T17:18:16Z")
> [@Gangster\_Octopus](#): > > I’m confused, isn’t Star Wars a documentary made with archival footage? No, a documentary is something like Godzilla. Star Wars is known as a docu-drama, all original footage, but based on actual events. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [August 23, 2010, 5:32pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/44 "2010-08-23T17:32:48Z")
> [@Uncle\_Jocko](#): > > I have a question regarding **Sam Stone’s** excellent post about the Kepler mission, watching for dimming of stars to determine that planets are passing in front of them. You say Kepler has already found plenty of stars that appear to have planets in orbits too close to support Earth-like life, because the repeat dimming occurs too rapidly. > > I’m sure the big brains at NASA have this figured out already, but … couldn’t the repeated dimmings come from more than one planet? You know, if the star dims three times in three months, instead of it being one planet whizzing around the star once a month, perhaps it’s three separate planets orbiting further out, closer to an Earth-type orbit? > > Otherwise, that’s a pretty elegant way to figure out if there are planets associated with a star and how large their orbits might be. Don’t suppose any NASA planetary experts might drop in and tell me why I’m full of empty-headedness. Kepler can not only determine the period of the orbiting planet, but it can also make a good estimate of its size based on the amount of dimming that takes place. So even if the orbital mechanics of two rotating bodies wound up looking like the orbit of a single planet, the planets would also have to be the same size. There are candidates however, that might not be planets. Kepler could be seeing a binary star system where one of the stars is much smaller and dimmer than the other. This is where secondary observations come in - once Kepler identifies a candidate, it can become a target for further ground-based and space-based observation. Once we know which stars have planetary candidates, and we know exactly when those candidates will transit across the face of the star, we can turn other instruments towards it at the right time and make further measurements. This may be the one of the biggest gains from Kepler - a catalog of exoplanets and their transit times, which makes study of them possible with other instruments. So as we observe and come up with questions, we can devise new instruments to answer those questions. Here’s some information on [Follow-up Observations](http://kepler.nasa.gov/Science/followupObservations/) and what they can tell us. So far, Kepler has unambiguously identified five planets in this group of stars. All of them have orbital periods of just a few days. They are mostly ‘hot Jupiters’ - Jupiter-sized planets orbiting extremely close to the star. There are currently about 700 planetary candidates being investigated through follow-on observations and other methods. And we’re still in the very early days of Kepler. In February there’s a huge data dump to the public which will likely identify hundreds or thousands more candidates. And as time goes on, and the candidates come from further out in the solar system, we’ll hopefully more multiple-planet systems, and start to get an understanding of the typical structure of solar systems. Kepler can measure the diameter of planetary candidates, and by measuring the star’s doppler shift as it wobbles, astronomers can determine the planet’s mass. With those two pieces of information, we know the density of the planet, and can differentiate gas giants from rocky planets. It’s a very exciting time in planetary science. Three years from now, our understanding of extra-terrestrial planet formation is going to be much better than it is today. We’re going to know what the ‘typical’ solar system looks like (or if there IS a ‘typical’ solar system). We’ll have a good idea of how likely it is for a sun like ours to have rocky planets and gas giants, and where they are likely to be. We’ll have a good idea of how many planets orbit the habitable zones of stars. Back to SETI - One of the more famous formulations used to determine the probability of intelligent life in the Universe is the Drake Equation: N = R\* X fp X ne X ft X fi X fc X L Where N = the number of civilizations in our galaxy we might be able to communicate with, and: ``` R* = the average rate of star formation per year 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 fℓ = the fraction of the above that actually go on to develop life at some point fi = the fraction of the above that actually go on to develop intelligent life 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. ``` We have a pretty good handle on the R\* term. Kepler is going to fill in fp and ne. In the next 25 years, we have a decent chance of determining fℓ, at least to some degree, through astronomical observation. The rest of it is a complete crapshoot. We have no idea for any of those values. But if we can solve the other terms, then SETI becomes an interesting piece of the puzzle and even negative results become positive results in the sense that they start giving us an indication of how unlikely it is for civilization to form (or to survive once formed). Let’s say we discover that half of all stars of our type have planets in the habitable zone, and measures of the atmospheres of them discover that at least half of those appear to have some form of photosynthetic life. That would mean that there should be life on about 25 billion planets in habitable zones around sunlike stars in our galaxy. Knowing that, if SETI continues to find nothing, then over time we’ll have a better and better estimate of the product of the last three terms of the Drake equation, and hopefully over time we’ll develop new experiments to help narrow down each of those terms. ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [August 23, 2010, 10:05pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/45 "2010-08-23T22:05:23Z")
> [@Grey](#): > > Why drop all the way down a gravity well to pull out resources when star systems are likely to have lots of left over bits just floating around? Because the aliens are there, duh. Can’t have heathen freaks using up all our God-given resources, can we ? Sure, we could use the bits lying all over. But we could also use the bits lying all over AND theirs. Now I’ll ask you, which one sounds like our manifest destiny, old chap ? ---
**Author:** ![Cisco](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Cisco](https://boards.straightdope.com/u/Cisco)\ **Post date:** [August 24, 2010, 10:47pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/46 "2010-08-24T22:47:05Z")
I wish I had my copy of _Pale Blue Dot_ with me. In it, Sagan says that SETI has found (IIRC) 4 signals that it can’t explain away as non-intelligent, all from the same area of our galaxy. Pretty exciting stuff. ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [August 25, 2010, 12:56am UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/47 "2010-08-25T00:56:46Z")
Carl Sagan? How long has he been dead? I imagine that the questions about these signals were resolved a long time ago, or there’d be a hell of a lot more buzz. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [August 25, 2010, 3:35am UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/48 "2010-08-25T03:35:55Z")
Here’s the most famous SETI signal: [The WOW signal](http://en.wikipedia.org/wiki/Wow!_signal) ---
**Author:** ![Dallas\_Jones](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dallas_jones/32/3277_2.png) [@Dallas\_Jones](https://boards.straightdope.com/u/Dallas_Jones)\ **Post date:** [August 26, 2010, 9:11pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/49 "2010-08-26T21:11:37Z")
From JPL today, Kepler finds first planetary system with at least 2 planets and a possible third. [http://www.jpl.nasa.gov/news/news.cfm?release=2010-279&cid=release\_2010-279&msource=k20100826&tr=y&auid=6886706](http://www.jpl.nasa.gov/news/news.cfm?release=2010-279&cid=release_2010-279&msource=k20100826&tr=y&auid=6886706) ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [August 26, 2010, 9:27pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/50 "2010-08-26T21:27:13Z")
I think some folks may be misinterpreting what “we will find ET” in 25 years means. A generous interpretation is that we will find evidence of LIFE in other solar/star systems (oxygen, methane…). Which IMO is not that much of a stretch from what we know now and the technologlies we have/are developling to answer that question with some certainty. A stricter interpretations is that we will literally find ET. Aliens folks with technology/intelligence/whatever. Now, IMO, that ranges from also not much of a stretch to virtually impossible (given that we have no real idea of how often technological life evolves from just general life). ---
**Author:** ![Clothahump](https://avatars.discourse-cdn.com/v4/letter/c/51bf81/32.png) [@Clothahump](https://boards.straightdope.com/u/Clothahump)\ **Post date:** [August 26, 2010, 10:25pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/51 "2010-08-26T22:25:07Z")
> [@xtisme](#): > > But they aren’t saying ‘will’…they are saying ‘could’. Big difference. Look at what the scientist quoted at the beginning is saying: > > > [@](#): > > > > Speaking at the SETI Con convention in Santa Clara, Calif., Seth Shostak – senior astronomer at the Search for Extraterrestrial Intelligence Institute in Mountain View, Calif. – said, “I actually think the chances that we’ll find ET are pretty good,” [SPACE.COM](http://SPACE.COM) reported Monday. > > The chances are GOOD. I’d say that this is entirely plausible. IF there is intelligent and technologically developed life out there, they COULD find such a signal in the next 25 years. > > As for life, I think the ‘enthusiasts’ are probably understating it…I won’t be surprised if we find additional life right here in our own solar system. There are several very promising places…it’s just a matter of getting off our collective asses and going out and really looking. > > -XT I think the ETs have already found us. And they put up signs warning other intelligent species away from us. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [August 26, 2010, 11:10pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/52 "2010-08-26T23:10:10Z")
> [@billfish678](#): > > I think some folks may be misinterpreting what “we will find ET” in 25 years means. > > A generous interpretation is that we will find evidence of LIFE in other solar/star systems (oxygen, methane…). Which IMO is not that much of a stretch from what we know now and the technologlies we have/are developling to answer that question with some certainty. > > A stricter interpretations is that we will literally find ET. Aliens folks with technology/intelligence/whatever. Now, IMO, that ranges from also not much of a stretch to virtually impossible (given that we have no real idea of how often technological life evolves from just general life). I’d presumed that the article linked in the OP was talking about searches for intelligent radio signals (that’s what SETI used to exclusively mean). Now I realize the term is used in the broader sense you mention, which makes my original snarkiness unwarrented. ---
**Author:** ![digs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/digs/32/14889_2.png) [@digs](https://boards.straightdope.com/u/digs)\ **Post date:** [August 29, 2010, 3:09am UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/53 "2010-08-29T03:09:54Z")
> [@Kobal2](#): > > > [@xtisme](#): > > > > As for life, I think the ‘enthusiasts’ are probably understating it…I won’t be surprised if we find additional life right here in our own solar system. There are several very promising places…it’s just a matter of getting off our collective asses and going out and really looking. > > > > -XT > > Yeah, but try as they might, finding a handful of mono-cellular bacteria tucked away in a methane puddle is just not all that cool. What the point of extraterrestrial life if it doesn’t have a disintegrator ray ? Hey, I grew up on 50s pulp Sci-Fi novels, so I’m expecting disintegrator rays, scary-looking faces (in fishbowl helmets), AND a penchant for Earth maidens. I guess I’m talking 19_50_’s-Style Death Rays… ---
**Author:** ![Captain\_Midnight](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@Captain\_Midnight](https://boards.straightdope.com/u/Captain_Midnight)\ **Post date:** [August 29, 2010, 10:52am UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/54 "2010-08-29T10:52:04Z")
My personal belief is that aliens have visited Earth in the past, took a few pictures and left. We Humans are a primitive, violent race who can’t get along with each other. The aliens realize that any contact with us humans will invariably lead to war, no matter what. I also think that Earth is more or less in a Galactic desert, with no other Oxygen like planets around with the nearest solar system being a great distance away. Space junk of the Earth has barely left the Solar System. That’s nowhere. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 29, 2010, 2:09pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/55 "2010-08-29T14:09:21Z")
> [@Lumpy](#): > > [Scientist: SETI success within 25 years?](http://www.spacedaily.com/reports/Scientist_SETI_success_within_25_years_999.html) > > Apparently, this statement is supported by nothing more than the conviction that a thorough enough search will find the extraterrestrial civilizations they’re certain are out there, without much justification of that conviction. Don’t get me wrong, I’d think it would be great if it happened; but I think it’s entirely plausible that we are the only technological civilization in our galaxy. Even life may be rarer than the enthusiasts believe. This assumes that anybody is actually transmitting and not just listening. SETI (AFAIK) does not transmit a signal. As Ferris said in his book “Mind’s Sky”, it’s very likely that nobody else is transmitting either, on the chance that a hostile civilization may decide to come find out who is making all the racket. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 29, 2010, 2:14pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/56 "2010-08-29T14:14:32Z")
> [@Sam\_Stone](#): > > > [@Uncle\_Jocko](#): > > > > I have a question regarding **Sam Stone’s** excellent post about the Kepler mission, watching for dimming of stars to determine that planets are passing in front of them. You say Kepler has already found plenty of stars that appear to have planets in orbits too close to support Earth-like life, because the repeat dimming occurs too rapidly. > > > > I’m sure the big brains at NASA have this figured out already, but … couldn’t the repeated dimmings come from more than one planet? You know, if the star dims three times in three months, instead of it being one planet whizzing around the star once a month, perhaps it’s three separate planets orbiting further out, closer to an Earth-type orbit? > > > > Otherwise, that’s a pretty elegant way to figure out if there are planets associated with a star and how large their orbits might be. Don’t suppose any NASA planetary experts might drop in and tell me why I’m full of empty-headedness. > > Kepler can not only determine the period of the orbiting planet, but it can also make a good estimate of its size based on the amount of dimming that takes place. So even if the orbital mechanics of two rotating bodies wound up looking like the orbit of a single planet, the planets would also have to be the same size. > > There are candidates however, that might not be planets. Kepler could be seeing a binary star system where one of the stars is much smaller and dimmer than the other. This is where secondary observations come in - once Kepler identifies a candidate, it can become a target for further ground-based and space-based observation. Once we know which stars have planetary candidates, and we know exactly when those candidates will transit across the face of the star, we can turn other instruments towards it at the right time and make further measurements. > > This may be the one of the biggest gains from Kepler - a catalog of exoplanets and their transit times, which makes study of them possible with other instruments. So as we observe and come up with questions, we can devise new instruments to answer those questions. > > Here’s some information on [Follow-up Observations](http://kepler.nasa.gov/Science/followupObservations/) and what they can tell us. > > So far, Kepler has unambiguously identified five planets in this group of stars. All of them have orbital periods of just a few days. They are mostly ‘hot Jupiters’ - Jupiter-sized planets orbiting extremely close to the star. > > There are currently about 700 planetary candidates being investigated through follow-on observations and other methods. And we’re still in the very early days of Kepler. In February there’s a huge data dump to the public which will likely identify hundreds or thousands more candidates. And as time goes on, and the candidates come from further out in the solar system, we’ll hopefully more multiple-planet systems, and start to get an understanding of the typical structure of solar systems. > > Kepler can measure the diameter of planetary candidates, and by measuring the star’s doppler shift as it wobbles, astronomers can determine the planet’s mass. With those two pieces of information, we know the density of the planet, and can differentiate gas giants from rocky planets. > > It’s a very exciting time in planetary science. Three years from now, our understanding of extra-terrestrial planet formation is going to be much better than it is today. We’re going to know what the ‘typical’ solar system looks like (or if there IS a ‘typical’ solar system). We’ll have a good idea of how likely it is for a sun like ours to have rocky planets and gas giants, and where they are likely to be. We’ll have a good idea of how many planets orbit the habitable zones of stars. > > Back to SETI - One of the more famous formulations used to determine the probability of intelligent life in the Universe is the Drake Equation: > > N = R\* X fp X ne X ft X fi X fc X L > > Where N = the number of civilizations in our galaxy we might be able to communicate with, and: > > ``` > R* = the average rate of star formation per year 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 > fℓ = the fraction of the above that actually go on to develop life at some point > fi = the fraction of the above that actually go on to develop intelligent life > 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. > > ``` > > We have a pretty good handle on the R\* term. Kepler is going to fill in fp and ne. > > In the next 25 years, we have a decent chance of determining fℓ, at least to some degree, through astronomical observation. > > The rest of it is a complete crapshoot. We have no idea for any of those values. But if we can solve the other terms, then SETI becomes an interesting piece of the puzzle and even negative results become positive results in the sense that they start giving us an indication of how unlikely it is for civilization to form (or to survive once formed). > > Let’s say we discover that half of all stars of our type have planets in the habitable zone, and measures of the atmospheres of them discover that at least half of those appear to have some form of photosynthetic life. That would mean that there should be life on about 25 billion planets in habitable zones around sunlike stars in our galaxy. > > Knowing that, if SETI continues to find nothing, then over time we’ll have a better and better estimate of the product of the last three terms of the Drake equation, and hopefully over time we’ll develop new experiments to help narrow down each of those terms. “Of all the sad tales That SETI might tell, The saddest would be A small value for L.” 😃 ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [August 29, 2010, 3:26pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/57 "2010-08-29T15:26:34Z")
> [@Chefguy](#): > > [ > This assumes that anybody is actually transmitting and not just listening. SETI (AFAIK) does not transmit a signal. As Ferris said in his book “Mind’s Sky”, it’s very likely that nobody else is transmitting either, on the chance that a hostile civilization may decide to come find out who is making all the racket. Given the obnoxious car alarm that awoke me this morning and then kept me company I have to agree on this one 🙂 ---
**Author:** ![Lust4Life](https://avatars.discourse-cdn.com/v4/letter/l/ecc23a/32.png) [@Lust4Life](https://boards.straightdope.com/u/Lust4Life)\ **Post date:** [August 30, 2010, 2:30pm UTC](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919/58 "2010-08-30T14:30:38Z")
Wouldn’t we look silly if we stopped spending the pocket money we spend now on SETI and missed the aliens ? [Previous page](https://boards.straightdope.com/t/seti-will-find-extraterrestrial-life-in-25-years-yeah-right/550919.md?page=2)