# Why Hasn't SETI Found Anything Yet? **URL:** \ **Category:** Great Debates\ **Created:** [December 1, 2005, 1:29am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492 "2005-12-01T01:29:24Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [December 1, 2005, 5:30am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/21 "2005-12-01T05:30:53Z")
Scientists are apparently convinced that the universe is so vast that the it’s near-certain there is other intelligent life out there. I’ll take them at their word. That said, though, the observable universe is a very tiny fraction of that. Then you reduce that further when you consider the portions of the observable universe that we can really interact with, especially by radio, and the odds of us making contact in this manner are sadly tiny. So it’s not surprising that we haven’t found anything concrete through our couple of little projects, I guess. > [@gooftroopag](#): > > Because they’ve already seen what we’re sending out! 😃 Hey, we’re beaming Hendrix into space. If they’re not cool enough to appreciate it, the hell with them. They can’t be that advanced. 😉 ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [December 1, 2005, 5:45am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/22 "2005-12-01T05:45:12Z")
> [@John Mace](#): > > In fact, our nearest star, Proxima Centari, is “only” 4.3 light years away. Theoretically, any Centarians with an antena could be watching the first few seasons of _Survivor_! With no knowledge of the reality-TV horror to follow, those poor devils. ---
**Author:** ![HPL](https://avatars.discourse-cdn.com/v4/letter/h/3da27b/32.png) [@HPL](https://boards.straightdope.com/u/HPL)\ **Post date:** [December 1, 2005, 6:21am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/23 "2005-12-01T06:21:56Z")
> [@John Mace](#): > > In fact, our nearest star, Proxima Centari, is “only” 4.3 light years away. Theoretically, any Centarians with an antena could be watching the first few seasons of _Survivor_! And just wait till we find out that, among intelligent civilizations, broadcasting reality shows is considered a war crime. ---
**Author:** ![gooftroopag](https://avatars.discourse-cdn.com/v4/letter/g/e8c25b/32.png) [@gooftroopag](https://boards.straightdope.com/u/gooftroopag)\ **Post date:** [December 1, 2005, 6:30am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/24 "2005-12-01T06:30:41Z")
> [@Marley23](#): > > Hey, we’re beaming Hendrix into space. If they’re not cool enough to appreciate it, the hell with them. They can’t be that advanced. 😉 Unfortunately that’s not the only thing being sent out into space. Wasn’t one of Hitler’s speeches one of the first?.. and if any of our news porgrams make their way out there, they all know what a violent civilization we are… If only we could filter what we send out, we may have better luck! 🙂 ---
**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:** [December 1, 2005, 6:32am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/25 "2005-12-01T06:32:24Z")
> [@Marley23](#): > > Scientists are apparently convinced that the universe is so vast that the it’s near-certain there is other intelligent life out there. I’ll take them at their word. I don’t know any scientists who say that. The problem with making any predictions about the frequency of life is that we only have one data point. Until we find life somewhere else that arose independently, we really don’t know. This is a bit reason why programs like SETI are important, even if they return negative results. Because in this case, a negative result is a result. And the question to be answered is one of the most important we can ever ask: are we alone? ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [December 1, 2005, 6:39am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/26 "2005-12-01T06:39:55Z")
> [@Sam Stone](#): > > I don’t know any scientists who say that. The problem with making any predictions about the frequency of life is that we only have one data point. Until we find life somewhere else that arose independently, we really don’t know. I don’t know any either. I do know what’s said every time we discuss things like “is there life anywhere else in the universe?” From that, I gather that some scientists think it’s a lead-pipe cinch, and I’m sure that’s not uncontested, but it makes enough sense for me in the abstract. In these threads, I think it’s an okay working assumption. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [December 1, 2005, 7:18am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/27 "2005-12-01T07:18:20Z")
> [@Sam Stone](#): > > It could also be that civilizations only tend to use broadcast transmissions for a short while before moving to more efficient ways to communicate - microwave, lasers, fiber, cable… Me no understand. Are those supposed to be not EM transmissions? ---
**Author:** ![Rune](https://avatars.discourse-cdn.com/v4/letter/r/e68b1a/32.png) [@Rune](https://boards.straightdope.com/u/Rune)\ **Post date:** [December 1, 2005, 7:46am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/28 "2005-12-01T07:46:01Z")
The universe might be a more dangerous place than we imagine. With lots of listeners and few senders. ---
**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:** [December 1, 2005, 8:13am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/29 "2005-12-01T08:13:22Z")
> [@John Mace](#): > > Me no understand. Are those supposed to be not EM transmissions? Who knows? The thing is, directed energy is much, much more efficient than broadband when sending point-to-point communications. And satellite relays means we don’t need high power transmissions. In the 50’s, HAM operators were operating 1000 watt transmitters to talk around the world. Today we do it with cellphones that use a tiny fraction of that power. TV transmitters may be moving to cable. Maybe the communications of the future involves very low power, extensive Wi-Fi grids that blanket most of the planet. Or maybe there’s a whole 'nuther communications medium that we just haven’t stumbled onto yet, and would be undetectible by us today if others were using it. It wouldn’t surprise me at all to discover that the EM signature of a civilization grows like crazy during the early industrial ages, and then suddenly drops precipitously as it becomes archaic and inefficient compared to new technologies. ---
**Author:** ![SentientMeat](https://avatars.discourse-cdn.com/v4/letter/s/43a26b/32.png) [@SentientMeat](https://boards.straightdope.com/u/SentientMeat)\ **Post date:** [December 1, 2005, 8:51am UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/30 "2005-12-01T08:51:43Z")
[SETI tells us](http://www.ess.sunysb.edu/fwalter/AST248/seti.html) that nobody within 5 light years (see [map](http://www.anzwers.org/free/universe/12lys.html)) is broadcasting TV or radio, nobody within 50 light years ([map](http://www.anzwers.org/free/universe/250lys.html)) is using military radar, and nobody in this galaxy has been sweeping the skies occasionally with a powerful gigawatt beam, like we did once twenty years ago (_ie._ [Arecibo](http://www.naic.edu/about/ao/descrip.htm)), just to see if anyone sent anything back. So, at 20 light years I believe they _could_ detect military radar (but not TV or radio) having “structure”, and could _certainly_ detect the _deliberate_ high powered emissions. TV and radio fades to become indistinguishable from noise within a few light years. Now, this does not necessarily mean that there is nobody there, but the alternatives are all unlikely for one reason or another:[ul][li]There _might_ be a ruthlessly enforced galactic silence policy, and nobody uses electromagnetic signals any more. However, each such civilisation could still not prevent the leaks from their technological infancy, and it is difficult to believe that _nobody_, not even a malfunctioning piece of equipment or a mischievous joker, _ever_ lets slip an electromagnetic signal detectable by the incredibly sensitive receptors on Earth.[_]The aliens might have encased this planet in a “shield” impermeable to transmissions. Unfortunately, this would require such enormous resources and manipulation of spacetime that we might as well suppose that they are keeping us in the Matrix.[_]To disagree slightly with **QED** , _perfect_ compression is indistinguishable from noise (_ie._ a signal which has been coded for optimum efficiency simply sounds like a detuned radio). This is a genuine possibility. However, again, there must surely be _some_ leaks from way back when the coding was imperfect, and it would seem imprudent to code _eg._ emergency beacons so that they couldn’t be identified.[/ul][/li] Put simply, if everyone is trying to be noticed as half-heartedly as _us_, we’ll never find them, and so it is still entirely possible they are out there in this galaxy. However, there are two definite facts:[ul][_]The technology required to emit a galaxy-wide audible signal is only as advanced as that required to make a nuclear weapon. [_] _We_ appear to be the only ones ever to have done so.[/ul] One wonders whether the two facts are related. ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [December 1, 2005, 1:29pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/31 "2005-12-01T13:29:11Z")
'Cause it’s a great big universe and we’re all really puny. Just tiny little specks about the size of Mickey Rooney… ---
**Author:** ![Snickers](https://avatars.discourse-cdn.com/v4/letter/s/5daacb/32.png) [@Snickers](https://boards.straightdope.com/u/Snickers)\ **Post date:** [December 1, 2005, 3:27pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/32 "2005-12-01T15:27:35Z")
It’s big and black and inky, And we are small and dinky, It’s a great big universe…_and we’re not_! ---
**Author:** ![HPL](https://avatars.discourse-cdn.com/v4/letter/h/3da27b/32.png) [@HPL](https://boards.straightdope.com/u/HPL)\ **Post date:** [December 1, 2005, 3:42pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/33 "2005-12-01T15:42:45Z")
> [@Rune](#): > > The universe might be a more dangerous place than we imagine. With lots of listeners and few senders. Didn’t Fredrick Pohl’s Gateway series mention something like that? That every race that got advanced enough to start broadcasting a lot got smushed by belligent silicon based aliens? ---
**Author:** ![kingpengvin](https://avatars.discourse-cdn.com/v4/letter/k/9dc877/32.png) [@kingpengvin](https://boards.straightdope.com/u/kingpengvin)\ **Post date:** [December 1, 2005, 6:03pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/34 "2005-12-01T18:03:33Z")
> [@Rune](#): > > The universe might be a more dangerous place than we imagine. With lots of listeners and few senders. So it’s like a Universe of Lurkers? Can you blame them for not calling out. The first time they catch first Run Gilligan’s Island and Lucy they will write off our whole civilization. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [December 1, 2005, 6:06pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/35 "2005-12-01T18:06:18Z")
> [@Q.E.D.](#): > > They would have to be. In order for a signal to carry useful information, it _must_ be ordered, somehow. There are several methods for imposing order on a radio transmission, and we know all of them. There are, after all, only so many ways to modulate an EM signal. Even scrambled or encrypted transmissions have patterns which can be identified as carrying information, even if we cannot necessarily extract meaning from it. I don’t think this helps us much in our search. Developments in the last 20 years on earth have made our signals appear much more random. Unless you know the exact symbols used for modulation the signals look pretty much like noise and this will be getting worse not better as time goes on. I don’t think there is much reason to believe that aliens won’t be using these wider bandwidth communication techniques. ---
**Author:** ![Angels\_Flight](https://avatars.discourse-cdn.com/v4/letter/a/6bbea6/32.png) [@Angels\_Flight](https://boards.straightdope.com/u/Angels_Flight)\ **Post date:** [December 1, 2005, 6:48pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/36 "2005-12-01T18:48:43Z")
Clearly, spacemen have other ways of communicating. Probably gamma rays. But not in code as we understand it. More like Indian smoke signals. ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [December 1, 2005, 7:43pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/37 "2005-12-01T19:43:14Z")
Perhaps all existing ET civilizations with interstellar-travel technology in this region of the galaxy have some sort of Prime Directive against interference with primitive races like ours, and their version prohibits them from even tipping us off that they exist. (But it does allow for the occasional clandestine anal probe! 🙂 ) ---
**Author:** ![HPL](https://avatars.discourse-cdn.com/v4/letter/h/3da27b/32.png) [@HPL](https://boards.straightdope.com/u/HPL)\ **Post date:** [December 1, 2005, 9:08pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/38 "2005-12-01T21:08:39Z")
> [@kingpengvin](#): > > The first time they catch first Run Gilligan’s Island and Lucy they will write off our whole civilization. Either that or they’ll come looking for us demanding to know if the castaways ever got off the island, and threatening to blow up the earth if they don’t see that episode. ---
**Author:** ![Bill\_Blazejowski](https://avatars.discourse-cdn.com/v4/letter/b/4bbf92/32.png) [@Bill\_Blazejowski](https://boards.straightdope.com/u/Bill_Blazejowski)\ **Post date:** [December 1, 2005, 9:47pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/39 "2005-12-01T21:47:00Z")
> [@Marley23](#): > > Scientists are apparently convinced that the universe is so vast that the it’s near-certain there is other intelligent life out there. I’ll take them at their word. > That said, though, the observable universe is a very tiny fraction of that. Then you reduce that further when you consider the portions of the observable universe that we can really interact with, especially by radio, and the odds of us making contact in this manner are sadly tiny. So it’s not surprising that we haven’t found anything concrete through our couple of little projects, I guess. > > Hey, we’re beaming Hendrix into space. If they’re not cool enough to appreciate it, the hell with them. They can’t be that advanced. 😉 I would think given the extreme size of the universe that intelligent life occuring at least one other time is certain. But for our purposes, isn’t finding another occurence of life here in the Milky Way the only thing that matters? ---
**Author:** ![BrainGlutton](https://avatars.discourse-cdn.com/v4/letter/b/82dd89/32.png) [@BrainGlutton](https://boards.straightdope.com/u/BrainGlutton)\ **Post date:** [December 1, 2005, 10:00pm UTC](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492/40 "2005-12-01T22:00:45Z")
> [@Bill Blazejowski](#): > > I would think given the extreme size of the universe that intelligent life occuring at least one other time is certain. But for our purposes, isn’t finding another occurence of life here in the Milky Way the only thing that matters? Remember, also, that if we were to visit another planet, even one with life on it, that planet has a very long past and (presumably) future, and all we see is the one momentary single-frame or snapshot in the evolution of its biosphere. And there’s no reason why evolution on one planet would be on the same timetable as on any other planet. If ET’s had visited Earth at any time in the past two billion years there has been life here, but before the emergence of the genus _Homo_ a mere 2.5 million YA (a mere eyeblink by comparison), they would have reported, “No intelligent or proto-intelligent life found.” And said ETs, by now, might have either gone extinct or evolved into something beyond our comprehension – either way, no longer reachable by SETI. [Previous page](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492.md?page=1) [Next page](https://boards.straightdope.com/t/why-hasnt-seti-found-anything-yet/333492.md?page=3)