How Does SETI Search for Alien Civilizations? With Seth Shostak

have you ever asked are we alone certainly not here the case could be made that you share a world with countless living things and other than fellow humans some of those can communicate with you on a rudimentary basis but at vall life that pervades our world there are very likely more habitable worlds that could have life in the universe than the sum of all living things that have ever existed or will exist in the history of Earth that is simply a matter of numbers the numbers of stars in the universe outnumber the mind-boggling numbers of galaxies and planets themselves may yet even be more numerous than that we don't know how many of those planets could Harbor life but the point is life in whatever form it might take from microbial to intelligent could be amongst the most common phenomena in our universe or perhaps it isn't or that intelligence is almost never a product of life rather it's a fluke of sorts that happens only very rarely and we as an intelligent civilization are the winners of a universal lottery the answer to that question are we alone however remains unanswered but can we answer it the answer is probably yes if we look and that's what my guest does through Radio Astronomy we can search the heavens for radio and laser emissions that could only have been created by another intelligence and while they would be very hard to spot it's not impossible and just maybe if my guest is right we will answer the great question sooner rather than later welcome to event horizon with John Michael Gaudi a [Music] [Music] [Music] [Music] Seth Shostak is a senior astronomer at the SETI Institute in Mountain View California and the director of the Institute Center for SETI research seth has an undergraduate degree in physics from Princeton University and a doctorate in astronomy from the California Institute of Technology for much of his career Seth conducted radio astronomy research on galaxies and for more than a decade he worked at the captain astronomical insatiate in horan england in the netherlands using the Westerbork radio synthesis telescope seth has been a distinguished speaker for the American Institute of Aeronautics and Astronautics dr. Shostak we talk about the hydrogen line 1420 megahertz but there are other frequencies that aliens might choose to broadcast on if they were trying to contact us what other ones are there what what makes mathematically makes sense well you can I mean they're people who make a small hobby out of concocting other frequencies for example you could take two times the hydrogen frequency instead of 1420 megahertz go to 28 40 megahertz or you could take PI times the hydrogen frequency you know the aliens will know the value of pi I mean you can concoct all you want but all of this in the end amounts to second-guessing where the aliens are gonna tune their transmitter and honestly if you knew that you're probably I mean if you knew that you know a lot of things and you'd know things that we don't know so the safest thing to do is try and listen in try and eavesdrop on as many frequencies as you can as much of the radio dial as you can instead of listening to one one frequency at a time you know today's SETI experiments typically monitor we monitor 72 million channels at once there are experiments that monitor even more than that so that's that's a solution instead of trying to pick a winner instead of deciding which ticket ticket is the winning lottery ticket you just buy them all when you look for this with the Allen telescope array how many frequencies to look at I mean do you like cover many millions of channels or what what is the capability that you have with your SETI project to look at frequencies and signal yeah well that all depends on what's called the back end which is to say and the computers that are behind the antennas the the ones that are in actually a small building there and as I mentioned we actually monitors 72 million channels simultaneously so that's a lot I don't mean compared to the past the first SETI experiment but only listened to one channel at a time then when we can listen to 72 million but I can assure you that if we have the money to keep going you know to another couple years we'll be monitoring hundreds of millions of channels simultaneously and that speeds up the search that's a good thing because it means that you can check out a given star system much more quickly if you can you know swallow a larger chunk of the radio tile at once how much for the sky do you look at well you look at as much as you can but when you have big antennas and you know these antennas vary in size but none of them is small enough to fit in my living room I mean they're big then you're only looking at a fairly small patch of sky and so you point them in the directions of the nearby star systems where you even hope to you know you expect put it that way that a star system like that will have some planets and we've looked at thousands of star systems thousands but thousands sounds like a big number and it is if you're talking about I don't know the number of siblings you might have but thousands is in fact still a very very small sample of the universe so as the equipment becomes faster and faster that number will continue to go up and I reckon that in the next 20 years we'll be able to check out a million star systems I think that's an interesting sample now out of that sample say you can look at a million star systems do you expect to find something what is your view on the Fermi paradox what is your view on what are our chances over the next years of actually seeing an alien civilization well I've I've publicly bet everybody a cup of Starbucks that we will find something in the next 20 years so either either people are going to have an interesting story to talk about at night or they're gonna get a free cup of coffee from me so that's kind of what what where my feelings are simply because I think that if you can monitor you know a million star systems or at least check them out you're not really monitoring them you only look at them once but but if you do that I figure if you look at a million you have some decent chance to actually find something so that's kind of where we are but you know if that technological progress continues then by the middle of this century say 2050 2060 you know now you've checked out many millions of star systems and that's becoming a you know that's a that's a large enough sample I think to find something if you're not finding something in you know say ten or a hundred million star systems then maybe you know you're barking up the wrong tree you have said that maybe we might instead of finding a biological civilization on the other end so to speak we might find a machine civilization and that might be more likely explain that yeah well that's simply an extrapolation of what we're doing here on earth I mean if you look at the aliens as they're depicted every year every weekend in the movies or on television and that sort of thing you know they're all okay maybe they're not terribly attractive maybe it's not that the kind of person you would want to you know have staying in your upstairs spare bedroom but on the other hand they do look kind of like us I mean they tend to walk upright and they have two eyes and you know usually four appendages two arms two legs whatever they're essentially extrapolations they're just sort of guesses as to what we might look like in another you know million years or something right but in fact in this century we're inventing machine intelligence it's gonna be at least as clever as we are and that's that's coming go rather rapidly down the pike and you can worry about that because there may be good reason to worry about it but whether you worry or not it seems to be something that we're doing and as soon as you have machine that can think well the first thing you ask it to do is design a machine that's better than it is then you build that and then you you know build a successor to that one and so forth and very quickly you have machines that are you know they'd simply dwarf all human intelligence they dwarf anything that humans can do cognitively now some of those machines are gonna get up and leave for I assume I don't think that's a crazy assumption because this is not where the action is I mean earth is great and all but you know they may want to go to the center of the galaxy where there's a lot more energy and the center of the galaxy is far away it's too far for us to go but you know if you're a machine and you can keep fixing yourself maybe you don't mind that it's a long run so it does seem to me that most of the aliens are gonna be machine like if they are machines though wouldn't they want to go to colder areas like the outer edges of the galaxy where you can compute more efficiently because of a cold yeah that's an idea that was proposed by a guy I think he's museum Bell Gary or someplace anyhow he's written papers about this in which he points out this is really sophomore physics but what he points out is that if you want to be a very efficient machine you want a big temperature between the Machine and you know the outside if you will the heatsink right so the colder it is around the more efficiently you can run as a machine okay fair enough that's true that's really true mmm that's why your refrigerator has fins on the back way but but on the other hand you know how much colder is it at the outskirts of our galaxy than it is where we are you know where two thirds of the way out in the galaxy yeah it's it's maybe a degree or two colder but it's not very much colder I mean space is cold and it doesn't matter whether you're you know halfway out in the galaxy or all the way out in the galaxy so I've never really understood this argument I don't think it would you know be worth it new the the travel cost to go out there I think you can do almost as well right here now that this brings up the idea of a Galactic habitable zone that you have less material out in the outer parts of the galaxy to you build a solar system so to speak now do you think biological life leaving intelligence aside do you think biological life is confined to a an area of the galaxy where we are essentially and that the center of the galaxy is just a bit too radiation intensive and the outer air parts of the galaxy are just a bit too devoid of material do you think that is a valid idea the Galactic habitable zone well it's hard to say there are people who indeed just love this idea of a galactic habitable zone just like they figured there's a galactical galactic habitable zone you know outside of Kansas City right there if you're in the center that's not good if you're too far out that's not good says you know the inner suburbs and how where you want to be oh you know come on you can make arguments against that you know easily enough and I think the same is true with when it comes to the Galactic habitable zone the problem is if you get too close toward the center then you're getting new stars being made including new big stars and big stars when they die and they die rather quickly they die very violently with a big supernova explosion that could ruin everybody's all day if they happen to be nearby so they're saying okay that's too dangerous you're never gonna get very long-lived a biology there in the center and you go to the outskirts there's plenty of stuff to make planets and stars maybe fewer than the inner parts but you know it you know it could might be a little lonely but who cares so I think that you could maybe rule out some of the central regions of the galaxy maybe even up to the one-third the diameter of the of the galaxies is you know the minimum distance you want to be hey you can make that argument but even if it's true even if you buy that you know the inner third of the galaxy is actually only about one tenth of the you know area the galaxy I mean you know there's that still leaves hundreds of billions of star systems so it's not a terribly great restriction it's sort of like saying you know the US can never become a great country because think of all those parts in central Nevada where nobody can really live yeah that's true but there are other places where they can live and on that note we must take a break we'll be back in a moment with dr. Shostak be sure to LIKE subscribe and share the video if you'd like to support event horizon you'll be pleased to know we've recently launched a patreon link in the description below or alternatively you can use your cellular telephone to scan the assemblage of squares on screen now and now back to John and we're back with dr. Seth Shostak a founding figure of Seti I suppose you could say dr. Joe stack you don't just look for radio signals radio beacons you also look for laser beacons as well what do you hope to see if you see if you see it either a radio beacon or a laser signal what are you looking for are you looking for something like that's just screaming alien life unambiguously or are you looking for something that could be more subtle like a a signal that's just some mundane communication you know from an alien ship to its home world what what are you looking for yeah well to be honest John I'd be happy with either of those I mean the real name of the game here you become a winner if you find any evidence that proves that somebody is out there now as far as the details go away what are they telling us I mean is this is this some sort of profound statement about the the universe is a beautiful poetry is it just an ad for toothpaste or something I mean you know to begin with we're probably not gonna know what it is but even that aside the real point is something else the real point is that hey you know earth is not the only place where intelligence has cooked up so that's what you're trying to do so when you look at something you know you look at the sky looking for laser flashes if you find a laser flash and bright laser flash the chances are very good that what you've discovered is somebody's technology right you've discovered some proof that there's somebody there you may have no idea why they built this giant laser that lashed at you or why they're flashing in in your direction but you know that the universe doesn't cook up lasers automatically it doesn't make lasers that require some sort of engineering so that's that's the idea here you just find some signal where you say that that's not nature that's that's something else so how do you tell though because if if I mean if you look up at the sky with a radio telescope you're gonna see all kinds of bleeps and bloops and weird stuff and we've seen that we've seen things like the WoW signal and you know other other radio signals that I mean I remember that one from a year or two ago that Arecibo picked up that just seemed to be some weird signal how do you eliminate the ambiguity you know how do you know this is an alien signal as opposed to this is a spy satellite yeah well the hardest thing to distinguish it from is a spy second okay I mean you really hit on it because what you look for are for example in the radio what are called narrow band signals so okay that's that's just a signal that's at one spot on the radio dial isn't everywhere on the radio dial right it's just like your favorite - FM station that's it one spot on the radio dial right at eighty eight point five megahertz on your table whatever it is okay that means it was made by a transmitter because if you were to listen to a quasar or a pulsar yeah I'm eating pulsars right they're all over the dial though it almost doesn't matter where you tune your gonna hear them right so that's that's nature but intelligence doesn't waste kilowatt hours right it's got to pay for them so any any creatures building a transmitter they're gonna put the information in one spot of the dial that's that's just a matter of economy but economy is something that nature doesn't always worry about so that's how we can tell the difference not because of the message whatever the message might be people have this idea that oh they're sending us prime numbers that must be et hey look if they're sending them on a signal that said you know 1425 megahertz or whatever right but not at 14 24 or fourteen twenty six then you say don't even know what these numbers are but I do know that that transmissions made by a transmitter okay now let's get into that though so why would a spy satellite transmit at 1420 megahertz this is sort of a set-aside signal you know or set-aside frequency to what that we leave alone you know because the hydrogen line why would why would a spy satellite transmit at that yes you'll have to take that up with a Pentagon you think they shouldn't there are protected frequencies and they're protected because of the interests of not so much SETI actually but because of the interests of radio astronomers right I used to very modest living studying galaxies at the 1420 megahertz line of hydrogen right so you learn a lot I mean the fact that we know about dark matter today is largely the result of those kinds of studies so you do learn about how the universe is built that's considered a worth wild social worthwhile social endeavor and so the government does try and protect these things is actually international agreement on this because that's what you need but it doesn't mean that you know some organizations will try and break the rules they'll say hey look look at this all this empty spot this empty space here on the radio dial we've got to get these pictures down from orbit or whatever we will just to build a little transmitter here and you know do it so you know that's all political that is not too much to do with the science is it a good frequency to downlink though it's not bad actually a lot of the you know it's in the microwave region of the spectrum the the wavelength is 21 centimeters so that's what I like 80 inches or something so that that's a good frequency comes straight on down without any difficulties microwaves are used for lots of stuff and indeed your cell phone works at microwave frequencies I mean yeah as a download downlink frequency it's definitely pretty good so it could be like for example a signal like the WoW signal which was pre closed 1420 and it was narrowband it's a good thing to say that may have been a spy satellite in the 1970s yeah well that's the thing you usually suspect first when you pick up a signal zero is that et Oh or is that just a satellite whether it's a spy satellite or some other kind of satellite I mean a lot you know there's thousands of satellites up there most of them I guess are not not spy satellites but there are satellites and they all have down Lok downlink capability the thing about the WoW signal however was that it didn't just go on and then off right again right away it stayed on and it stayed in the same spot on the sky apparently judging you know from the shape of the signal for on the order of a minute or so right and a satellite of course they move around the sky the exception being if you're looking at these geosynchronous satellites but it wasn't aimed anywhere near the geosynchronous belt so it wasn't one of those I mean you can go out at night you can see satellites right if you're in a place where it's pretty dark and you look up and you'll see the move across the sky and it takes him I don't know maybe 10 minutes to move from one side of the sky to the other so they're moving and that can't be the key the explanation for the wireless signal now it was it was out late I suppose 2016 maybe 2017 someone suggested that maybe the while signal was hydrogen lying emissions from a comet was it's that a good explanation or is it terrible I think it's you know closer to the latter than to the former I and here's why in fact that that paper had a hard time getting published because of this look saddle sorry the Comets you know I mean they're probably quite a bit of hydrogen in a comet because it's mostly ice and ice is h2o but it's not the kind of you know gaseous hydrogen that can make a 1420 line emission I don't think anybody has ever ever ever ever seen a 21 centimeter that is a 1420 megahertz signal from a comet but even that aside that even if you assume that it's there the thing about the WoW signal was it was seen at Ohio State really Observatory the signal came in and then you know it went out and then automatically a second receiver on that antenna looked again in the same spot so 70 seconds later like a you know like a minute later and it did not see the signal if it had been a comet you would have seen it again because comets don't move across the sky in one minute they don't do that that's real if a comet is moving across the sky in one minute it's too close he better be you better jump underground or something so that that explanation just didn't fit the facts at all so it essentially the debunk that the while signal might have been of alien origin is debunked now I wouldn't say that it's not a comet that's for sure it could have been et that et was on the air and then for some reason they went on vacation took a lunch break who knows what flipped off their transmitter and that was it right so we heard it for a minute and we didn't hear it ever again and it hasn't been heard ever again we spent some time looking forward to other radio observatories have as well never been seen again and that's the problem when you see something only once it's very very difficult to figure out what it was because you you know you can't do any experiments you can't you know try a different kind of receiver or different antenna or you know different way of analyzing the data I mean you're just stuck and so the WoW signal is still a puzzle maybe it was et maybe it wasn't et but you certainly can't claim the Nobel Prize on the basis of what we know a half-assed data as dr. Amon that wrote Wow said you can't you can't go up with it you can just say about that was weird now that signal was narrowband right well yes it was it was in a few of the channels of the receiver there at Ohio State that's right so narrowband is weird because that tends to suggest technology right whereas broadband tends to suggest nature but is there are there natural objects natural sources for narrowband radio emissions well not too many I mean in fact essentially none I mean there are some phenomena in space called lasers interstellar lasers and they produce signals that are relatively narrow band a couple hundred Hertz why a couple hundred cycles per second but you know we're looking for signals that are one hertz wide one cycle per second so even when the mazes can't produce signals that narrow as far as we know there's no no phenomena in in outer space that produce those narrowband signals nope now narrowband signals there's actually a practical reasons for that if an alien civilization were shooting out radio signals narrowband is efficient right it's it's efficient to broadcast those narrow bands so that you're not wasting energy whereas a giant broadband beacon would waste huge amounts of energy correct yeah no that's true I mean even the Klingons are gonna have to pay their local power company for the achievement being burned up by their transmitters that's for sure and it's the case that if you simply want to get in touch if that's what you're trying to do then in fact taking all those you know kilowatts megawatts gigawatts where they are and putting all that energy into a very very narrow part of the radio dial narrow spectrum signal that gets you the most visible signal for the energy oh yeah everybody knows this if you have a laser pointer right now those laser pointers they're not very powerful they're a couple of tens of millets or something you know the hundredths of a watt kind of thing and yet you can see that red red light from quite far away I'm sure you could see it from a hundred yards away without any any difficulty at all on dark night so how does that work well it's taking all that energy such as it is from the batteries inside and putting it into a narrow bit of the spectrum you know red light green light whatever it is so yeah that's a technique they may use if they're really trying to get in touch if that's not what it's on their mind if they're doing something else and their news to say now sometimes we get you know if you if you watch like for example Cornell's archive of reprint papers you get these weird papers that sometimes delve deeply into the possibility of alien civilizations a year and a half ago or two years he had a paper that there was 234 detections of some kind of light emissions that looked like alien civilizations I think the paper was by hermano Bora each Trottier why what happened with that is that is that a real you know possibility or were they off-base well nobody knows whether they were off days but I think that the idea here is that in the early days of looking for et via this technique you know trying to eavesdrop on radio signals there were all sorts of the signals that came in that thought and where people thought man this could be it this could be the big one and the reason that that would happen in the early days when I say early days I mean the 70s the 80s was simply because there was no way to quickly follow up in other words you pick up a signal but you don't know that because you're recording all the data back in those days you'd have none of the antennas connected to you know those big tape drives he always saw in the science-fiction movies then you knew that this was serious stuff I mean these guys had a huge computer because they had all these tape drivers trade tape drives spinning back and forth they would record all the date and then they would go home to wherever home was and they would play the tapes back and some machine you know look for signals okay you would always find signals I mean you find signals all the time but you couldn't check them out right away because you're no longer at the the antenna you're back home somewhere and so you know the majority of those probably maybe all of them I would say we're just interference from you know satellites or whatever but as soon as it became possible because of improved computer speed to check things out right away then suddenly you didn't get these hundreds of mysterious signals now that's that's an interesting observation that we're getting really really good equipment these days and we can look for not only radio signals but we can look for techno signatures and bio signatures in the coming years and we can look for alien civilizations not just by the radio emissions or laser emissions but we can look for things like weird oxygen levels in an atmosphere when do you think do you think it's it's possible that we will find an alien civilization or evidence of an alien civilization or at least an alien biosphere within the next 20 years yep well the former NASA chief scientist did indeed say that within 20 years she figured will find life in space what she was referring to was the kind of life experiment that NASA does which is indeed to look for you know single celled life and you know maybe by finding oxygen in the atmosphere some planet around another star that that's that capability is coming down the pike the James Webb Space Telescope for example might be able to do some experiments that would allow to find oxygen if there is any in the atmosphere or some planet around another star and that would be a you might be a strong hint I mean you know look at the planets near to us Venus well it's got a really thick atmosphere but it's mostly carbon dioxide or Mars well it's got a really thin atmosphere but it's mostly carbon dioxide our atmosphere has you know 21% oxygen whatever it is and that's because of plants you know photosynthesis so if you found oxygen in somebody's atmosphere you'd say well I mean you know we can't be sure Bob but that kind of looks like a you know there might be some plants there so you might be able to find maybe single-celled plants by the way so you might be able to find life that way and as soon as you have that capability you know I think I think it's not gonna be a very long wait before you've detected at least biology and on that note we will go to break and move back in a moment with dr. Seth Shostak [Music] if you're in the market for a new bookmark check out event horizon show.com we've had a snazzy website built by professional of some variety because John wanted to use Geocities or something with unicorn gifts no John you're a designer saw and we're back with doctors that's Joe stack dr. szostak Enrico Fermi posited long ago that if the galaxy were full of civilizations we should see them everywhere we should see evidence where are they but since then people will start asking questions like well what's what might be solutions to this so-called paradox you know might there be brick walls for a civilization what is your favorite solution to the Fermi paradox yeah well I I'm not sure I think it I think it varies from week to week yeah what Fermi was saying was indeed that you know it doesn't take very long to colonize the entire galaxy you know 30 or 40 million years to me that sounds actually like a long time but you know if you're really an advanced society of your machine intelligence or or whatever maybe you're willing to undertake a project like that and just colonize every star system in the galaxy and that was kind of his point he asked where you know where is everybody they should be all over the place and we don't see any evidence of that but on the other hand on the other hand the fact that we don't see any evidence doesn't mean that they're not there right I mean there did the books written about how you could explain the Fermi paradox without also assuming that there's nobody out there if somebody spins me around 20 times you know puts them in an airplane and takes me to you know if central Nevada or something like that I I can look around when I get out of the plane and not see anybody but that doesn't mean that North America is uninhabited it just means I'm in a place where there you know isn't too much action okay so you know maybe that's it maybe where we are here our part of the galaxy is kind of a desert you know an intellectual desert and I certainly get that impression when I walk around my neighborhood I mean that could be you know there are other explanations that I think are maybe even more compelling it's very expensive to colonize the galaxy I don't know that anybody's you know actually budgeted it but it's it's a really big project and there are a lot of downsides to it so maybe nobody has found it very interesting to do or it could be that everybody kind of lies low because of course you know you don't know what's out there that kind of argument and so you don't want to tract any attention to yourself so you do your thing but you you know you don't brag about it it's a say there are hundreds and hundreds of explanations and only one of them is that well actually Earth is the home to the only intelligent species in the galaxy I know people would like to think that's true because it makes them important but there's not a lot of good historical precedent for making such an assumption so you go back to old ideas now nineteen sixties ideas like the Kardashev scale where civilization goes in in cases every star in a galaxy or every suitable star in a Dyson Sphere quote-unquote could you say that that's that may not be practical and the reason we don't see that is because it isn't practical for a civilization to do that that they're much more subtle that certainly could be I mean you only have to consider if you would ask some of the the best minds of I don't know anyway Europe say in 1850 and said ok what do you think a society in the year 2018 it's gonna be building going to be doing and I'm sure they'd have plenty of ideas but they'd all be wrong right that's only you know a century and a half ago so it may be that you know we just we're worried about something that isn't actually something that makes sense to worry about dyson sphere's I think you're kind of a nifty idea where you you know take apart some planet and your outer solar system or wherever and rebuild it into a giant swarm of solar collecting satellites or whatever that are outside the orbit of your planet so that you can collect all this energy and use it for whatever you want it was pointed out by a fella by the name of Joe when I said Gerald nordley Gerald nordley a science fiction writer amongst other things that if you actually had a Dyson Sphere you would have so much energy at your disposal and also the capability of focusing that energy because he'd had this huge baseline as they call it in the radio astronomy biz you would be able to incinerate another planet halfway across the galaxy and so he was suggesting that maybe Dyson Sphere should be made illegal because if you have one you really have the Death Star you can you can do whatever you want with it that's kind of an aside but but it is the case that just because the society is rampant that is to say it's all over the place doesn't mean that they make a lot of noise maybe they don't long ago again I think 2006 astronomer in France I think his name was Luke Arnold he released a paper where instead of a Dyson Sphere if you want to make a beacon and say we're here you know you're an alien civilization you want to tell everybody you're here he came up with this idea of louvers where if you had like a Kepler space telescope you could see very very strange signals and a light curve of the star you know and this became important during the the tabie star affair which of course turned out to be probably dust but do you think aliens would be more economical rather than sending out a radio beacon they would just do something like put an Arnold Luger and in orbit of their star or several of them you know so that people could see them is that more a more efficient way to say we're here I shudder to think well yes I mean maybe they build essentially what you know the Navy used to use during the war to send confidential information from one ship to another at night by flashing Morse code on these you know louvered searchlights okay it worked worked for the Navy but they don't do it anymore I think the only problem with that is yeah yeah maybe it would work I mean but you have to build a really big set of louvers you know like a million miles across or some fair fraction of that in order to block enough of this star light that you would even see that it's sending you know the Klingon equivalent of Morse code to you and I think that the real problem is that something that big can't react terribly fast and as a consequence you can't send very much code per second right the amount of information you can send in the course of an hour is very very limited whereas if you spent that same money and built a giant radio beacon you could send you know you could send TV you could send something but you could send you know millions of times more information per second so while this this scheme has an advantage in that you know maybe anybody could find it because any society that has astronomers is going to be a society where somebody's kind of monitoring the the brightnesses of stars occasionally they may notice it but on the other hand it's it's sort of like saying you know Chris we're not gonna fund the Nina Pinta and Santa Maria here because that's gonna cost a lot of money but I'll tell you what we wanted what we will do just in case there's something to be discovered on the other side of the Atlantic just in case you might have discovered America in order to still give you that opportunity at a lower price point what we're going to do is buy you a bunch of bottles so why don't you just go down to the beach put some notes in the in the bottles and throw them into the surf okay well maybe that would work and it certainly is you know an interesting idea but you can't write much on a little note that you stuff into a bottle you know so I think that that's kind of the nature of this sort of signaling this leads to a question if we can detect an alien civilization via radio wave leakage or lightsail leakage or any of these many things that we can talk about how visible are we if an alien civilization looks at earth would they see us as a civilization certainly I guess they'd see our oxygen at least as long as you know weird oxygen levels have been present in this this on this planet but if they looked at us would they see us I mean would they see you know the proverbial speech from the Olympics in 1936 would they actually see us or would they just say there's probably a biosphere there but we don't know if there's a civilization yeah I think the latter is the correct answer actually they do by the way they would not be able to pick up that 1936 broadcast you couldn't even pick it up in the outskirts of Berlin lettle from light-years away so don't count on that I mean it makes a nice story point you know a plot point in a movie script or a novel but it's it's not actually very practical in fact in a more general sense yeah if aliens looked at the earth okay for the last two billion years they would see the oxygen so they would know there's photosynthesis here now I don't know if that intrigues them enough for them to send a signal let alone a rocket to earth a let's go visit the lettuce they may have on that planet I don't even know it's lettuce it's probably single-celled stuff doing photosynthesis but they would be able to detect that and they could detect that from essentially any place where they have a telescope big enough to actually see the earth alright so you know maybe a lot of aliens know that there's life on Earth but all they know is that it makes photosynthesis they don't know about us to find Homo sapiens is much harder because there's nothing that we do that is very obvious from you know 100 light years away beginning with the war we develop radar FM radio television all those things they go into space but that's only since the war so that's like 70 some light years out there in space and it would take a very big antenna to pick up our TV somewhat smaller antenna to pick up the radar so maybe they picked up some radar that they could do but if they're more than you know 70 light-years away and then they don't know about us and if they're more than 35 light-years away there absolutely has not been enough time for them to learn about almost sapiens and decide to come here and ruins every ruin everybody's whole day now if you have a civilization that's say 35 light years away super close what kind of radio telescope would they need to see us I mean what they need something huge like the size of a city or would they be able to do it was something like Arecibo or or the VLA or something like that do you need a giant radio telescope to see us from 35 light-years out well probably you do if you're lucky you know you might be in the beam of some big radar somewhere the biggest radar actually on earth is the Arecibo radar believe it or not I mean that's an antenna that's a thousand feet across and you know the power that transmitters what two and a half million watts I think so that's pretty powerful but the trouble isn't only no hello you lights up one ten-millionth of the sky at any given time so the chances that you happen to be in the right place to see the air see what radar pretty pretty small if you want to pick up the other radars there you know 30 percent of the sky is more or less covered with radars then you need would need an antenna yeah if you're 35 light-years away you might be able to do it with an antenna that's you know as big as the biggest antennas we have if you want to pick up our television forget the programming if you just want to know that we're on the air pick up the carrier waves then you need an antenna the size of you know Massachusetts or something like that okay so that's pretty big but you know one should never begrudge the aliens the ability to build something big so maybe they have that kind of antenna capability so they could probably see us now if they see us and this you know this will be my last sight question for the segment if they see us could they even decode what you know could they even decode a television station or could they would they look at us and see oh the humans are are using radar from Arecibo I mean a radio signal does not necessarily need to contain information but if it does could you ever decode it well it depends on how clever the aliens are are better than that how clever their computers are you know radar doesn't have very much information radar is designed to find you know ships and planes and stuff like that so it's a fairly simple signal compared to many others and you know they probably understand that that's what it was so they say okay they got radar all right good but if you say television you know the old analog television signals the ones that went away about a decade ago those who are fairly simple and they might be able to decode those and end up with a picture you know and they might not know which way is up and which way is left and right but you know they could get the picture perhaps they certainly wouldn't understand the jokes but they could figure out that signal today we have digital technology for television and that makes it tougher on the aliens because that's all proprietary you know that's that's very personal the way we decide to encode things but on the other hand it does make good engineering sense so maybe they could figure it out they would probably spend an awful lot of time on it trying to figure it out and when they got done with all that effort then they would finally be exposed to reality television and ask themselves whether it was worth it thank you for appearing with us dr. Shostak I enjoyed the conversation and I hope you come back thank you very much so how common is intelligent life in the universe it seems at least right now an answerable question we are early in the game as far as SETI goes in fact we've barely started looking but what happens if after centuries of searching we still see nothing after radio searches laser searches looking for bio signatures and techno signatures studying seemingly earth-like exoplanets all of it and we still seem to be alone at that point we must ask ourselves if we may actually be alone even after all of the statistical numbers that might say we shouldn't be alone given the sheer numbers of stars in the universe what happens if we still see nothing this could simply be a matter of distance in the end and that anyone that might share our universe could reside in a galaxy sufficiently far away that we simply can't ever detect them but what of the other side of the coin say the answer to the great question is yes and we do see evidence of other civilizations what could come of that can only be speculated about would we establish contact with them or would we satisfy ourselves with simply knowing that they are there would in some far future scenario we interact with them would we merge our civilization with them or would there be a bitter end to contact none of this can be known before it happens but regardless of any scenario whether there is other intelligent life in the Milky Way or not anything we might discover or not discover will make for an interesting future indeed I've had a thought Oh Momo John you really like saying that of course I did it's a great name and the other one you mean kic 8 4 6 - 8 5 - yes John tabby stell you just love saying those things we should probably thank the viewers for bearing with your obsession my obsession what do you want it to be Europe and on that note next week I'll be joined by Fraser Cain for discussion about the current state of astronomy both amateur and professional and what we might discover in the coming years see you Thursday [Music] [Music]

Channel: Event Horizon

Views: 74,007

Rating: 4.8665233 out of 5

Keywords: SETI, Universe, Seth, Shostak, Allen Telescope Array, Alien, Extraterrestrial, biosignature, technosignature, Wow! signal, KIC 8462852, ASMR, UFO, Godier, John Michael Godier, Life in the universe, exoplanet, astrobiology, exobiology, radio, signal, astronomy, science, oumuamua, VLA, Contact, Hydrogen line, isaac arthur, joe rogan experience, event horizon, event horizon john michael godier, Seth Shostak, Search for Alien Civilizations?, How Does SETI

Id: ag6g0y0H9ww

Length: 46min 27sec (2787 seconds)

Published: Thu Dec 06 2018