The Search for Intelligent Life Among the Stars: New Strategies

good evening everyone my name is andrew frak noi i'm the astronomy instructor here at foothill college in Silicon Valley and it's a great pleasure for me to welcome everyone in the auditorium and everyone listening or viewing us on the web to this lecture in the 11th annual Silicon Valley astronomy lecture series this is a series sponsored by the Foothill College astronomy program by the NASA Ames Research Center one of the premier NASA centers around the country by the venerable Astronomical Society of the Pacific which is devoted to sharing astronomy with the public since 1889 and by appropriately tonight the SETI Institute the search for extraterrestrial intelligence Institute which is devoted to the science and education of the search for life in the universe this is a series of six programs every year when noted astronomers share with us the exciting results of what's happening in our quest to understand the universe tonight's speaker is dr. seth shostack one of my personal favorite speakers in the world of astronomy um who's going to talk about the search for intelligent life among the stars new strategies dr. Shah stack is senior astronomer at the SETI Institute and a spokesman not just for the Institute itself but for astronomy in general you often hear him on local and national radio and television programs he also hosts his own syndicated radio show called are we alone which is broadcast locally here in the Bay Area on ka LW & KL IV and can be heard on the web if you go to the SETI Institute website you can find that program and every week he has exciting guests talking about interesting developments in science and Sciences relationship with other fields dr. szostak has written hundreds of articles and web pages on the quest for life elsewhere and other topics in astronomy and a strobe he has a degree in physics from Princeton University and a doctorate in astronomy from Caltech for the last six years he's been a distinguished speaker for the American Institute of Aeronautics and Astronautics he's written and edited a number of books on the search for life elsewhere and his most recent book is designed for the public at large it's called confessions of an alien hunter a scientist search for extraterrestrial intelligence it was published by National Geographic books and I highly commend it to everyone who is listening to this lecture so we've asked him to talk about one of his favorite subjects the search for cosmic company it's a distinct pleasure and a privilege to introduce dr. seth shostack thank you very much Andy for such a nice introduction I'm afraid that the packaging will be better than the meat but is very nice and also by the way always warn audiences not to applaud beforehand because you will always have regret later it's nice to be back at Foothill College actually when I first came to this part of California more than 20 years ago now I had a lot of free time which not the case now but I had quite a bit of free time in the evenings and I came up here and took some courses in creative writing actually it was somewhat by accident I just wandered into the wrong room by my mistake and I have the fondest memories I think that the Foothill College to the extent that I can write taught me how to write so it's very nice to be back here and to be back part of the lecture series it's been a been a while since I've given a talk here my last talk was what happens if we find et and in that I described a little bit about how SETI and in particular the SETI Institute which by the way at an oaf Andy mentioned is in Mountain View so a local institution here how we're doing the experiment tonight I'm going to simply try and provoke you this is not entirely malevolence but it's just to suggest other ways of doing SETI that you might think about and if the hit rate on these ideas is as much as five or ten percent that'll be pretty good as far as I'm concerned so first off here's just a picture of the universe or part of it you see a whole bunch of stars there's some you know hot gas and so forth there's some cold gas you can't see in the background some galaxies the number of stars in our galaxies on the order of a couple of hundred billion I think most of you know that number and the question that has been asked now for a very long time and that we're finally getting an answer to is well how many of them have planets now those of you who follow this thing know that we've discovered more than four hundred planets around other stars that per se it's not so interesting what's really interesting is what fraction of stars have planets and if you talk to Geoff Marcy you've spoken in this series or other people who look for extrasolar planets and say what Geoff if you had perfect instruments what fraction of stars do you think would show planets and he said well maybe maybe three quarters okay now for an astronomer half is the same as all okay you know worried about factors of two in astronomy pi is one or some yep so so what that means is that they're on the order of a trillion planets in our Milky Way and if none of those seems suitable enough for you if you're particularly picky about your planet you can always go to another galaxy and find another trillion planets but this is a big number I just want to emphasize this people say why do you think there's life out there right it was a reporter at the Institute recently the last me do you really think they're out there which I found a very bizarre question to ask of someone who's working at the SETI Institute I mean yeah why would you do it and and but I said yes and he said well why and I said well it really it comes down to this it just comes down to this number because if only one in a million of those planets meets the requirements for your gussto grabbing free living lifestyle that's still a million worlds just in our galaxy so you know the numbers look good because they're large there's something else there are other indications that might suggest to you that maybe what's happened on this planet is not really a miracle and that is the fact that life got started here very early this is a photo I made down in the northwest corner of Australia in the Pilbara Hills you see these sort of round things this laser pointer isn't really a laser pointer it just have telepathically tell you where to look and there's a business card there for size or something like a business guy you see those round things that look like frozen cantaloupes those are fossilized stromatolites okay those are just the colonies of bacteria and we know how old this rock is from radioactive dating we know that fairly accurately it's about 3.4 billion years old what this is saying is that 3.4 billion years ago right there was plenty of life on Earth so since the earth is only four and a half billion years old that what this is saying is that life got started very quickly on earth and that suggests doesn't prove it's only an example of one but it does suggest that life wasn't a very difficult experiment certainly not an improbable experiment because it got started very quickly okay so how are we looking for not just life but the kind of life that could hold up its side of the conversation namely intelligent life well I think many of you heard Jill charters speak here recently talking about the Allen telescope array which is a joint project of the SETI Institute at the University of California at Berkeley to build our own telescope to do this sort of search and for the Berkeley people also to do some top-notch radio astronomy by the way there's a dime in this photo for a scale but you don't see you see me going around flashing the antennas this thing is located about 300 miles from where you're sitting up in the Cascade mountains of northeastern California and it's located there by the way not because of the cuisine but because it's it's surrounded by mountains and therefore shielded from all the you know interference from the Bay Area in any case it's named after Paul Allen who's given the money to get this thing under way and it's as I say an instrument that's really designed from the get-go to be very good for SETI research this is a big step forward by the way because people will often say you know SETI is celebrating its fiftieth year this year in fact in April you haven't found anything don't you doesn't that embarrass you or you know don't you get discouraged or something like that keep in mind we've had to do these experiments intermittently using other people's antennas so you know it's like trying to find the cure for cancer but always having to borrow the microscope it's very slow going that this will have an in-house microscope telescope we can use it 24/7 that that's a factor of 10 improvement in speed right there covers a very much wider range of frequencies these are all technical things there will be a few technical things in this talk not too many I'm told that every time you show a graph this was a lessons I learned in grad school every time you show a plot you learn lose 10% of the audience so I have 12 plots in this talk put them all at the beginning so that you don't have to suffer long and it can also this is a really an important point this has to do with the nature of the antenna arrays it can look at the more than one star at a time so you're not just looking at one star and then looking at another star looking at another star when I say looking at a star of course I mean we assume that they have planets around them this is an aerial shot of made about a year ago they're currently 42 antennas in this array but the design goal is to make 350 of them but it's not the only way we do SETI we also do optical SETI so called optical SETI and this is a photo up at the Lick Observatory this is a telescope that's about a meter in diameter so it's you know small telescope an old telescope but perfectly adequate for aiming at nearby stars using some electronics in this white box behind that by the way was put together by Shelly right here it was a student at the time an undergraduate student at UC Santa Cruz and and look for very brief flashes of light right if you get a brief flash of light in a nanosecond in a billionth of a second and maybe you count you know 100 photons or a thousand photons that's got to be something special because the Stars don't do that right a star 100 light years away like the Sun would never would produce less than one photon in a nanosecond for a one meter telescope so this is another way to look for life in space they may be flashing us with their lasers we do we have these dual approaches now this whole field was begun as I mentioned 50 years ago by Frank Drake here's Frank he always put on a tie and a jacket when standing out in the cold air West Virginia this is the 85 foot antenna that he used in the spring of 1960 pointing it at two nearby stars hoping to eavesdrop on signals coming from those stars this was project Ozma and he started what is known as today's targeted search strategy because he didn't point the antenna at random he picked two nearby stars they were about to 11 or 12 light-years away they were stars like the Sun and he looked first one and then the other he actually scored on the second one he got a signal but it turned out to be the US Air Force so that didn't count as alien intelligence there you go okay now I want to emphasis this was the strategy that was chosen then and this is the strategy we still use a lot today the SETI Institute is very keen on targeted searches and the Allen telescope array is planned to also look at individual stars okay and the idea is that you look at the nearest ones first then you work your way up but I'm going to suggest tonight some alternatives to that now that this plot which was made up for a magazine article just gives you some idea of how much search space we've looked at right I mean you're looking for et you haven't found it well this tells you why these are all the you know just a couple of the parameters of the signal right they've just been plotted as three axes here you can see various experiments actually this Allen telescope array is you know for the future we haven't actually filled that in yet so you can see that very little of the search space has actually been examined right and so when people come up they say you know you haven't found anything you guys ought to give it up and I get emails like that every day I respond to them that this is completely analogous to going to Africa in search of megafauna right landing your ship on the shore and examining one in one city block of Africa and then saying well that's it no hippos no elephants here you know I think I'll go home there's no mega fauna there are no megafauna in in Africa and that would be early days that would be premature the same with SETI okay now the Allen telescope array has a design goal of not 42 antennas which is what it has now but 350 ok now building the rest is pretty straightforward we know how to do that now what's missing here is the check so if one of you want to buy an antenna you can buy an individual antenna I recommend you buy the whole array it's per antenna less expensive for you and so that's the deal here this is the possible result of that okay what's flawed here this is one of those twelve thoughts it's what's plotted here yeah I just did a little bit of geometry here and then an extrapolation of what this instrument will do in the future because we know what the technology will do you're all well aware of Moore's law you live in the Silicon Valley you know that the price of computers drops by a factor of two at any given performance level every 18 months so the same is true for SETI said he's mostly digital electronics it gets faster all the time doubling in speed on average ever since Frank Drake's original experiment every 18 months so what I got plotted here is how far out into space a say how far out have we examined all the interesting star systems okay so you know here 100 light-years out and then you know a few years later we're 200 light-years and so forth what's really interesting here are these numbers these are what are called estimates which is a euphemism for guesses as to how many societies are out there broadcasting a signal we could pick up Carl Sagan figure there might be a million if he's right then we should trip across CT before 2015 Isaac Asimov figured 670,000 and it takes till 20 to 22 or something Frank Drake himself typically says 10,000 okay now I've asked Frank many times I don't know Frank's in the audience he may be here you can ask him why he came out or how he came up with this number and that's some sort of secret sauce but in case it's the most conservative number and even if you take the most conservative number then it's still the case that this experiment is going to pay off in two dozen years okay all right now you might say yeah but you know these are all guesses they're all guesses and they are they are guesses but on the other hand these are guesses by people like Carl Sagan Frank Drake and so forth these are the people that motivated this whole search so if you feel sufficiently impressed with the arguments that have been made for doing this then the result of that is that you should expect success fairly quickly right this is not like building Salisbury Cathedral and in England which took you know what I don't know how many centuries it took to build that pile of stones there okay where you say well my great-grandkids we'll do it you know either it's going to work within a generation or there's something fundamentally wrong with the premises now I think we might even be able to speed things up but in order to do that you have to know this number here typical sensitivity for SETI these are the best numbers but these are the sorts of things you can get down at Arecibo and maybe eventually with the Allen telescope array when you get it built out is 10 to the minus 25 watts per meter squared okay that's that's the weakest sort of signal you could find coming in on a 1 Hertz channel and so forth now you know what is that well I mean it's just a number but let me give you another example if you taken one of those Allen telescope array antennas and you aim it at this guy and you're collecting a signal that's at that level and you've been doing that ever since the dinosaurs were snuffed in other words for 65 million years after 65 million years of collecting that when one of our antennas the total amount of energy will have collected is the amount of one amp raising one leg once ok so it's not a lot I mean that would suggest to you that that should impress you in something very little of this talk will impress you but that should impress you because that shows you how good radio technology is if I'm very very weak signals okay and it sounds like we should be able to find really pipsqueak transmitters out there but of course space is vast alright and the consequence of that is that the signals of course are attenuated by distance so here's a computation this is another number you could if you don't like this number you can try this number here on the bottom at your next cocktail party let's assume that the aliens were aiming an antenna our way trying to get in touch because they want to sell used cars or whatever there are thousand light-years away that's pretty far that's far than we generally look but let's say a thousand light years away they've got an antenna as big as the one down in Puerto Rico at Arecibo which is a thousand feet across right hold four billion scoops of baskin-robbins right they've got that aimed at us and we're looking at them with a similarly sized antenna what would it take for them to get in touch with us at a thousand light-years they need a six mega watt transmitter six million watts that's not much I mean the Arecibo antenna has a radar on and I think it's it's either one or two megawatts I think maybe two megawatts these days used to be won in other words it's very close to that number in other words what I'm telling you is that even the kind of technology we have you could establish this communication link even over a thousand light-years distance okay however there is there's an insect here in the ointment because I've assumed that they have an antenna aimed at us and they're just you know transmitting away now why would they be doing that and they have to be doing it for a long time because remember when we go down we look at some star system you know we might look at some star system over here three years now and we'll spend you know like three minutes looking at it at a given frequency like three minutes the aliens get three minutes to get in touch from that star system so in order to have any chance that we're going to hear them they've got to be beaming there's signal at us for a long time typically thousands of years this is the Drake Equation but but that's what they have to be doing so here's an alien I was pointed out to me that his hands are not great but any kid is an alien so you have to ask you know are they going to do that are they going to beam a very powerful signal at us for thousands of years because that's an assumption in what we do now right there it seems to me that it is and I'm somewhat doubtful that they would be willing to do that because they don't know we're here alright now here's a I Love Lucy of course which I think was first broadcast 1953 I think is 53 so that's what that's 57 light years out those early episodes okay so you can work this out that the you know I Love Lucy is washing over another star system at the rate of about one a day which you think would make the advertisers happy but you know they might not like Fred Mertz as jokes or something okay but that's still it's only you know 50 some light years out and we haven't been broadcasting too much before that well that means that anybody who's responding to us now can't be more than half that distance because you know you want to see the response and within the distance of the signals that we've been sending out within half that distance there are only a couple of thousand stars don'ti couple of thousands that know we're here I think you can safely tell your neighbors that nobody knows homosapiens exists except maybe domesticated cats nobody knows that we're here right so when your next-door neighbor you know tells you the stories of how they're being hauled out of their bedrooms at night by little gray guys who are you know doing things that their moms wouldn't approve up you can think insane gee that's remarkable that they've come all the way here to do that because they don't know we exist just unlucky for you okay all right they might say oh yeah but maybe they found some other signal well the facts are our city lights have not reached them either to find our city lights by the way is very hard you might work out how big an antenna or rather a telescope you need to see the lights of Earth from you know a couple hundred light years it's big it's like an antenna about the size of the solar systems are a mirror that's big it's very big a chlorophyll aura fluorocarbons in our atmosphere that would tell them that we have refrigerators that information hasn't reached them smoke smog the co2 in the atmosphere the aliens are always coming here to save us from ourselves why are the aliens here now Bob well because they're unhappy about what we're doing to the environment and and also they're worried about nuclear war well doggone it they don't know about any of that stuff right and so you know if they're here now it's not because they knew about that stuff it's like you know you're going to save the hippos without knowing about the hippos okay so you know it doesn't make too much sense to me that they're going to be relentlessly targeting of targeting us with a very big antenna with a lot of power but you could say yeah that's okay maybe they're really broadcasting making maybe they're brought in you know transmitting a signal that just goes to everyone like kgo right maybe they're doing that so they got it maybe they have a big transmitter down in the center of the galaxy because after all it's you know that's the place to go and it's just belching out you know used car ads as I suggested maybe you know join our book club whatever it is okay and we'll pick that up well that that that's maybe not a bad idea we should look at the galactic center that's the one special place in the whole galaxy after all the one very special place I always think of you know in Captain Kirk is beaming down some guys down to some godforsaken planet you know beam them down I'll see you down there what do you mean you'll see me down there you know I don't have a map of the place they can always beam to the north of South Pole everybody knows find those in the galaxy there's only one unique place of course and that's the center so maybe they're broadcasting everywhere all we have to do is look at the center of the galaxy and so say good idea however you work out the numbers in order to produce a signal that we could detect with our present SETI experiments looking at the galactic center would require that their transmitter have a power of 5 times 10 to the 17 watts that's a 5 followed by a you know 1700 that that's the big number in fact that's more than all the sunlight following on the earth and indeed to put that in perspective if you work that out in kilowatt hours right that's 10 to the 18th kilowatt hours I sort worked out and you pay here to PG&E for a kilowatt hour you pay about 10 cents and they're trying to give you the cheapest electricity they can they do it by doing things like burning coal and then you know natural gas is over they try and make it as inexpensively as they can so at 10 cents a kilowatt hour this transmitter to produce a signal that we could find here two thirds of the way out in the galaxy would cost 1 million billion dollars a year ok now I never begrudge the aliens you know money or energy you things like that but that sounds like a lot to me 1 billion billion dollars a year sounds improbable ok so the idea of a galactic beacon saying join our book club or whatever centered at the you know the middle of the Milky Way you could do it but it's extraordinarily energy expensive ok so summarizing this little argument so far I don't think they're going to be targeting earth relentlessly with a signal because they just don't know we're here ok and on the other hand while they may be broadcasting to the entire Milky Way maybe there's a galactic GPS system right or something like that maybe the weather report for the Milky Way right it's being broadcast the facts are that to do it at a level that we could detect is very expensive so where are we what how we deal with is well we could I say be smarter I'm not sure that it's smart but we we could think of some other ideas one way to do that is to simply say look it's not going to be that strong a signal right because the 10 to the minus 25 watts per meter square which is the number I gave you at the beginning that's how sensitive our experiments are that's what we can do a hundred years after Marconi we just invented radio right now the aliens you know they may assume that the invention of radio is as far in our past as you know the invention of the wheel and you know you probably don't remember who invented the wheel his name was Rodney by the way but you know you don't remember much about that story and yet use the wheel every day and they may you know if they're ten thousand years ahead of us they're not going to assume that our radio technology is that the level that it is we will clearly have done much better and consequently their transmitters will be more attuned to what they think is reasonable at this end and they may consider antennas that are measured in tens hundreds or even thousands of feet as not particularly reasonable well are we going to be able to build a receiving system that can do much better than what we do today well quoting Yogi Berra I think Yogi Berra said it's tough to make predictions especially about the future actually it's also possible that it was niels bohr who said this but niels bohr you'll get there but what's the diff let's see if we could go from weaker signals well this is one way we can go for weaker signals building bigger antennas and of course we're going to do that this is a artist rendition of the Square Kilometre Array which will have ten times the collecting area of the one down on Puerto Rico so that's pretty big and with with the something like that you could obviously push the power requirement at the other end down by a factor of ten so instead of a hundred million billion dollars a year of electricity it's only ten million billion dollars of electricity I don't know that that helps a whole lot but I point out that there's an interesting aspect to this kind of technology regular antennas of the future radio telescopes of the future may not have these you know dishes they may they may not but when you have a dish you know a physical 3d structure like that then the cost of each antenna goes is any dimension cubed obviously okay but if you have flat antennas and it may be possible to do these all is some sort of substrate and you just have a whole bunch of dipoles on the ground then then the cost per element only goes up is the square of any given dimension and that might be a real win there but in any case here's sort of the bottom line on all this stuff what I've done here is I've just taken a bunch of my favorite radio telescopes and plotted them on this plot as to how how much collecting area they have and so this was you know one of the first ones built by an amateur rotary burr and in Wheaton Illinois back in the 1930s and there's the Square Kilometre Array you know that date is more or less there but you can shake that that thing around and you can see some other telescopes in there now the point is they're getting bigger at least on average they get bigger the bigger biggest ones get bigger and this is a least-squares fit plot there and you may or may not believe it but what it shows is that over the course of 100 years the antennas have gotten about a hundred times bigger okay so you know every every hundred years every century you get two orders of magnitude improvement now you may not believe that but that seems to be the case I'll give you an optical example on Mauna Kea in Hawaii now a Caltech and others are building the thirty meter telescope okay it's they haven't actually broken ground honor maybe they have but you know most of the ground is still there thirty meters across a mere 30 meters across for comparison 400 years ago Galileo built the telescope with a three centimeter aperture in fact was probably smaller than that because in the old days they would stop the lens down yeah in other words that's a factor of a million improvement in size in 400 years right so that's six orders of magnitude in 400 years that's not too much different than two orders of magnitude in a century or so you know so you get orders of magnitude improvement over the course of a few centuries right so that suggests that when we get a little bit farther down the line here we could build an antenna that was big enough to find the kinds of signals it would be pretty cheap to broadcast to the entire galaxy okay this this is an example with the the Square Kilometre Array but you could get down to this sort of sensitivity and that means that the aliens would be able to broadcast a signal we could pick up with only 10 to the 13 watts and 10 to the 13 watts is still a lot that's 10 trillion watts but actually humanity consumes somewhat more than that already so you know it's now getting to a level where you think you know really advanced society might be able to afford something like that so that's one way to do it we just sit around for a couple of hundred years and then do the experiment again needless to say this isn't very interesting okay but the other possibility is to do what's actually proposed here and that is to take an antenna bigger the better and just aim it all the time at the galactic center for example for a year just beat down the noise you would gain a couple orders of magnitude over current limits if you did that and maybe that's enough to give you success and maybe not but it strikes me as something that's worth trying in other words a very highly sensitive search of at least one spot on the sky and that spot on the sky I would think would be the galactic center by the way this harkens back to the idea of Barney Oliver known to many of you in the audience he was the R&D director at Hewlett Packard for its first 20-some years Bonnie Oliver was in the 1970s proposing that we ought to build a huge array of antennas to try and find et but you know unfortunately yeah these artist impressions that sort of scared everybody off because that looked expensive okay and I'm sure well in fact it was expensive they were you know these billions of dollars but I mean that was sort of a misconstrued what his idea there was his idea was look you build one antenna and you do the experiment and if it doesn't work you build four or and then you build maybe 16 and so forth that you just keep building it until it works and that way you never build more than you need okay which I thought was a clever approach hasn't been done okay here's another way we might approach study this is just you know to get your creative juices going special cases something like special cases this is an idea that goes back a ways primarily espoused by Jeremy Lamar Sean who is Argentinian astronomer and physicist and here's the way it goes it turns out that although he wrote a lot of papers about this turns out that 20 years earlier the Russians had already thought of it but actually when you look into any idea and said he it turns out that the Russians had always thought of it earlier and you know they the interesting thing about that is that it's usually true too by the way they really did they're very clever I see the Russians didn't have a whole lot of money for equipment so they would sit around with pencils and papers and they were very smart still are actually okay so the deals suppose some supernova goes off you know in our galaxy nearby galaxy BAM big explosion well the astronomers here some alien planet there right - the astronomers on that alien plant they wake up they go WOW supernova and you know that means we can get to maybe you know some PhD theses for the grad students here whatever maybe I can get tenure if I write something up so they all the telescopes on that world are aimed at that supernova for a couple of days a couple of weeks they study the heck out of it but one guy you know is clever enough to say wait a minute wait a minute and he waits half a day and he just sends a signal out in the direction opposite to the supernovae okay now here we are on earth and at some point and you know who knows what that that signal is you know hi we're the Klingons and we'd like to meet you okay so here's earth and at some point you know the supernova lights up for us heywho supernova so every antenna every telescope in the world is aimed at that supernova and you know 12 hours 15 hours 20 hours whatever 1/2 day is for the aliens later after we start studying we get this message it says hi we're the Klingons you want to come to our parties ok so this this is pretty nifty because it tells you that tells you when to look and where you don't don't you know just have a long long list of star systems to look at you just look at a supernova whenever it goes off it trouble is that person aren't that many supernova going off in our galaxy in another galaxy it's a little unclear whether it's big enough to get anybody interested but this is a clever idea it's very clever idea here's another idea I floated this idea years ago at a conference in Italy where it got essentially no notice and since then it's been ignored but here it is it turns out that on the basis of theoretical calculations you could have planets around double stars now about half of all stars 60% I think it's an actual better number are multiple stars stars you know like to have buddies and they have many of them do okay and you can have planets around these buddies if either they're very close together so the plants go around both it was or they're separated by not very much maybe the distance from from where you are just Saturn which isn't a whole lot and you could have plants around both of those things okay in fact we found planets around double stars that that has happen okay but well if you can imagine some society growing up in a system like this and maybe you grew up on a planet around this lower star you would as soon as you invented rockets and radio all of which are sort of contemporaneous right you invent radio and then within 50 years you invent Rockets then you invent the h-bomb all these things happen at the same point so just when you go on the air you blow yourself up okay so that's a different story okay so you're on a planet around this guy and very quickly you colonize some of the planets assuming there are any are just build satellites around that star because a second star could be useful for you get some energy out of that who knows just study it right and that means now you've in some sense your society extends over both stars and they will communicate right they'll be communication back and forth between these two star systems now imagine the situation and this obtains for one in a couple of hundred of such stellar pairs that they're seen kind of edgy on and they become what are called eclipsing binaries you can see the the animation of an eclipsing binary over there and here are actual observations of an eclipsing binary where you see this star you know get brighter and dimmer because you know the big star which is kind of dim gets in front of the small star which was kind of bright a small star as a white dwarf in this case doesn't matter then you can see the light curve here okay so these are called eclipsing binaries you don't actually see the stars going around one another but you know when one gets in front of the other because suddenly the light goes away okay well all you have to do is say when that happens you're looking right down the communication pipeline between these double star systems so again this tells you when to look and where to look this hasn't been done but you know I think maybe something worth worth considering here's another idea this has also been proposed it was a big fight about whether we thought of it first or some guys at NASA thought of it first and it turns out that the Russians had proposed it 20 years earlier but the problem is that nobody reads the Russian literature by I suppose except the Russians but this is a piece of art by Lynette cook here in the Bay Area showing a planet transiting a star we know about many of these now but imagine for a moment that this is the earth going in front of the Sun so you know this is what Kepler is looking for of course transiting planets but imagine that the aliens had their own Kepler project years ago and and they found the earth that way I think just happened to be in the right parts of the the universe that they would see the earth cross in front of the Sun so they know that there's earth there and you know maybe they say well it's kind of a rocky world and we can measure a little bit of oxygen in the atmosphere so maybe has some life why don't we occasionally give them up paying and see if they'll join our club okay so maybe what they'll do is they'll say look we have to figure out when to broadcast soon we don't know that there's any intelligent life there but we'll broadcast to them sometime during the transit which takes a couple of hours in an entire year the earth takes a year to go around the Sun and for a couple of hours it'll block the Sun from their point of view okay so all we have to do then to get in touch with the aliens is examine the ecliptic we just look at the path of the Sun through the sky we move the antenna one degree every day all right so there goes the Sun around the ecliptic we're looking in the aunty sun direction of course right and expect their signal to come in you know wherever they are when when we're translating the Sun they will time their signal to get to us when we transit the Sun as seen from their star now that requires that they know the distance from where they are to the Sun fairly accurately but not in a you know unconscionable accuracy it's a kind of accuracy we might have in a hundred years so again tells you where to look they know we know where to transmit you can't read this if they target the Sun by the way if they're good enough if they have big enough arrays that they can do that doesn't cost much in the way of power here the alien transmitters over there and their beam whether it's a light beam or a radio beam just covers the Sun they know we're somewhere in that disk then you know they can send us 100 bits per second with only the power of an automobile headlamp ok so that's that's pretty cheap ok we don't do this either but seems like an easy thing to do because all you need is an antenna about 25 meters across you know an 85-foot antenna or something like that and you just look at the anti Sun Direction all year long trivial there plenty of 25 meter antennas around ok you could look in the infrared we don't do this either but this is a matter of economics and the reason to look in the infrared I pointed out Shelley right here looking for flashing lights in the sky but those photomultiplier tubes that are doing this they're just sensitive the kind of light that your eyeball is sensitive to ordinary light the light the few photons in this room here ok but ordinary light it's great for a lot of things but it's not maybe so good for signaling over long distances in the galaxy these are the picture of the Milky Way at night here and a little bit of earthly topography but you see all these dark clouds there's all this dust in the Milky Way in the plane of the Milky Way and what this does is it makes it very hard just signal over distances greater than on the order of a thousand light years depends on where you are which direction but on that order if you're trying to signal farther than that with ordinary light it isn't going to get through it's going to get blocked by all that dust ok so but not in the infrared infrared goes right through the dust ok so doggone it all we need to do is have a SETI optical SETI experiment in the infrared and let's look for things the problem of that is the infrared doesn't penetrate the atmosphere so in order to do this you have to move the experiment into space or maybe the backside of the moon or wherever and that that that's too expensive at the moment but it's a very obvious thing to do ok here's another idea SETI is you know sunny experiments we're looking for a signal in space but we only look at one little tiny patch at a time it's kind of you know like looking for we're looking for comets now you don't use the world's biggest telescopes to look for comets because they're looking a little tiny patch of the Keck telescope we'll never find a comet comets are found by amateurs mostly in Japan it seems with binoculars they get up very early of you know where to look okay because you need to scan a big part of the sky well maybe there all sorts of big signals coming from et you know just a pain once every year in that direction big blast of radio waves and we never see it because we're not looking in the right spot at the right time I mean that could be if they just once a year made a big ping in any spot on the sky you would say I don't know what it is Bob but there's something very weird in that direction and you would spend whatever money you had to examine that spot on the sky and then you might find a very low powered transmitter that was you know giving you their version of their encyclopedias or their internet or whatever it is okay but we have no way of finding something that's going off you know intermittently in some part of the sky because we don't cover enough of the sky at once well here's one way you could do that you can use the moon as a garden ball you know those silver garden balls you put them putting them back I don't know how many of you have those anymore if you had the storks in the front yard probably under those either okay ladies guard Bowl these silver garden balls in the D list if you look at this thing you see the whole sky right you see your neighbor's house and all as you see everything it's a really really fishy fish eye lens okay well the moon works that way with radio waves so the radio is coming in from at least half the universe they bounce off this thing and of course unfortunately they get scattered in all directions but something gets scattered back toward your telescope so by looking at the moon you're looking at at least half the universe okay now because of these geometric effects of course your sensitivities down by a small factor fifty thousand a hundred thousand but you know what are what are 5 orders of magnitude when you're talking about aliens because if it was a really honking signal one that you know with just about fry your toast then this is work and again the size the antenna you need for this is again on the order of 25 meters at least that the kind of frequencies that said he usually uses so you could just cover the whole moon with this thing and just follow the movie in fact you want two of them like the moon tends to set so you have one on one side of the earth the other on the other side of the earth and you just just look at it all the time look at all the time just in case listen good okay here's another scheme this is a spectrum of the earth as seen from space now you notice a couple of things in the spectrum this is just a distribution - like this kind of a rainbow of the earth and you see as ox better known as ozone here at carbon dioxide things like that these are indications of life not so much the carbon dioxide but the oxygen is right the oxygen in the atmosphere here does extent there is any after you've been in here for a while the oxygen in here is due to plants you know that right mostly you know bacteria blue blue green algea they're as they're called there's also methane in the atmosphere here which you could detect in space and the bethe ain is due to what's politely called bovine flatulence here on earth also porcine flatulence so this is a way to find pigs in space if you find methane in somebody's atmosphere right okay so this is another way to be smarter in this sense they may have done this experiment we haven't done this experiment with other other planets really to speak of but they may have the instruments that we'll have in 20 30 40 years to be able to get really good spectral information coming from planets around other stars and the point is this signal from Earth about the plants has been going out into space for two billion years right that's when the oxygen began to build up on Earth's atmosphere that's the best number okay so for two billion years we've been broadcasting to space not I Love Lucy that's only been in the last 50 years but for two billion years we've been broadcasting hey earth has plants I guess the fact that the aliens aren't here says there aren't too many alien vegetarians maybe that's just cursing me out but okay alright so they know about our plants now knowing about our plants you know might be interesting for the botanist among the aliens but it doesn't mean that they would send any signals our way because after all you know you could have aimed signals at at Earth 300 million years ago we had a lot of plants there was plenty of oxygen the atmosphere but there was nobody to pick up I mean the trilobite were not big in radio technology or if they were you know they hid all the information so you you could you just because you find that a world has life doesn't mean that it has intelligent life we've had you know close to four billion years of life on this planet right and only in the last hundred years has it been technological so just because you find a lot of worlds that have oxygen in their atmosphere or whatever you consider the spectral signatures of life doesn't mean ah now we know where ET is no now you know where maybe trilobite SAR bivalves or in any case you know ferns ok but this may suggest a strategy for them because they may have done that they may have done this experiment so thoroughly that they have hundreds of thousands of so-called bio worlds right they've got a long list of these things and we're on it we're on this list of worlds known to have biology or at least plants okay which consider biology right okay and maybe those lists are very long being optimistic here that this is that that life is not a miracle of some sort or you know very very exceptional then there will be large numbers of worlds that have biology and they may have long lists of these and then we say well we don't know which of these have intelligent life but these are these worlds with life well so why don't we try and get in touch with them but we can't spend a lot of time on each one because each one has a pretty low probability of having in life so maybe they just ping them sequentially here's an example a real number of numerical example suppose ET pings a billion targets they found a billion of these that's a big number over and over and over again you know every three days or whatever it is they just go through the whole list again they send each of them just a one nanosecond ping is do this with light say all right thousand photons per second so the are per meter squared that would be an easily detectable signal even for our experiments today so every couple of days they do this if they have a that kind of duty cycle then the repeater intervals three hours so every three hours you would get a ping from these guys every three hours big pain okay and again that would tell you well there's not much information in the ping but there is this information in paying it gives you a spot on the sky you know they're there there's something funny there and then you would again you know you put all your grad students on it okay now to do this this is requires a five gigawatt laser which is pretty powerful but again that's something we can build so this isn't so so much of a demand on the hayleen so what this suggests to me is that maybe if he tees really trying to get in touch aiming big antennas at the earth all the time this doesn't seem to me as reasonable as maybe a two-tier transmitting strategy where they just first I get your attention with a pain right and they just that just means you're on a list okay and then they have a low-power always-on transmitter that has all the information that's just always on regurgitating the information over and over again remember feeties hundreds of light-years away 500 thousand light-years away we're not going to get in conversation I mean it's going to be very tedious right you finally hear from these guys these Center was my high where the Earthlings we'd like to you know know what you look like and whether you have rock and roll okay and you send that it takes 500 years to get there and if they gain to replied it's another 500 years so the response and then they come back and say you know please repeat that or whatever so so that's that's tedious right it's going to be one way communication essentially one-way communication and I am fond of pointing out that I took a Latin in high school and we had one-way communication with Julius Caesar he was talking to us and not the reverse well the kid next to me was talking to him but Julius was not listening to him so it's one-way communication but it's still interesting because after all Julius had something interesting to say so the aliens may have something interesting to say but the point is that they did you know that's the low level transmitter because it's cheap for them but now they got your attention with the ping so they don't have to spend a lot of money on the low level transmitter so here's the logic I haven't talked too much about this but as technology improves on our planet we're not belching big signals into space anymore right Sutro Tower is doomed you're going to get your television in your internet via a fiber optic or some other way and the aliens are already there so I don't think we're going to pick up the accidental radiation that comes off their planet could be but you know it doesn't seem so likely so I think we should expect some sort of deliberate broadcast deliberate transmissions but there don't know we're here they don't know Homo sapiens is here but they do know there's life on this planet so we're just in a list and the list has to be long to be interesting because the chances at any given planet with life also has intelligent technologically competent life isn't so good so they'll do these intermittent and short pings so I think that you know we should at least consider some aspect of our SETI strategy where we look for very short pulses right either in the optical or in the radio with reasonable repetition rates okay they may not send us a signal that's always on let me just sort of conclude this going into something that I think may be relevant I often talk about this a tile is beyond the greys this is sort of the impression we have of what the aliens will be like of course these little gray guys who obviously have no sense of humor and not much dentition who sit around and as I point out all the time these are merely projections of our future this is what we're going to become because you know we're losing our hair but these guys are gone way beyond that we're losing our olfactory sense so their noses are pretty small too and but the only thing that's gotten bigger are their eyes because in the future your job description will be design websites so is this is this your descendants right yeah that's yeah this is the way I think many of my colleagues think many people in in science in general if you asking what are the aliens like they start give me a laundry list of things about us really you know carbon-based life points carve dates life forms captain and you know that makes sense carbon carbon works better than anything else but you know homo chirality they got either left-handed or right-handed molecules plate tectonics big moons big planet around to chase away actually bigger than rats more than ten elephants they have to have something to pick up a soldering iron otherwise you don't hear for them a lot of people tell me you know that dolphins are really smart well they may be but they're not building radio receivers or transmitters and I figure the reason is if you try and hold a soldering iron in your beak and use it underwater it doesn't work okay stereovision think that okay that's that's what that's this is the assumption about what et is going to be like and then it arguments are well they have four appendages or six or you know their brain be up here down there whatever that kinda stuff but of course I think this all misses the point and the point is given by this plot here my favorite plot by Hans Maravich at Carnegie Mellon institutes ten years old now so we ought to fill in some data up here but anyhow it just shows the amount of compute power you can buy per thousand dollars ever since 1900 okay it's going up and those of you who are still conscious may notice that this is a semi-log plot which is to say it's going up exponentially did a highly overused word exponentially you hear it every morning on the news in exponentially but I'm sure the newscasters have no idea what it means but any up this really is exponentially so you can feel confident that you won't be exposed yeah the point is that by 1997 then $4,000 you buy the compute power of a spider not so interesting unless you're in Iraq no file today you know filing the curve up here you buy $4,000 the compute power of a lizard which might be interesting if you're trying to sell car insurance okay so but the but the real point the real point is that by twenty by twenty it's bad when I find my own jokes funny and I just have fortunately almost never happens yeah by 2020 right by 2020 your laptop has the compute power of you right now this is being pointed out by lots of people now okay and there's very little doubt about this unless you know there's some sort of nuclear implosion or something like that this is going to happen and the usual question is so what happens then to us and your mind yeah that is some student at you receive Washington said they'll kill us all right and that's I explained that as a natural optimism of youth I I said today I said that the student you know look I have some goldfish at home and I'm smarter they are but I don't wake up in the morning saying gotta kill those guys cuz it never occurs to me my personal plan is when this happens I'm just turning the keyboard around you know you type whatever okay now video so that doesn't mean that they're as smart as we are of course all it means is that they can do as many you know computations for a second we have big massively parallel variants but in the end you know the software may catch up and maybe they really will be intelligent I mean the Silicon Valley is the home of John McCarthy's here in the Silicon Valley the home of artificial intelligence and the artificial intelligence community bloats their hearts have been saying for 30 years we're going to have a thinking machine within ten years okay and of course they're well aware that there's some disconnect here but but they will tell you don't confuse lack of success with lack of progress there is progress so I have no doubt that it'll happen a lot of people do have doubts it's saying you're never going to build a machine I can teach high school chemistry and deal with the students too right they'll say that but that's that's assuming there's something miraculous going on between your ears I don't know about yours but I know there's nothing miraculous going on here but if you ask people could you make an artificial heart you bet could you make an artificial kidney they got them artificial liver I'm yeah that sounds right artificial pancreas don't know but maybe you could do it but somehow when you say though what about that organ between your ears well that sacred man can't do that right Philip Morrison who was important in the first stage of SETI of course described the human brain as a slow-speed computer operating in salt water which I think kind of gives you a better perspective anyhow ok so if you can do this and the point is once you do it maybe you don't do it by 2040 or 2050 maybe it takes to 2100 so what doesn't matter 20200 still doesn't matter as soon as you've done that within 3040 years that single machine now is better than all humankind put together now my point here is not to you know concern you that you may be the last generation of hominids to run the planet which I know many of you will take as an incentive to adopt a hedonistic lifestyle I think many of you've already done that let me make that point I like this guy made this graphic up from a bunch of stuff I found the web but I I think that it's sort of instructive again to understand that this is a time scale argument right here's a horse sixty million years ago right when they were about the size of a collie dog here's a horse today they can find in for example Portola Valley and it's about the size of a horse okay now that's 60 million years okay now on the other side you have personal computer I had a personal computer in 1977 and it had a 1 megahertz clock rate and I think in an 8-bit bus I was 8080 so 8-bit bus my computer home now has a 2 gigahertz clock rate and I think it's 32 pip bus so that's a what is it that's a that 4,000 times no eight thousand times better eight thousand times faster so eight thousand times faster in 30 years on this side collie dog to horse and sixty million years you get the point Darwin is not only unpredictable but it's really slow it's slow it can make something change this quickly if you're a fruit fly but if you're talking about intelligence right our IQs may not really be any different than they were in the Roman Empire let alone maybe not even in the days of you know when we still share the planet with Neanderthals so that that's slow this is fast so once you develop this in artificial intelligence assuming you do it then it quickly swamps Darwinian evolution okay so here's the argument no people say you know what that's okay we're going to put chips in our brains of course we're going to do that I have friends that already have chips in their brains here's we're going to become like the board we're going to be half human and half machine right we're going to prove on this silly molecule over here that this you know that that we're sort of it going to keep up with the machines because we're going to make you know it take advantage of machinery ourselves well undoubtedly we will do this I don't doubt that we'll do this and this will be very interesting for you personally but to me this is like putting a four-cylinder engine you know into a greyhound you get a faster dog but in the end you say let's get rid of the four-cylinder engine and just I would rather get rid of the dog part and just you know build a Maserati or whatever okay so although I think that this will happen it's just transitory and can't possibly keep up with the machines okay so here's the timeline argument somebody made this plot here's Homo erectus did this these back and forth curves are because they didn't want to draw one long line but they just sort of some sort of timescale indication how long we spent you know sort of ambling through the forest on two legs eating you know whatever we found and not leaving a whole lot of great literature and then you know then at some point you get Homo sapiens whose brain is now three pounds doing a little bit better there a little dot up there that's all the time since the invention of the steam engine the thing is things happen very fast at the end here so here's the point you invent radio so that you go on the air right within a century two centuries maybe three probably more like two you invent your successor so the time in which the aliens spend as little soft squishy gray guys is very short and consequently if we find them we're much more likely to find and those gray guys right are some sort of machinery I mean think you can forget this guy although I like him because he had the same plastic surgeon as Michael Jackson there on this note this is this was from the film that I actually enjoyed the arrival it had the bad form to come out you know two weeks before Independence Day so nobody went to see if it was actually pretty clever and yeah very anthropomorphic alien it this is great Hollywood loves anthropomorphic aliens but it I just don't think you should take that terribly seriously now what are the machines going to do because maybe it comes down to this how can we second-guess the machines where are they hanging out what are they doing how can we find them because our SETI experiments might have more luck looking for the long-lived kind of intelligence and not the transitory intelligence that is biological well Ray Kurzweil was at the SETI Institute a couple of months ago and he said they're all going to be there they're going to build nanobots and the nanobots are going to you know swarm through space well there's a problem with that as far as I can tell they haven't been done I have been doing that I mean maybe they have maybe that's why space is so empty the nanobots have eaten it all but you know really this doesn't make sense to me if you want to maximize intelligence you really want to keep things compact otherwise you have time-of-flight problems you know you it takes too long for information to get back and forth this also leads to grey goo maybe the aliens are turning everything into grey goo somewhere but this is much more likely that you just have very compact very compute-intensive entities right that are sitting around and I don't know what they do I mean people will ask so what are these guys interested in I really haven't any idea we may be there sitting around playing freecell all the time it's hard to say you would think that they would have some curiosity about the universe and you would think that they would ultimately be concerned about the fact that the universe will run down that's a problem that they will have to but that problems far into the future I think it's rather hard to speculate on what their sociology will be despite the fact that I get emails and phone calls every day with people telling me about why the aliens are here abducting their neighbors this is all alien sociology and for alien sociology the dataset is sparse so if it's sparse for the little gray guys you can imagine it's sparse for things that are completely different than we are one of the gentlemen in the audience in fact pointed out to me Marc pointed out to me that I ought to read a book by Stanislav slam a short story called the golem 14 which they invent a thinking machine which I did by the way I did they greeted thanks to Marc and their the machine you know he sort of interacts with the humans for a while and helps him solve some problems here and there but then he gets really bored with the whole thing or who knows what happens but he just shuts himself off it's sort of like you know you get tired of the goldfish after a while and you walk away okay so maybe that's what happens but anyhow if you want to answer this question you got to say is there anything you can say it all or is there nothing you can say it's entirely speculative all of this entirely speculum and there are if I ask you what's really important in life right the young people here will all say sex and money but in fact it's really matter in energy which on earth we turn into sex and money but it's matter and energy okay because it they presumably will need both right okay if they want to keep up whoo all right so let's consider where there's a lot of matter and energy well one place I've already mentioned this is the galactic center seen in infrared there it is down in there we've already talked about that the other places where you find a lot of matter and energy or where new stars are being born you get these hot stars like Oh stars no fewer than 1% of all stars are Oh stars but Oh stars are very much hotter than the Sun they can put out a hundred to fifty thousand times as much energy as the Sun so if you're gusts of driving free living lifestyle requires a lot of energy you want to hang out near one of these bright stars now mind you they burn out in 10 20 50 million years but maybe that's good enough to have fun okay Molecular clouds they have hot stars and lots of material okay here's one Taurus molecular clouds here's another one the Orion cloud which you can see tonight the pair of binoculars if it hasn't clouded over again and they're you know they're not some material in here radio observances shown that the things that have you know like a few percent or ten percent of the mass of the Sun in a fairly small small amount of volume and that's a lot of material you know that's a hundred times all the mass in the solar system so if that's of interest to you if you need if you have built big building projects and you need a lot of energy then these are the kind of places you might go and you might in fact be making your presence known this is again spective why would they broadcast not sure but one thing that they would want to know is who else is out there and unlike you know biological intelligence machine intelligence could actually you know converse with one another in a sense that they might be able to improve one another conceivable black holes Roger Penrose in the UK there's a black hole up there has suggested that you know maybe they hang out around black holes or he didn't really suggest that but maybe we are descendants should hang out around black holes because you get a lot of energy out of a black hole which you can essentially do is by throwing your garbage around the black hole my kind of you can extract the angular momentum energy of the black hole you need spinning black hole okay and by the way the the angular momentum of the Sun I worked it out is like 10 to the 36 joules that's a lot of energy so you know if you have a black hole that's made from a star about the size of the Sun ten to thirty six joules will keep a society like ours going until the last star has burned out right the long long time so you know maybe they gone there I like these guys he's so-called Bok globules because Bart bak famous Dutch astronomer actually found these guys you just start patches of dust and gas they they're typically the nice size to just cover with a radio telescope too and sometimes there's some bright stars in your body but the real point is that these things are really cold a lot of molecules they're 20 to 100 solar masses a lot of material very cold very cold might be interesting if your machine because those of you who've taken thermodynamics know that a machine is much more efficient if it's got a good heatsink if it's in a really cold environment you want the temperature difference between the engine and the environment to be great so these very very cold places which are only a couple of degrees above absolute zero might be the places where some really clever machines are hunkered down well then let me finish off here it's been 50 years since Frank Drake who comes into the Institute every morning writes this equation on the board a little unclear what it means keep meeting gas rank and yeah 50 years we haven't found a signal yet and that may sound like a long time but again the total number of star systems that we've looked at carefully up until now is 750 so even if you think that's the best scheme that's such a paltry sample like such a small sample is a paltry is to denigrate it it's actually a lot of work but a lot of people is an incredible tour de force to do that experiment but it's still a very small sample of the star systems in the galaxy okay we've just begun to fight as it were thanks to new instruments like the Allen telescope array we'll be able to speed up the search and I've already suggested to you that if our assumptions about how many societies are out there are anywhere near correct we may trip across the signal in the next 2,000 years so it's it's the wrong strategy to give up this is not the time to give up this is the time in fact to get optimistic possibility the future I just show you this last plot just in case anybody still has their eyeballs open these these dots show you the speed some metric of the speed of SETI searches since 1960 there's Frank's original experiment there you see the red line is Moore's law and you see the speed follows Moore's law very carefully and with this slide here this is a picture I made in June of 1997 and this is the basement of the SETI Institute when we were in our old quarters this this picture was made at 3:30 in the morning you see Tom Pierson our CEO there Kent colors the blind physicists in the movie contact it's working there at that time and we had found a signal that for a long time 16 hours looked like it had the characteristics that we were looking for very interesting this it really is 3:30 in the morning I was so nervous I couldn't sit down I just have to walk around taking pictures because it gave me something to do nobody went home nobody went to in-n-out burger well there wasn't any in-n-out burger in Mountain View then nobody got you know food we just sat there and watched this signal well that turned out to be a false alarm that was the Soho satellite and was largely due to an instrumentation problem that we had that we even thought it was real but it was an extraordinarily good test run to show what happens when you get a real signal which what happens when you get a real signal is you stay up all night and by morning the media are calling you the New York Times called me in the morning they already knew about it hours into this they already knew about it you needn't worry that all this will be kept from you it won't they'll be writing stories about it long before we've confirmed the signal that's for sure as you'll read about a person the checkout line that's not usual and yes you will this hasn't happened yet but I think it is likely to happen in this next generation I bet everybody a cup of coffee on that and I think that the other thing we might do is although we've been doing Frank's experiment now for 50 years there are other approaches that I hope I've thrown at you some of which I think may appeal to some of you that I think we ought to try thank you very much for your attention yeah my question is so a couple of things you pointed out in the talk were essentially looking at waste products you know I Love Lucy broadcasts oxygen which is really a waste product for plants as you look at ideas about more advanced civilizations computronium idea that kind of thing has anyone ever given any thought to what kinds of waste products a civilization like that might produce and what you might look for to just see if they're leaving a trail of trash behind them right can everybody hear that question I'm not going to repeat it because this PA system here I'm sure desi arnaz would thank you precious little for calling his long-running program a waste product but but you're right I mean in a sense you're looking for the the residue and oxygen by the way is actually useful for us if not so much for the plans but somebody has to answer your question somebody has done that there was an it there was a presentation I heard a couple years ago and unfortunate can't remember the guys name he was an economist and what he did is he said imagine there's a really advanced society and they're you know they're they're kind of aggressive and they just sort of sweep through big sectors of the galaxy and what are they going to leave behind they're going to leave you know if you if you look behind Alexander's army no walk out around Europe and the Middle East and into India there was all this junk left behind right though the remains of the encampments and the food and all that stuff dead bodies whatever and so he tried to figure out indeed the answer to your question what would be left behind unfortunately don't remember the answer to your question but it was it but there was a you know among the things to look for were strange radioactive isotopes because presumably they would have of course some part of nuclear power and some of the obvious reactions were considered and they all produce these isotopes that you wouldn't find in nature right in the abundances that you might find in the trail of some colonizing force so that that article actually is probably published somewhere send me an email and maybe I can find it but indeed at least one person has looked at it I think it's a good idea although it's kind of disconcerting to think that we're looking directly for the trash over here let's try this again since you mentioned the movies and indeed it is a great pleasure and honor to know you personally and because of that I know that you like to watch really bad science-fiction movies do you did you even bother to watch the recent wonderful science-fiction movie that everyone was talking about and what did you think thank you which one was that I'm sorry I got everything but the title avatar avatar oh is it like a set up mark because I wrote a review of it I read a review it yeah you can read it it's actually on the Huffington Post but you find it on the Huffington Post is actually not so easy the best thing to do is go to the SETI Institute website at WCG org right go there and you'll find a link to it and you know I talked about it yummy look there's so many things you could say about avatar and it just seems like a cheap shot to say most of them you know but they live in a tree okay I by the way I had dinner with the with Cameron was here in Los Altos I committed a faux pas and he nearly stabbed me with his fork but but I actually like the film video but the most of the article describes the feasibility and this was the premise that film not giving anything away here really it involves on mining operation on a distant planet and we go to a distant planet Earthlings we go to a distant planet to bring back unobtainium thought was a singularly unimaginative but daring name for this stuff unobtainium that was worth 20 million dollars a kilogram and all I did in the articles work it out how much it costs to bring that back and the bottom line of the article says this is like ordering a book from Amazon latest bestseller and having to pay sixty thousand dollars for the postage you probably wouldn't do it and yet and the reason I picked on this is because this is a very familiar trope in science fiction that will go mine somebody else's worlds III don't think that makes a lot of sense myself but the film was good but I commend the film too you might be okay back we'll be here there any plans to do very long-term searches of individual stars lasting months perhaps years yeah I didn't catch all of it it was the idea to change the targeted searches instead of looking for a few minutes to look for a few years instead of a few minutes stare at a star star system stare at the same star for a few years once in a while yeah well I mean you did that it's certainly been advocated you know God we only spending a couple of minutes at any given frequency on any given star that doesn't sound like much maybe we ought to spend longer well maybe we ought to spend longer tickley if they're pinging us you know that kind of but here's the trade-off if you're looking at individual stars one at a time looking for these long-lived signals is it a better strategy to spend that time staring at this one star or is it a better strategy to say look that star had its chance I'm going to other stars maybe only one I mean if you think Frank is right about 10,000 societies in the galaxy that are clever enough to try to want to get in touch with you then one and roughly one in a few million stars will have such a society so how long should you spend on any one of them and this is you know you don't know the answer to this question until you've learned the answer to the question in other words until you found something then you'll know what the better strategy is and until then you just have to sort of go with what you think is most reasonable and at this point it's always considered better go to another target I have sympathy for your idea yes me requests when you're one slide where you reference Marconi could you please add the name Tesla and the second question is you said nobody reads Russian literature what if they send messages to us in Russian I okay what I'm trying what I'm trying to say is if your equipments reading a math system with base two and they're sending a message in base twelve you know how are you reading these things okay I got to cut you off there because that's four questions okay but but they're good ones all right and and the rest was to mention Tesla okay I'm a great fan of Tesla to Nick you know and indeed he was is important for radio as I'm sure as Marconi in fact maybe more but of course you know radio waves were predicted by Jim Maxwell right in the 1860s during the American Civil War some of you ought to give him credit and then again there was Heinrich Hertz who actually generated radio waves in 1888 so you know it's a long history it was it was a shortcut for which I apologize the second question was yes they won't nobody reads Russian papers what if they're sending us messages in Russian let me point out something about that actually people usually assume that one of the things that said he does is even you get all these bits coming down the pipe out of your radio telescope and you're analyzing I'm looking for patterns I on I think their value pies in here George I don't know I learned that in seventh grade be kind of disappointing if they sent me the value pie but okay maybe it's a Fibonacci series I read Dan Brown you know we don't do that because what we do what we do do is we integrate we average the signal for a couple of minutes the couple of minutes we're looking at any given frequency in order to beat down the noise it's like making a time exposure on Skyline Drive out here of the Silicon Valley at night if you hold the shutter open for a minute you know you can see all this faint stuff but the stop lights all look simultaneously red yellow and green because you've lost the temporal information right well we do the same so we're losing all the bits right all the modulation that's all gone away it's just a signal we all we know is they're on the air and if it's if you take for example the television signal you average it for three minutes you know a lot of the entertainment value goes away and I know my friends in the audience if there is no entertainment well yet it's okay so hey you and that with an example if you could just barely detect this signal in three minutes then you would need 10,000 times more sensitivity to get time resolution of like a microsecond so you can see the signal so in other words in other words for the lay audience here's the deal you find that they're on the air and now you have to build something much much bigger to have a chance of getting the message at least in the radio and the optical is a little different when in radio okay and you know you say well is that going to happen I think it's going to happen I mean if the SETI Institute or one of the other SETI experiments around the world not many by the way you know did small handful where to announce God we got a signal coming from 750 light-years and it's at this frequency and it's around that star there I think that funding would cease to be a major problem and I think you would have the money you'd have a worldwide effort to build that very large antenna and then get all the bits and everybody would download these bits on their hard drives and there would be plenty people who spoke Russian in case that's what they're doing so I don't worry about that but I don't know that they'll be in Russian Chinese or anything like that they're going to be who knows what they're going to be a lot of people say mathematics I'm not that keen on the mathematics approach to language because it's hard to describe things like art and government you know with mathematics but maybe they'll just send said some guy they'd just send a picture dictionary a lot of pictures with a lot of words and then after that's in plain text or just send their version of the Internet so redundant that you'll figure some of it out so I'm not too much worried about the language problem with the 350 arrays isn't afraid of the FCC will find Teddy for producing a signal a signal for more than 50 Hertz causing earthquakes and lightning strikes you're gonna have to have to repeat the essence of that my hearing I guess it's not very good because I didn't I didn't quite get it we're worried about the FCC being concerned about the signal being broadcast by 315 signal more than 50 Hertz which is the standard that they only allow a certain signal I believe it's less than 50 Hertz okay can somebody or that tell me tell me did you do it you worried about a signal at 50 Hertz I believe that the FCC has a standard worthy huh yeah right oh you're worried about okay so you're worried about the health effects of powerful transmissions yes there is a satellite Artemus excuse me there is a system in Alaska oh yeah okay 1 billion Hertz yeah yeah you know you're worried about the HAARP system and stuff like that now look to begin with we're not broadcasting at all all right we don't have any transmitters on those antennas I mean Arecibo has a transmitter used for radar studies of the sources solar system and also the upper atmosphere but we don't broadcast at all so there's not much danger there right in fact the only danger at the observatory are the bees and the snakes but nothing the antennas the so I don't see that as a problem for us you might say well the aliens you know they're not going to allow very very powerful transmitters because of the health effects but you don't have to have the transmitter on your planet I mean I think if you had a transmitter you know running at 10 to the 17 watts if you could do that right you would definitely have it in space and intended 17 watts at Barney Oliver I used to say you know waveguides Milt he had a point there and I don't think 10 to 17 woz is very feasible yes yeah what if they're not using radio waves are using some other communication mode that we don't know about I have to tell you it's a good question and I get this question every day in email usually five okay along with the ones that are having difficulties with aliens and their personal lives I get five of those too he by the way I don't think anybody's hoaxing me they're all very sincere people I kind of enjoy talking to him but I don't know that any of them proven to me that they're being really visited but getting off this up here what was the question yeah yeah you know they what if they're not sending radio well that could be and the suggestions that I get or what you know why not gravitation ways it we haven't chosen radio simply because we can do radio I mean there is some element of that right why are we doing more Radio City for example than optical SETI well I think that's mostly historical radio was invented really before lasers were invented and took it took a while to figure out that the lasers actually offered you the opportunity because you name a laser into a mirror this big it makes a very tight beam on the sky I mean you know optical photons are very expensive in terms of energy but you can focus them very inexpensively and consequently that makes sense had we invented the laser before we invented powerful microwave radio maybe we would do be doing more optical and less radio but it's all the same thing it's still all electromagnetic radiation and we know that that travels at the speed of light and it's relatively inexpensive to produce and at least in the radio goes right through all the stuff that hangs between the stars without impediment so it really works as a communication medium people suggest things like gravity ways that's their favorite gravity ways now you know we haven't even detected gravity waves yet oh you know they're big instruments it's very hard to detect gravity ways and by the way it's also very hard to make gravity waves of any of any size right you've got to do things like take a star and shake it right now that's a big project even when left to the students that's a big project whereas making a radio way that you could find you know thousand light-years away requires building a transmitter that fits on this stage okay so so what I say to these other people is well what do you suggest and you know sometimes the suggestions sound intriguing neutrinos and so far they're often suggested hard to detect neutrinos but they have advantages the one big advantage of entry knows you don't really have to aim the receiver by the neutrinos come right through the earth so even if they're down there you can find them that kind of thing but on the other hand their detection efficiency for neutrinos is very very low and so for and so and they're very expensive so you know if you got a better idea send me an email but I have to warn you that a lot of people done a lot of thinking about this what do you think about the latest reported evidence indicating possible bacterial life on Mars in particular they've ruled out meteorites as the source of the amount of methane - detecting the atmosphere and also a reinterpretation of the art meteorite suggested that the small fossil like structures were similar to magnetically sensitive bacteria on earth yeah well I think many of you are familiar with the story of life on Mars having several lines of evidence suggesting life on Mars of course the big science news story of 1996 in August was the Martian meteorite alh84001 and some NASA scientists in Huntsville and also Richard's air here at the Stanford University open that thing up and they claim that they have seen evidence inside that indicates that there were microbial Martians at least four billion years ago now that's very contentious and it has been ever since the announcement and I think it's still contentious a lot of it hangs on the interpretation of these these magnetic materials in their wood look which look like the kind of magnetic materials that bacteria make on earth but I'm not the one to ask about that actually the SETI Institute we have on the order of 60 scientists 50 60 scientists and almost all of them are astral biologists said he is a small part of that okay and the single subject that is most studied at our Institute is Mars so I recommend you get in touch with some of those guys and ask them their opinion but at this point I think they would all agree that while there are many suggest some things like the methane on Mars is very suggestive right that it's not at the point where you say you know we know there was life on Mars or that there is life on Mars it's still indicative and not definitive I think that that's fair to say yes sir I read something a while back that was thought-provoking and I'd like your thoughts on the possibility of detecting signals depends not only on how many intelligent civilizations exist but on how long it how long their technological capability persisted and since the age of the universe is what roughly 13 11 billion years or something like that 13:15 big number if there's only 10,000 order magnitude intelligent civilizations to look for the probability that they all exist at the same time is us seems pretty remote so how do you factor in the simultaneity of our technological capability to listen and the capability of someone else sending to be existing at the same time yeah the gentleman's question has to do with the fact that you know why do you think that they're out there broadcasting now you know the universe is very old and maybe they you know those radio waves that would indicate details out there have washed over this planet you know 300 million years ago and the bivalves didn't find them or maybe they're going to come in another 300 million years but all of that is encompassed in the Drake Equation right because that last term in the Drake Equation L how long a civilization lasts actually deals with it and this this is the way to look at it suppose I ask you how many students are at Foothill College for example or at Stanford Assembly make it easier because its four-year school how many students are enrolled at Stanford well you could figure that out you can make a pretty good estimate by saying look how many freshmen are admitted every year take that number and multiply it by the average number of years they stay there which is four right so that gives you the number of students at Stanford fairly accurately well what Drake was saying and this is this is the right way to look at it seems how many societies are born every year in the galaxy right intelligent societies societies that are technological how many come online if you will every year and then that number might be less than one but it's some number and then how long do they stay in that transmitting state is completely analogous to the Stanford example there and that gives you the number that are broadcasting signals that are going right for your bodies as you suffer through this presentation and that's the number that was estimated at being millions by Carl Sagan or 10,000 by Frank Drake it's the number that are contemporary contemporaneous with us that are out there now if you will broadcasting now and their you know their time of flight issues here but they're not important okay got that let's take two more questions because I know looking stultified yes all right assuming that we do find an extraterrestrial intelligent life and paranoia aside what rational planning have we done to prepare for this mathematically probable yeah you're asking what planning have we done to prepare the world for this news more like what do we what are we going to say to them what are we going to say to them oh that's okay that's a different thing you can answer the other one too yeah yeah answer both okay as far as preparing for how we deal with the news there is in fact there's not a whole lot of preparation I mean I don't know that Spain did a whole lot of preparation for the eventualities that you know Chris Columbus might trip across a new continent but we've done more than that and there is actually a document it's called a protocol which i think is a very unfortunate name and in fact a committee that I chair at the International Academy of astronautics is has recently revised that document it's very simple we've simplified it and removed some incongruities in it all it does to say look if you find a signal you verify it and then you announce it to the world right the first thing you do is you tell all the all the astronomers in the world because you want them all to train some instrument whatever instrument they have in the direction of this thing and then you know then you tell the press and the government in fact we've already seen that what happens is that the first people to know are the press I think it's as though there's no secrecy in SETI there's no policy of secrecy okay a lot of people like to think that there is but there's not it really is not as soon as we get a signal it looks interesting everybody's emailing their you know girlfriend you know well my edge don't tell anybody but we got this thing magics brother puts it on his blog you know five minutes later I mean in a sense it's not such a good strategy because that means are going to be a lot of false alarms and you know you could worry about credibility but in fact there is no secrecy so that's what it says and then it says one more thing and that is no response to a detected signal will be made without international consultation now that originally arose during the time when the Soviet Union was still in existence and also doing SETI and you know there was some level of distrust that if the Soviets found the signal they might monopolize it not tell us in broadcast back signals and you know get them on their side kind of thing make a lot of sense to me but I am alright or that we might do it from the Soviets point of view so in order to forestall this we all agree look if you find a signal you tell everybody and you don't start trying to get in touch without international consultation and it was never specified what international consultation was right did you tell the Swedish checkers team was that international consultation I was at the UN you know that kind of thing nobody knows so but on the other hand it was kind of a guarantee that you nobody would rush to the transmitters and start broadcasting their personal philosophies to the aliens now there are people who think broadcasting anything would be dangerous and in fact there are people in the world who wanted us as a setting group to forbid anybody to transmit even Abba Nishio in other words without finding a signal to transmit to you know baitul juice or something your favorite the you know the song you compose last weekend because they might launch the rockets and you'll be responsible for the destruction of the world very sick people who think this is an issue I don't think it's an issue not just because I'm sanguine that the aliens are not going to you know launch their missiles against earth they're very far away but beyond that and are they really that aggressive it of course who knows but the real point is this if you're really worried about that you better petition tomorrow to shut down the BBC NBC CBS and all the radars down at the local airports because they are broadcasting and they have been broadcasting for a long time so that's what they'll get first okay oh yeah hey I hope that answers your question in terms of what it means of course to get a signal that depends on whether we can ever figure out what it what the information content is if you can statistically they're way ahead of us okay they're not at our level that would be highly improbable that's like taking a wheel of fortune with maybe ten thousand slots on it I think would be zero years ahead of us one year - you're all the way up to ten thousand for example spin it once what are the chances that there are fewer than 100 years ahead of us you know one percent so they're going to be way ahead of us so if you can understand it it might be very interesting might be very interesting indeed I don't count on that but you know I think the real thing you learn is that what's happened on this planet has happened on many other places in the universe okay I see that that is it I want to thank you very much if you want to come see me I'll be upstairs in the back if you bought a book all great so thank you all for coming we hope to see you at future lectures Thank You Seth for a wonderful evening and he will be available to sign books right at the top of the auditorium thank you all you

Channel: SVAstronomyLectures

Views: 171,244

Rating: 4.5444841 out of 5

Keywords: Astronomy, space, SETI, life out there, SETI Institute, search for alien life, extraterrestrial life, radio astronomy, radio telescopes, ET, universe, cosmos, aliens, astrobiology, Seth Shostak, life on other worlds

Id: m9WxW2ktcKU

Length: 89min 58sec (5398 seconds)

Published: Mon Feb 25 2013