This is a transcription of a video-conference interview with Dr. FRANK DRAKE, President, the SETI Institute conducted on January 26, 2001 by the class members of STS497 I, "Space Colonization"; Intructor: Dr. Chris Churchill; technical aspects of conference call by Bob Jones; location: Wartik 108 at Penn State. Video transcription by Dr. Jane Charlton. ------------------------------------------------------------------------- Pronko: I'm going to introduce group 1. We were in charge of putting the questions together. (Group 1, Brock Pronko, Walid Dimachkie, and Laura Yingling introduce themselves.) Pronko: We'll be going to the other people who asked questions for you as we move along with the interview. As you can see by the list we send you we have categorize the questions into different topics but they all flow together. There are personal questions for you in particular, questions on SETI, questions on extraterrestrial intelligence, questions on the Drake equation. We might want to modify those questions because Dr. Churchill just gave a lecture on the Drake Equation and we know more about it now. DRAKE: I wouldn't want to contradict him, either. Pronko: We also have some technical questions about the hardware that you used, and a question on science fiction. Many of the students had questions on science fiction and some optional questions. There were a lot of good questions we had but they weren't exactly to the topic so we'll save those to the end if we have time. The first question is from Matt Hughes and it is a personal question. Hughes: How do you keep hope or rather how do you make a test that needs so much patience and faith interesting and seem worthwhile? And I say faith because I see lots of similarities between SETI and religion because basically you are both devoting your entire lives searching for something for which you don't have as much concrete evidence but yet that you are certain exists? DRAKE: Well, first you have to be both optimistic and really convinced that the evidence suggests there is life out there to find. You have to feel that discovery is going to be very important, very exciting and full of richness in the way of new information, experiences, learning of other civilizations and such. In other words it has to be an extremely exciting prospect because as you are realizing, quite correctly, SETI is a very boring enterprise. It sounds very exciting but when you actually do it and the hours, first the minutes but then the hours go by and you see nothing but noise or hear a hiss, it could get old very fast. So you have to have something that keeps your attention and one of the things we do is to simply have the data be visible all the time so there is something to look at and you always have in your mind well maybe in the next minute or the next two minutes something will appear on your computer screen and you will learn that there is another intelligent civilization in space. So in a way, you compare it to religion, but I think another analogy which is maybe closer though not nearly as noble of one is a gambler playing slot machines in Las Vegas. Every time you pull the handle you have this hope that the jackpot is going to come up. And in a way that is the way SETI works. Every time we start an observation we have in our mind, maybe this time we'll hit the jackpot. So in a way (and we really probably shouldn't admit it) we are of the same mentality as gamblers in a casino. Now there is more to it than that. If that was all there was, as the years go by eventually you would lose interest. And so all of us have other activities. Almost all of us adopt some normal, if you want to call it that, kind of astronomical research or some other kind of research. So you do get results, something tangible to work with. It isn't SETI but it is something. And that keeps your mental processes alive and keeps you feeling secure as a scientist and as somebody who could accomplish something. So that's pretty much the story but I think the main driver (and for me it has been for forty years) is the idea that any day if you just keep plugging away you might make this great discovery that would be so fascinating that it would change the world. Pronko: We'd also like to congratulate you. We understand that you lifetime achievement award and teaching award from the AAS. DRAKE: Yes, that was just in the last week and it was quite and honor and makes me feel very good. Pronko: Another question in the same category. The question is posed by Jason Camilo. Camilo: I was interested by the reaction you got from various sections of society. Particularly I know congress hasn't always been that supportive of what you are doing, but I was wondering how the astronomical community and the public reacted to what you are proposing. DRAKE: It depends if you are talking about 1960 when these ideas first surfaced or the present. If we go back to 1960 the scientific community was skeptical, although really not negative. The were just skeptical that searching for life could succeed. And so they were willing to tolerate (I think that is the word) as long as it did not utilize a lot of resources. As long as it didn't divert major instruments away from conventional astronomical research. And for the first many decades we were very always careful that we did not create animosity by taking resources in the way of telescope time and such that other people might want. The general public back in those days, as today, is very enthusiastic. They find life in outer space very exciting. And of course that is reflected in the popularity of many movies. And in fact many the most successful movies of all time have been on this subject. And so the public has always been enthusiastic and in fact today if polls are made of people's likes and dislikes in this subject. Typically 90-95 percent of the people (that's a big percentage) think we should put a lot of resources into searching. About 60% of the American people think that we have already actually made contact. And of course they they are buying into UFO stories and things like that or they have watched movies like contact and they think well you know this really happened but I just didn't read the newspaper the right day or something like that. So the public has always been enthusiastic. In modern times, that is in the last decade, the scientific world has been very supportive also. And so there is no conflict there. Again, there is always a little worry about how the funding and telescope resources can be divided up. But again we are careful not to consume large quantities of those resources. We do need more resources and that is why we are right now building our own telescope. And that will totally finesse this problem of worrying the astronomical community that we are going to overwhelm them and take away their stuff so to speak. Politically there has always been a problem and it is a strange one. It is not that politicians think this is wrong. In fact most politicians are as supportive as the general public. What they fear is negative publicity. And they are afraid that if they endorse a project such as ours that their opponents will accuse them of being muddle-headed and supporting searches for little green men (In fact that is what is often said), supporting pseudo-science. And they don't want that publicity. And for that reason politicians are very reticent to speak out in favor of SETI. Although in fact in their hearts if you talk to them in person they are very enthusiastic. The press has never mocked us. The press has been very supportive. The press people are very knowledgeable and what we know is that anyone who is knowledgeable about this subject is in favor of SETI and searches for life in space. Hughes: You just mentioned the movie Contact, In that movie Elly's chief skeptic was really David Drummond who proposed two outcomes of her research: that there would either be nothing there or that she would waste her whole lifetime and she would never find anything and she wouldn't be taken seriously as a scientist. How would you respond to someone like that? DRAKE: Well, there are people like that. There are still a few skeptics, and again, their skepticism is based entirely on their belief that our present searches are not yet powerful enough to succeed and that we are wasting resources and time. And the only answer to that is that if we don't search we surely won't succeed. And in any case the amount of resources that we expend is trivial compared to what we do in other activities, and this is such and important subject that we should put a lot more effort and a lot more funding etc. into it. So yes there are people like Drummond but they are very rare. The great bulk of the scientific community is very supportive and helps us in any way they can to raise money, develop our equipment, etc. The movie Contact, by the way, was a great help to us because it educated the public in a big way about what the realities are about how you look for life in space. That you don't go out and look for UFOs - that you take a radio telescope and nowadays also optical telescopes to look for signs of life and that is how you win this contest. So that helped a lot and it also helped a lot in encouraging young women to go into science. Yingling: We have one last personal question from Lauren Chung: Chung: What were some of the motivations behind creating project Osma in 1960 and that was humanities first attempt to detect interstellar radio transmission? DRAKE: First it wasn't humanities first attempt. It is one of these things where you have to put in a lot of qualifying words. It was the first powerful attempt, the first modern attempt, the first quantitative attempt. But in fact, back in the 1800's Nicholas Tesla actually transmitted messages from Colorado Springs with a radio transmitter in an attempt to communicate with intelligent life. He received replies, as he reported. We now recognize that what he received was the phenomenon known as "whistlers". Later Marconni tried to communicate and listen for extraterrestrial signals, and he too heard whistlers. Now what neither of those understood was that the ionosphere gets in the way and that there is just no possibility whatsoever in detecting an extraterrestrial signal in that way because the ionosphere of the Earth was shielding the Earth from such signals. But nonetheless those were the first attempts. There was also an attempt in 1924 to receive messages from Mars when it made its closest approach. And there is the famous story of most of the radio transmitters on Earth being turned off when Mars was at closest approach and everyone listened and surely enough they heard 3 dots followed by 4 dots coming in a mysterious message. And this was thought to be planet 4 calling planet 3 and there was a lot of excitement. Subsequently it was learned that this was transmission from a radio transmitter near Seattle and it wasn't from Mars at all. Too bad. So the first modern search, which was 1960, came about because one could then approach the problem in a properly scientific way by making quantitative estimates of how far you could detect signals of different powers. We were then building the first large radio telescopes. At that time new two forms of very sensitive radio detectors were invented: the maser, that is the microwave maser, and a thing we never use anymore called a parametric amplifier. Both of these improved by the previous vacuum tube receivers (this was before transistors) by a factor of ten to twenty in sensitivity. And so what I did, because from a very young age, about age eight, was interested by how do you find life in space. It always has fascinated me. I made the calculation of how far could these new telescopes we were building using these new receivers detect signals of the same intensity we were then radiating in the year 1959. And the answer came out that we could detect those signals from the nearest stars. And this was a breakthrough and this had never been possible before. You could have searched as Tesla and Marconi did but the minimum signals intensities were way more than what we were radiating. And so if you made a search you were searching for something we didn't know existed. But in 1960 you could make a search where you were searching for something we knew existed, with transmissions like ours. And it was easy to do. It was cheap and cost about 2000 dollars. And so we said why don't we do it? We searched for about 200 hours. We searched in the direction of the stars Epsilon Eridani and Tau Ceti which are the two nearest stars like the Sun. Epsilon Eridani is now known to have a planet, like our Jupiter very close to where our Jupiter is, so we now know that it was a good target. So that was how it started. And the motivation was first interest and secondly you could calculate with hard numbers that you were searching for something reasonable and not just hoping that there was some wild, super-powerful advanced civilization out there sending messages. Pronko: Next category is about the SETI program itself and Lauren also has that first question. Chung: What is the evidence that leads astronomers to believe in and keep searching for life in the universe? DRAKE: There is a lot of evidence and it is building all the time. The prime fact is that when we examine our solar system and all the things we know about its history we as yet have not identified any freak situation that was required for us to be here. As best we know it our solar system is typical of many planetary systems. Our earth has nothing unusual about it. The origins of life have been traced and at least many chemical pathways toward the origin of life have been identified. All of them would have utilized the most common elements in the universe - the elements that were surely present in the early earth. We understand how biological evolution works. We know that DNA is the key method of transmitting information in living things, how it works and how it can be altered and how all of this works. We look at our fossil record and see that the size of the brain has always increased in a very steady way. So again when you trace all the necessary things: planets, Earth-like planets, origins of life, evolution - none of them seem to require a very special situation. So it is on the basis of that and the fact that there are 100 billion stars in the galaxy that one concludes that the same sequence of events that occurred here must occur in many many places, in fact maybe even in a multitude of places. That is why we believe we know enough to know that the Solar System is at least close to typical and there are so many stars that we could be very wrong about a lot of things and still would be a lot of life out there. Dimachkie: Followup is a question by Pronko Pronko: You are familiar with the book "Rare Earth" by Peter Ward and Donald Brownlee. In that book they argue that complex life is uncommon in the universe and they cite many special conditions on Earth that are unlikely to be duplicated elsewhere in the universe. So how do you respond to that thesis, and if that were true wouldn't it make contacting extraterrestrials a nearly impossible task? DRAKE: That book is very provocative and useful because it make us sharpen our arguments and recognize where there are weaknesses. Just by coincidence I debated Peter Ward just two nights ago, as many of us at SETI have done. And the answer to this is to just look at that book very closely and one will find that many of the arguments are on very shaky ground, for instance the abundance of earth-like planets. Sure enough we have found a lot of planets and they tend to be Jupiters very close to their stars, very different from our system and doesn't that suggest that maybe the Solar System is an anomaly? Well, the data simply are not adequate to reach any such conclusions. We've looked at 1000 stars and it turns out only about 5% have these so called hot Jupiters, and 95% of the stars don't. In fact 95% of all the stars we look at in these studies present exactly the same evidence, the same phenomena, in the radial velocity of the stars, as you would see if you looked at the Solar System. And the most recent discoveries, because they've looked with better equipment for long periods of time where they can see less massive planets further out, have been finding those. And so we are seeing that as your observational capabilities improve you are starting to pick up systems like ours, in that other 95%. And so that is suggesting that most of the other planetary systems are like ours. But no hard evidence yet. One other aspect of that is that we now have enough extra-solar planetary systems (over 50) that we can do statistics on planet masses. And that shows that among the planets that we've found, the number of planets is inversely proportional to the mass. Which is to say that for planets of a given mass there would be ten times more planets with one tenth that mass. And if you work that out it comes close to predicting our solar system. You are going to find about 10 small planets for every big one like Jupiter. So those arguments fall apart. There are some other problems which are kind of interesting ones. They have to do with the fact that there is a great difference between the time that biology takes to evolve or adapt to compensate for changing circumstances as compared to the geological timescale. One example, and again 3 minutes is not enough time to address everything in Ward and Brownlee's book. Although you can if you have enough time, but it takes about an hour. One example is this recent, very interesting discussion that the Earth's axis rotated about 90 degrees so that what was a point on the equator became the pole. And this happened about 500 million years ago, and may have stimulated the so called Cambrian explosion in biology. Ward and Brownlee proposed that this was a very important event that changed everything. But when one looks carefully at this event, and it is stated in their book, this event did not happen overnight it happened over 15 million years. So for 15 million years parts or continents were migrating from what was the equatorial regions to close to the poles. Is this a big deal? No it isn't. 15 million years is enough time for life to evolve and adapt and it does very readily. And if you think about it, over 15 million years there is time for about a million generations of all creatures (typical lifetime of 15 years) and in a million generations you can both migrate or adapt yourselves physiologically to the changing circumstances. So an event like that on a geological timescale is a big deal but on a biological timescale it will hardly be noticed. Our earth is changing today. It changed in the last 100 years due to global warming. That rate of change is much greater than the rate of change that occurred during this inertia event, as it is called. One other example: Ward and Brownlee make a big deal out of our having a large moon and that this stabilizes the tilt of the earth and that this is important. And if you think about it, it's not. It doesn't matter at all. If we had no large moon, and if the tilt of the earth wobbled around, what would happen? The intensity of the seasons would change. We at times would be pole-on to the sun perhaps and what would happen, well, the polar regions would be warmer and the equator region would be less warm on the Earth. But in fact the temperature changes that occur would actually be much less than already exist between the poles and the equator of the Earth - less than the seasonal changes we already experience. So again this is a nothing. Another question which I think is very interesting because it is important: is whether the planets of M-type stars, small red stars, could support life bearing planets. And the argument there is that because the intensity of the light from the stars is 1 percent that of the sun, any planets that would be warm enough for life (they would have liquid water) would have to be very close to the star, and as a result, just as our moon is tidally locked to the Earth these planets would be tidally locked so that they kept one face to the star (synchronous rotation). And isn't this awful? And the worry is that on the dark side of these objects, which are always in the dark, it would get so cold that it would be cold enough to freeze out the atmospheric gases (carbon dioxide and nitrogen). And as a result the atmosphere would totally freeze out on the far side and there would be no atmosphere to support life. Well, it turns out that there are many calculations now that show that will not happen. You'll get a heck of a wind all the time. The sub-stellar point gets very hot and hot air blows out from there and it keeps the cold side of the planet warm enough that the atmosphere never condenses. And in fact if the atmospheric pressure is about 1 atmosphere, like on the earth, not even water freezes out. And we actually have some near good examples of this in our own solar system. Venus rotates very slowly and any point of Venus is in the dark for about 50 days. And yet the dark side of Venus is not even a fraction of a degree cooler than the warm side and that is because of the massive atmosphere. And similarly, Uranus has this weird polar orientation such that one pole for 40 years points toward the Sun. That means the other pole for 40 years is in the dark. And again the temperature on the dark side and the light side are the same. Again, a massive atmosphere. I've gone on way too long, but what this says is that when you really get down to it the arguments in Ward and Brownlee are red herrings. The one argument that I think one really has to think about is how often you get intelligence. This is argued very strongly in all directions by paleontologists. I am not an expert. I look around our earth and I think to me, given the great enormity of cosmic time, that you will get intelligence, but the experts argue about this. I should probably stop on the answer to this question because I could go on all day. Yingling: Another question from Lauren, but first a related question: If we do contact an extraterrestrial civilization, how do we know that they will want to talk to us? Chung: How you figure that other forms of intelligence will use radio signals to communicate with us and what sparks the confidence that life is reaching out for life and that these other intelligences are as interested in searching for us as we are for them? DRAKE: This one is easier to answer. First, in SETI we don't count on them reaching out to us. In the radio we have the sensitivity to detect the radio signal such as we transmit, our television signals and our radar signals. So we search expecting that what we will pick up are radio transmissions the other civilization uses for its own purpose. Now if they are trying to signal us that helps a lot - it will make the signals a lot more visible - but we don't need it. They don't have to be trying to signal us. Now why radio? People worry, and they should, that this is an anthropomorphic choice. That we choose radio just because we are good at it, and we have big radio telescopes. In fact that is not so. The reason radio is most promising (and I use those words carefully - it is not the only way) is because the universe is darkest and quietest at the radio wavelengths. There are sources of noise that jam any detection system and the laws of thermodynamics say there are no technologies that can evade this jamming and those cosmic sources are predominant at all wavelengths. At the very longest wavelengths (such as that of an FM radio) the universe is very noisy because of the electrons orbiting in the magnetic field of our galaxy. When you go to the optical wavelengths, remember that is a million times higher in frequency, a million times shorter in wavelength - a tremendous span. At the optical wavelengths there is dust which absorbs light in our galaxy, but worse there is starlight. And if you look at a star in search of a signal you collect a lot of light from that star and unfortunately it comes in the pitter patter, if you will, of a rain of photons and they are very energetic photons and so there is a lot of noise. It is like rain on a tin roof. And so the optical signals have to be very strong or you can't hear them in effect through that rain. And so it goes, and one can measure these things as we've done. We know the spectrum of cosmic noise extremely accurately through the entire electromagnetic spectrum as do the extraterrestrials. And when you do that and look at it you find there is a minimum in the noise that is very pronounced. Pronounced by factors of thousands up to millions compared to other frequencies, and that minimum is what we call the microwaves, roughly at 12 cm in wavelength. Knowing that we exploit it. Our communications links to satellites, the down-links to people's television sets, all are right at that wavelength because you can communicate most clearly, your equipment can be most simple and cheapest. So we exploit it and the extraterrestrials will exploit it. They will know we understand this. That isn't hard to know. And so if they are trying to signal us they will use this wavelength. That's an argument. At the same time their signals on which we might eavesdrop are likely to be at this wavelength too. So it is not our technology. It is not our prejudices at all. The universe in a way has a big sign in the sky that says, "search at radio wavelengths". Now having said that, I mentioned that we say most promising because radio is best if you are being logical, but intelligent creatures are not always logical. Not long ago we put our resources into building pyramids, and not radio telescopes. And you wonder if perhaps out in space there are people --- not people --- creatures who favor things other than radio for reasons we can't imagine. Maybe it's political. Maybe politically each country has been given a piece of the electromagnetic spectrum for example. Crazy idea, but it could happen, and each country is trying to be the first to contact somebody in space and so they are sending signals as strong as they can in whatever band has been assigned to them. And for this reason, and for some others I can tell you later, it does make sense to search for optical signals and infrared signals even though the universe is very noisy at those wavelengths. Pronko: Thank you very much for that answer. And since you touched upon optical SETI we are going to move over that question just for now and move onto the last question in the SETI category. Combine the question, part of mine and parts of Nahks', and let Nahks ask that question. Nahks: In view of the exponential growth of radio and other electromagnetic noise from other sources, how is SETI going to deal with that in the next years? To follow that up, if we start to move off the earth, with bases on other planets, does SETI have any future proposals to move off planet? DRAKE: The radio interference is our most difficult problem and it has grown, as you have noted, all the time. The thing that has happened in recent years, which has made rapidly a very major problem is a tremendous number of satellites orbiting the earth and transmitting things down, like the GPS system, the Russian GLOMASS system, the iridium telephones, global star telephones. All of this creating interference - strong interference that not only blocks out certain frequency bands, but a lot of the signals are so strong that when they get into our equipment and they saturate the equipment and make it so you can't see other frequencies other than the ones that are already blocked by the interfering signals themselves. Now there is no where on Earth you can go where it is quiet. Because again the prime source of interference is satellites, and also airplanes. Now, we thought of many clever ways to evade this. The one we use in our Project Phoenix is one which is expensive, and nobody else can afford it. We wish they could, because it is a good way. When we search we use two telescopes. Right now, we use the Arecibo telescope in Puerto Rico, but then we have a second telescope standing by, with very excellent receiving equipment upon it and that is the 250 foot telescope at Jodrell Bank in England. That is the world's largest telescope. And the way we identify interference and its origin very quickly is, when we get a signal which looks as though it might be from the stars we measure its frequency. Of course we know where we are looking with the telescope, and we send the information to Jodrell Bank. They are always following the same object as we are. They tune to the frequency and see if they see the same signal. Now, if it is a local source of interference, or even an airplane flying over Arecibo, of course Jodrell won't see it. So we realize immediately that the signal is of local origin near Arecibo. If we do see the signal, which is possible if it is coming from a distant spacecraft, then we have a definitive test which we can do immediately -- that is, we make use of the fact that the Earth is rotating. And as a result of that rotation, both of the telescopes have a velocity vector toward whatever the source is, and those velocity vectors are different because the telescopes are on different parts of the Earth. They are far apart so the difference in velocity is very great and creates a much different Doppler effect, and we can calculate from the geometry exactly what this may be. We can say, "ok the signal at Jodrell should be exactly 75.1 Hz different in frequency from what we are seeing at Arecibo". And we look. And we see if the difference is right, and if it is right it is also changing, and actually change can be sensed in literally a few seconds, because the velocity vectors themselves are changing due to the rotation of the Earth. Now, that may sound really hard to do but we are measuring frequencies to an accuracy of about 1 Hz at frequencies that are 3 billion Hz. A tiny change in velocity, as much as my finger is moving, can be sensed by our systems. So in this way we can immediately identify whether the signal is coming from anywhere in the Solar System, in fact, or whether it is really coming from the stars. And in this way, so far we have been able to conduct a good project and work around the interference. Never less, as I mentioned, the strong interferers can cause the instrument to work improperly, they mask many bands, and it happens more all the time, and so it is desirable to go to some quiet place. And as you ask there are plans. Just going into low Earth orbit is worse that being on Earth - you have the whole Earth radiating at you. Doing something with the Space Station, for example, makes no sense at all. That would be a big step backwards. That would be the most ridiculous SETI observatory that humanity has. There is a place not too far away that is ideal, and that is the far side of the Moon. And why is that? It is the only place in the Solar System that never has the Earth in its sky. And so it is always shielded from these sources of interference, other than a few spacecraft that are out by Jupiter or whatever. And so for years we've been talking about building the ultimate SETI observatory on the far side of the Moon. There are plans. We've even picked out a crater. It is the Saha crater, which has a nice shape and is just far enough around the limb of the Moon that it is shielded from the Earth but not so far that you can't run a fiber optic link to the station on the near side which NASA is planning, but so far not doing anything about. That is the picture and it is going to be a while. It will be at least 20 years and maybe 40 years before we have a station on the Moon, but that's the right place to be. Pronko: Dr. Drake, we'd like to move to a different category, extraterrestrial intelligence, and the first question from Josh Brosious. Brosious: In the event that in the future we do find an extraterrestrial signal, what would be the next step. What would we do after that? DRAKE: Well I think we always say the next step is to get the champaign out of the refrigerator. And that's not a joke. We keep a bottle of champaign in the refrigerator all the time when we are searching. But in fact there is a protocol that has been agreed to by all of the SETI observatories and all the international scientific organizations - eight pages long. But it really says two things. One is first be really sure it is truly an extraterrestrial signal - not a hoax, not a distant spacecraft. That may require you to get a second or third observatory to observe the signal and confirm what its origin is, Step two is that the information will be released to the general public immediately. And we're in a position to do that because all of the SETI projects are now publically supported. There is no government control so there is no way - no legal way that anybody can stop us from announcing this information to the world. So there is no secrecy in these projects and there won't be after the discovery is made. Now what do you do after that? My hunch is that the first signal we detect will be very faint. We will see there is a signal but we won't be able to extract information from it. And that is because to be able to detect the signals we average over long periods of time, several minutes. Whereas the information coded in the signal will have a timescale of a fraction of a second. Television is a millionth of a second and all that information is smoothed out. It is lost in your detection process. So you will know there is a signal but you won't know what it is saying. And that will be the big challenge and it will surely be exciting. I am looking forward to that day because you just know that there is going to be available to you any amount of money it takes to find out what the information is in that signal. So what you will have to do is study that signal and get some idea of how much sensitivity and bandwidth you are going to need to extract the information from the signal. And then build what it takes to accommodate those requirements. It make take a giant telescope. It may be a five year project. But it will be the crash bangest project you ever saw and I'm sure countries across the world will compete. So that is what will happen next. There is one step beyond that which is probably mainly what you had in mind. And that is what do you say to the extraterrestrials. Do you say anything? There is no general answer. The correct answer to that question is "it depends". It depends on what you are seeing. what you think that other civilization might be like, how far away are they, does it make any sense at all? And so sure enough there will be a lot of consideration given to sending signals to this new civilization, but what those will be can only be decided when you know a lot more about that civilization. Yingling: I have the next questions here. If we do find an extraterrestrial signal what risks and benefits would there be from sending our signal back, making contact with them? DRAKE: Well, first risks. It is too late. We've already made our presence known. There is a shell of very intense television signals around our planet that extends out 50 light years. Something like 2000 stars have received those signals already. And with very little effort they can know all about us. So if there is a risk we have already unwittingly taken it. Whatever is going to happen is going to happen. As to benefits, I think all of you can imagine those benefits just as well as I can. Which benefits are most valuable depends on who you are. There are people who are religious who are very interested in what the religions are of other civilizations. Do they have souls? Are they redeemed? Are the things many of us believe taking place there? I'm sorry I'm not being very articulate about this. Many people are interested in the philosophical implications. It is likely that any civilization we find would be much more advanced than we are. It may have a much longer history. I don't mean 10 years, 100 years, but literally thousands, millions of years more history than us. What have they become? What have they learned? Where do we fit in the hierarchy of living things? What can we become? Can we equal them in ability, or are they way ahead of us? Can they, for example, learn ways to connect computers directly to their brains so that they are a combination of machines and biological entity? What does that make if you really do that? What is a creature is it, that is like that? What is important to it? What is its way of life? Something very different than ourselves. Something that is not even really touched by science fiction because it is so far out. Science fiction always assumes some variation on a pure biological entity, at least most of it. Now I'm talking about an entity which is part machine, part biology. It can be immortal, by the way. What does that do? If you live forever how would your civilization change you would have to stop reproducing pretty much, except to replace the creatures killed by accidents. Safety would become extremely important. Speed limits would be three miles an hour so that you could have a head on collision and survive. Airplanes would be banned because they might fall on somebody. Every home would have a cave that you'd go hide in if a meteorite was going to strike. It could be a terribly different and fascinating situation, and also a very repugnant one. The world I just described to you does not sound very appealing, actually. Usually we think being immortal is a really neat thing. But when you think about it, maybe it is a terrible life. Having the same friends for ten thousand years. Wouldn't that get boring? There are all these things that influence how we would see ourselves. How we would understand what our future might be and make choices as to what that future might be. Like for instance some of you have probably seen the movie "Logan's Run". That's an example of what could come out of all of this. Immortality is possible, but for just the reason I mentioned, undesirable. Strange world. On a simpler level first there is just the great adventure in contacting other creatures. And we see that in our science fiction movies all the time. And there will be great practical benefits because we will see what technologies are possible and we will be given clues, and maybe even plans for how to accomplish such things. Things like controlled nuclear fusion, space colonization, cures for genetic diseases. All of these things which would make the quality of life on Earth much better and greatly diversify what is available to us in terms of things to do and places to live. Those are the things that come to mind as a response to your question. I'd be glad to hear any others anybody there at Penn State has thought of that particularly interest them. What they look forward to. What you look forward to and will want to know at highest priority when we do contact another civilization. Pronko: OK. Thank you for your answer. Since we are running a little behind here we are going to skip down to the optional category to questions that are not exactly about SETI but that we feel are interesting and we'd like you to touch upon. The first question is by Loren Chung: Chung: A straightforward question - what are your feelings on space colonization? DRAKE: Space colonization is wonderful. It is surely in our future. You say, "how do you know that?" I'll tell you in a minute. It is surely in our future and it is a wonderful thing as long as you build big space colonies. I think small space colonies are just not very pleasant places to live. But if we talk about large space colonies - space colonies that are really miles in dimension and have populations of a million people or so - we then have in a way an encapsulated civilization which is rich enough and diverse enough that it is a good place to live. It is pleasant. And of course space colonies have some tremendous advantages in that you can control the weather. You can control the length of the day, and in fact you can completely control your environment and have what you want. If you want to make your place into a little Hawaii you can do that, and with a little bit of adjustment you can turn it into a ski resort for a week until everybody has broken their leg and then you can make it into Hawaii again and they can all recuperate on the beach. So space colonies are really a more satisfactory place to live than planets like the Earth where there are storms and unpredictable catastrophe and all that. On a space colony you can have no mosquitoes for example. That is a good deal. No cockroaches in space colonies. I think they are a good think and actually I said they are in our future. They are in our future, either soon because of the reasons I just said, or eventually for sure when the Sun starts to get too bright when it heads into the giant and supergiant phase and that is several billion years away. That's why it is far in the future. But when that time comes the solution to the survival of humanity will be to build space colonies and move out further in the solar system where the brightness of the Sun is what we are used to. And then as the brightness of the Sun eventually dims the space colonies move back in. And so they are the ticket to survival eventually. Pronko: I believe the next question is posed by Chris Hynick: Hynick: I believe the next time there will be a planetary alignment of Earth and Mars is around 2010 or 2013. If SETI were to receive a signal of extraterrestrial life from Mars, what would the next steps be in order to explore Mars and what kind of funding would be needed? DRAKE: We are not going to colonize Mars in the next, probably, two decades. That is a very difficult mission, primarily not for the reasons people think. It's primarily because you have to protect the people on the spacecraft from solar flare radiation. It turns out that takes about a foot of concrete. You need sort of a storm cellar on the spacecraft. You need a storm cellar large enough to hold all the astronauts and that ends up taking up all the payload when you are planning on using the boosters we now have today. So there is a real practical problem with going to Mars very soon, and that's why it will be at least 20 or 30 years. But we will go there several decades from now, and the funding will come from the taxpayers. And we already know what the funding is. It is of the order of 100 billion dollars to mount this mission. Mars makes close approaches every year and a half or so, so there will be lots of opportunities. Certainly some of them are closer approaches than others but any of them can be used for one of these missions. Yingling: Dr. Churchill, here, has a question about the prospect of life on Europa. Churchill: There are other sites in the Solar System. Now we are not talking about intelligence, obviously. But when we get into the factor n_e in your Drake equation, the possibility for life to arise in many circumstances, we've seen that on the Earth it is quite robust in environments that we consider extreme. And I just wondered if you had any opinions or wanted to muse about life on Europa or any other sites in the solar system before we wrap up today? DRAKE: OK. There are a whole lot of important and related subjects there. One has to do with Ward and Brownlee. The idea that the habitable zone - the zone in which a planet has to be to suitable for life is very limited. And Europa, of course, shows us that one has to be very careful about that concept. What we know is that life requires liquid water and a source of energy and some organic compounds. And we've been befuddled in the past by thinking that the requirement for liquid water means it has to be a certain distance from the Sun, that is the distance the Earth is from the Sun. What we failed to recognize and appreciate is that either the presence of an ocean or a very deep atmosphere can cause a planet that is exposed to very little starlight or sunlight to be warm enough to have liquid water and to give rise to life. And Europa is a prime example of that. There it is way out at the position of Jupiter where the sunlight is 1/25th what it is on Earth, but there is liquid water. And why is that? It is because of the shield of ice that protects that liquid water from the severe cold of the surface. And we also know that if you go down in the atmospheres of Jupiter or Saturn or Uranus or Neptune there are places where the temperature is as it is in the room you are in right now. If there were a surface there you could have life. So the habitable zone is almost becoming a very muddy concept. Of course the greatest expert on that is Professor Kasting here at Penn State. What this says that you can have life almost anywhere in a system so long as there is ice or a deep enough answer. The test of this will be Europa. Other requirements are there. We have liquid water. There are certainly organic compounds. We see them on the surface and surely deep in the oceans there are the equivalent of deep sea vents which provide the energy and perhaps the chemicals for the origins of life. So I would bet there is life there but this is going to be a very important test as will searching for sub-surface life on Mars be a test of this whole idea that given an protection in the form of an atmosphere, or an ice sheet, or in the case of Mars just the surface, you can have life in places you would not expect. And that would make n_e very much greater and it is an important counter to some of the objections of Ward and Brownlee. Pronko: That just about wraps it up. I thank you very much for your time. We are going to take some video clips and put this on our web site. I think we mentioned this last week. And we'll send them to you ahead of time for your approval. DRAKE: I don't think I made any big boo boos. Churchill: Thank you very much for today and for sharing your thoughts with us in this teaching environment. And so, thank you. DRAKE: It has been my pleasure and I hope I provided at least something for a lunchtime conversation today. Churchill: Indeed I'm sure you did. Thank you and have a pleasant day out in sunny California. DRAKE: It has been pouring rain here and I'm supposed to observe tonight at Lick Observatory, but there are five inches of snow on the road so I don't know if I'm going to make it. Churchill: OK sir. So we're going to sign off here. Again, we thank you and give our regards to all the hard working scientists at SETI who keep their faith so high. /end/