Steve Mirsky:    Welcome back for part 2 of the July 20th announcement of the new $100-million initiative to look for alien intelligence. Back now to Yuri Milner.

Yuri Milner:       Now we can answer a few questions; of course, all the panelists will be here to do so. But we collected a few questions from some of the participating journalists that wanted Stephen Hawking to answer those questions, so obviously they have been prerecorded by him. And I will ask some of those questions now, and I hope Stephen will be able to answer.

So the first question was why are you hopeful that this initiative might bear fruit?

Stephen Hawking:     It is sure to bear fruit. Experimental astronomy is always worthwhile. If a search of this scale and sophistication finds no evidence of intelligence out there that is a very interesting result. It will not prove that we are alone, but it will narrow the possibilities and it's likely to produce data that is fascinating in its own right.

Milner:      The second question was what does it offer that earlier initiatives have not?

Hawking:  Resources, lots of time on major telescopes around the world, a huge data capacity, and a long-term commitment that is not at risk of being withdrawn.

Milner:      Thank you. And the third question, and why is it important for mankind to pursue this endeavor?

Hawking:  Mankind has a deep need to explore, to learn, to know. We also happen to be sociable creatures; it is important to us to know if we are alone in the dark. Beyond that, as I said in my presentation, there is a deep question about the universe; a universe full of technological civilizations is a very different place from one with only us. Perhaps even different at astronomical scales. That makes it astronomy's job to find out.

Milner:Another question that was asked was do you believe that there are intelligent forms of life in the universe?

Hawking:They might be there, they might not, but recent experiments like the Kepler mission have changed the game. We now know there are so many worlds and organic molecules are so common that it seems quite likely that life is out there, but intelligence is a great unknown. It only took 500 million years for life to evolve on Earth, but it took 2.5 billion years to get from the earliest cells to multi-cell animals, and technological intelligence has appeared only once, so it may be very rare. And when it does evolve we only need to look in the mirror to know that it can be fragile and prone to self-destruction.

Milner:      You said once that making contact with aliens would be a really bad idea. Why do we need to avoid contact with them?

Hawking:  We don't know much about aliens, but we know about humans. If you look at history, encounters between humans and less-intelligent organisms have often been disastrous from their point of view, and encounters between civilizations with advanced versus primitive technology have gone badly for the less advanced. A civilization reading one of our messages could be billions of years ahead; if so, they will be vastly more powerful and may not see us as any more valuable than we see bacteria.

Milner:And the last question was we have not discovered any sign of intelligent life in the universe so far. How do we look for it?

Hawking:  It's an open problem, so we need to try lots of solutions. Keep doing what we are doing, but also develop fresh ideas. The Breakthrough initiatives are a great start to that. They are bringing traditional radio astronomy to another level of power and sensitivity. They are taking a new approach to laser searches, and by opening up their data and source codes to everyone they are building in lots of room for innovation.

Milner:      Thank you, Professor Hawking. So now, please, if anyone wants to ask any questions.

Nick Miller:        Nick Miller from the Sydney Morning Herald. Can I ask the panel, obviously there are famous equations about how likely it is life is out there; given the new capability of this search how likely is it that we will find something in the ten years?

Milner:      Well maybe you want to ask the author of the equation.

Frank Drake:     You just asked the question that we hate to hear, and the reason is because we don't have sufficient knowledge to answer the question. As you know, the presence of intelligent life, technology-using life has to be the result of many phenomena; planetary formation, origins of life, evolution, so forth. And many of those things we can now quantify and we can put real, not just guess at how often those occur, but actually we have observational evidence to support our ideas. But there is one about which we know very little, and that is the longevity, the length of time that civilizations, having created a technology we can detect, continue to use that technology.

         We ourselves have been detectable for almost 100 years at this point. But we are moving on to more sophisticated technologies, which may in fact make us less easy to detect. Even though we are thriving and richer and living better lives than we ever have before, we may be harder to find. This has given us pause; we worry about it. We wonder if there might be things that counter that, such as the establishment of electrical power generating stations in space that transmit energy to Earth on radio beams, some of that energy would be reflected back into space and make a strong signal.

The point is that we are the beginners, the inexperienced ones. We don't know what we will become and we don't—as a result we cannot use ourselves as a good example as to how long civilizations remain detectable. And so we are left with this great difficulty that one of the key terms that we use to establish the number of detectable civilizations we know really nothing serious about; there's a tremendous possible range of plausible answers.

My way to put this is that we have what we call a very serious catch-22 situation, which by the way gets in the way when we go to governmental bodies to ask for funds; they ask, "How many dollars do you have to spend to succeed?" Well, if you're spending a spacecraft to Pluto, as we just did, you can answer that question. But when they ask us, as you just asked, "How much do you have to do to find another civilization?" there is this catch that we cannot tell you the answer until we have succeeded. We must succeed before we can tell you how much it's going to cost to succeed. And that is very awkward, and what it says is that we just simply have to explore in the dark and hope that there are people like Yuri Milner, who will keep us going for however long it takes to succeed. And that's the best I can do with your question.

Male 1:What type of question would you ask it? What would be the first thing that you said to it?

Milner:      So, Ann, you want to take this one?

[Laughter]

Ann Druyan:     Well, I mean "hello" would probably be right up there. Well, obviously we'd want to know their history and their social forums, their—how they understand the origin of the universe. Obviously if we're talking to a civilization which is likely to be far more advanced than ours, because we've only been at this for about a minute and a half, we've only really been doing science for 400 years in any kind of systematic way, and so it's very likely that the civilization that we might encounter would either be—would probably be more advanced than ours, and if that's the case then I want to know I think 100 answers, 100 questions at least about how the universe came to be, the nature of time and dark matter and no end of questions.

But the first thing I think would be to establish a kind of means of communication and a kind of intention, which is to learn.

Milner:      It is going to be a very slow dialogue, by the way. So the nearest star is four light years away, so you'll have to wait eight years at least, and within our galaxy it could take 100 to 200,000 years to get the answer. So if you are kind of a little bit patient then the dialogue will make sense.

Yes, you are the next. There is a microphone there.

[Inaudible Question—Not Speaking into Microphone]

Drake:       He started looking at me as he asked this question.

Milner:      So the question is why—for those who couldn't hear,-

Drake:Why aren't we transmitting?

Milner:      —why we're not transmitting.

Drake:This has been a very active subject recently and there are many people who have said we should be sending signals, isn't that the fair thing if we expect them to signals, shouldn't we be doing it? Fairness in the universe is perhaps a universal law. Now in the Breakthrough Listen project we have no intention of sending and there are two reasons for this. First, we know that there are people who are afraid that something is in fact going to endanger us. We don't particularly believe that, but why cause anxiety and paranoia, if you will, with people? The main reason we don't transmit and don't plan to transmit is that it will not bring us any benefit at all. The nearest star is four light years away; the nearest civilization is more likely 100 light years away at least. So if we transmit and wait for an answer to come back, that will be—it'll arrive 200 years from now, and by that time we will have learned of other civilizations by listening to their radio signals.

So when funds are short, as they are, and limited we don't want to use funds for anything that's not going to help us detect extraterrestrials. So sending messages uses funds in a way that will not produce any useful benefit to us. Such funds should be used only to aid in the search and increase the power of the search.

Male 2:From what you were talking about earlier, I take [inaudible] and we actually do find civilization out there and it's not too far away you might enter into some kind of _____.

Drake:Yes. If we found a civilization. You know, that's another part—I guess you didn't hear the question. He suggested that if we did indeed find a civilization not too far we would engage in a dialogue with it, and I was saying yes, we would, but in that case we would know what we were dealing with and we could construct a useful message. When we have no contact, know nothing about a civilization, it's very hard to conceive or plan a message which would be effective, and that's another reason why we should not just shout in the dark; we don't know what a sensible message might be.

So the answer—the two answers to this one is that at the present time it's a waste of resources to send messages, better to apply the resources to the search. And the second is if we do find a civilization then you study it and develop a message that makes some sense and send it to them.

Druyan:    And if I may add, while it's true that we don't contemplate sending a message at this point, the exercise of formulating what message we would send is useful I think in the same way that Voyager's pale blue dot image of the Earth and Carl Sagan's magnificent meditation on the significance of that one-pixel Earth, that tiny Earth is a degree of consciousness on this planet that I feel a certain urgency about. And so while it's true we won't likely send a message, the actual creation of the message is a step forward and a very positive gesture.

Emily Martin:Yes, hi. Emily Martin from France. I was wondering, you were talking about a new level of technology and innovation. I was wondering how do you achieve that? The Green Bank telescope is not new, you're not building a 30-meters telescope in order to detect signal. So I was wondering what is it about—how do you achieve that? Is it a question of time of telescope now available? And also the other question was do you assume that an extraterrestrial intelligence would actually focus a signal towards us in order to be detected?

Milner:Yeah. Geoff, you want to answer?

Geoff Marcy:      Thanks for that question, Emily. There's a very important technological innovation that's required to do this search properly and the reason is that we have absolutely no idea what frequencies of electromagnetic radiation, light, we don't know what frequencies the advanced civilizations might be broadcasting at. It might be 50-megahertz, 100-megahertz, a gigahertz, 10 gigahertz, 50 gigahertz. When you think about our own radio dial, the fact that you tune your radio in your car to some specific frequency, one frequency after another, shows that we humans broadcast one frequency at a time and then we in turn have to tune our radios. But we don't know from the advanced civilizations which frequencies they are broadcasting at, so we have to search all of them. And there's something like 10 billion hertz or 10 billion separate frequencies that are in the so-called microwave region, the quiet region of the electromagnetic spectrum, from about 100 megahertz to 10 gigahertz; that's a factor of 100 in frequencies.

So how do you search all 10 billion frequencies? Every time you point the telescope you'd like to be tuned in to all 10 billion of those frequencies. What we're going to develop at Berkeley is the use of some technology, I'll tell you the names of them Field programmable gate arrays, FPGAs, are just becoming quite popular, very fast computational ability. And another one is called a graphical processing unit, GPU. It's similar to a CPU, but much faster for array-type arithmetic computations.

         So we're going to be developing FGPAs and GPU electronic systems, indeed spending from the innovation in Silicon Valley. We'll be assembling them at UC Berkeley in ways that allow us to sample 10 billion frequencies simultaneously.

Milner:      You've got a pretty old radio in your car, right?

Clive Cookson:  Yes, Clive Cookson from the Financial Times. I'd like someone to address more directly Stephen Hawking's fears. I mean I know you're being cautious, but would someone like to put forward the positive reasons why we might want to send out a message?

Milner:      Martin, you want to?

Lord Martin Rees:       Well, I agree with Frank that we would not wish to devote effort to sending out a message now. I have to say that I don't share Stephen's concerns at all; I suspect that these aliens, if they exist, would know we're here already, they may be watching the Earth for a very long time as a propitious source of intelligent life. So I don't share this concern.

I think if I can just add a footnote, I think we mustn't imagine that any intelligence is like ours at all. We think of our human intelligence, which has become technological in the last few centuries. If we survive this century it may become AI, which is inorganic and may spread through the galaxy and beyond. So we are thinking about the possibility of intelligences possibly quite different from ours, maybe not on planet at all, and maybe so different from us that we can't communicate at all. So the thing that we should try to do is to find evidence for some signal which is manifested artificially. We can do that and that's the aim. But even if we can do that then whether we can decode it or not is a separate question. And if they're very advanced they probably know we're here already.

Druyan:    Yes, may I also say something? I agree with Professor Rees passionately, because if you look at the extraterrestrials depicted in popular culture, they're always a projection, a mere projection of our fears. And we are primates and we have evolutionary baggage which makes us act shortsightedly and violently too often. But we also may be passing through a period of our development. We may get to a point in the not-too-distant future, certainly on these time scales, where we outgrow that evolutionary baggage and evolve to be less violent and shortsighted. And it's my hope that the extraterrestrial civilization is not just more technically proficient than we are, but also more aware of the rarity and preciousness of life in the cosmos.

         So if you wanted an optimistic view, there it is.

Thomas Kinese:Thomas Wallace Kinese. What do you think a message would look like? Do you think it would be just a repeated series of frequencies, or do you think it may be a more complex burst of code that you would then have to try and understand?

Milner:All right, you want to take this one?

Drake:I'll take that, 'cause-

Milner:You sent the first one, so.

Drake:       Yeah, I've actually sent a message and I'm not going to apologize or that. It was actually sent as a proof of concept that you could actually send a message that somebody could decode. And when you go to send a message you have to think of exactly the issue that you raised, which is how do you code it in such a way that it will communicate accurately what you're trying to communicate, and more than that, you have to be very careful that you don't create an ambiguous message, one that has an alternative decoding which is not your intent, but may actually be scary or frightening or aggressive or embarrassing to us.

So when you construct a message, and that's one of the reasons we're proposing to have this contest, is so people recognize that they have to deal with these issues that I just raised to make a good message. Now there have been other attempts to make messages, and some recent ones could—cloud sourcing messages from people that were to be sent into the cosmos, most of those turned up as sentences, statements in a written human language: English, Russian, so forth. Frankly, these are nonsensical to send because there's no way the extraterrestrials will know how to decode those things into an intelligible sentence unless you send along an enormous dictionary and a teaching manual for the language you're using.

         So you don't do that; you cannot just send a—well, one suggestion was in Braille, a message in English. You have to send something that can be decoded into something sensible clearly without having a common language. You cannot count on having a common language or even the ability to identify and understand how that language works. The way it works that we know of is to send pictures. You send them pictures, if necessary moving pictures, and in our wildest dreams you send holograms, moving holograms. You can send three-dimensional messages which have actions in them, which will tell the extraterrestrials everything you could; it's just as though you were there talking to them. Because when you get pictures you can decode those without having to know a language, and we have sent things encoded in such a way that were easily decryptable and we were careful that there were no alternative decryptions that made sense.

So to my mind what works, and you may think this is simplistic, pictures work, or three-dimensional pictures, or a three-dimensional movie or holograms. No language involved.

Alexander Martin:Thank you. Alexander Martin from the Register. I'm wondering if you might have an estimation for how much data Breakthrough Listen would be producing and when that might begin to be published.

Milner:Geoff.

Marcy:You can do the calculation in your head, and I'll walk you through it. It's very interesting, actually. At 10 gigahertz, if you digitize that set of voltages coming down the back end of a radio telescope, 10 billion different voltages per second, 10 billion per second, if you sample them it requires something like 10 billion bytes, 10 gigabytes per second. Now if you stare at a star hoping to pick up a signal let's say for an hour, 3,600 seconds, you see quickly that you're up to tens of terabytes after just one hour. And now if you carry out the Breakthrough initiative for years, you're talking about millions of terabytes per year and even more. It's such a severe problem that we have to do on-site sieving, that is to say signal detection on-site at the telescope, trying our best to assess which portions of the data are plausibly interesting with some sense of a signal above the noise, and retain that data. Because there's no way to store millions and millions of terabytes of data from just one telescope.       

This is a standard problem in radio astronomy; you simply can't save all of the raw data. You can save those data segments that look somewhat interesting, and even that will require us to store hundreds of petabytes.

Male 3:      If you do make a really earth-shattering discovery, how will you react to political pressure on you to keep it quiet?

Milner:      First of all I just want to remind you that all the data will be made open, so the project is very apolitical in that sense. But maybe it's going to be not a professional astronomer who is going to detect the signal in the data. So it's hard to say how you can keep it contained. But that was never a goal obviously, so.

Male:I think Frank wants to take a push at that.

Drake:Yeah, we've actually had experiences with this. We've had signal—we've captured signals that looked as though they were the real thing and we tried to keep them to ourselves because we didn't want to cry wolf and embarrass ourselves by revealing, oh no, this was just somebody's microwave oven gone awry. And what our experience has been is that it was impossible to keep them a secret, because the people go home at night and tell their wife or their kids, "Hey, I think we got a signal today" and the next thing you know, you see it in the New York Times. It's just amazing how quickly the word gets out. So in practice we have found it impossible to keep the apparent detection of a signal a secret.

Oliver Morton:   Yeah, Oliver Morton for Frank really. You've written before that the—and this will be the longest, most persistent study program in history. And you've written before that the thrill wears off a study program very quickly and that it always needs to be combined with other work, or people just find the lack of results too depressing. What would you like to see this work combined with?

Drake:       Yes, I guess you've heard me talk before or something. But a study is a very exciting business, and when you're taking the data it's very exciting, because every time a new spectrum comes out of the machine you take a good look at it and hope you see a bump in the spectrum, which is the clue that there's a signal there. And it doesn't happen. And after a few days of this it starts to get boring and then you realize something else, that it's very likely that you're not going to get any published papers out of what you're doing. And this is very bad for a person's career. It's hard—you don't get pay raises when you don't produce results.

And so what we've learned is the people who do SETI are very enthusiastic, but they are indeed humans; they're not machines. And they need to do work which is rewarding and gives them a career path to greater opportunities, better salaries, and so forth. So the right thing to do, and it's what I hope we're going to do in the Breakthrough initiative, is engage people in this, but always they will do partially SETI, but also with another part of their intelligence, do standard astronomical research so that they will be doing something that produces results, keeps them from getting frustrated, and allows them to establish a record as a successful scientist.

Milner:      And, Geoff, maybe you can also elaborate on that, that indeed that is the plan, to record all the data and then maybe non-SETI result will come out?

Marcy:       Yeah, so there are two I think very exciting side benefits to the first Breakthrough initiative. While we're searching for SETI radio signals we will of course also allow pulsar searchers, quasar searchers, people looking for fast radio burst signals, to pick off our data, look at the data, and try to make detections of those objects anew. And maybe even more importantly, the data we do examine and the data we store may reveal new astronomical objects that nobody ever dreamed of. It's quite common when you open up new parameter space in astronomy, new frequencies, new detection thresholds, that you discover astronomical objects that you had no clue about, and they suddenly appear in the data because you're sampling a domain of signals that no one's ever sampled before. So there's a chance of discovering the unexpected.

Milner:      Why don't we ask one last question?

Warren Nettleford:    Thank you. Warren Nettleford from Channel 4 News. So for the panel really, going forward in the 21st century do you think then that private investment is the future of space exploration?

Marcy:       I'll take a first crack at this. The question, just to repeat it, I think was the role of the private sector in space exploration and astrophysics research generally. I think it's a very important question, it's a profound question, it's a question that casts a spotlight back on our current global economy and our society, how do we operate, how do we fund science, how do we fund indeed the arts. I'll give two short answers, and others may want to chime in.

First, in the domain of space exploration, of actually sending spacecraft, which is somewhat different than what we've described today, I think all of us in this room are impressed, is perhaps the right word, impressed that NASA, for example, is beginning to engage the private sector, contracting out major portions, booster rockets, capsules, and so on, and I think the realistic situation logistically, financially, managerially, is indeed that the private sector has a very important role to play. And NASA headquarters understands that, the White House understands that.

Back on astrophysics research, in fact there is a long history, going back over a century, of the private sector playing the key role. The Mount Wilson telescopes in Southern California, the Mount Palomar telescopes, both funded by the private sector. The Keck Observatory, the world's finest in my view, in Hawaii, those ground-based telescopes were all funded by thoughtful scientifically minded entrepreneurial folks.

Male:         Lick Observatory.

Marcy:       Lick Observatory, thank you. So there's a long history of the private sector stepping forward, using their resources to fund astronomy research.

Milner:      Well I understand that we probably don't have any more time. Oh, please, Martin.

Rees:         If I could comment, of course some research in terms of public good and its right the public should support it. And things aren't quite the same outside the U.S. And for instance, the world's biggest optical telescope is being built from public funds in Europe, and that's an example. But I think it's very good that space research is being funded by private people; they can afford to take higher risks than NASA can, particularly man space flights. And I think the SETI, which is dependent entirely on private funding, that's great. Although I feel that there's no reason why there shouldn't be supplementary public funding for SETI, because if you were to ask people coming out of a science fiction movie would they like some of their tax revenues from the movie hypothecated for a SETI search a lot would say yes. And I'd actually be happier if I was an American to defend public expenditure on SETI than on many rather arcane topics in pure research in other areas.

So I don't see why there shouldn't be public funding as well, but it's wonderful that in the U.S. private funding has dominated and also that in SETI searches it belongs to entirely private funding, and that's why this particular huge break forward is so welcome and we're so grateful to Yuri.

Milner:      I want to thank everybody for participating in this. Thank you very much.