Paul Horowitz and the Search for Extra Terrestrial Intelligence

I recently had the opportunity to attend a lecture by Harvard Professor Paul Horowitz. It’s a name you likely recognize. He is best known for his iconic book the Art of Electronics which is often referred to not by its name but by the last names of the authors: “Horowitz and Hill”.

Beyond that, what do you know about Paul Horowitz? Paul is an electrical engineer and physicist and Paul has spent much of his storied career learning and practicing electronics for the purpose of finding intelligent extra terrestrial life.

Link Budget: How Quietly Can We Hear?

The first thing Prof. Horowitz taught us was that the signal-to-noise ratio (SNR) over 1000 light years with an Arecibo-equivalent antenna at each end is four orders of magnitude above the cosmic background radiation. That is quite good for communications. It is entirely plausible to transmit signals between intelligent extra terrestrial civilizations if they exist and this plausibility motivates the search for extra terrestrial intelligence (SETI).

Paul’s involvement goes way back. On of his earlier contributions to SETI involved the use of conventional dish-based radio telescopes, listening at 1425 MHz, looking for strong narrow band emissions. One example is his ‘suitcase SETI‘ system built from wire-wrap boards and other early 80’s tech. Many such emissions were detected and logged, but unfortunately the duty cycle of observation was so low that they were never able to confirm.

Duty Cycle: How Frequently Can We Listen?

The key to SETI is duty cycle. ‘Pencil beam’ radio telescopes proved to be limited by the fact that they could only look at one signal/direction at any given time. Software was in place to quickly re-visit for several minutes in the event of a narrow band signal detection, but none of the many narrow-band extra terrestrial signals were ever confirmed (observed more than once). Paul chalks this up to duty cycle, the percentage of time and area of the sky searched. In other words, the more area of sky you can search and the more often you can search it, the better your chances for a SETI detection.

With this in mind, Paul is leading the development of a new optical sensor array assuming that ET might be trying to reach other intelligent civilizations via pulses of coherent light. This effort will use two separate arrays that can see the entire sky above their location at the same time. Two arrays are used so that coincidence detection can filter-out spurious signals, where the same pixel on both arrays must trigger a detection at the same time in order for any detection to be logged.

View the lecture for yourself here:

Are We Alone? Are We Alone in Our Own Galaxy?

We are almost certainly not alone. We are probably not even alone in our own galaxy. But according to the Drake Equation it depends on how long an intelligent civilization will last (L) before either destroying itself, its planet, or being wiped out by a celestial event. A large L factor increases the number of overlapping advanced civilizations thereby increasing the likelihood that transmissions will be exchanged. Lets just hope that the average value for L is very high!

Paul Horowitz paid a visit to our Radar lab and presented a lecture on his latest efforts in the Search for Extra Terrestrial Intelligence, from left to right Greg Charvat, Amanda Wozniak, Paul Horowitz, and Devon Clark.

What an experience to meet Paul Horowitz and hear first hand his experiences building equipment to listen beyond our civilization. I have been a fan of SETI since early in my engineering journey, and I even built a radio telescope receiver in high school. There are still so many frontiers to explore, and building custom hardware to communicate with sources of unknown origins, using unknown technologies and protocols is a great place to let your skills wander.

102 thoughts on “Paul Horowitz and the Search for Extra Terrestrial Intelligence

  1. Cool radio telescope. I want to build one in high school (1970’s) but did have access to any surplus (hell, my neighbors would not cough up old tube based clock radios because they thought i’d shock my self. The jokes on them, I been shocked many times since then). Nevertheless, despite my failure to build my own telescope, I still had sufficient nerd cred to be disqualified for a prom date.

    By the way, cool high school photo in the gallery. I wore a denim jacket as my sole act of rebellion (even the “hoods” came dressed in suits).

      1. Favorite quote from The Simpsons:

        HOMER: I suppose you want to probe me. Well, might as well get it over with…
        [unzips, pulls down pants and bends over]
        KANG: [rearing back and averting his eye] Stop! We have reached the limits of what rectal probing can teach us.

  2. Hmm, does anyone really believe there are aliens out there? (for real?) This seems like it borders on the search for other things that we don’t have any proof exist. Lochness monster at least has some fake photos to fool us, but is there even a shred of any evidence that there is something to be found?

    I was looking for a pair of shoes once for hours, found out they had been thrown in the trash. So no matter how hard I looked, I would never, ever find them. But at least they existed at one point to justify the effort.

    1. For example, I don’t believe in god because there’s no proof one exists. But if I were shown proof of a god, I would then hypothesize that there might be more gods out there. We’ve been shown proof that life exists, now we hypothesize there might be more of it among the stars.

      1. You first need to define god’s existence. Because if you accept the existence of the idea of god as existence of god (and IMO you should, because that idea can and in many people indeed DOES influence behaviour), then not only god exists as long as a single person grasps the concept of deity, but also there are as many gods in existence as there are individual minds that bear any idea of a deity.

    2. There are a surprising amount of people including myself who have seen or video’d ufos, not just the unreliable but highly educated men. It is not a case of attributing such lights to satellites or weather balloons, because many of them move in manners that cannot be natural or manmade.

        1. UFO may or may not = ET, but 100% chance it = WTF
          In other words it’s “unknown”.

          Do little gray men visit Earth, probe people’s anus(es?), have a violent vendetta against cows, and mess with people by making weird shapes in farm fields? IMO possible but very improbable.

          1. They are on such a high level of intelligence that we cant possibly fathom why anal probing is necessary. Maybe they try to communicate by that method with us, like the blue smurfs in Avatar do with their Dreadlocks

    3. Yes I think there is a fair chance there is life elsewhere but no I don’t think you have some advanced technology aliens secretly flying around earth.
      I’m also of the believe that an advanced species will use radio for communications all that long (on astronomical scale) for that matter, so I’m not sure there is much point in looking for alien life that way. But it’s the only viable way we humans have really at this point to look for any evidence over the distances we are talking about, so I guess it’ll have to do.

      Now how likely actual intelligent life is as opposed to just general basic primitive microscopic life is yet another question and it might well be the development of a brain is actually an incredible fluke in this universe that isn’t repeated.

        1. From the numbers I’ve seen, there is a number big enough that means it will never happen. Explosion in a print factory creating a book is an obvious analogy. How many trillions/quintillions/gazillions of times can you blow up a factory, and would you truly believe there is ever a chance, _ever_, it will make a book?

  3. We had to cover our rental textbooks in jr high. The choice was advert covered sheets from the school or self made paper bag covers. I had the Drake equitation on the plain paper cover of my math book. Other subject’s books had similar “titles”.
    It was only a year or two old. In science we discussed Barnard’s star as it had a unconfirmed wobble. We are now filling in some of the factors in the Drake equitation.

  4. In addition to the obvious life-hospitable factors, such as a temperature suitable for liquid water and a suitably-sized sun, there are many more factors required for a planet to be fit for human-like intelligent life (with more factors likely to be discovered):

    Suitable gravity for atmosphere, with appropriate pressure, to retain oxygen and water vapor but not hydrogen; suitable axis rotation rate; appropriate tilt of planet axis for seasons; suitable orbital distance from star to prevent tidal locking; magnetic field from planet molten core to shield atmosphere from cosmic radiation; sufficient planetary plate tectonics for crustal mineral recycling; suitable distribution and shape of continents to sustain deep ocean currents; sufficient supernova-produced actinide radioisotopes in planet interior for decay heat; suitably-sized moon to create needed tides and stabilize planet rotation; giant outer gas planets to prevent large asteroids and comets from frequent collisions with planet; suburban galaxy location providing sufficient distance from recent supernovas; far enough away from gravitational disturbances by higher density of stars in inner area of galaxy; only minor orbital variations caused by small chaotic gravitational interactions between nearby planets.

    With these factors the number of planets in our galaxy capable of sustaining human-like life is much smaller than the media and SETI astronomers imply in their articles. The estimated probable number is likely very close to the experimentally known value of one.

    1. +1000

      This is a very intelligent and compelling argument for why SETI seems to be a waste of time and therefore a fraud to all but the naive.

      I could also add another list to that, one that shows that advanced civilisations would not necessarily be detectable even by their waste infrared emissions. Quantum communications is possible, generating neutrinos and detecting their spin states is possible, thermal diodes are possible, right now on Earth. For reasons of security and energy efficiency an advanced civilisation will not advertise it’s existence nor will it radiate energy as all waste will be dumped back into the fusion core/s that they are using, be that a star or something they have engineered. Temporal efficiency is also another factor that drives technology and this is where quantum links are essential.

      If they are 100 years younger than us, we will not notice them, nor will we do so if they are 100 years older. That pretty much slams the window shut on SETI’s fingers.

      The only thing we can say about SETI with certainty is that their chances of success leading to genuine two way communications with another civilisation are greater than zero, but the odds are equal that we are in a simulation run by said civilisation anyway. :-)

      1. Simulation theory is a giant logical fallacy. The argument goes “If we could make many simulations, then there would be a lot more simulations that reality, so the odds of us being in reality are low, so someone created simulations and we’re inside one.” It assumes 1. that it’s possible to stack many very complex simulations inside each other, 2. That alien life has an incentive to run such simulations, 3. That they did and they ran a lot of them, which then nested more simulations inside them, 4. That simulations can become conscious, 5. The odds of being in any given simulation are equal to the odds of being in reality. And that’s not even getting to weird philosophical stuff about what “reality” even means. Just because Elon Musk believes it doesn’t make it true.

        1. Nope you simply don’t understand the idea fully.

          There is just one conscious entity, you, I am just part of the simulation and all that you know is simulated sensory input and constructed memories, there is no need to actually simulate the universe, only your perception of it. The problem is nowhere near as large or as complex as you imagine.

          Go deeper Matt, go deeper.

          1. That makes even less sense. If you’re the only conscious mind then who started the simulation? By definition a simulation is begun by a consciousness. If nobody started it it’s not a simulation, it’s just reality with onky ine conscious mind. Unless you mean you’re the only mind in the simulation and other minds exist outside it, in which case everything I said still applies.

          2. Matt you really need to get used to admitting you are wrong because using lame straw men is no substitute for having intellectual integrity.

            You Matt have no way of knowing if you really exist or if your mind exists on it’s own within a simulation that just feeds in perceptual data. There is simply no way out of that paradox.

          3. I’m not saying it’s impossible, I’m saying there is no evidence whatsoever and all of the statements that we “probably live in a simulation” are based on logical fallacies. In particular I’m refuting the argument recently made by Elon Musk.

          4. But you are talking to me, 𐂀 𐂅, on HAD and I am not Elon Musk. You are even confusing terms, evidence of their being a sim is proof, not a measure of probability, in fact logically if you have proof the probability becomes 100% Duh!. There is not likely to ever be proof even if it were true as the sim would just get rolled back to the point before you found the proof. This may have already happened to you a million times and you simply wouldn’t know. However there are a few ideas about how to examine the universe to find such evidence and they centre around the idea of pixelisation. If you knew anything about the topic you should already know about that, not that it matters given the roll-back gotcha.

          5. Study quantum field theory and see what side of the fence you find yourself on with regard to the quantum fields being continuous or not. If they are limited in range and quantised then the sim theory is possible. Is reality infinitely divisible or not? However that does not get around the problem of you never being able to know reality directly and only ever having your sensory input and memories to cognate with.

            It is a pradox as the logical arguments for and against can contradict each other because we can never frame the question without being trapped inside the frame. It is actually a variation on the god meme, you can’t prove that one one way or another either because all you can ever know is within the universe and what you need to test/examine is outside of it.

            So do you really need specific links about quantum field theory, or can you google and youtube search those yourself?

          6. There’s a fatal problem with the simulation theory: and that’s thr problem of complexity and energy consumption growing very quickly beyond all limits.

          7. No Marek, see what I have said to Matt, your view of the problem is naive because even a comprehensive multi-agent sim can be sparse, but not even that is required.

          8. Of course I need specific links? Quantum field theory is an entire field of study and I’m asking you to back up your specific argument with evidence. I’m beginning to think you’re trolling me. Also Marek makes a good point.

          9. No marek does not make a good point, because I have already pointed out that the sim only needs to simulate a single mind’s memory and perceptions, not an actual universe. Even if it did have more than one mind the sim can still use a very sparse and self trimming data set. You simply have failed to move on past that initial point. I am not trolling you, you just are not trying very hard to get you head around some very simple logic, or you are incapable of doing so. Your request for evidence ignores the points I have already made, there is no point commenting further until you demonstrate that you can grasp the basics. I have pointed out where others have said they need to look for evidence, and the nature of that idea plus the problem with seeing that as real proof anyway.

          10. You have to decide which description of reality suits you.

            Is it this,

            And are continuum limits finite?

            Perhaps you don’t understand what the word paradox means? There is more than one logical way of describing reality and they are not necessarily compatible even if valid within themselves. Make them compatible, unify them, and you get a Nobel Prize.

            And to put my view in a snarky manner, you Matt are proof that a sim would not require much complexity at all. So there is the proof you ask for, you are the proof. LOL.

            How many bits does it take to store “Derp Derp Derp…” anyway, 3? One for the symbol and two for the run length?

          11. You have no links you can provide to any relevant work on the subject? The burden of proof is on you to convince others of your theory. If all you have to offer is condescending ramblings about pixels and “quantum field theory” you won’t get many people interested in your idea. If you or anyone else has any clear outline of what you think sim theory is and why you accept it I’d like to read it.

          12. Oh but I have Matt, as everyone can see. You have only achieved one thing in this dialogue, you have demonstrated that you are a prize idiot.

            It isn’t my theory anyway, and I already pointed that out, this is a reoccurring problem with you, enough to wonder if you abuse THC and have a short term memory deficit.

            Behold the Matt version of the universe sim.

          13. I have, Matt..Josh… whoever, I have, see the URL in my post.

            It is pretty obvious that the discussion is beyond your ability to track, you probably don’t even understand that as far as computation is concerned space and time are interchangeable. Did you know that, and if so do you realise why this is relevant to your claim that a sim would be unmanageably complex?

            And here is the funniest part for me, go back to the start of the thread, I never said a sim was probable, I did imply something about something else in relation to the probability of being in a sim. Do you recall now?

            OK I’ll spell it out for you, both are improbable and one is untestable with the other being very hard to test because it requires interaction over vast amounts of space-time and even if you were able to test it you still can’t prove that your result wasn’t just part of a sim being run by aliens rather than a direct communication with real aliens. This is self contained logic that you either understand or you don’t, all you achieve by denying it is that you demonstrate that you can’t get your head around it.

          14. The link you provided is too broad. This is like if I told you unicorns are real and you asked for proof so I linked you to an intro biology textbook. You wouldn’t be convinced.

          15. Name or descriptor? Show me enough respect to argue a point about what I have actually claimed or don’t expect respect or even diplomacy from me.

          16. Irrelevant Josh I made a logical point and there is nothing to prove outside of that logic because there has been no proof offered for the existence of aliens or the probability of their existence only logic. You can’t have your cake and eat it, prove any theory about aliens first, then look at what others have proposed to test the sim theory if you wish, furthermore I have already pointed out that the sim argument is a form of the god meme, then again so is string theory. Go back and read what I have posted next time it will help you to avoid looking like a fool.

            And you really need to work on your one URL posting skills. Having something actually relevant to post would help too.

          17. Something else that I hinted at that has been ignored or missed completely.

            There is no correlation between simulated time units and real time units, therefore if you are in a sim you cannot know how long any time period for you took to be calculated in real time units.

            So what does that prove (logically) about the complexity burden of runing a sim? The simulator can be “smaller” than the simulation, but it has to run at a multiple of the time period within the simulation.

            Also here is a key point to consider about “proof”, physical proof is not actually a proof, only logic can have an internal integrity that is able to prove something, physical evidence is always an approximate record of a limited observation. So when you ask for proof, thinking that means evidence, you are completely missing the point about what proof is. Logic and mathematics provide proofs yet they still allow a paradox to exist Godel demonstrated that.

            Anyway I finished “arguing on the internet with idiots” about this, you lot clearly don’t even understand the nature of computation very well but still think you can make a statement about a sim being possible or not based on the required complexity then you go on about “proof” but don’t know what the word means.

          18. The “physical proof is not actually a proof, only logic can be used to prove something” argument is used extensively by Ken Ham, the creation museum guy who teaches kids that humans rode dinosaurs. He gets that by refuting all physical evidence and insisting logic and the bible are our only guides. Once you reject physical evidence you can “prove” anything.

          19. That is a fallacy in itself as one person’s misuse of mathematics or logic does not prove anything about anyone else or about the validity of their logic. You have to examine the actual logic to see if it is complete.

          20. What I can’t wrap my head around is, hypothetically, why would some advanced civilization create such a realistic simulation/AI?
            What do they want to know, why are we so important to them? Why are we stuck in the box?

          21. One scenario is an alien historian trying to understand human history to determine why we became extinct. The sim is constructed from information, artefacts, found by an AI probe during an exploratory expedition to our solar system . We are living in a historical sim.

            But the “why” doesn’t really matter the entire idea is actually a trick to make people think about their reality differently. See what the game is now?

          22. Says: I’m wondering why there would be evidence of a pixelation in a sim, since the quantum research is being done by the simulated researchers and not by me. Or no researchers at all if I never see them. Just data the sim feeds me.

          23. Yup, that is the problem that proposal has, hence my assertion that it is impossible to prove, even if you did hack your way out of the sim they would just roll it back in time and move forward again with tweaked parameters.

    2. Moon has to come from a collision with a smaller planet to redistribute heavier elements. Must have rain to erode chemicals into the seas. The rain puddle-lightning bolt routine isn’t going to do it.

    3. Also, I would add the obvious. The closest stars are really far away. So if we do get any signals, it would be from a billion year old civilization, right? How old is the universe? We have to take that into account now, because if it takes a couple billion years to even make life, it would have to have started at the SAME TIME as it did on earth.

      Why? Because the universe is only 14 billion years old. That is not many billion years to work with.

      So, now you have the issue of a finite amount of time for all of these life forms to start, and then one of them to be billions of years _early_ than us, so their transmissions can reach us.

      It’s seems to far fetched, I am stunned so much money has been put into this.

      1. A couple decades ago, I had a scientist tell me they had not found a solution to 3 body gravitational interaction. This video shows complexity I never imagined!

        1. It demonstrates very clearly why complex modulations of signals, of cosmic origin, can be attributed to simple processes and should not be taken as evidence of intelligence.

  5. What about the GAF (Give A F*ck) factor? How many messages have we sent out? How many messages are we likely to send out? We don’t seem to care about communicating so why should anyone else?

  6. I read a few years ago in an online Q&A with someone involved with a major SETI array, don’t recall his name, that WE could detect the “RF leakage” from OURSELVES from only one light year away. Another scientist has claimed, correctly I think, that our RF emissions will soon be virtually impossible to detect at cosmic distances due to our shift to more sophisticated and efficient modulation techniques requiring less TX power and fiber optics. So, unless the aliens just happened to be pointing high gain antennas in our direction during our, what, 80 year detection window, good luck. The same goes for detecting THEM within a tiny time window in the (hopefully long) lifespan of a technological civilization.

    Now, if a civilization were -STUPID- enough to break the wise rule of -keeping it’s mouth shut- in an unknown neighborhood and broadcast its location via high power RF, something might be detected, but once again the likelihood of matching broadcasting and listening time windows and the need to have the high gain RX and TX aimed at each and thereby detecting each other during their scans of the entire sky make the odds of detection tiny.

    So, I think that even if one assumed many technological civilizations in our local area our odds of hearing them via RF are tiny. Thus, I’m not at all surprised that we’ve heard nothing. I think the detection of planetary atmospheric components of life will be more promising although the detection of technological civilizations is once again limited by a very narrow time window as they will probably also go from a high polluting to virtually zero polluting civilization very quickly on a cosmic time scale.

  7. Anal probing? Just proves how smart “they” are: they know that all our brains are in our asses. (Yes, in our donkeys, but also in our colons, too. What little is left over from the donkeys).

    Get a life, folks. As Carl Sagan pointed out: you look up and don’t recognize something in the sky–no problem. It’s an UNIDENTIFIED flying object. No further discussion needed, required, or wanted.
    See how easy all this stuff is?

  8. They are likely out there.
    They likely know about us. They have no interest in communicating with us.
    We will never detect their communications due to advanced noise like modulation methods.
    We might one day detect some unusual energy distribution that is very unlikely.

    They might ( small chance ) intervene in our affairs when we are on the brink of destroying ourselves.

    1. +2

      This is being offered in all seriousness–

      First, put yourself ” in the shoes” of an intelligent race, which also has the means to know all about us–either directly or indirectly. OK. Ready? Now…

      I FIRMLY believe what was said by Calvin, speaking to Hobbs, in a Gary Watterson Calvin and Hobbs cartoon. The subject was the existence of extraterrestrial life. Calvin said something like (it would take too long to find, but this is close),

      “I think the best proof that intelligent alien life exists elsewhere in the universe is that they’re staying away…”

      Wouldn’t you?

  9. In the Drake equation are two parameters:

    fₗ, the fraction of those planets, that actually develop life
    fᵢ, the fraction of planets bearing life on which intelligent, civilized life, has developed

    We know about how life appeared on Earth, which was basically as soon as the water stopped boiling. Whether it arose de novo or was imported from elsewhere is not important, regardless of the source, fₗ is probably close to 1, and not required.

    fᵢ on the other hand, I think is an oversimplification. Again using the one example we know of, after life appeared on Earth, it didn’t evolve beyond algae mats for almost 4 billion years. Only 600 million years ago did we get the Ediacaran Fauna (failed) and 450 million years ago, the Cambrian Explosion (in progress). Delay this by a billion years, and with the Sun gradually getting hotter as it ages, the Earth at that time would be inhospitable. This step, the evolution of life to complex forms within the time limit, was the “hardest”.

  10. I am no astronomer, physicist, chemist, or biologist, but I lightly follow this. We basically use light or RF to figure out atmosphere and elements and there are those zones..

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