No planet but this one

The Voyager 2 spacecraft has just passed through the heliopause and into interstellar space, forty years after it was launched.

On the one hand that’s a stunning technological achievement and a reminder of the wonderful universe we live in. On the other, it’s a reminder that humans will never go out to explore this universe, or even leave Earth in significant numbers.

Although Voyager 2 has passed the heliopause it is still within the gravitational field of the sun. It would take another 30,000 years to fly beyond the Oort cloud which marks the boundary.

These facts could have been computed when Voyager was launched though at the time its mission was limited to five years. But if they had been pointed out as an argument for the impossibility of interstellar travel, the response would surely have been that the problem would be solved by technological progress. Forty years before Voyager was launched, flying across the Atlantic ocean was a major feat. Forty years or so before that, the first heavier-than-air flight was undertaken by the Wright brothers.

Extrapolating one could reasonably expect that forty years more progress would produce massive advances in space travel including human space travel. In fact, though no one knew it at the time, the heroic age had already passed. No one has travelled to the moon since Voyager 2 was launched and, quite possibly, no one ever will. The promise of the space shuttle has been abandoned in favour of the 1950s technology of the Atlas rocket. Meanwhile physicists have closed off just about every possible loophole that might allow us to evade Einstein’s conclusion that the speed of light is an absolute limit.

The other achievement of the Voyagers and their successors has been a comprehensive exploration of the planets and moons of the solar system. They have revealed many marvels, but nowhere remotely habitable compared to, say, Antarctica or the Atacama desert.

The biggest lesson of our decades of space exploration is that Earth is the only planet we have.

43 thoughts on “No planet but this one

  1. Maybe the very wealthy and their robots will make it .Or maybe just very wealthy robots will. The rest of us are doomed to be stuck here on this boring miracle living out our mundane and unimaginably wondrous sentence .Wanting to be somewhere else all the time.

  2. There are likely to be many planets like this one but we just cannot as yet, and perhaps never, contact their residents – there are various explanations for why contact has not yet been made – a core one is that other civilisations might destroy themselves before they develop the capability of communication. The probable existence of life elsewhere is a serious point since in several billion years, at most, the earth will crash into the sun wiping us all out anyway – unless as seems almost inevitable, we wipe ourselves out much earlier than that though climate change, epidemics, wars or scientific experiments gone wrong.

    A cheery Xmas thought.

  3. But to people who were brought up after the end of the heroic age things don’t look that bad.

    Old people complain the cost of getting a kilogram into orbit has hardly budged. Young people think the cost of satellite communications has fallen by orders of magnitude thanks to electronics becoming a billion times more powerful.

    Old people complain we are not exploring mars. Young people look at them like they are idiots and point them to a live stream of images coming from the planet.

    Old people babble about the Fermi Paradox, young people get denied funding for space telescopes that could resolve continent sized features on planets hundreds of light years away.

    Old people shake their heads at the difficulty of getting a 500 tonne Daedalus style probe to a nearby star using nuclear fusion. Young people look at getting grams or kilograms there to do the same job using laser sails and other methods.

    Old people feel cheated they never got Star Trek. Young people were never promised the stars and see only wonder instead of failure.

    And if you’ve never heard young people say these things that’s probably because you’re old. Old people never listen to young people. God knows I never do.

  4. The physicists might be wrong. Maybe we could travel faster than the speed of light if we had the right technology. You never know, and since it won’t happen in the lifetime of anyone reading this blog, you never will know.

  5. The Fermi Paradox is easy to answer. The answer is implied in J.Q.’s original post. We won’t leave this solar system and only two probes have ever left it. Each planet with intelligent life must be enormously distant from the next planet with intelligent life, on average. Each advanced civilization will have sent relatively few probes out into the cosmos. The “density” of probes (probes per cubic parsec) in the cosmos will be vanishingly small. The chances of finding or getting a message from such a probe will also be vanishingly small.

    In addition, not only can intelligent civilization likely collapse before it sends out a probe, it will more likely collapse before any other probe reaches it. Finally, the universe is so big that light from the other side of the universe hasn’t reached us. Probes from such regions certainly can never reach us.

  6. I had a go three years back at an argument to the effect that manned space flight is impossible because of all the junk. Our sun is surrounded by the vast Oort Cloud of trillions of rocks and dirty snowballs of every size, stretching half the way to the Centauri neighbours. Since our star is boringly typical, other stars surely have Oort clouds too. Space is full of junk.

    If you try to go fast, collisions with football-sized rocks are fatal and radar detection looks impracticable. Go slow enough to be safe, and even local trips stretch to centuries. I’m afraid that interstellar exploration will always be reserved to robots, ours or others’ .

    I ended up with a twist in Fermi’s question. Where are all the alien robot spacecraft?
    *****.samefacts.com/2015/10/woolgathering/the-odds-are-approximately-3720-to-1/

  7. @James Wimberley

    It’s funny that you mention Larry Niven’s “Pierson’s Puppeteers” in your blog post. When I read Ronald’s comment about the “old and young people” upthread, his description of young people reminded me of the Puppeteers who, despite having advanced interstellar technology, had no desire to physically leave their home planet, apart from those of their species who were clinically insane.

  8. It’s easy to prove Quiggin wrong: most rich countries are run by people who clearly have a planet B in mind after we wreck this one; therefore planet B exists and if there’s not already a colony there, one is surely under construction. Either that or they’re suicidally short-sighted and that’s unthinkable.

  9. Smith9, we can directly observe long period comets, so some sort of reservoir of icy objects oort to be there.

  10. @Moz – I suspect Planet B is still Earth, but the social arrangements will have been rolled back a few hundred/thousand years.

    John some of your comments suggest you’re not familiar with current developments in space flight/exploration – which is OK – or are just really hard to impress. SpaceX’s reusable 1st stage, something which was still being laughed at only a handful of years ago, the landings of which have become so regular it’s almost a non-event? You want to drop the cost of getting to low earth orbit, this is how you do it. Japan’s Hayabusa 2 and other asteroid probes, rovers on Mars, China in the process of putting another rover on the moon. China has plans to put people on the moon by 2030, and given the Chinese and long term plans they’re a pretty good bet unless the country tanks for some reason. Private money like Jeff Bezos with Blue Origin and his serious aspirations to getting off Earth – another case of a person and organisation which can maintain its focus beyond the next electoral cycle.

    If all you watch is the slow spiral of the drain that is the Russian space program, or the rage/face palm inducing pork barreling and lost opportunities that is the US’s Space Launch System and related programs then sure it looks terrible, but outside of that it’s never been better since probably the Apollo era, and it’s looking a lot more sustainable.

    Maybe I’m just Ronald’s young person? (Actually I’m a bit old for that)

  11. You must be an old young person, LSJ. According to 1960s Star Trek earth’s first crewed interstellar ship was launched in 1996. Issac Asimov’s stories mention we are mining the moon in 2006 and have a Mars colony in 2010. In the early 80s kids were told the 2020 Olympics would be on the moon and a space shuttle would soon be launching every week. There are people so bitter there are no humans beyond low earth orbit there is an entire category of old people who apparently use the internet solely to argue that humans in space are superior to robots — although they appear to have mostly died. Things are way different from what people were led to believe they would be.

  12. @LJS

    But none of those things is more ambitious than what was achieved during the ‘heroic age’ – which I think is Prof Q’s point. The reusability of the SpaceX falcon first stage is a genuine technological advance, but at the end of the day it’s a non-crew rated, light launch vehicle that’s capable of reaching low earth orbit – not exactly a dramatic step forward in human space exploration.

    To me it seems more like it’s roughly the same as it’s been since the end of the Apollo era: ongoing robotic exploration of the solar system, ongoing activity in Earth orbit (including some human presence) that is mainly commercial and military, and no real plans for human space travel beyond that.

    But I think Ronald’s point about old and young people was well made – as a middle aged man, the future seems less exciting to me than it used to, but that is probably because, as a individual, I have less of it. The future doesn’t belong to me, but to another generation. I hope they have the luxury of dreaming of other worlds, rather than a struggle to stay alive on this one.

  13. LJS, all of what you write validates Prof John Quiggin’s comments. Yes, there are still some “stunning technological achievement[s]”, to use John’s words, but the rate of advancement in terms of where it gets us, has slowed from giant leaps to baby steps.

    Wake me up if and when Musk terraforms Mars. Hint: not gonna happen in any time span that makes sense to us, if ever.

  14. Smith9, Ronald: the Oort Cloud is the prevailing hypothesis in cosmetology. Planets are born from junk ejected by earlier supernovae. I’d like to see some reasoning telling me why the collision risks to a fast crewed interstellar spaceship can be ignored.

  15. @James Wimberley
    IIRC, the designers of Project Daedalus postulated launching an artificial dust cloud ahead of the spacecraft to control the collision risk. AC Clarke in one of his novels envisaged starship with a giant ice shield at the front.

  16. James, the Oort cloud really ought to be there because without it there’s not really an explanation for the existence of long period comets that seems sensible as far as I can see.

    As for reasoning collision risks to a fast crewed interstellar spaceship can be ignored, well, I’d like to hear some reasoning as to why I could swim nude in a Hawaiian lava flow without harm but i don’t think I’ll be getting any. And if I did I wouldn’t believe it. If you travel to Alpha Centauri you are going to get about 1,000 impacts with particles a tenth of a micrometer or more across per square centimeter of frontal cross section. That’s the butcher’s bill.

    But a crewed interstellar spaceship? Those are words that don’t really go together. Putting a crew on an interstellar spaceship is like building a kindergarten into an artillery shell. It’s not very safe and it makes the artillery shell less effective at its job. I mean — what would a crew do? Practice becoming Jedi? It’s not something that makes a whole lot of sense.

  17. Pr Quiggin – I have to agree.

    My problems with the grand space dreams tend to centre around the economics, but unreasonable expectations that technological advances will make them possible (any day now) figure in it too – progress and growth are not intrinsically exponential. I think more like an S-curve, following in aggregate the way individual technologies develop. Being at the steep part of an S-curve can fool you.

    Close to Earth, servicing Earth based needs and customers – communication and remote sensing – is space based activity that can pay it’s way. Beyond Earth it can’t. When it comes to the opportunities further out there, there is an abundance of hype but little substance. Not that there aren’t resources in abundance – they are just uneconomic to exploit resources.

    Colonies? Colonies that can’t pay their own way fade away and die. No proposal I’ve ever seen for space colonies – orbital, Moon, Mars – can pay it’s own way. Earth is littered with ghost towns – in circumstances far more conducive than the Moon or Mars – as testament to failed dreams.

    Asteroid mining? Staggering amounts of platinum group metals in metallic asteroids “they” say – this estimate would be based on it’s known presence within nickel-iron meteorites and is true. What is also true is that it is locked up at ppm in those nickel-iron alloys and would be extremely difficult to extract economically even if it were here on Earth. With pig iron worth about US$400 a metric ton delivered to the sea port of your choice as a rough benchmark for bulk commodities any asteroid mining venture has a very serious uphill battle – no analogy needed, given it is so uphill it is beyond the top of the highest mountains; NASA’s Osiris Rex mission aims to return up to 2kg of asteroid back to Earth, at a cost of US$500 million per kilogram/US$500 billion per ton. That gap between what is possible and what is economically viable isn’t amenable to waiting for just a bit more technological progress. Maybe exploration – more of those Osiris Rex missions – will find something unexpected that has better prospects. But maybe it won’t.

    Asteroid mines supplying water and other materials to space based activities at lower cost than from Earth? I doubt it but I suppose, maybe. But there is no separate space economy; the core activity itself, even if made more efficient by this, still has to be economically viable within the greater Earth economy. What economically viable economic activity is that?

    I had vague expectations of significant industrial processes in zero gee, that could kickstart something; best I’m aware of is a company sending flawed but potentially very valuable microprocessor chips for heat treatment in zero gee, apparently this is able to fix some of the flaws. It’s possible – even likely – the initial fabrication processes will be improved over time and then it will be all over for zero gee heat treatment. At multi-million dollars per tonne to put materials into orbit, the value of things that can only be made in space have to be extremely high. How many products – even hypothetical ones – are worth multi-million dollars a tonne?

    Interstellar? I think a space colony requires, at minimum, the equivalent of an entire working, advanced industrial economy to achieve self sufficiency – now put all that in a spaceship along with all the resources to last thousands (tens of thousands?) of year and you have an interstellar “generation ship”. Seriously? And if it reaches the new star and then what? Colonising Mars is beyond our capabilities, but colonising planets at Tau Ceti isn’t? And if there is a planet with life – why would anyone imagine human biology is even compatible? If there is existing life it seems to me that would make it much more dangerous and difficult to occupy, not easier.

  18. My knockdown argument on interstellar travel: If people could survive for thousands of years in interstellar space, there would be no need to leave the solar system.

  19. Correct.

    And I like to say: If we could terraform a planet in a life-supporting way then there would be need to leave this one.

  20. Of course, if for some reason you did want to send humans through interstellar space you could do so quite easily using the ABC method that uses three ships. Ship A goes first and clears the interstellar medium of dust and other particles. Ship B follows behind protected by ship A, and ship C travels behind ship B in the safest position of all. All ships will be designed to withstand normal impacts but if ship A has the misfortune to hit something large and is destroyed then ship B takes over its protective function.

    The A in Ship A of course stands for “Average”. It contains all the people who might be useful to have around but aren’t particularly special or vital, such as telephone sanitizers. The B in Ship B stands for “Brilliant” and contains scientists, politicians, philosophers, artists and so on. All the people who are really intelligent or talented.

    The C in Ship C stands for “Cunning” and it contains the people who are in charge of crew assignments.

  21. My take on interstellar exploration and travel is that humans have curiosity. For example, right now people are curious about what other solar systems are like. We are of course curious about a great many other things, but what’s in space is one of them. Provided our tool use continues to improve and we remain sort of human, or at least retain curiosity, then people are going to be curious about what’s out there. We can learn a lot with space based telescopes but we are still going to want to go there in some form otherwise the telescope ends up being so large one end could be in another solar system anyway.

    If earth remains peaceful and prosperous then I think we are likely to send probes to other stars. The cost and technological challenge will not be a problem for us provide we can refrain from screwing up too much.

    Sending biological humans across interstellar space is far more difficult than sending probes, but it could be done if people really wanted to. But it seems kind of sick to me. Using advanced technology to send humans through interstellar space would be as crazy as building some kind of global information and communications network and then using it to bully schoolchildren.

    It might make much more sense to just send information to another solar system and build the body at the other end. Or just simulate a body, which would probably be preferable. I mean imagine choosing Picard as your physical form and then realizing you prefer Kirk? Much better to be simulated so you can change on a whim.

    Of course, people with good taste will choose to look like Uhura.

  22. Me: “the Oort Cloud is the prevailing hypothesis in cosmetology.” Cometology of course, but the typo is so good I’d probably leave it even if we had editing.

  23. JQ said: “though no one knew it at the time, the heroic age had already passed.”. How is it you preceed the news JQ?

    Science Is Getting Less Bang for Its Buck
    “Despite vast increases in the time and money spent on research, progress is barely keeping pace with the past. What went wrong?”
    https://www.theatlantic.com/science/archive/2018/11/diminishing-returns-science/575665/

    Suggested Christmas /new year thread: The Future. 
    “The year 1904 was an exciting time for many Americans. Teddy Roosevelt was president and the Wright Brothers had just made their first successful flight less than a year earlier on December 17, 1903.
    Everything in the future was going to be automated and wireless, fast moving and electric.
    The world simply looked incredible from the vantage point of the early 1900s, at least if you were a young kid who didn’t know any better.”

    Kids In 1904 Had Wild Predictions About The Future Of 2019
    https://www.gizmodo.com.au/2018/12/kids-in-1904-had-wild-predictions-about-the-future-of-2019/

  24. Space travel is like Formula One racing. The machinery is designed only for a single purpose that costs a lot of money. Few people will ever enter a race. The benefits are outweighed by the costs. Yet they are held up as a great achievement.

  25. This planet is no doubt our only actual residence. But that wont stop people trying to escspe it.

    I agree with David Bowie that human narcicissum would drive us to explore inner space rather than outer space, irrespective of the “dismal science” of inter stellar imperialism. Its alot cheaper, easier and quicker to live in a fantasy world of wishful thinking. Our forebrain seems purpose built for contriving pretty lies to get us through the long dark night of the soul.

    Hollywood, religious cults, utopian ideologists, psychotherapists, drug dealers and lately Mr Zuckerbergs have al bet on that aspect of human nature, and that looks to have paid off handsomely.

    Virtual reality is do much more palarable than the actusl one, if only the game could go on gorevrr. The development of AI holds forth the tantalising prospect of Digital uploading of human personalities, which would certainly push the makers of video games up the Rich List. This would require a great deal of cokoutationslmpower.

    One plausible explanation if the Fermi Paradox us that Radio Civilizations only bother to get to Stage II and then construct Dyson Spheres to power their parallel universe generating computers.

    For all we kniw they msy gave already done that which might explain the daunting distances between solar systems and the eerie silence that has fallen on the space between them. The game designers want us to focus on our own backyard. As a nationalistic well-wisher of mankind i can only agree.

    PS The discovery that our galaxy hosts billions of probable exoplanets in the solar “habitable zone” is cause for despair, not elation. That is a huge population of planets that fill a key term in the Drake Equation:

    “ne = the average number of planets that can potentially support life per star that has planets”.

    Yet still not a peep, despite all the best efforts of SETI to strike up conversations with alien von Neumann probes with which the galaxy would be teeming by now

    The complete absence of any ETI radio signal implies that there are what Bostrom calks “Great Filters” to the evolution of enduring galactuc scsle civilizations. Moreover they are more likely ahead, rathet than behibd, us.

    No planet but this one, and maybe not even that.

  26. The information we currently have about the galaxy beyond our solar system is consistent with both:

    1. Humanity being the only species to have sent members any distance into space at all.
    2. The galaxy being totally Star Wars and teeming with intelligent, interstellar traveling life.

    If there was an advanced Star Warsy civilization around Proxima Centauri, the nearest star other than the sun, we’d have no way of knowing that. The only thing that we know is we know we don’t know enough to know anything definite. Except the very obvious such as no civilizations have arranged stars into geometric shapes in our clear field of view.

    So we can speculate all we want about great filters and so on, but to pretend we have anything that we can base any conclusion on — apart from things that are bleeding obvious — is as nutty as a lumpy chocolate bar.

  27. Ronald said:

    If there was an advanced Star Warsy civilization around Proxima Centauri, the nearest star other than the sun, we’d have no way of knowing that. The only thing that we know is we know we don’t know enough to know anything definite.

    Wrong.

    How big an antenna would the aliens need to detect Earth’s
    microwave broadcasts, and what could they learn about the Earth
    from them? Sullivan, Brown, and Wetherill discuss the information
    interstellar observers could deduce about the Earth from its TV and
    FM radio emissions in their 1978 article in Science (vol. 199, pp.
    377-388). They say that strong video carriers could be detected at
    about 25 light years with an antenna like Project Cyclops, one
    having an aperture equivalent to 3 km.

    Since detection depends on the power received across the area of
    the antenna, observers in the Alpha Centauri system only 4.3 light
    years away could detect strong video carriers from Earth if their
    antenna has only 3% the area of Project Cyclops. They could detect
    strong video carriers with a dish 520 meters in diameter, but they
    could not detect program material in our TV broadcasts even if
    their antenna was as big as Project Cyclops.

    http://www.contact-conference.com/c18c.html

    So we can speculate all we want about great filters and so on, but to pretend we have anything that we can base any conclusion on — apart from things that are bleeding obvious — is as nutty as a lumpy chocolate bar.

    Implying that Fermi, Dyson and von Neumann are “nutty”. Good luck with showing that lot a clean pair of heels.

    We do have some substantial evidence to makes informed guesses on the ptobability of ETI. Partivularly the widespread avaiability of lifes chemical building blocks – sulfur, phosphorous, oxygen, nitrogen, carbon, and hydrogen – the ime frames for evolution of life on earth, the frequency of mass extinction events, the galactic population density of habitable exoplanets.

    So far, no sign of other life. I am agnostic, leaning to disbelieving on the question of ET abiogenesis.

    I believe Tipler has offered the best resolutuon of the Fermi paradox, based on the absence of von Neuman probes queuing up in our orbit.

    https://en.m.wikipedia.org/wiki/Self-replicating_spacecraft#Implications_for_Fermi's_paradox

    Bostroms “simulation” argument deserves careful consideration but is of course completely untestable.

  28. My view is that the notion that an intelligent civilisation would seek to project itself physically through space if it had the technological means to do so is largely a product of a particular, historically specific, Western cultural bias.

  29. Jack, yeah… that’s what I see as a problem. Pointing out that aliens could detect earth if they wanted to and then concluding this means they are not there is not a sound conclusion to reach. It does not follow. If you like Latin it’s a non sequitur.

    All we can say from our end is if there is a civilization at Proxima Centauri they have not been emitting powerful radio waves our way at the times we have been listening or shining a giant laser pointer at us at the times we have been looking.

    If Fermi, Dyson, and von Neumann ever said we know aliens don’t exist because they could have detected us, then I have no problem saying they were nutty in that regard. But Fermi’s Paradox got its name from what was just a lunchtime discussion and as far as I am aware Von Neumann never never mentioned the topic. As for Freeman Dyson, well, he’s said some clearly nutty things about economic development so I don’t have a problem believing he’s said some other nutty stuff as well.

  30. Please tell me you are joking, Paul.

    To go boldly where no man or woman has gone before is clearly a cross-cultural phenomenon. The fact early humans had such a drive is observably obvious and explains why humans left Africa and inhabited all four corners of globe (bar Antarctica) thousands of years prior to there being anything so recent as “western culture”.

    In fact we can take it for granted that it is a hominid characteristic, given the archaeological record. Heck, even non-hominids are colonising imperialists.

  31. Paul, it’s not people using cultural bias that I regard as lazy. It’s them refusing to even think through the implications of those biases. If there was an expansionist culture that could travel at average of 10% the speed of light and set up interstellar bases capable of sending out probes they could explore and dominate the entire galaxy inside of 2 million years. If cultures capable of interstellar travel arise less than once every two million years on average then it is likely the first civilization to try it would be completely unopposed.

    But instead of “If alien civilizations exist and expand then we are probably living in a galaxy where one has and expanded set the rules,” we usually only get, “If alien civilizations exist they would expand and since we haven’t seen them they don’t exist.” This is lazy thinking in my opinion because it’s not even based on what expansionist humans do or did. Our history shows you get ignored until you have something worth stealing.

  32. Ronald said:

    Pointing out that aliens could detect earth if they wanted to and then concluding this means they are not there is not a sound conclusion to reach. It does not follow. If you like Latin it’s a non sequitur.

    I would be guilty of a falkacy if I made that stupid argument but of course I didnt which is why you didnt bither quoting my words. In fact my first point did nit address the probability of ETI. I merely empirically refuted your claim regarding the practicality of radio communucstin with nearby stars.

    You asserted that “we would have no way ot knowing of…an advanced Stsr Wars civilization around Proxima Centauri”, which is obviuosly wrong going by the state or radio astronomy. In your last comment you appear to have discreetly back tracked from this silly assertion.

    More broadly I said i was “agnostic, tending to disbelief” on the Drake equation probability of ETI. Based largely on the fact that Stage II radio civlizations would have long since popipulated the galaxy with von Neumanns probes, as we are already beginning to do.

    But i do not rule out ETI because obvious paucity of evidence and other plausible interpreations of von Neumann probe behaviour, eg they observe athropological ethics and dont make intrusive First Contact with primitive species. Or their probes use focused energy point to point means of communication not detectable with our diffuse energy radios.

    But the deathly silence that Fermi noted is not looking good, especially when set against thr vast number of habitable exoplanets. Quite a large numerator yet still no positive resukts. The frequency and mqgnitude of cosmologicak and ecologicsl mass extiction events may just put too many Filters in the way of ETI.

    Ronald said:

    If Fermi, Dyson, and von Neumann ever said we know aliens don’t exist because they could have detected us, then I have no problem saying they were nutty in that regard.

    None of these great scientists made a strong claim either way. Nor was I suggesting they dud. You fabricated that inference in your head. I was again refuting your straw man claim that “we can speculate all we want about great filters and so on, but to pretend we have anything that we can base any conclusion on is…nutty”. The skeptical arguments made by Fermi, Von Neuman, Tipler etc are basucally exploring the logical validity and empirical plausibility of Drake-type equastions which essentually extrapolate Darwinism on a galactic scale.

    If Darwin is right the galaxy should be teeming with life pace Drake and current cosmology. But it appears not to be. So something may well go wrong with the evolution of life. It seems like a good subject to make informed guesses on given humanitys evident suicidal tendencies.

  33. I’ll quote your words Jack. Or word:

    “Wrong.”

    I don’t think I’m wrong. I wrote, “If there was an advanced Star Warsy civilization around Proxima Centauri, the nearest star other than the sun, we’d have no way of knowing that.”

    And I wrote — “All we can say from our end is if there is a civilization at Proxima Centauri they have not been emitting powerful radio waves our way at the times we have been listening or shining a giant laser pointer at us at the times we have been looking.”

    And you wrote, “which is obviuosly wrong going by the state or radio astronomy.”

    But it’s not wrong, it’s correct.

    And because I once read a pamphlet on Charles Darwin (forgive me if you were referring to some other Darwin) I will point out that on the subject of abiogenesis he said — and I quote — “the intimate relation of Life with laws of chemical combination, & the universality of latter render spontaneous generation not improbable” in private correspondence, but he never published anything on it because he knew no actual conclusions could be drawn given their state of knowledge at that time and the impracticality of conducting experiments at that time. And so he confined himself to speculation.

  34. Paul: “My view is that the notion that an intelligent civilisation would seek to project itself physically through space if it had the technological means to do so is largely a product of a particular, historically specific, Western cultural bias.”

    Yet I have seen clear evidence that the Lizard People from Orc already walk among us.

  35. Ronald said:

    if there was an advanced Star Warsy civilization around Proxima Centauri, the nearest star other than the sun, we’d have no way of knowing that… it’s not wrong, it’s correct.

    [Emphasis added]

    As i orinally stated your first sentence, on the face of it, is incorrect or incoherent with the rest of your argument . We do have a way to conduct inter-stellar conversations with ETI: radio telescope.

    Ronald said:

    All we can say from our end is if there is a civilization at Proxima Centauri they have not been emitting powerful radio waves our way at the times we have been listening or shining a giant laser pointer at us at the times we have been looking.

    Polite applause for stating the bleeding obvious. That statement is trivially true, not just for SETI, but for all for all forms of communication.

    Conversation is a two-way street so if one party or bith parties are not speaking or not listening at the same time then it doesnt work. That goes for the reclusive man next door who works night shift. Or your wife and yourself, in one of those poisonously enduring marriages.

    But even that concedes too much ground. If ETIs are pumping out long enough or strong enough signals (plausible for Stage II radio civilizations) we will pick em up, whether they want to talk or not. Eavesdropping is an occupational hazard in radio comms, as any Signals corp will tell you.

    Ronald said:

    On abiogenesis… Darwin…in.. private correspondence….”thought it not improbable”…never published anything on it because he knew no actual conclusions could be drawn given their state of knowledge at that time and the impracticality of conducting experiments at that time. And so he confined himself to speculation.

    Again with the stawmen and bait and switch.

    I metely argued thst abiogenesis, whether terrestial or extra-terrestial, is clearly implied by Darwinian theory. An assumption shared by most participants in the ETI debate. And by Darwin himself, as you so helpfully show. So thankyou for proving me correct, chspter and verse, straight from the horses mouth.

    I dont think one can draw any conclusions from Darwins publication wariness. He was an “eminent Victoruan” in his own right and bent ovrr bacjwards to stay on the right side of respectable opijion. Also was notorious for holding back publication, and not credting rivals. He sat on the “origin” for over a decade, after cribbing the best bits from Malthus.

    More generally none of the scientists i have quoted (except Tipler, a mathematician) have come down firmly on one side or the other of this debate. Nor have i for that matter.

    What they have done is suggest reasons or point to evidence which makes one conclusion more probable. This is not “nutty” – fancy a person with your poor comprehension skills implying Von Neumann is nutty) – it the method of hypothetical science.

  36. Sullivan, Brown, and Wetherill discuss the information interstellar observers could deduce about the Earth from its TV and FM radio emissions in their 1978 article in Science (vol. 199, pp. 377-388). They say that strong video carriers could be detected at about 25 light years with an antenna like Project Cyclops, one having an aperture equivalent to 3 km.

    Only if the receiver bandwidth is filtered to less than .1 Hz.

    http://internal.physics.uwa.edu.au/~agm/eme-articles/1979.pdf

    But surely scanning the entire UHF range one day at a time in .1 Hz increments would take a ‘dedicated global network of high powered receivers’ several billion years…

    Meanwhile, analogue television on Earth evolved and was phased out in less than 100 years. And DTV which replaced it requires 75-90% less power to broadcast.

    Which suggests the probability interstellar life could detect a stray carrier signal originating from Earth is less than one in one quintillion.

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