What Are We Learning from SETI?

The weekend is a good time for a topic like SETI — the search for extraterrestrial intelligence. At PhysOrg we came across UK launches Search for ExtraTerrestrial Intelligence Research Network. The first half of the article is about stuff like this:

A network has been launched to promote academic research in the UK relating to the Search for ExtraTerrestrial Intelligence (SETI). The UK SETI Research Network (UKSRN) brings together academics from 11 institutions across the country. The network’s Patron is the Astronomer Royal, Professor Martin Rees. UKSRN will present current activity and consider future strategy in a session and panel discussion at the National Astronomy Meeting in St Andrews on Friday 5 July.

That meeting has already come and gone. Here’s the new outfit’s website: UK SETI Research Network. It doesn’t tell us much, but it gives a link to the website for the conference: UK National Astronomy Meeting NAM2013 1-5 July 2013. We don’t find much there either, but the PhysOrg article has some good material which ought to get your juices flowing. For example, they say, with bold font added by us

Back in 1950 during a conversation on SETI, the physicist, Enrico Fermi, posed the question ‘Where is everybody?’ The paradox between the high estimates for the probability of the existence of extraterrestrial civilizations and the lack of contact or evidence remains a key area of SETI research. Dr Anders Sandberg, of the Future of Humanity Institute at Oxford University, is investigating the question of how far away in space and time a civilization could start and still have a chance of interacting with Earth today.

The Fermi paradox is at the heart of all SETI work. Let’s read on:

“If this were a very limited range, the Fermi question, “Where are they?” would be easy to answer: they couldn’t have got here yet. However, we show in our paper that, beyond a certain technological level, civilizations can spread not just across their own galaxy but across enormous intergalactic distances. This is mostly limited by how fast their devices are and the expansion of the universe. There are millions or billions of galaxies from which a civilization could have reached us, if it were established early,” said Sandberg.

So where are they? We continue:

Sandberg and his colleagues have concluded that the answer to the Fermi question is more extreme than normally thought. “If life or intelligence is rare, it must be millions or billions of times rarer; if advanced societies wipe themselves out, or decide to not go exploring, they need to converge to this outcome with extremely high probability, since it only takes one that escapes this fate to fill the universe,” said Sandberg.

Great stuff here, but we’ll have to skip a lot. Here’s something to ponder:

[Dr Austin Gerig, senior research fellow in Complex Networks at the University of Oxford] and his colleagues have focused on a specific consequence of this reasoning, called the ‘universal doomsday argument’: long-lived civilizations must be rare because if they were not, we would find ourselves living in one.

“If most civilizations are small, then our own civilization is likely to be small, i.e., it is likely to die out within the next few centuries. Our research indicates this is the case, but that our estimates of survival are greater than previously thought using a more traditional form of the doomsday argument,” said Gerig.

There’s lots more in the article, and there’s also your own speculations — Where is everybody? If they’re out there, why don’t we see any trace of them?

Your Curmudgeon’s own primitive thinking is like this: Assume we could travel at, say, around one-third of lightspeed, so that a large shipload of settlers could travel to a nearby star in about a dozen years. We can’t do anything even close to that now — our chemical-propelled rockets travel at far less than 1% of lightspeed — but it’s not unreasonable to project that we could develop the technology to do better.

Then assume that stars with habitable planets are, on average, not more than about 5 light years away from each other, so we can gradually expand our domain without encountering any impossible distance barriers. And then assume that each new settlement — if educated and well-equipped — could develop itself sufficiently so that in, say, about three generations (less than a century) it would be able to launch some of its own people to settle the next habitable system. Population growth will be the biggest constraint to such rapid expansion, but once a new world is settled more ships will arrive, so population shouldn’t be a problem.

If those assumptions are reasonable — and we’ll all be dead before anyone really knows — then the domain of human-occupied space can expand every century at a rate of roughly 5 light years in every direction. That’s a sphere which grows 10 light years in diameter every 100 years. In a thousand years the sphere of human-occupied space will be 100 light years across. That’s nice, but it’s no big deal. There could be several isolated pockets like that here and there in the galaxy, but they’re so far away that we’ve never noticed them. However, it doesn’t stop there.

Multiply our expansion time by 1,000, and conservatively assume no technological improvements over all that time. You get a sphere of human space that’s 100,000 light years across in only a million years. Think about that. The Milky Way galaxy is roughly 100,000 light years across. If our projection has any validity, then we could occupy the whole galaxy in a mere one million years — that’s a blink of an eye in the lifespan of the galaxy. If we could do it, then why hasn’t anyone else already done it?

There could be many reasons why we appear to have the Milky Way all to ourselves. There’s a small library of literature on the subject. Whatever the reason may be, at the moment we seem to be presented with an opportunity that comes only once in the lifetime of a galaxy — we can be the first to occupy it all. So why don’t we get busy and do it?

If some other species does it before we do, then we’ll be dependent on their benevolence for our very existence. Maybe they’ll treat us well (they’re often so kindly in the movies), but maybe they won’t. Our own history of encountering primitive people around this world isn’t very pretty. There’s no reason to expect that some other species will behave better toward us than we have done to our fellow humans. We’ll probably behave better than we have so far, but it would be best to let others worry about our benevolence rather than the other way around. Anyway, if we can be the first to occupy the galaxy we ought to get started.

Copyright © 2013. The Sensuous Curmudgeon. All rights reserved.

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22 responses to “What Are We Learning from SETI?

  1. I think the biggest problem we have with space travel is not the speed and distances involved. It’s how will we survive it. Space is really harsh to the human body. One of the biggest problems is radiation. There are only two ways (of which I’m aware) that we can deal with it. One is shielding; the other is treatment. Shielding has thus far been a no-go. It’s either too heavy or requires too much energy to make it practical. The only other option is to find treatments that will essentially cure us constantly from the bombardment of radiation our bodies will receive on long-distance space travel.
    As for the “benevolence for our very existence”, you mean all aliens might not be like ET? Really!?!?

  2. The PhysOrg article, considering the Fermi Paradox, contemplates

    if advanced societies wipe themselves out, or decide to not go exploring

    We need look no further than our own dear planet for examples of how ‘advanced’ societies could so falter. Compare and contrast our intellectual and technological advances since the Enlightenment and the shrill hucksterism of the Discoveroids, Ol’ Hambo, Rev. Rives &c &c &c

  3. There are a couple of other arguments against rapid expansion of a civilization into the galaxy.

    Assuming alien civilizations had the technology to cross interstellar distances, they would surely also have the technology to terraform worlds in their home systems, create eden-like places to live, control their populations and resources, and so on. Life could be very good. In that case, who would volunteer to risk a voyage to an unknown new star system, and endure the hardships of establishing a colony away from the luxuries of home? Would they send their prisoners (like the British did with Australia)? It might be that advanced civilizations grow too comfortable and aren’t motivated to settle new systems.

    The other argument is that while interstellar travel may eventually become feasible, interstellar communication will still be limited to light-speed and will require huge amounts of energy. After sending a message from Alpha Centauri, for example, the sender would have to wait more than 8 years for a reply. From one of Epsilon Eridani’s planets, a reply would take 21 years, and it only gets worse with increasing distance. Communication as we’re used to thinking of it would cease, and the only likely messages between far-flung settlements would be status reports or a simple periodic “we are still here” message. Each colony would thus follow it’s own path – some might disappear, some might colonize the worlds in their system but choose to go no further, and all would evolve in unique ways (biologically and culturally). The idea that there could exist a coordinated galaxy-wide civilization in a universe where communication is limited to the speed of light seems far-fetched to me.

    Even where a colony is motivated to expand further, it would take a very long time to settle the planet if has landed on. If, say, 1,000 humans were to arrive on a world like the earth, how long would it take to colonize the planet? Population growth would be a limiting factor, especially amongst advanced people who perhaps aren’t enthralled by the idea of raising especially large families. Building infrastructure, finding resources and exploiting them, etc., would take many generations. New arrivals could help the situation, but it could still be thousands of years between the settlement of a planetary system and the movement to another, more distant one.

    I’m sure there would be many other factors that could constrain expansion as well.

    This assumes that civilizations don’t generally destroy their planets, as we seem to be doing.

  4. Ed says:

    It might be that advanced civilizations grow too comfortable and aren’t motivated to settle new systems.

    It’s been suggested that they could opt for immortality, transferring their minds into chips or something. A reasonable choice for some — but for all? And if some worlds choose not to go further, people in neighboring systems can keep the expansion going.

    interstellar communication will still be limited to light-speed and will require huge amounts of energy.

    True. There won’t be any interstellar empires. Worlds will be localized, and 2-way communications with even “nearby” systems will take years. But they can still send books, etc., so although there will be lags — and they’ll grow large as distances increase — there will still be contact.

    it could still be thousands of years between the settlement of a planetary system and the movement to another, more distant one.

    My “one century” estimate, which also includes travel time, is optimistic, but not impossible. If the settlers are selected for their training — and they continue their education during the trip — they can get to work building their society immediately. It took the US, starting with minimal industrialization in 1865, only 100 years to reach the point where were were sending rockets to the Moon in 1965. If there’s enough population, I think a century is more than enough for them to be able to send a ship to the next system.

  5. docbill1351

    Yep, we’ll go robotic. Carrying biology around is a real waste of energy. We’ll move our (some) minds into positronic brains and nice, versatile exoskeletons – like the Borg without the “org” – and move off into the void leaving the Bios out to pasture on Earth until the Sun goes super red and melts the whole thing.

  6. docbill1351

    BTW, not to brag, but I completed over 5,000 SETI data sets using the Seti-at-Home software. I had two old Macs that I set up to run the calculations around the clock. I got certificates, too!

  7. Our Curmudgeon considers far future generations:

    It’s been suggested that they could opt for immortality, transferring their minds into chips or something. A reasonable choice for some — but for all?

    To so preserve the combined wisdom of the Discoveroids, I am happy to let them have a 1972 vintage Memorex 650 floppy disk (capacity: 175kb) I had been keeping as a curiosity.

    I’ll let someone else worry about the fact that no devices that can actually read the data back still exist…

  8. retiredsciguy

    It’s been just a little more than 100 years that we’ve even known about radio waves and the extent of the electromagnetic spectrum. Perhaps there are entire realms of physics about which we are still totally ignorant that may yield the means of instantaneous communication. If you think this is a far-fetched idea, consider the fact we’ve known about dark matter for some time now, but we don’t have the foggiest notion of what it actually is — and then there’s dark energy.

    Along more conventional lines of physics, I recall reading a wonderful essay by Timothy Ferris (author of Galaxies) that discussed a society in the distant future in which the communication was not between individual living organisms, but rather, it was between computers networking entire galaxies. I believe it was in Atlantic magazine, and it was at least 25 or 30 years ago. It made no difference to the computers that two-way communication between the Andromeda Galaxy and the Milky Way took over 4 million years.

    Key point — we are just at the very dawn of our technological civilization. We still have cultures that have yet to move beyond the Stone Age. And although we have developed incredible technology, our own culture is still based in Stone-Age tribal rivalries. If we are to survive and continue evolving, we have to overcome our warlike instincts.

    Peace, Brother and Sister. I certainly didn’t intend to get so serious here, so may the farce be with you.

  9. retiredsciguy

    Megalonyx, your post does a great job illustrating how far our technology has advanced in just a cosmic eye-blink. There is no way we can sit here in 2013 and predict where we will be in the year 2525. (Let your brain imbed lyrics and music here.)

    Here’s another thought about SETI (not at all original). We may be alone, or nearly so. Life started on Earth at least 3.8 billion years ago, and took about 3 billion years to advance beyond single-celled organisms. Conditions on our planet had to remain fairly stable for a very long time to get where we are today. Speculation is that having a large moon has a lot to do with our rotational stability. So to have advanced life, a planet needs 1) a stable star, probably not in a binary system; 2) a stable orbit; 3) a large satellite to stabilize its rotational axis; 4) the right mix of elements, which would require at least a third- or fourth-generation star; and 5) an incredible amount of luck.

    There probably is a lot of life out there; but most of it is single-celled.

  10. Ceteris Paribus

    If our civilization is any guide, beyond some point of no return in the evolution of “intelligent beings”, there just won’t be any intelligence to be discovered.

    If SETI merely re-tunes their receivers to pick up interstellar sports broadcasts, they will gather enough input to melt their antennas.

  11. retiredsciguy


  12. I’m currently working under the hypothesis that The Discoveroids are in fact aliens who have come here with the secret agenda to turn us all into Scottsmen. The Intelligent Design bit is just a ploy to disguise their true intent. Here are links to parts 2 and 3 of their secret plan.

  13. Tomato Addict, that’s the craziest thing yet.

  14. Crazy? It’s makes at least as much sense as anything else we hear from The Discotute. Maybe more.

  15. Ceteris Paribus

    That would explain why all the recipes for blancmange are irreducibly complex.

  16. Before reading the article or the comments, I’ll take a wild guess that no one mentioned the most important thing we learned from SETI. Which is that you can fool a great majority of the people, most of whom are NOT Biblical literalists, with a “heads I win, tails you lose” game involving ID and. “Darwinism.”

  17. SETI has applications had some beneficial spinoffs like the SETI @ home docBIll mentioned. It was the first to employ idle computer time over the internet to process data sets. In addition the technology to simultaneously tune in a billion channels at once seems like it could have some interesting spin offs as well.
    As for detecting alien signals, well don’t hold your breath but considering how inexpensive SETI is in the grand scheme of things taking a look or a listen is very reasonable. Intelligent life capable of radio is out there but maybe not in our corner of the galaxy.
    Another possible issue restricting the number of intelligent species in the universe is that the combination of intelligence, communication, and opposable thumbs of human beings might be a bit more rare when you consider that our intelligence may have evolved more as a flourish for sex selection rather than strictly adapting to environmental challenges.

  18. Or maybe we are in the middle of a galactic civilization and we just don’t know it – because their Prime Directive forbids them from revealing themselves to the “primatives”.

    Or maybe a lot of the burgeoning space cultures realize that they don’t want to get gobbled up by bigger, more predatory space civilizations, so they advance cautiously and quietly.

  19. @Greg: Stephen Hawking made just that point when he said it’s unwise of us to broadcast our existence. Given our own history I don’t think it’s a bad idea to heed his advise.

    Another thought strikes me. Could we be the first “intelligent” species capable of producing a technological civilization? There has to be a first. Sure it’s probably unlikely given the age of the universe and how long it took for us to evolve, but impossible? After all, it did take time for the universe to reach a point where conditions would be conducive to the formation of a relatively stable star like the sun and for sufficient heavy elements to be present in the stellar nebula that gave birth to the sun. Maybe intelligence is just now starting to get a foothold in the universe. Far fetched you say? Well, I would argue we don’t have enough data to say one way or the other.

  20. TJW: ” Could we be the first “intelligent” species capable of producing a technological civilization?’

    This is the point I referred to in my second post in this string above. There are many unusual happenings in Earth’s history contributing to the long-term stability of conditions here, which would seem to be necessary for the evolution of a species capable of developing technology. The universe is not infinite — at least, not the universe we can observe. It has a finite age of about 13.7 billion years. True, there are billions of galaxies, each with hundreds of billions of stars and possibly trillions of planets. But that is nowhere close to infinity.

    We may never know.

  21. @TJW: I didn’t know Stephen Hawking was of that opinion. Very interesting.

    I only recently discovered that comic legend Jack Kirby didn’t think it was wise for us to broadcast our existence. I wonder how many people involved in science or science fiction are of that opinion?

  22. Techreseller

    Read Bill Joy (a founder of Sun Microsystems) vs Ray Kurzweil. Those two guys to at it. Joy thinks Terminator is definitely possible and that most of the aliens we will encounter will be hostile. Kurzweil argues the other side. Both very bright and interesting.