Dragon Debris?

Apparently the causal path from simple dead matter to an expanding visible civilization is very unlikely. Almost everything that starts along this path is blocked by a great filter, which might be one extremely hard step, or many merely very hard steps. The most likely location of this great filter is that the origin of life is very very hard. Which is good news, because otherwise we’d have to worry at lot about our future, via what fraction of the overall huge filter still lies ahead of us. And if we ever find evidence of life in space that isn’t close to the causal path that led to us, that will be big bad news, and we’ll need to worry a lot more.

One of the more interesting future filter scenarios is a high difficulty of traveling between the stars. As we can easily see across the universe, we know that photons have few problems traveling very long distances. And since stars drift about at great speeds, we know that stars can also travel freely suffering little harm. But we still can’t be sure of the ease of travel for humans, or for the sort of things that our descendants might try to send between the stars. We have collected a few grains of interstellar dust, but still know little about them, and so don’t know how easy was their travel. We do know that most of the universe is made of dark matter and dark energy that we understand quite poorly. So perhaps “Here Be Dragons” lie in wait out there for our scale of interstellar travelers.

Many stars, like ours, are surrounded by a vast cloud of small icy objects. Every once in a while one of these objects falls into a rare orbit where it travels close to its star, and then it becomes a comet with a tail. Even more rarely, one should fall into an orbit that throws it out away from its star (almost always without doing much else to it). Such an object would then travel at the typical star speed between stars, and after billions of years it might perhaps pass near one other star; the chance of two such encounters is very low. And if the space between stars is as mild as it seems, it should arrive looking pretty much as it left.

Astronomers have been waiting for a while to see such an interstellar visitor, and were puzzled to have not yet seen one. They expected it to look like a comet, except traveling a lot faster than do most comets. Well within roughly a year of a new instrument that could see such things better, we’ve finally seen such a visitor in the last few months. It looked like what we expect in some ways. It is traveling at roughly the speed we’d expect, its size is unremarkable, and its color is roughly what we expect from ancient small space objects. But it is suspiciously weird in several other apparently-unrelated ways.

First, its orbit is weird. Its direction of origin is 6 degrees from sun’s motion vector; only one in 365 random directions are closer. And among the travel paths where we could have seen this object, only one in 100 such paths would have traveled closer to the sun than did this one (source: Turner). But one must apparently invoke very strange and unlikely hypotheses to believe these parameters were anything but random. For now, I won’t go there.

Second, the object itself is weird. It does not have a comet tail, and so has apparently lost most of its volatiles like water. If this is typical, it explains why we haven’t seen objects like this before. The object seems to be very elongated, much more than any other natural object we’ve ever seen in our solar system. And it is rotating very fast, so fast that it would fly apart if it were made out of the typical pile of lightly attached rubble. So at some point it experienced an event so dramatic as to melt away its volatiles, melt it into a solid object, stretch it to an extreme, and set it spinning at an extreme rate. After which it drifted for long enough to acquire the usual color of ancient space objects.

This raises the suspicion that it perhaps encountered a dangerous “dragon” between the starts. Making it “dragon debris.” If the timing of this event were random, we should see roughly one a year in the future, and with new better instruments coming online in a few years we should see them even faster. So within a decade we should learn if this first visitor is very unusual, or if we should worry a lot more about travel dangers between the stars.

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  • Dave Lindbergh

    Well, maybe. What you’re suggesting seems unlikely from what we know of the interstellar medium.

    I suppose it also fits pretty well with the Berserker scenario: An early civilization created a technology that prevents …somehow… later civilizations from threatening them. Making interstellar travel difficult would be one of the more humane ways to do it.

    You’re making a big guess from one data point.

    We could launch some interstellar probes and find out more. (At some risk, of course.)

    • 5ive

      Forced to make a bet, I’d wager that the event that sent it our way is also the one that made it weird.

  • Patrick Staples

    There is an upside to studying objects like these. If these are all naturally formed (untestable assumption at present) and we can guess their initial form (possibly testable), then they provide minimal cases for stable interstellar vehicles.

    We also have the bonus of being able to engineer materials that are cosmically unlikely, such as rigid carbon.

  • Oleg Eterevsky

    > The most likely location of this great filter is that the origin of life is very very hard.

    It sounds likely, but one piece of evidence against it is that life on Earth appeared very soon after Earth became barely habitable — within one or two hundred million years. If biogenesis was hard, but evolution was relatively smooth, one would expect a planet to stay uninhabited for a long time.

    • Patrick Laske

      Except that *IS the case*.

      Eukaryotes only occurred at about half way in Earth’s history, and sexual life only in the past quarter of it’s life. If we break down life into 4 stages: Abiotic / Single Cells, Photosynthesis, membrane-bound organelles, Multicellularity, and Intelligent, you have a smooth line over that 4 billion years, with each of those events taking a few hundred million years.

      • Oleg Eterevsky

        Yes, and the appearance of the first life itself took shorter period of time than any of the following 4 stages.

      • Patrick Laske

        Yes, but I’m saying that that if you start the clock at Photosynthesis, you do see the smooth line you’d expect. Early stages of life must be very very common and also uninteresting. It probably even emerged multiple times on Earth’s own history, in multiple places.

        Most life in the universe probably never gets past to the photosynthesis stage, and those that do, almost certainly drive all life on their planet to extinction with an oxygen crisis.

      • Oleg Eterevsky

        I agree, to me based on the timeline of the Earth life, the development of complex life sounds like a more likely Great Filter, than abiogenesys itself.

      • xyz

        Something I’ve wondered about from time to time… conspicuously absent from Earth’s ecology are radio communication, and what one might call mechanosynthesis–deriving metabolic energy from natural motion in the manner of a power dam or wind turbine.

        I’ve always found it particularly strange that sight evolved a dozen times and radio never made an appearance even once.

        Further, agriculture is enormously advanageous and it isn’t particularly hard relatively speaking, and since ants practice it in limited fashion its total absence among large-brained mammals (present company excepted) seems a bit strange.

        Is this true of most worlds with complex life or is it an oddity of life on Earth? Perhaps human-like toolmaking intelligence and technological civilization only appeared because they were able to exploit the presence of such lacunae in the natural order?

    • Curt Adams

      One big problem with the origin of life as a particularly difficult step in the great filter is the plausibility of microbial panspermia. We know that it is at least possible for life to travel between Mars and Earth on occasional lucky rocks, and that makes interstellar panspermia at least plausible in deep time. So a single origin of life might suffice for an entire galaxy.

      Personally, I’m leaning to a large role for interstellar travel. If it turns out that fusion power is not workable in an isolated object the size of a comet, interstellar travel is probably not possible. This happens if fusion reactors are just not possible apart from stars, if the necessary societal complexity is too high for a small object, or if workable reactors require some scarce nonrenewable resource such as a particular isotope.

      • Robin Hanson

        I agree that panspermia can be seen as an anti-filter. The more it happens, the bigger the net size of all the other filters must be.

      • Daniel Böttger

        I’m not a physicist, but wouldn’t fusion on starships be prohibited by heat dissipation? To my naive mind, this seems a bigger problem than mere energy production via fusion.

        We’ve found no better cooling technology (that works in vacuum) than radiating it out in infrared, and that takes a lot of mass. Apparently current space tech needs 12 kilos of mass for radiating away 350 watts. Nowhere near good enough for a fusion (or any) reactor that probably makes gigawatts of waste heat.

      • Curt Adams

        Well, at that ratio the smallest nuclear reactor, producing 582 megawatts, would need about 20 kilotons of coolers. That’s about twice the weight of a destroyer and much smaller than any vehicle that could function independently for thousands of years. I suspect a reactor could produce hotter radiators than a satellite, too, so you could get by with less. So while it’s yet another complexity to deal with, I think it’s a small issue compared to fusion itself, or to the not-yet-understood problems of making a comparatively small society+ecosystem+mechanism than can function for thousands of years without a major breakdown.

      • Daniel Böttger

        Oh, you’re talking about craft with biological systems such as people in it? I thought those were way too heavy to accelerate and then slow down again. I was thinking about something like von Neumann probes.

      • Curt Adams

        Oh, yeah, definitely no reactors on a von Neumann probe! Unless a von Neumann probe needs to as large as a generation ship, which it might – we have no idea how big a von Neumann probe would have to be. With anything like current tech, you’d need chip fab plants, which would require complex supporting chemical and manufacturing industries, at the least.

  • Depends on what you mean by near the casual path. Microbial life may not be that rare, or even more advanced life confined to hydrothermal vents or oceans without much possibility of progression beyond that, or with the possibility but only within a narrow time window.

    While space is very empty, it could have been moving at high speed for a very long time experiencing erosion, much more so than that of material in organized flow such as the Oort cloud, though origin seems most likely

  • Chris Hibbert

    ʻOumuamua is very interesting. The experts I’ve been hearing from agree that (as with LIGO) our first observation of an interesting event came soon after we had a significant ability to see this kind of interstellar visitor, so I’m expecting to see more of them, quite possibly at a rate of one a year or more frequently.

    From the initial descriptions, I thought it was understood to be spinning on its axis, which would have been a surprise for a natural object. Instead, it’s rolling, which isn’t significantly different from an uncontrolled tumble. That seems pretty unsurprising. The speed of it’s rotation is only surprising given its elongation, which is unusual. I’m waiting to hear some suggestions of how such an object could be produced naturally.

    If similar objects come through our solar system relatively frequently, it would be extremely valuable to send a probe for a closer look. It looks feasible to do it and get results back in a few decades. (It would be hard this time, but if someone starts designing and preparing now, catching the next one will be much easier.)

  • mgoodfel

    I think the Great Filter is the existence of nerds. I can see social skills evolving — living in groups, any increase in ability to understand/predict your fellows gives an advantage. But why do we have any ability to do math? If there were anatomically modern humans 70,000 years ago, could you have taught one to do calculus? But why would that animal have that ability? What survival value does it have?

    I think our evolved mental machinery for analyzing other humans and understanding social interactions somehow got co-opted into an ability to analyze things and do math. And I’ll bet that’s a rare development in an animal.

    So there would be lots of life out there (it occurred quickly on Earth), smaller numbers of worlds with complex creatures (was the Cambrian explosion as weird as it seems?) and some number of worlds with intelligent creatures. But engineers are rare.

    And that’s what we’re looking for with SETI. Your species could be the most brilliant polar bears possible, but if they don’t build radio telescopes, we’re not going to see them.

  • Justin Loew

    Filter? All of the evidence we have so far indicates we are alone. It seems like there should be other life, and we should have seen it by now. But alas, no.

  • arch1

    Re: “Its direction of origin is 6 degrees from the axis of rotation of the sun and solar system. Only one in 182 random directions are closer.”:

    Per wikipedia “ʻThe incoming direction of motion of Oumuamua is 6° from the solar apex (the direction of the Sun’s movement relative to local stars), which is the most likely direction for approaches from objects outside the Solar System”. So:

    1) I wonder whether the rotation axis and the solar apex are being conflated (perhaps not, both statements could be true)
    2) Re: “random directions” – the wikipedia excerpt suggests that these should be weighted (though alas this weighting can’t just be a trig function of the angle w/ the solar apex, as the origin might not be local)

    • Robin Hanson

      Oops, thanks for catching my error. I’ve corrected the text above.

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  • Robert Koslover

    Hmm. “If the timing of this event were random, we should see roughly one a year in the future…” I’m not a statistician, but making statistical projections based on one data point seems a bit iffy to me.

    • ParanoidAltoid

      Our prior expectation for how common these things are ranged from “never” to “the universe is full of them”. Anchoring on a year is better than nothing. It’s a year, plus or minus a factor of ten.

    • cwcwcwcwcw

      You would disassemble something as amazing as Jupiter so that could be more people? Do you see a connection between that future and the earths past?

  • cwcwcwcwcw

    The Chinese sci-fi author Cixin Liu wrote a trilogy ( the Three Body Problem, The Dark Forest, Death’s End, which I highly recommend) that suggested that when a civilization became advanced enough for interstellar travel that other more advanced civilizations would destroy them because basically that was always the safest course of action. So emergent civilizations would either hide, be destroyed, or destroy anyone else they could find. So maybe everyone is hiding and we are not yet advanced enough for another civilization to reveal itself to us (basically in the form of an attack).

    Alternatively, Kim Stanley Robinson’s Aurora, colonists from earth reach a nearby seemingly habitable planet after a multi-generational journey, only to have all the colonists that went to the planet be killed by some kind of prion type organism. KSR suggest that maybe all life is uniquely and only suited to the planet that it arose from. That conditions for our particular earth born form of life are so exacting and numerous that chances are on other planets with life we would inevitably meet fatal hazards (such as weird viruses or the wrong composition of elements in the air, land, or water) because that life on that planet arose in it’s own different exacting and numerous conditions. I’m not explaining it right, but basically, there would inevitably be health damaging conflicts.

    Something that I have always thought is that we always look for other civilized through a very specific lens of our own humanity. Maybe only primates evolved to be insatiable about power and security like us would even dream about colonizing the universe, filling every niche, reconfigure galaxies, and other crazy megalomaniac type acts (the term the paper uses is “exploding” which I think is telling.) I personally would very much like to visit other planets, but I would just want to look, maybe gently interact. I really really really have no interest in disassembling Jupiter to create a bigger and better… what?

    • Aaron Docherty

      >I really really really have no interest in disassembling Jupiter to create a bigger and better… what?

      I can think of some uses that favor anthropocentric outcomes much more than what it’s being used for now. If life is a good thing, using our solar system’s resource endowment to allow for more life is also a good thing.

    • Duncan Urquhart

      Eh, the idea of complex life evolving but not having a desire for power and security seems unlikely to me. Even if it lasted long enough to form a civilization, it would only take a single individual being born slightly more greedy to kick off a spiral of competition.

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