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
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.
>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.
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.
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?
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.
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.
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.
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.
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.
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.
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)
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?
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.
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.
You would disassemble something as amazing as Jupiter so that could be more people? More cheeseburgers and cellphones?
ps. This reply goes to Aaron Docherty one comment up.
>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.
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.
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?
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.
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.
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.
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.
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.
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.
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.
Oops, thanks for catching my error. I've corrected the text above.
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)
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?
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.