The Fermi Paradox -- Where is everybody?

Cad said:

Anti senescence is different from immortality though.

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True; good points.

I've also seen the actuarial statistics implying that there's a soft lifespan cap of 700-1000 years simply due to the risk of acute infections or catastrophic accidents, even if you remove all age-related or degenerative causes. (Obviously this extends as medicine becomes more advanced.)

Sentagur said:

Yeah i keep seeing this pop up and i disagree. No, the tech to move humans outside of the solar system does not exist yet unless you count shooting off living corpses into the ether as an option.

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We have the tech to get SOMETHING very far away over a long period of time. On the scale of millions of years that time is still fairly trivial. You're right that no humans will be on that trip, but I don't think anyone making the "we have the tech" point is proposing in that context that we transport people. If anything goes it would be a self-replicating probe and/or some kind of miniaturizable digital intelligence. (No, we don't have those things now, yes, we probably will within the next couple centuries.)

Sentagur said:

Yeah i keep seeing this pop up and i disagree. No, the tech to move humans outside of the solar system does not exist yet unless you count shooting off living corpses into the ether as an option.

The chemical rocket propulsion is terrible and requires very heavy fuel yet its the best thing we currently have. You could try using nukes to blast the ship forward but even that i consider scifi at this time.
Life support systems that are self sustaining and failure tolerant enough to provide travel to 100+ passengers for multiple generations are also pipe dreams.
Hibernation is multiple decades away in a best case scenario.
Particle shielding for any propulsion that operates in reasonable "c" fractions also doesnt exist or would be to heavy to push around degrading the above chemical rocket fuel duration even further. Full redundancy is expensive and questionably effective.

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WTF what are you disagreeing with? That technology ABSOLUTELY exists today, even without considering Dyson's Project Orion shit. You think that ion drives like the engine that kept NASA's Dawn spacecraft constant acceleration for 5.9 years doesn't exist? Because it existed and its measly ion engines STILL produced more delta v over the life of the mission than the massive Delta-2 Heavy rocket that boosted it into space. Are you arguing that magnetoplasma engines like the VASIMR drive that uses several orders of magnitude fewer propellant mass than current rockets don't exist? Because that ALSO absolutely exists:


Maybe you're arguing, like some others, that a megawatt-range nuclear reactor simply doesn't exist for the VASIMR to be feasible in space---but we know the new A1B reactors on the Ford carriers can produce 700 MW and were small enough not to require barges for assembly. Even NuScale's SMR reactor can produce at least 60MW and are only 9 feet in diameter and 65 feet long. They aren't designed for use in space but the point is it's an ENGINEERING challenge for full blown reactors. As for RTGs, NASA has had kilowatt-range RTGs since the 60's and they haven't stopped scaling them up since:


Again, there's no reason to boost adult humans on interstellar missions simply because you'd have to boost their BIOSPHERE with them. Even when we're well past Kardashev-1, the whole prospect will remain inefficient. It's far more likely we'd just send virtualized humans in a simulated substrate or just self-replicating von neumann machines and frozen embryos.

Some of the simpler engines do exist in reality. Others have been diagramed and should work if you built it (the Orion drive). That drive would be dangerous to develop. But so we're the Apollo rockets.

Some are straight fantasy though. Haven't heard about the em drive recently. Hopefully that didn't just go into the bin, and it's quiet because the military realized it wasn't a fraud.

iannis said:

Some of the simpler engines do exist in reality. Others have been diagramed and should work if you built it (the Orion drive). That drive would be dangerous to develop. But so we're the Apollo rockets.

Some are straight fantasy though. Haven't heard about the em drive recently. Hopefully that didn't just go into the bin, and it's quiet because the military realized it wasn't a fraud.

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Some Germans enclosed the test apparatus with mu metals and concluded the EM drive's "thrust" was just the test's cables interacting with the earth's magnetic field.

Don't need the EM drive at all tho. Just assemble fifty-year-old rocket technology in orbit and launch the fuel up tank by tank until you have a small lake's worth of fuel to keep it accelerating for a few months. That's why that paper stuck to the 1969 tech...cuz it's not a hypothetical technology and it was more than sufficient.

I don't think anything outside our solar system is worth doing without propelletless. Last time I was over at nasa space flight forums, they were talking about spinning / turning magnetic fields. Mike McCulloch got money to try out some modified inertia artificial horizon drive type stuff, and there's still the woodward devices.

Related to our previous discussion on mass at high speeds: Streams of stars reveal the galaxy’s violent history—and perhaps its unseen dark matter

Article is full of hand wavey dark matter stuff, but an object going fast enough might do the same thing.

Sentagur said:

My whole point of contention was that we are not going to be sending people outside the SOL because that tech doesnt exits.
Yes Ion drives and VASIMR exist but they are not fully baked yet for the above goal of shooting sentient apes beyond the Oort cloud and keeping them alive.

I was agreeing with you up until the last paragraph where you swerve hard into scifi tech that is still decades if not more away from us.

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Even with conventional kerolox engines we ABSOLUTELY have the technology to boost live humans into some doomed interstellar mission. That's just an engineering problem. The question is why the fuck would we want to?

We could build their ship in orbit, fill it with the biosphere and a closed agricultural system to sustain a couple hundred generations' worth of the exact same amount of crew and boost all the fuel they'd need for constant acceleration for a few months till they get to a decent fraction of c tank by tank in hundreds of rocket launches. We can even boost an asteroid or two ahead on the ships' proposed flight path to sweep interstellar space of matter that might damage the ships.

As for the last paragraph it's not all that many decades away. Virtualized human connectomes or self-replicating robots aren't speculative propositions that don't exist, they're both rooted in existing technologies.

Self-replicating von neumann machines are just contemporary robots with access to a 3D printer; both technologies already exist and would just need to be iterated upon for that specific mission.

Virtualized connectomes would definitely take a few more decades but the technology for THAT also already exists, in fact we've already scanned and virtualized the entire connectome of two biological species. The first one, the C. Elegans worm, was successfully virtualized a couple decades ago, it's an open source project now:


Since then the study of human connectomics has exploded with teams exploring a framework towards virtuallizing a human brain. The Human Connectome Project is only five years old, but the NIH-funded USC/Harvard project is grounded in applied principles and not some speculative sci-fi thing. There are plenty of peer-reviewed studies that have successfully scanned and virtualized small sections of human brains for whatever reason and much like the human genome project, the human connectome project will rapidly accelerate towards completion as scientists find ways to flip the work from a bioengineering proposition and into an information processing problem.

There's a big difference between "tech existing" and "tech existing at a certain level". Trying to say we have the tech today for an interstellar mission is like saying we can use ENIAC from the 40s to render a Pixar movie. I mean, I guess given enough time you could maybe get there, but the timescale and hurdles are so insane that it isn't practical and essentially not possible from a realistic perspective.

Sentagur said:

And the tech for flying cars and fusion reactors exists today as well yet here we are driving on streets and powering homes with mostly coal.
Existing and being viable are two very different things.

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That's just pointless and argumentative. You said that you disagreed with the point of Hair and Hedman's paper that 1969 chemical rocket technology is more than sufficient to boost seedships to a quarter of lightspeed to other stars. But that basic point is ABSOLUTELY true, that's why they didn't postulate more advanced technologies like photon thrusters or laser-powered sails---because they didn't need to.

Objections on the basis of insufficient motivation or insufficient refinement of that technology is irrelevant. The whole point of their paper was to illustrate how long comparatively advanced civilizations could transmit their genetic legacy across the galaxy, not whether or not the inability to send paying tourists to other systems would impair our motivation to ever attempt it.

Cybsled said:

There's a big difference between "tech existing" and "tech existing at a certain level". Trying to say we have the tech today for an interstellar mission is like saying we can use ENIAC from the 40s to render a Pixar movie. I mean, I guess given enough time you could maybe get there, but the timescale and hurdles are so insane that it isn't practical and essentially not possible from a realistic perspective.

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You're a fucking retard. "Given enough time" is exactly what it took to get from ENIAC to Pixar's first Renderman farm...and it was barely more than forty years from one to the other.

khorum said:

"Given enough time" is exactly what it took

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Time and technology are funny things. The future looks like it will never arrive, and yet when you look back at the past the sense is always "holy shit, that was fast".

My grandfather grew up in a sod hut without electricity or indoor plumbing and rode a horse to school. Within 30 years he was building the first digital computers at MIT. By the time he died we all carry more computing power in our pockets than existed in the whole world a few decades prior, and talk to each other across the world through machines we put in space.

That's just one human lifetime, and progress is generally exponential. The future is going to be unrecognizable.

khorum said:

You're a fucking retard. "Given enough time" is exactly what it took to get from ENIAC to Pixar's first Renderman farm...and it was barely more than forty years from one to the other.

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I'm just pointing out the argument that "aliens could colonize most of the galaxy with 1960s era rocket technology!" is vapid. Can it be done? sure. Is it practical and realistic? not really.

And yes, I understand development of technology. Our development in the past 100 years has been on an insane vector compared with centuries past. The invention of the transistor and then the microchip revolutionized computer technology vs. the old vacuum tube stuff. But that path wasn't a straight arrow, nor guaranteed...it took development of unrelated advances (transistor) to even get us to modern PCs. If the transistor was never invented, or its invention was delayed, then we wouldn't even be having this conversation right now online more than likely and computers would still be the domain of government or corporations.

The point being is the hurdle for colonizing space is an overly complex web of various technologies that all have to come together and be something that can be realistically constructed. All it takes is for one of those various technologies never coming to fruition and the whole thing falls apart.

Cybsled said:

I'm just pointing out the argument that "aliens could colonize most of the galaxy with 1960s era rocket technology!" is vapid. Can it be done? sure. Is it practical and realistic? not really.

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I think we all agree that sending short-lived fragile sacks of meat between the stars is a harder way of doing it.

The point everyone else is making is that colonization is most likely not contingent on the transportation technology. What we can already do gets the job done since you can trivially substitute time for speed without much effect on the general outcome (where the "job" is "getting anything there ever" and the time scale is thousands and millions of years). The limiting technologies are most likely mechanical miniaturization and self-replication, biological programming, and/or AI/intelligence digitization. While we don't have those now, there's no good reason to think we won't "soon" (a few centuries tops) or that any alien intelligence wouldn't have them.

Cybsled said:

I'm just pointing out the argument that "aliens could colonize most of the galaxy with 1960s era rocket technology!" is vapid. Can it be done? sure. Is it practical and realistic? not really.

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You're a fucking retard. Why wouldn't it be practical and necessary when we have LITERALLY PROVEN the realism and practically of the technology in question? Hair and Hedman's paper was published in Cambridge Univerity's International Journal of Astrobiology after being peer-reviewed.

They used the best extant propulsion technology to make the most plausible assumptions about a civilization's capability to transmit colonies to the wider galaxy. They used our current understanding of physical laws and economic constraints as empirically observed and ran 250 iterations of their model. Even if the seedships speed was limited to 1% of lightspeed, any given civilization would've colonized a substantial portion of their lightcone within 20,000 years:

Study said:

Given a conservative travel speed of 1% of the speed of light, a uniform distribution of habitable systems with an average separation of 5 light years, and a 500 year period to build the infrastructure necessary for subsequent interstellar emigration from a newly colonized system, one iteration of the algorithm is 1000 model years. Figure 6 shows the distance per iteration of the farthest new colony of 20 graphs for 20 iterations each (20 Kyr), using m values of 3, 4, 10 and 20 and c=1. Note that, not only does the radius of a civilization’s maximum extent grow linearly (0.0025±0.0002 light-years per year), but it also grows at the same rate independently of the value of m.

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But your persistence on its "vapidity" is founded on what, exactly? Because you FEEL that humans may not be sufficiently motivated to commit to a generations-long project based on your "lived experience"? Not only is that not true, but individual objections to macroscale resource exploitation and the progress of our civilization along Fourastie/Clark's Sector Model has __YET__ make a difference. This is absolute cliometric destiny. Farmers never imagined losing their prominence to manufacturers and manufacturers never imagined losing their prominence to service workers and the service sector never imagine themselves losing out to knowledge workers, yet the arc of modern economics follows that pattern without fail:



Nothing you or me or the Pope or the Dalai Lama say or feel will ever impede our civilization's drive to comply with the laws of Thermoeconomics, we will expand to meet our energy capacity, then we will either adapt to expand that energy capacity or some entropic externality will make us extinct. This is as true for microorganisms as it is for galactic civilizations, regardless whether or not you BELIEVE that the perennial challenges of paying your mortgage and voting for Democrats would confine our choices to the mundane. There is no such thing as an infinite Malthusian Equilibrium because entropy will eventually intervene, as it did on Earth five times throughout the planet's history. At some point ferns and sauropods thought they had a pretty good handle on balancing the universe. Then they died.

We will either expand our capacity to exploit more energy for survival or we will go extinct.

wormie said:

While the rest of your arguments may be grounded in some reality, the above yielding anything useful is the breaking bad levels of purity of hopium.

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Which of the above? The fact that it absolutely happened with the the Human Genome Project? For the first seven years of the project they had only mapped 1% of the genome, then acquisition costs came down and new algorithms turned it from an bioengineering problem into an information processing one and they finished the last 99% of the genome in less than 10 years.


Or are you arguing that a similar paradigm shift in mapping the human connectome wouldn't yield the same results? Because the Human Connectome Project is planning for precisely that outcome.

khorum said:

There is no such thing as an infinite Malthusian Equilibrium... We will either expand our capacity to exploit more energy for survival or we will go extinct.

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In fairness, unless we misunderstand the basic physics of the universe we're eventually going extinct no matter how much energy we control. It's entirely possible that we could achieve a "very long but not technically infinite" period of fixed-energy stability before something goes wrong. Whether that's "success" or "failure" depends on where you draw your time horizons. IMO the question is really arbitrary and drawing the line in the sand at infinity isn't practically useful since survival is a constrained maximization problem no matter how you look at it.