[Ultra-Tech] Conservative hard SF... but not implausibly conservative

[Michael Thayne]

I considered titling this post "minimum technological capabilities for precursors", but people tend to read "precursors" as "sufficiently advanced aliens" (i.e. ones whose technology is indistinguishable from magic), which is very much not what I want. Rather, I'm interested in this: if you have a civilization that's been around for a million years, but the setting is making very conservative assumptions about what things are possible in principle, what technology will they have?

The answer is probably close to what Ultra-Tech calls "conservative hard SF", i.e. mostly limited to TL9, but that can't be the whole answer. For example, some form of Dyson sphere is almost certainly possible to build, it would just take a long time. Many examples of human genetic engineering that Bio-Tech lists as TL10-11 are almost certainly possible as well. In particular, if we know something exists in nature, and it isn't at odds with the energy requirements of a large brain, then it's probably possible to engineer a parahuman that has the trait, even if it takes centuries of trial and error.

Conversely, some TL9 technologies are of questionable feasibility. For example, the idea of a fast-acting and safe "sleep gas" (UT160) is highly questionable, no matter how much Hollywood seems to believe such a thing already exists.

Thoughts? What other TL10-11 tech belongs on the "definitely" list? What other TL9 tech belongs on the "questionable" list?

[Say, it isn't that bad!]

Let the soothing voice of *Elmer Fudd tell you all about this:
https://www.youtube.com/channel/UCZF...6grh54g/videos

The answer: Some frankly amazing stuff.

* Given that his channel icon is the aforementioned character, I think it's ok to make that reference. :)

[sir_pudding]

If you have the capability to build a Dyson sphere, you are a Type II civilization and a lot of things are available to you. You could also build any class of stellar engine. You've ended poverty, probably also disease, and have likely achieved some level of biological immortality if you are into that. You have survived for a million years at this level so you aren't probably worried about civilizational instability. Your are probably in it for the long haul now, so you are definitely looking to move eventually, so you may be using your entire star system as a starship and are using it to move closer to a younger system with habitable planets. You might be worried about the Great Filter, so you might be trying to figure out where everyone else is. You might be interested in becoming a Type III civilization, especially since you may also be worried about the end of the stellar era, and taking control of the galaxy is a good first step to emigrating to a new universe.

[Michael Thayne]

Originally Posted by Say, it isn't that bad!

Let the soothing voice of *Elmer Fudd tell you all about this:
https://www.youtube.com/channel/UCZF...6grh54g/videos

The answer: Some frankly amazing stuff.

* Given that his channel icon is the aforementioned character, I think it's ok to make that reference. :)

Highlights?

Skimming the video titles, it's not clear that all of them describe things that will definitely be possible one day. For example, there's a video on the Alcubierre drive, which probably requires exotic matter that may or may not be possible within real physics.

[Michael Thayne]

Originally Posted by sir_pudding

If you have the capability to build a Dyson sphere, you are a Type II civilization and a lot of things are available to you. You could also build any class of stellar engine. You've ended poverty, probably also disease, and have likely achieved some level of biological immortality if you are into that. You have survived for a million years at this level so you aren't probably worried about civilizational instability. Your are probably in it for the long haul now, so you are definitely looking to move eventually, so you may be using your entire star system as a starship and are using it to move closer to a younger system with habitable planets. You might be worried about the Great Filter, so you might be trying to figure out where everyone else is. You might be interested in becoming a Type III civilization, especially since you may also be worried about the end of the stellar era, and taking control of the galaxy is a good first step to emigrating to a new universe.

I'm not sure all of this follows. Per Wikipedia, true Type II status may require solar sails thinner than can be built with any real material. I had in mind more what Wikipedia calls a "Dyson swarm". I lean towards biological immortality being possible, but I'm not sure what it has to do with Dyson swarms. Nor is it obvious using the whole star system as a ship would be feasible—emigrating to a new universe even less so.

[sir_pudding]

Originally Posted by Michael Thayne

I'm not sure all of this follows. Per Wikipedia, true Type II status may require solar sails thinner than can be built with any real material. I had in mind more what Wikipedia calls a "Dyson swarm".

A Dyson swarm is a type of stellar engine, and Type II civilizations aren't completely lossless (Kardeshev wasn't proposing a violation of the 2nd Law); they are very nearly collecting all the energy of their star, regardless.

I lean towards biological immortality being possible, but I'm not sure what it has to do with Dyson swarms.

Death is in some ways a problem of resources, and they have vastly more resources now than they evolved to use. Turning that wealth into more life, if that is something they are into, is likely to be successful.

Besides, they have a million year old civilization that hasn't collapsed from war and they have a very conservative approach to new technology, that says "really old people" to me; they definitely have something that endures and gives them a long view.

Nor is it obvious using the whole star system as a ship would be feasible

They built a Class B stellar engine, Class A engines are actually easier. If they build a statite Shkadov thruster, or even better convert their swarm into a Dyson bubble, they'll have a Class C engine that collects energy and generates thrust.

—emigrating to a new universe even less so.

It may not be, but it still may be something that they might be interested in doing.

Or maybe they are playing video games on a mastroika brain, and waiting to go extinct because that is the inevitable doom for all things in this universe.

[Say, it isn't that bad!]

Originally Posted by Michael Thayne

Highlights?

Skimming the video titles, it's not clear that all of them describe things that will definitely be possible one day. For example, there's a video on the Alcubierre drive, which probably requires exotic matter that may or may not be possible within real physics.

Yeah, he goes into speculative physics, but from the grounded perspective of a physicist. Where something is probably impossible or unlikely, he notes that. And his explanations are good.

Pick a likely-looking video and watch it. I'd be very surprised if it wasn't good. :)

[Anthony]

Outside of what we think of as hard sciences: they have a culture that has managed to cope with what we would see as insanely low growth rates. A 2.3% growth rate, which we consider reasonably healthy though not spectacular, is a factor of 10 increase in economy in a hundred years, which will put you at a type II civilization in about 1,000 years and a type III in another 1,000 years, and would consume the entire energy output of the observable universe in another 1,000 years. If they're 'only' a type II civilization in a million years, their growth rate is 0.0023%.

[Michael Thayne]

Originally Posted by sir_pudding

A Dyson swarm is a type of stellar engine, and Type II civilizations aren't completely lossless (Kardeshev wasn't proposing a violation of the 2nd Law); they are very nearly collecting all the energy of their star, regardless. Death is in some ways a problem of resources, and they have vastly more resources now than they evolved to use. Turning that wealth into more life, if that is something they are into, is likely to be successful.

How does throwing lots of resources at the problem of death work in detail? If aging is all about DNA damage, injecting someone with cloned stem cells that you've gone to great effort to remove all damage from might work. Or maybe you could extensively re-engineer the human body to stop aging entirely. But I'm not sure we understand aging well enough to state with confidence that these things are possible.

Besides, they have a million year old civilization that hasn't collapsed from war and they have a very conservative approach to new technology, that says "really old people" to me; they definitely have something that endures and gives them a long view.

To be clear, I'm not assuming the species' technological limits are self-imposed, a la the Vilani from Traveller. I'm trying to make pessimistic assumptions about what is physically possible, and see what we get.

They built a Class B stellar engine, Class A engines are actually easier. If they build a statite Shkadov thruster, or even better convert their swarm into a Dyson bubble, they'll have a Class C engine that collects energy and generates thrust. It may not be, but it still may be something that they might be interested in doing.

Is this right? What are the materials engineering requirements to make the statite Shkadov thruster work? Is it within the realm of near-future solar sail designs, or does it require significant advances in materials engineering?

[ericthered]

Originally Posted by Say, it isn't that bad!

Yeah, he goes into speculative physics, but from the grounded perspective of a physicist. Where something is probably impossible or unlikely, he notes that. And his explanations are good.

Pick a likely-looking video and watch it. I'd be very surprised if it wasn't good. :)

Isaac Arthur is very good, and he has a great respect for physics that serves the channel well.

The problem is there are days of material up there, and I wouldn't describe his future as "conservative SF". Its got some strong transhuman leanings, though he tends to seriously consider whether a given option would be adopted or not. He also thinks that strong AI (or at least human level) and mind uploading are very doable, though he emphasizes the uploading, not the strong AI.

From the channel:

• Building Big is usually just a matter of resources.*
• Space habitats are more efficient than terraforming.
• If you can feed your populace from food grown in artificial structures, you can house them luxuriously.
• Automation is world-changing, and we're on the cusp of achieving a lot of it, rather than finally winding down.
• Post-scarcity is temporary, limited, comparative, and often gradual.

I think those parts will be the most useful to you in building your setting.

*he actually describes how to build a "solid" ringworld without breaking the laws of physics. Its utterly nuts, but physically possible. The key is active support structures.