Realistic STL Interstellar Missions

[AlexanderHowl]

The problem is differences in delta-v and vector. Galactic escape velocity in our neighborhood is ~540 km/s, and we are talking about traveling ~15,000 km/s, so you would likely need to burn massive amounts of reaction mass to explore a wandering object. If it is not sharing the same vector, the problem is only magnified, so I think that most rogue object will be avoided rather than explored by interstellar STL missions. They are likely fairly common (a couple hundred per cubic light-year) and quite dangerous navigation hazards though.

[johndallman]

Originally Posted by (E)

There may be opportunities to hitch a ride on a passing chunk of reaction mass. A hypothetical chunk of ice might heading in roughly the right direction. Other once in a thousand year occurances might be exploited as well. A wandering planet sized object might have the resources to support a population for quite a long time.

The problem is that they take a very long time to travel between star systems, of the order of one light-year every 20,000 years. You're talking about setting up a permanent colony on an interstellar object, which has to be a closed cycle for everything except what you can replenish from the object. Something will go wrong over the next half-million years.

Meaningfully travelling between stars on a human timescale needs much higher speeds.

[Flyndaran]

That is an interesting setting on its own. A last ditch effort to survive a doomed system perhaps due to "insert star destroying technobabble here".
One could also avoid the stereotype of denizens regressing into low tech primitives, of course.

[AlexanderHowl]

Hypothetically, a swarm of dwarf planets could provide enough gravity to form an asteroid/come try cloud with a mass equivalent of the Kuiper Belt (RVM+2 to RVM+4). A TL10 society could colonize such an object and support a population between 4 billion and 15 billion people (depending on the RVM), though they would be dependent on fusion for energy (not a major issue at TL10). As long as they maintained their population levels above 500 million, they should not face any major issues beyond the threats of their environment.

[Anthony]

Originally Posted by AlexanderHowl

They are likely fairly common (a couple hundred per cubic light-year) and quite dangerous navigation hazards though.

A couple hundred per cubic light year is not a dangerous navigation hazard; the odds of a collision are about 2/10^18 per Earth-sized object per light year, and the odds of being close enough to care are not a lot higher.

[whswhs]

Originally Posted by Flyndaran

That is an interesting setting on its own. A last ditch effort to survive a doomed system perhaps due to "insert star destroying technobabble here".

If there's not real technology and real physics, it doesn't seem like an interesting mystery to solve. It just comes down to a mix of "read the GM's mind" and "you'll succeed when the GM decides it's dramatically appropriate."

[whswhs]

Originally Posted by AlexanderHowl

Hypothetically, a swarm of dwarf planets could provide enough gravity to form an asteroid/come try cloud with a mass equivalent of the Kuiper Belt (RVM+2 to RVM+4). A TL10 society could colonize such an object and support a population between 4 billion and 15 billion people (depending on the RVM), though they would be dependent on fusion for energy (not a major issue at TL10). As long as they maintained their population levels above 500 million, they should not face any major issues beyond the threats of their environment.

I don't know. It seems as if it could be interesting to set a story in a world where you need, oh, 500 billion people to maintain economic and technological functionality, and face new and exotic challenges from that scale that require quite different institutions.

[Anthony]

Originally Posted by whswhs

I don't know. It seems as if it could be interesting to set a story in a world where you need, oh, 500 billion people to maintain economic and technological functionality, and face new and exotic challenges from that scale that require quite different institutions.

It might be interesting as an intellectual exercise, but necessarily on that scale individual human activity, other than the top tier of leadership (however that works) just isn't that relevant, which makes a compelling story that relates to the challenges of the society hard to make (you can of course have a story that is just using the society as a backdrop).

[AlexanderHowl]

The population of the setting really does not matter that much as long as there are enough people to keep civilization going (for example, a TL10 society should need 500 million people). A colonization effort needs enough population to maintain civilization (or enough regular imports). In the case of a STL colonization effort, it will likely come in multiple waves rather than in one surge because of the sheer expense involved.

[Johnny1A.2]

Originally Posted by AlexanderHowl

Our velocity has not increased dramatically over the previous 25 years, much less than the proceeding 25 years, due to diminishing returns on investment (11 km/s for Apollo 10 versus 16.2 km/s for New Horizons).

Which proves precisely nothing.

It's true that technology does not advance along the naïve exponentiating curve that some futurists like to imagine. It rises in S curves, slow-fast-slow, then later another S curve, as a rule, when some new development happens.

But whenever one is planning for multi-decade time spans, the risk of an S curve surge (i.e. a breakthrough) is always present, and by its very nature unpredictable.

That's also why trying to plan things centuries in advance is a crapshoot at best.