[Star Trek like] number of planets and sapients

[isf]

Does this look plausible enough for a harder space opera setting loosely based on Star Trek?

I'm planning on using real star data to roughly emulate the spread of the various polities in explored space, so I need a firmer timeline.



Due to Preserver activity, if there is a possibly habitable planet 10% of them have or had some form of life [1.8B]. About 1% of those have sapient life [18M]. About .1% have warp drive [18K]. for a given radius from Earth and a maximum height pf 1000 ly. This is assuming a galactic habitability zone of 22K-30K ly.



100 ly r (0 warp, 2 sapient, 170 live)
250 ly r (1 warp, 500 sapient, 50K live)
500 ly r (43 warp, 43K sapient, 4.3M live)
1000 ly r (172 warp, 172K sapient, 170K live)
2500 ly r (1100 warp, 1.1M sapient, 1M live)
5000 ly r (4300 warp, 4.3M sapient, 4M live)

[maximara]

Originally Posted by isf

Does this look plausible enough for a harder space opera setting loosely based on Star Trek?

I'm planning on using real star data to roughly emulate the spread of the various polities in explored space, so I need a firmer timeline.


Due to Preserver activity, if there is a possibly habitable planet 10% of them have or had some form of life [1.8B]. About 1% of those have sapient life [18M]. About .1% have warp drive [18K]. for a given radius from Earth and a maximum height pf 1000 ly. This is assuming a galactic habitability zone of 22K-30K ly.

100 ly r (0 warp, 2 sapient, 170 live)
250 ly r (1 warp, 500 sapient, 50K live)
500 ly r (43 warp, 43K sapient, 4.3M live)
1000 ly r (172 warp, 172K sapient, 170K live)
2500 ly r (1100 warp, 1.1M sapient, 1M live)
5000 ly r (4300 warp, 4.3M sapient, 4M live)

The flaw in this as pointed out in several of Isaac Arthur's videos (IMHO the entire channel should be a must see for anyone interested in "hard" sci-fi) once warp drive enters the picture with the idea of planets being isolated goes south fast.

In classic Star Trek it was decided that the cube of the Warp number was how fast you were going (there are obvious problems with this idea but let's run with it).

So Warp 6 was 216 times the speed of light. So in one year that civilization could send colonist ships to any (or every) habitable planet 216 light years away. Unless every one of those colonies are abandon our high tech for the simple life they have warp drive and I think you can see where this is going.

[AlexanderHowl]

You have ~16,000 stars in ~11,000 systems within 100 ly, which probably translates to ~110,000 asteroid belts, gas giants, and/or terrestrial planets around the stars. Our current numbers are based on what we can detect, which is fairly limited, as the majority of the detections depend on either large objects close to small stars or objects oriented exactly so that we can observe transits across the star reliably. We are likely seeing the unusual systems rather than the normal systems.

If you take the above assumptions, then we can extrapolate further. Let us extrapolate that a minimum of 20% of the systems have worlds with complex life, a minimum of 20% of those worlds have supported technological sapients in their past, a minimum of 20% of those worlds currently support technological sapients, and a minimum of 20% of those worlds have warp. You would end up with ~2200 worlds with complex life, ~440 worlds with previous technological sapients, ~88 worlds with existent technological sapients, and ~18 species with warp. That is more Star Trek numbers and allows a Warp 6 ship a decent probability of finding something or someone of interest.

[isf]

Originally Posted by AlexanderHowl

You have ~16,000 stars in ~11,000 systems within 100 ly, which probably translates to ~110,000 asteroid belts, gas giants, and/or terrestrial planets around the stars. Our current numbers are based on what we can detect, which is fairly limited, as the majority of the detections depend on either large objects close to small stars or objects oriented exactly so that we can observe transits across the star reliably. We are likely seeing the unusual systems rather than the normal systems.

While I agree that our current data on exoplanets is limited, I'm inclined to use numbers proposed by astronomers as a base if Ii can. I'm basing these numbers on the estimate of "In November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs in the Milky Way, 11 billion of which may be orbiting Sun-like stars."

Originally Posted by AlexanderHowl

If you take the above assumptions, then we can extrapolate further. Let us extrapolate that a minimum of 20% of the systems have worlds with complex life, a minimum of 20% of those worlds have supported technological sapients in their past, a minimum of 20% of those worlds currently support technological sapients, and a minimum of 20% of those worlds have warp. You would end up with ~2200 worlds with complex life, ~440 worlds with previous technological sapients, ~88 worlds with existent technological sapients, and ~18 species with warp. That is more Star Trek numbers and allows a Warp 6 ship a decent probability of finding something or someone of interest.

I'm not assuming that warp 6 is a commonly achieved speed until late in the setting. Do you have a reason for those specific extrapolations or do those numbers just feel better to you?

[AlexanderHowl]

These are numbers that would fit best with a Star Trek like space opera, large enough to be interesting and small enough not to be overwhelming. As for population growth, the past fifty years of our history has shown that, on average, human fertility drops as average wealth increases, to the point where every developed nation has negative population growth without immigration, so a warp capable society not expanding beyond a defensive perimeter would be quite possible. Women have better things to do than to just have babies and/or families require two incomes to maintain economic stability.

It is highly unlikely that a warp capable humanity would have high population growth after the influx of wealth from the Sol System. High levels of social support (universal health care, subsidized day care, direct payments to parents, etc.) may be enough to turn negative population growth into low population growth, but the majority of women will stop at two children. Since the minorities that embrace high population growth are the ones that would most likely leave to start up colonies and get eating by unfriendly creatures, their contribution would likely be negated.

[isf]

Originally Posted by AlexanderHowl

These are numbers that would fit best with a Star Trek like space opera, large enough to be interesting and small enough not to be overwhelming. As for population growth, the past fifty years of our history has shown that, on average, human fertility drops as average wealth increases, to the point where every developed nation has negative population growth without immigration, so a warp capable society not expanding beyond a defensive perimeter would be quite possible. Women have better things to do than to just have babies and/or families require two incomes to maintain economic stability.

At TL today, that is the case: higher TL;s may change that especially if there are advances that make pregnancy and childcare easier.

Originally Posted by AlexanderHowl

It is highly unlikely that a warp capable humanity would have high population growth after the influx of wealth from the Sol System. High levels of social support (universal health care, subsidized day care, direct payments to parents, etc.) may be enough to turn negative population growth into low population growth, but the majority of women will stop at two children. Since the minorities that embrace high population growth are the ones that would most likely leave to start up colonies and get eating by unfriendly creatures, their contribution would likely be negated.

Maybe, but higher growth rates on colonies seem to be a feature rather than a bug. I think that a core/periphery [or developed/developing] dynamic could be useful.

[Johnny1A.2]

Originally Posted by AlexanderHowl

These are numbers that would fit best with a Star Trek like space opera, large enough to be interesting and small enough not to be overwhelming. As for population growth, the past fifty years of our history has shown that, on average, human fertility drops as average wealth increases, to the point where every developed nation has negative population growth without immigration, so a warp capable society not expanding beyond a defensive perimeter would be quite possible. Women have better things to do than to just have babies and/or families require two incomes to maintain economic stability.

It is highly unlikely that a warp capable humanity would have high population growth after the influx of wealth from the Sol System. High levels of social support (universal health care, subsidized day care, direct payments to parents, etc.) may be enough to turn negative population growth into low population growth, but the majority of women will stop at two children. Since the minorities that embrace high population growth are the ones that would most likely leave to start up colonies and get eating by unfriendly creatures, their contribution would likely be negated.

Over time, Darwin will take care of that.

Even on shorter scales, population growth is more tightly linked to cultural/religious factors than is commonly realized. There's no reason to assume that a warp-capable society would have either low or high female fertility rates, either is equally plausible at any given historical time.

[Pursuivant]

Originally Posted by AlexanderHowl

Women have better things to do than to just have babies and/or families require two incomes to maintain economic stability.

Remember, for most Federation planets, you're dealing with a post-scarcity economy. Additionally, at least for humans, by the 21st century you've got artificial wombs (the Augments from Enterprise). By the 24th century, you've got the potential to transfer fetuses from one species to another (e.g., the transfer or Keiko O'Brien's child to MAJ Kira Nerys in DS9). Furthermore, by the late 24th c., you've got well-developed holodeck technology.

All those advances make it much more appealing for women to have children. A 22nd to 25th c. Federation female knows that her kids will grow up safe (except for the odd interstellar, planet-eating monster), healthy, well-educated, and well-fed. If they can't find a way to survive on their home planet, they can emmigrate to a different world or to a space habitat. When pregnancy advances beyond the first trimester or so, she can transfer the kid to an artificial womb or a surrogate. Childcare is provided for free/cheap by trained specialists, or, in the late 24th c. by androids or holograms.

[David Johnston2]

Originally Posted by maximara

So Warp 6 was 216 times the speed of light. So in one year that civilization could send colonist ships to any (or every) habitable planet 216 light years away. Unless every one of those colonies are abandon our high tech for the simple life they have warp drive and I think you can see where this is going.

Assuming it really was like Star Trek, then there are a few things to bear in mind:

1. Humans are freakishly aggressive in their expansionism. Almost none of the species with warp drive capability are nearly as fond of homesteading as humans are.

2. Star Trek is an insanely dangerous universe. Far more, than, say, Star Wars. Human colonies routinely fail as they are eaten by crystal entities, abducted by the Borg, killed by strange radiation and attacked by aliens marking territory.

3. Humanity has a limited shelf life. All the indications are that we'll be extinct in no more than a couple of thousand years. No matter where they go they discover that the planets they visit were previously occupied by people who are gone now, Whether humanity will be gone because they were devoured by eldritch horrors, slaughtered by rebel AI or ascended into balls of light the planets they are occupying now and expanding into in the future will soon be unoccupied again. The races that actually last for a long time are the stodgy conservatives who are disinclined to innovate and expand at more than glacial speed.

[David Johansen]

I liked the premise Lost Unicorn's Star Trek game had, that the Galaxy class ships were essentially seeder ships carrying enough people to start over if Earth finally fell.