Is everyone in the Spinward Marches a Rabbit

[Gray Pennell]

With this debate about the fleet I went through and the Imperial Spinward Marches adding up the subsector populations. I got 800+Billion I didnt say million or 8 Billion or 80 Billion but 800+Billion. Does anyone want to take a crack at rationalizing how in less then 1000 years this area has nearly a trillion people?

The five sisters has 1.8 Billion this seems pretty rational especially since the Darians and Sword Wordls plus other alliens live near by. But how do you explain 250+ Billion for Regina which is said to be vargin territory when settled. This is roughly a 500 people arriving in Regina every minute for 1000 years. Lets be nice and give 50%population growth so its C.250 people a minute.

 

[far-trader]

Population growth is not linear is the thing

Running some quick numbers, with a 2% population growth (peak human growth rate a few years ago), and final population goal of about 800 BILLION* we need to start with...

...2000 people. Yep, that's right. JUST two thousand people.

*796,529,303,316

 

[Gray Pennell]

Okay we should be looking at trillions then.

 

[aramis]

Let's show how a 2% population increase looks...

if the average person lives 100 years...
then every year, you lose about 1% of the population.

So that means that you need to have 3% of the population give birth to children that live.

3 out of 100... one to replace the dead, and 2 to increase the population... which means the population will be about 18*3=54% children, and about 42% parents... Oh, and that's about 6 kids per family.

Now, given that the death age is more like 70, you're losing 1.4%, so you need about 3.4 kids per adult. Which means around 7 kids per couple, rather than 6.

Note that sexually imbalanced populations can change the numer of children per woman down... if the ratio is 3 wives per man, each woman needs only birth 4.133 kids... and the percentage of the population with minor children goes down.

If you lower the age of first child, you reduce the number of children who are not also parents...

Oh, and note that infant mortality often isn't counted in figuring the average age of death... so up the number of children by 0.5 to 3 per adult, depending upon how bad the rate is, to hit 2% population growth.

So, yeah, 2% per year is rapid... but doable. It's 6-7 kids per couple with reasonably low infant mortality.

Given a 1% population gain (3-4 kids per couple), you need 38.5million starting.
Given a 1.5% population gain (5ish kids per couple), you need 277,000 starting.

cranked out a nifty table for you:
APG __ start pop for 1000y to 800B.
0.1 _ 294745094074.0
0.2 _ 108701660245.0
0.3 __ 40128959545.7
0.4 __ 14828966729.8
0.5 ___ 5485223048.84
0.6 ___ 2030987487.45
0.7 ____ 752746775.677
0.8 ____ 279266221.873
0.9 ____ 103708634.558
1.0 _____ 38551171.3336
1.1 _____ 14344504.5168
1.2 ______ 5342665.6416
1.3 ______ 1991838.26853
1.4 _______ 743315.081768
1.5 _______ 277660.294533
1.6 _______ 103818.738397
1.7 ________ 38855.9934424
1.8 ________ 14556.593834
1.9 _________ 5458.58609513
2.0 _________ 2048.88883963
2.1 __________ 769.792440924
2.2 __________ 289.497677603
2.3 __________ 108.97626237
2.4 ___________ 41.0613575615
2.5 ___________ 15.4863282582

 

[far-trader]

Okay we should be looking at trillions then.

Yep, obviously there's some other factors involved. A much lower growth rate for whatever reason or reasons....

...massive extinction events?

...plagues leaving large populations sterile.

...excessive murder rates.

...huge numbers recruited to the Scouts (low survival rate )

...enormous sleeper ships loaded with colonists bound for the galactic core.

But I expect it was just never really thought out. Left for individual players and refs to work it out.

This is another case for the argument of collapsing the time line considerably.

 

[aramis]

Simpler still - once certain baseline populations are established, people stop being willing to have 6 kids per family, and naturally it falls off. Likewise, much of the maximal growth here on earth in various nations is from immigration - tho some states are growing while being net exporters of people, quite likely due to religious reasons for large families and low local opportunity.

 

[rancke]

Also, depending on the composition of the original population, you can have some quite massive population increases in the first 50 years. If everyone are in their early twenties, you won't have any deaths (from old age) for the first fifty years. Theoretically, you could have a population increase of 50% the first year, 0% the next year and another 50% (of the original number) the third year, etc.. In practice, the population, even of a planned colony expedition, would have a leavening of older people and pregnancies would probably be staggered a lot more. But you could still get a lot more than 3% pa. population increase in the first stage. The initial limit is likely to be the building and running of infrastructure.


Hans

 

[77topaz]

With this debate about the fleet I went through and the Imperial Spinward Marches adding up the subsector populations. I got 800+Billion I didnt say million or 8 Billion or 80 Billion but 800+Billion. Does anyone want to take a crack at rationalizing how in less then 1000 years this area has nearly a trillion people?

The five sisters has 1.8 Billion this seems pretty rational especially since the Darians and Sword Wordls plus other alliens live near by. But how do you explain 250+ Billion for Regina which is said to be vargin territory when settled. This is roughly a 500 people arriving in Regina every minute for 1000 years. Lets be nice and give 50%population growth so its C.250 people a minute.

I thought Regina had 250 million people.

 

[rancke]

I thought Regina had 250 million people.

Regina system has 700 million inhabitants. Strangely enough, I've never actually toted up the populations in Regina subsector despite having done a lot of work with the history of the region, but the original writeup (in The Kinunir) says 90 billions total. The Spinward Marches says 165.6 billions.

(How's that for a canon conflict? And people complain about a discrepancy of a few measly tech levels... :devil


Hans

 

[Tobias]

Regina system has 700 million inhabitants. Strangely enough, I've never actually toted up the populations in Regina subsector despite having done a lot of work with the history of the region, but the original writeup (in The Kinunir) says 90 billions total. The Spinward Marches says 165.6 billions.

The 165.6 billion number is impossible to reconcile with the given population codes for the individual worlds. Even if you assumed a pop multiple of 9.999... for every single world in the subsector, so that each and every world was just one person shy of the next higher pop code, you would not end up with 165.6 billion.

I'd disregard the subsector populations mentioned in Sup3 altogether.

 

[Fritz_Brown]

Let's show how a 2% population increase looks...

Aramis has it right. I once worked out the population growth required to go from 6 people to 8 billion over 4,500 years. It worked out, iirc, to about 0.5%. Of course, there is a slightly higher rate in reality when you have to account for a 1/3 extinction event about 600 years ago.

 

[aramis]

The 165.6 billion number is impossible to reconcile with the given population codes for the individual worlds. Even if you assumed a pop multiple of 9.999... for every single world in the subsector, so that each and every world was just one person shy of the next higher pop code, you would not end up with 165.6 billion.

I'd disregard the subsector populations mentioned in Sup3 altogether.

Unless you use Bk6, in which case, it's merely a severe stretch...

 

[Timerover51]

With this debate about the fleet I went through and the Imperial Spinward Marches adding up the subsector populations. I got 800+Billion I didnt say million or 8 Billion or 80 Billion but 800+Billion. Does anyone want to take a crack at rationalizing how in less then 1000 years this area has nearly a trillion people?

The five sisters has 1.8 Billion this seems pretty rational especially since the Darians and Sword Wordls plus other alliens live near by. But how do you explain 250+ Billion for Regina which is said to be vargin territory when settled. This is roughly a 500 people arriving in Regina every minute for 1000 years. Lets be nice and give 50%population growth so its C.250 people a minute.

I keep adjusting the populations in Spinward Marches down a greater or less degree based on the planet characteristics. Very thin to no atmosphere, tainted atmospheres, asteroid belts, very little water or 90% water, and exotic atmospheres (including insidious and corrosive) all serve to reduce the population exponent. And then, there are planets were I simply change the population to something that looks about right, and I can justify to myself.

For an idea as to what current birthrates are, see the CIA World Factbook for birth, death, and immigration rates.

 

[rancke]

Based on the UWPs in Regency Sourcebook, the total population of the Regina Subsector in 1117 is 67.6 billions. However, there's quite a bit of uncertaincy to those figures. For example, Rethe has a pop level of 10 and a multiplier of 3. I've counted that as 30, but it could be anything from 30 to 39 billion. The six pop 9 worlds could add another 6 billion. I'll see if I can dig out my copy of Behind the Claw and get some more accurate figures out of that.

Regina subsector
----------------

(Ignoring all worlds with population level 0-4)

            Population (millions)

               33 321
Efate           8,000.0
Alell             400.0
Yres               30.0
Menorb          3,000.0
Uakye               0.3
Whanga                -
Knorbes            80.0
Forboldn            3.0
Ruie            7,000.0
Jenghe              3.0
Pixie                 -
Boughene            0.6
Hefry                 -
Regina            700.0
Feri              600.0
Roup            3,000.0
Pscias                -
Yori               70.0
Dentus              0.9
Kinorb              6.0
Beck's World          -
Enope           6,000.0
Wochiers          700.0
Yorbund             0.2
Shionthy           70.0
Algine          7,000.0
Yurst               8.0
Heya               70.0
Keng              800.0
Moughas             0.8
Rethe          30,000.0
Inthe              40.0
-----------------------
               67.581.8

Hans

 

[Ishmael]

linking population growth rates to population density can make things interesting for worlds of differing sizes, especially when you work out what the population's extinction threshold might be for use in determining Allee effects.

Naturally, this growth rate is fed into a log model of growth for a nice sigmoid curve when carrying capacities are considered.

Another idea might be to look into a world3 model.
http://en.wikipedia.org/wiki/World3
http://world3simulator.org/

 

[Gray Pennell]

Hans thanks for your work.

I used the Spinward March Supplement 3 for my numbers. Your numbers start to seem reasonable. However, I looked up Rethe and its 30 Billion people. Its a poor desert world. While poverty does result is higher birthrates and over population no way would a world like Rethe support 30 billion when Terra cannot really pull off 15 billion. I think we are beginning to see the population numbers are unreasonable high.

Based on the UWPs in Regency Sourcebook, the total population of the Regina Subsector in 1117 is 67.6 billions. However, there's quite a bit of uncertaincy to those figures. For example, Rethe has a pop level of 10 and a multiplier of 3. I've counted that as 30, but it could be anything from 30 to 39 billion. The six pop 9 worlds could add another 6 billion. I'll see if I can dig out my copy of Behind the Claw and get some more accurate figures out of that.

Regina subsector
----------------

(Ignoring all worlds with population level 0-4)

            Population (millions)

               33 321
Efate           8,000.0
Alell             400.0
Yres               30.0
Menorb          3,000.0
Uakye               0.3
Whanga                -
Knorbes            80.0
Forboldn            3.0
Ruie            7,000.0
Jenghe              3.0
Pixie                 -
Boughene            0.6
Hefry                 -
Regina            700.0
Feri              600.0
Roup            3,000.0
Pscias                -
Yori               70.0
Dentus              0.9
Kinorb              6.0
Beck's World          -
Enope           6,000.0
Wochiers          700.0
Yorbund             0.2
Shionthy           70.0
Algine          7,000.0
Yurst               8.0
Heya               70.0
Keng              800.0
Moughas             0.8
Rethe          30,000.0
Inthe              40.0
-----------------------
               67.581.8

Hans

 

[aramis]

Hans thanks for your work.

I used the Spinward March Supplement 3 for my numbers. Your numbers start to seem reasonable. However, I looked up Rethe and its 30 Billion people. Its a poor desert world. While poverty does result is higher birthrates and over population no way would a world like Rethe support 30 billion when Terra cannot really pull off 15 billion. I think we are beginning to see the population numbers are unreasonable high.

Which simply means it must needs be a net importer from somewhere. Perhaps from other worlds in system, perhaps from out-system, perhaps from orbital farms.

 

[Timerover51]

When you look at the birth rates for industrialized countries, they are for the most part just barely above replacement level. For some, like Japan, they are not even that. In an agricultural, low tech society, children become productive workers fairly quickly, and large families are a benefit. In industrial societies, children do not become productive workers until into their teenage years or later. Large families become unsupportable or close to it.

Japan has a current growth rate of -.077, with 8.39 births/1,000 population and 9.15 deaths/1,000 population, source CIA World Fact Book.

Sweden's growth rate is 0.168%, with 10.21 deaths/1,000 population and 10.24 births/1,000 population, so fractionally above the replacement rate. Same source.

Denmark's growth rate is 0.239%, with 10.22 births/1,000 population and 10.19 deaths/1,000 population. Same source.

The European Union overall has a growth rate of 0.212 %, with 10.27 births/1,000 population and 10.05 deaths/1,000 population. Same source.

I would expect most of the Traveller universe to have growth rates on this order, except for more frontier planets. With that sort of growth rate, in 1,000 years the population would increase by a factor of 8.312.

 

[pendragonman]

Texas has a growth rate of 2.12%...

 

[Gray Pennell]

Armis

I am going to respectfully disagree with you. The cost of supporting 30 billion on imports would be impossible. Looking at Dubai the nearest economy to match this situation they spend 100s of billions and its barley political and economically sustainable. With a population of a few million. So I cant see how this would work out. These numbers are just ridicules based on some random generation without editor oversight.