How can I determine the number of years it would take to reach my desired population growth?

[Erebus]

The gods have given up on the habital planet scheme and have decided to design this universe differently. They have filled it with a space structure called a banks orbital. These habitats are purpose-built space habitat forming a ring many miles in diameter. The rotation of the ring simulates both gravity and a day-night cycle comparable to a planetary body orbiting a star.

These rings are massive, having the planet surface of 25 earths. Its inhabitants live on the inside of the ring, where continent-sized "plates" have been shaped to provide all sorts biomes. Many exist, such as deserts, jungles, etc. The natural environment and climate are similar to Earth, only covering a larger area. Earth has an area of about 500 million ktu, of which 400 million ktu is habitable.

 

[Erebus]

The deity known as Kali has given up on the habital planet scheme and have decided to design this universe differently. It has filled it with a space structure called a ringworld. This habitat is a purpose-built space habitat replica of earth forming a ring many miles in diameter. The rotation of the ring simulates both gravity and a day-night cycle comparable to a planetary body orbiting a star. At a certain point, the ringworld will experience a "rapture" like event. The deity will rapture the living humans by devouring the mortal world, absorbing the humans into itself to increase its power. Then the cycle begins anew with a new batch of mortals.

The ring is massive, having the planet surface of 25 earths. Its inhabitants live on the inside of the ring, where continent-sized "plates" have been shaped to provide all sorts biomes. Many exist, such as deserts, jungles, etc. The natural environment and climate are similar to Earth, only covering a larger area. Our Earth has 500 million kmu, of which 400 million kmu is habitable. As this ringworld is 25 times larger, this provides space for 5 - 6 trillion people.

Based on these parameters, I need to determine a way to predict the number of years it would take for the ringworld to reach this level of population growth. How can I do that?

 

[Prince of Spires]

Impossible to tell based on these parameters. They're actually the least important ones.

the important ones are:
- technology level of the people
- friendlyness of the habitat
- predators

Just look at the increase in human population on earth. The growth is very exponatial simply because as our technology has become better we live longer, can feed more people, can heal injuries better and so on. We can survive easier in harsher climates and we have less and less to fear of predators.

if you're starting from cavemen, then it took humans something like 100.000 years to spread across the globe. Though again, that spread wasn't uniform. It took us 50k years to get out of Africa and another 50k years to spread everywhere. So for something 25 times larger it might take anything from 25 times longer to only twice as long.

Once humans settle down then all bets are off. In cosmic terms we conquered the earth in the blink of an eye, going from a few million to 7 billion in only 3000 years or so. Once they're spread everywhere, then I wouldn't expect this speed to change simply because it's down to how fast can a single group of people grow locally.

So if you want an estimate then I'd go with 175.000 years, give or take 100.000 years.

 

[ThinkerX]

uhhg...

starting population x 1.02 per year might be something to start with...or if they have especially large families, maybe starting population x 1.05 per year...

 

[Puck]

There is no definitive answer to this. It depends on the level of civilisation, the nature of the environment, social conventions and other factors such as disease etc. It is like asking 'how long is a piece of string?'

The area that became the Roman world saw growth of 0.1% per year from 1200 BCE to 200 CE. That was pretty fast growth for the ancient/medieval world. From about 200 CE to 1800 CE, the European half of the empire only saw about 0.06 to 0.07 percent annual growth. Populations in places like Africa and parts of Asia saw no significant growth at all during the middle ages.

Of course the average hides many ups and downs (the Black Death reduced European populations by 1/3 to 1/2 in a few short years for example).

In more modern times population growth accelerated far more rapidly.

 

[pmmg]

I am questioning if this would really be an issue. Seems like something planners want to know, but never turns out to be actual anyway.

Population will rise and fall for many reasons, one of which will include the perception of many that the place can or cannot sustain more population. And as population rises, so would the ability of these to live off world.

If you need an exact number, take the number of people currently, apply a growth rate and start doing the math. Would that number be actual in a real world sense...probably not.