102

To shamelessly crib an answer from Isaac Asimov: The ones who went to the stars were the best humanity had to offer. Those left behind were not; therefore to be 'Earthborn' is (in the eyes of the Starborn) to come from inherently inferior stock. This prejudice can set in and become entrenched in the minds of the Starborn, especially if they have a period of ...


69

This is quite dependent on technological/medical knowledge. For example it has been calculated at 160 for space exploration, provided the explorers return home after 20 generations. This of course assume pretty good medical availability and actually fairly low risks to individuals. The resultant reduction in genetic variability has been analyzed as not ...


31

The answer by @Nick Wilde is very good, but the quoted number of 160 (the source actually claims 80 is possible with social engineering) refers to what is minimally required to sustain a stable population for 10 generations. This could be relevant if your planet would be very far away, however if you look at the distance between Earth and Mars, it just ...


31

Historical context of population growth Population expanded significantly in the middle ages, between the low after the ravages of the Justinian Plague of 541-542 to the high middle ages peak of ~1300 before the Little Ice Age brought famine. According to the Medieval Sourcebook (possibly the best thing on the internet), the population of Iberia went from ...


26

15 individuals, 8 males and 7 females are certainly enough to create a sustainable population, capable of growth without any out-breeding, albeit with some genetic diseases due to in-breeding. The reason we know this is because of a small island on the Atlantic Ocean, Tristan da Cuhna, which has a robust, growing population of 266 (May 2016), and have been ...


20

The sins of the past still haunt us. During the early decades of space exploration, before the abundant wealth of the Belts (and later the outer planets) made star-born life safe and prosperous, we Earthers practically enslaved the colonists and miners. We added our own greed to the already numerous rigors of deep space and virgin planet colonization. ...


16

Earthborn people are of lesser value because they were born on a planet that's almost depleted its resources leading to less genetic modifications They may be similar to Starborn people, but their only chance to make sure that their bloodline will thrive is by getting away from their old, basically resource-deprived, planet and coming to the new and fancy ...


15

According to Robert Zubrin's "The Case for Mars," we could have had a mars base right now. What has stopped us (humanity) from colonizing mars, according to Zubrin, is our lack of focus on space exploration. If we had retained the same enthusiasm for exploring space during the Apollo Missions, humanity would likely be on Mars by now. This book was written ...


15

This is known as the Minimum Viable Population, and many computer models and studies based on various circumstances and species have been run. For Humans, including the desire to ward of genetic defects due to inbreeding the median MVP reported is 4,169 individuals. You can read up more on this on the wiki article here.


15

To maintain 2014 levels of technology, an order of magnitude estimate is between 10 million and 100 million people. The key point here is specialization. The higher your level of technology, the more specialized individual workers must be to maintain it. A good modern example is the island of Cuba. It has to be highly self-sufficient, because it is ...


15

I suspect there will be a rather odd hybrid system. Safety is going to be first and foremost on everyone's mind, so a very draconian safety regime will be installed so no one can accidentally or maliciously cause a system or cascade failure that will threaten the colony. The "crew" of technical staff which run the systems will be built and operated on ...


15

You could do this. Inflatable building elements are real. http://www.buildair.com/our-company/our-business-model/ BUILDAIR STRUCTURES ARE USUALLY IDONEOUS FOR MOST OF THE AVIATION (AIRPORTS, AIRLINES, MAINTENANCE MRO COMPANIES) INDUSTRY APPLICATIONS, DUE TO THEIR POUTSTANDING CHARACTERISTICS AND ADVANTAGES: Engineered to resist very hard and ...


15

Using only balloons that permanently hold helium could a city be built in the sky? No, because helium just doesn't lift that much. According to https://science.howstuffworks.com/helium.htm a liter of helium only lifts 1 gram of mass. And if the weather turns cold, it'll lift even less. High in the sky they are protected from what lie beneath. Don't ...


14

At least the Artemis project thinks it is possible. The process they describe is $$\rm FeTiO_3 + H_2 \to Fe + TiO_2 + H_2O$$ and then split the water to hydrogen and oxygen (note that after splitting the same amount of hydrogen is resumed as is put in at the beginning, so apart from replacing losses, you don't consume hydrogen in the process). Interestingly,...


13

The first concern is always going to be fresh water. Next to the coast there is a ton of salt water but without fresh the colony won't last long. A nearby river that feeds into the coast or wells quickly need to be discovered. Harbor: fishing may provide a food source, but if you don't have a good harbor, natural or manmade, your fishing boats will be ...


13

One of the very basic things you need for complex Earthly life is water. Human need water to drink, taking baths, washing clothes etc. So the planet you are going to send the pioneers has to have a large body of water. Without this, it would be simply impossible to sustain a human settlement on any planet in the long term. For the sake of this answer, let ...


13

People traded internationally before the invention of currency The pop idea of barter prior to the introduction of currency is an invention, and it has little to do with how people actually traded. The idea that people were limited to on-the-spot exchanges of say two chickens for a sword and a cabbage is completely ahistorical. In fact, people were making ...


12

Actually, an 48 hour cycle is great, because it's exactly twice the normal 24 hour cycle. Thus adaption would be easy; people would just sleep twice for each planetary day. There might, however, be the need to have bright enough illumination during the "night-day" time, in order to stay healthy for a prolonged time (I guess they are on that planet for the ...


12

You have to consider the cycle: You need energy to live, how does this work, you eat plant and use oxygen and in effect you breathe out CO2 and water. What a plant does is, breathe in CO2 and take in water and energy (from sunlight) and uses this to make the plant you eat and O2 in the oxygen. And this would be exactly what your vat grown food source ...


12

There are two major factors that limit the ability of central government to exercise control: Speed of communication Frequency and dependability of travel Fast and frequent travel makes it easy for central government to know what is going on in distant province, make quick adjustments to policy, or send troops, if necessary. Genghis Khan's empire owns its ...


11

As well as the biological, social and genetic diversity issues of maintaining a viable population you also need to consider maintaining technology. Clearly a small colony on another planet is going to very very reliant on technology to survive. Just for a start it is not difficult to imagine a situation where a new strain of a disease could cut a ...


11

There is no real way to give a number here as the city can support however many people you want it to support. The support infrastructure just has to scale up to the size of the population. The most likely situation would be large hydroponics farms providing both oxygen and food. The diet would be essentially vegetarian. You may have park-style areas inside ...


11

Old war. Consider white southerners in the post civil war US. In the North (the victors) there was and is tremendous prejudice against southerners, the losers in this war, and this continues to this date. From the Harvard Crimson - a letter protesting an editorial written in 1996. The final biting prejudice against Southerners I will highlight states ...


10

Depending on the kingdom, they might actually welcome the creation of a new town. Towns don't just appear on their own. Normally to create a new town, a kingdom must sponsor or subsidize it, build a market in the area, giving tax breaks, and bonuses for anyone to move into the area. They have to make it attractive enough for nobles and merchants to make ...


10

Three tangible factors I can immediately think of: humans who left Earth in the first wave were the best and brightest, their genetic base has had a lasting influence, Spaceborn are just plan smarter, call it founder effect. adaptive genetics, first wave orbital and exoplanetary colonists have had their DNA tweaked, not so much for direct advantage but for ...


10

Humans really don't need a beneficial reason to do this to people who are different. Given something to be tribal and insular about, we will be tribal and insular about it regardless of how stupid and pointless it is. We can be tribal about being opposed to being tribal. We can even be tribal about being being opposed to being tribal about being opposed ...


10

Alexander's answer is, IMHO, the best answer and should be upvoted and accepted. I am only adding to it. That list of "other factors" he mentions is, as a whole, equally important when compared to communication and travel. For example, if a widespread society "trusts" or "has faith in" their government, then that government is stable pretty much by ...


10

Buckminster Fuller had this idea many years ago, but instead of helium, he had an insight into geodesic domes that suggested when built large enough, they would become hot air balloons. Calling it a "Cloud Nine", Fuller's thinking was A half mile (0.8 kilometer) diameter geodesic sphere would weigh only one-thousandth of the weight of the air inside of ...


9

I'm going to ignore genetic diversity because the necessary population to sustain a technological environment will always demand enough people to satisfy that requirement. Assumptions: Maintenance of the basic technology that brought them to the new planet. Not necessarily rocketry... but vehicles, automation, manufacturing, etc. In other words, I'm ...


8

In a situation such as the one described and commented upon, where there are no large scale outside threats that are not already being dealt with externally, and the colony can be assumed to be a single polity, then it is unlikely that any standing military force would exist in order to secure the world. Instead, there would be police/public safety force(s),...


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