An outpost on a 2G (gravity) water planet (95% of the world's surface covered by oceans) becomes stranded / abandoned by the Galaxy Government, probably forever. The warp gate in orbit broke, nobody is coming to help them, period. There's no supply chain issues because the issue is that's there's no supply chain.

99% of their power supply (per capita use before was 9 MWH/y) was nuclear. Because of some weird cosmic hiccup, all radioactive isotopes outside the planet mantle were forcefully stabilized. No more alpha, beta, or gamma emissions. Or fusion/antimatter/whatever.

The people on the surface, about two million humans, is stranded. Chemical rockets cannot reach orbit as the fuel mass required is more than the lift it could generate. And the ships they had all ran on nuclear fuel, which is as useless as a slag brick now.

They now need to contend with the planet's gravity as most of their power expenditure was to keep their living quarters in comfortable 1G. They have only 180GWH/year of installed power capacity available, (7,5kWH/month*person). Most of their databases and costly machinery are forcefully put offline.

The databases don't contain blueprints for heavy machinery, space vehicles, or sophisticated microprocessors. They have CNC, 3D printers, and tools, as well as the machines left on the planet. What they have in hands is usable but comparable to what someone back on mid XXI century had.

The atmosphere is breathable, the water is drinkable, and there's plants and animals imported from Terra. The colony and useless is in a comfortable tropical location, they don't have to worry about bad weather.

How long would it take for this colony to revert to a medieval society (technology (mostly) and/or customs)? Frame challenge: prove they don't.

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    $\begingroup$ I have a suspicion I know what you're asking, but "medieval" here being... Medieval level of technology? I smell the stench of the "linear technology levels" assumption, too. Who is to say they don't reach some technological state that we simply have nothing comparable to? $\endgroup$
    – PipperChip
    Commented Sep 27, 2022 at 19:30
  • $\begingroup$ @PipperChip thanks. $\endgroup$ Commented Sep 27, 2022 at 19:39
  • $\begingroup$ This seems like a question where depending on the specific actions of characters or organizations you can have it take however long you want. To answer this we effectively need to write your story of your world for you. Questions about the actions and decisions of characters or organizations are off topic for this site. $\endgroup$
    – sphennings
    Commented Sep 27, 2022 at 19:47
  • $\begingroup$ What "medieval" level are you referring too? The Middle Ages lasted for about a 1000 years. (Or roughly, at two-thirds of the time from the start of the Middle Ages till now, the Middle Ages ended) Society and technology in the 600s was quite different from the 1400s. But they're both in the Middle Ages. $\endgroup$
    – Abigail
    Commented Sep 28, 2022 at 12:08

1 Answer 1



A medieval society means superstitious beliefs, often feudal politics, non-existent medical care, terrible sanitation practices...

...None of which are necessary to happen just because your people loose their nuclear power plant(s).

Most people in the world today do not rely on nuclear power. They rely on coal/propane, wind/solar, hydroelectric & geothermal. Your colonists would be lousy colonists if they did not arrive in-system with no contingencies—like wave power on a world with 95% surface water.

Your colonists would include technicians, scientists, engineers, and many other people who are more than capable of cannibalizing various equipment to create interim power sources while new power sources are established—assuming they didn't already have that in-process. I find it unbelievable that millions of people wouldn't have manufacturing, meaning the ability to get to replacement power sources is a lot easier.

They're on a water world. All they need is a source of heat and they have steam power. There's millions of people who had to be transported there and housed there so there's no lack of materials to build steam engines and biodiesel can be made out of algae. That's instantly the Industrial Revolution or later.

So unless there's something you've not told us about that's affecting these people's memories, behaviors, and training.


  • $\begingroup$ So unless there's something you've not told us about that's affecting these people's memories, behaviors, and training. - don't assume, the question is supposed to be self-sufficient. Thanks for the answer, it means I need to tweak the abandonment to cause such reversion. $\endgroup$ Commented Sep 27, 2022 at 21:07
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    $\begingroup$ While I always appreciate the coveted green check mark, is is the recommendation of this Stack (which you should know by now) to not award that check mark for at least 24 hours. We have a planet-wide user base and human nature is to generally ignore questions with accepted answers. This means a better answer might be lost by a hasty acceptance. (BTW, did you really chastise me for pointing out there would need to be something else to cause your goal only to tell me you'd create that cause? No question is perfect.) $\endgroup$
    – JBH
    Commented Sep 27, 2022 at 21:16

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