I am building a world where several Empires and Federations ally to bring a destroyed old empire back to life. The High advanced alliance has magic (I'd prefer not to use) and technological skills. They are also geneticists capable of reconstructing any living thing from its DNA.

Each system in the destroyed empire saw its sun blackened by layers of Dyson Spheres that only let through 5% of the sun rays. Subsequently, all planets in that system entered an icing era.

I searched for the Dyson spheres, and I know how to destroy them. What bothers me more is having a credible solution for the active planets when the attack occurred. Each of these planets is now covered in ice.

What I envision is too simplistic IMO.

Just a note: Events take place in 17000 years from now.

  • the Dyson spheres are gone, (Prerequisite)
  • the planet receives its regular quota of sun rays. That process reboots a barren planet over a long time. Not acceptable.
  • the alliance drills heating devices in the ice till about 2/3 of the ice's thickness (Highest pressure point)
  • The alliance deploys condensation devices floating around the planet. They set in when the damp is too high. The rain is falling on the ice and freezes again but in lesser proportions.
  • The melting ice builds rivers; lakes, and seas
  • When the first dead vegetation appears, specialized crew (humanoid robots) collect DNA.
  • when the first roofs or walls appear, the robots find more DNA. They also sample animals and insects DNA
  • First corpses, They collect DNA of 5000 corpses all over the planet, to have all the genetic material of the race. (Theoretically, less is already enough)
  • The alliance destroys every carbon-based remains to prevent rotting and spreading diseases.

The rivers go back to their original beds, lakes, seas, and oceans as well. The alliance knows the continents will rise again now that the ice is gone. Seismic precautions are taken. The alliance reintroduces Wildlife first, then the former race occupying the planet, they receive a proper education.

The whole terraforming event must not last more than ten years (Maybe not credible), not counting the education of the race.

What is not credible? What should I add? Is the scenario completely unrealistic?

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    $\begingroup$ Just by way of advice and as a comparison. If he The sun was to disappear tomorrow the Earth would freeze over within 2 months. So assuming starting conditions (same type of star, planets the same distance from them etc. ) it would take the same amount of time to warm them up. i.e not very long. The key issue which you haven't addressed in your question is how long its going to take the alliance to destroy all or at least most of the Dyson spheres. If its more or less immediate then the warming process will take care of itself. $\endgroup$
    – Mon
    Commented Aug 25, 2021 at 23:22
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    $\begingroup$ Maybe your alliance has the energy budget to implant regularly spaced space heaters across the surface of a planet, but it would be much more efficient to melt the ice with orbital bombardment using asteroids, or crank the co2 in the atmosphere to some unreasonable level like 1000ppm to induce a worldwide greenhouse effect. Let the growing plant life extract the co2 to bring it down to normal levels. 10 years is quick for any kind of terraforming project. If you had the right sort of comets, you could use bombardment and co2 simultaneously. $\endgroup$ Commented Aug 25, 2021 at 23:22
  • $\begingroup$ Destroying a Dyson sphere supposes to be able to retrieve material. The alliance has all it needs to use wormholes who could then act as some giant vacuum cleaners and transport the material somewhere else. In my imagination, destroying the Dyson spheres should take less than two months. Concerning the attack on the suns, I had reckoned with 2 months, indeed. All living beings dying quite rapidly: Nothing can survive with temperatures less the -100°C. $\endgroup$ Commented Aug 26, 2021 at 5:51
  • $\begingroup$ Bombardments supposes to destroy the former traces of life. I want to avoid that. Thawing the planets with the greenhouse effect may be a possibility. I wouldn't use CO2 but another greenhouse effect gas, more effective, easily trapped, and allowing to lower the albedo effect. I will do some research on this. I also can combine the two technologies: Greenhouse and Heaters. I know 10 years for terraforming a planet is not much. I'll change that to 20. Can't be 100 years because of the story workflow. $\endgroup$ Commented Aug 26, 2021 at 6:10

1 Answer 1

  • Was intended to be a comment, but it too much so I'll leave it here

"The rivers go back to their original beds, ..." not necessarily, if there is a prolonged state of the ice age, the stuff is capable to plow surface as can be seen from ice age events, depends on duration. So maybe some artificial effort here or attention to this aspect.

5% of the sun is not covered is obvious story plot, DS can work in a way planets won't have a clue it is there, with more full coverage. 5% is not impossible and it is your story driver, but if you make it 0% it will raise fewer questions.

For a planet, it takes take thousands of years to cool deeper than the surface layer and there is a limit to how deep(for active ones, magma, and stuff).

Too deep drilling is also not too realistic, it seems you are looking for 150K surface temperature(for Earth-like planet), the atmosphere gets frozen, so depth to surface more like oceans rose 15 meters, meaning most of places depth to surface 15 m or less, as drilling it just no effort depth. And the layout won't be changed that much with wind and snow as there is no atmosphere anymore.

Nanotech can help locate and collect genetic samples of every multicellular creature. Way before it all taws. Restoring may take time but with nanotech, you probably can restore the old ecosystem to a functional state in 10y or less, without it ehh not going to happen, forests play a significant role in ecological balance and air flows and rain regulations and it just does not grow that fast.

If restoring an old ecosystem is not a goal, just seed the life and do not care how long it takes for the situation to settle down, or let those resurrected to care then, with or without nanotech there is nothing to do for 10y, 1-2 max, 8 y is just monitoring and fixing stuff, and then depart it will continue to break down, some will survive some will die out - not your problem, god evolution will sort out.

If you are intending to leave quality work, then nanotech or longer efforts.

Generally, nothing is super wrong with the described stuff, overall score 6/10.

(wormholes for DS destruction, eh 1/10 but hey hey, why not, does not matter, not included in the overall score)


  • Just so you know, I increased the terraforming time to 70 years. And I use nanotech to collect DNA. I removed the DS covering only 95% of the sun, as it brought nothing to the story, though a fully solid DS can’t exist due to physical constraints. I wrote the prequel and the first book. I am checking them now for inconsistencies.

Yes, 70 years is good for a lot of things, especially if technology is on par with the task, which nanotech is sure is.

As Dyson swam, which is correct both in the way it can be done and how it should be done, compared to Dyson sphere - yes, it is not solid, it is a large number of orbiting objects, independently orbiting objects. It is not impossible to make a solid sphere, maybe not in the way people imagine, but if you give a shot to Isaac Arthur youtube channel, especially his earlier videos (2-3-year-old ones, I guess) where he was talking more about active supporting structures and concepts based on that and some use cases - it is possible to make a shell without gaps around a sun with that approach, I mean it will look like a solid one, but underneath will be some fast-moving stuff which keeps the thing from collapsing, and sure it will have different properties than those monstrose fantasies with km's thick shells which is not possible because there is not enough matter in a star system for that and without active supporting strength is not enough. So it can be done in both ways. But opting for Dyson swarm, like many independent objects is a good and solid choice.

As for 95% or 100% - I could probably do a better job writing this part of the answer. And thinking about it now - maybe it wasn't such a big deal, and maybe it was not a bad choice. Have a little bit of a hard time saying how it may look like with a swarm setup - like flashes of full-powered sun time to time, or dimmed sun yeah.

But with a swarm is it really worth taking the last percent of output, as it means more overlapping between satellites, which, and a be statutes as well(so not so much orbiting stuff, but more like solar sail floating around stuff) less efficient - so with orbiting stuff there is some optimum coverage which is not necessarily a 100% one if the who build(machines, aliens, humans) do care about such aspect - it is never a loss in absolute numbers to catch 100% of what there is, especially if it is nanotech-based solutions as which if you think it does not have that much use where it can easily be repurposed - no nanotech is like money - never too much.

I mean, in essence, I was rather too categorical about the number and there are legit explanations to basically any number from 80-100%, or maybe even less. As well as to have that swarm way beyond Neptune s an example (or near it, which is many many astronomical units beyond planet orbit) - it requires more matter to implement the solution, but it more efficient conversion of that energy, in terms of heat machine that cold end is closer to hydrogen boiling point and hot end, is star surface temperature and it gets (theoretically) close to 99.99% percent efficiency.

So basically any number can be explained this or another way.

  • $\begingroup$ Just so you know, I increased the terraforming time to 70 years. And I use nanotech to collect DNA. I removed the DS covering only 95% of the sun, as it brought nothing to the story, though a fully solid DS can’t exist due to physical constraints. I wrote the prequel and the first book. I am checking them now for inconsistencies. $\endgroup$ Commented Dec 13, 2021 at 8:19
  • $\begingroup$ @MattXanthis Hi, thanks for letting me know. Just now got the opportunity to answer you, and added an update section, nothing major on my part, considering that 95 percent aspect didn't matter for you at the end. Sure use Dyson Swarm, not a shell, also the channel I mentioned do recommend it, do not know how it is doing now, but its old videos for sure can be a source of space thinking inspiration and in a sense what can be done in space - they are great for adjusting perception of scale what fits the space. $\endgroup$
    – MolbOrg
    Commented Dec 24, 2021 at 2:43

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