What cosmological event could snuff out the sun without destroying Earth?

twofish-quant

1) It doesn't have to build them. Just maintain.

2) The other question is how closed does the ecosystem really have to be. For example, if you have a space ship and you leak oxygen, then you are dead. Even with a dead earth there are going to be supplies of oxygen lying around. It might be frozen oceans of oxygen. It could be ice that can be broken down by electrolysis.

3) Finally my gut feeling is that the small the number of people, the more easier it will be to maintain a closed ecosystem

From a "mouths to feed" people are easy to replace. The reason I think that "life will be cheap" is that when resources are limited, one less person is one less user of oxygen.

Ryan_m_b

Given the huge variety and complexity of equipment inherint in modern life this doesn't change much. Also part of maintenance will be replacing damaged parts that innevitable wear and tear will damage, these are going to have to be built.

I'm not just talking about the systems to maintain the ecosystem here, I'm talking about all the technology we need in everyday life and all the technological industry required to provide that from factory robotic arms to MRI machines.
Sure there are advantages of being able to harvest from the world but you've still got to keep an ecosystem going. That's no mean feat juggling so many species interactions when failure will result not just in habitat destruction but possibly the end of the human race.
I'm sure there's an optimum number decided by the carrying capacity for the ecosystem and the labour force needed to maintain it but that's ignoring every other part of industry.
There's a lot you're not taking into account. A skilled worker requires a significant investment, you can't just execute your uppity neurosurgeons and replace them in 9 months time. For a skilled worker you need at minimum one full time adult for 5-10 years to make sure it doesn't die from starvation, disease or accident. For support this requires the input of specialist products e.g. vaccines, nutritious food, developmental toys which all rely on other workers and industries for everything from child psychologists to chemical factories. Then you need 10-15 years of education to get them to graduate level (with all the associated industry and workers) which makes them entry level tea-making-person for a period of years until they have the relevant experience to be considered a fully fledged skilled worker in their field.

Bottom line a high tech civilisation has a wealth of hidden complexity (just look at your smartphone and try to think of how many industries and skilled workers have had a hand in it e.g. exotic material mining, software writers, transport logistics etc) filled by skilled labourers and both they and the infrastructure are huge investments in resources. You can't just stick anyone onto a training course and in a short amount of time get a skilled worker. It takes years and it takes a large education sector stocked with current skilled workers (in other words you need to keep a pool of every speciality perpetually to prevent the loss of noncodified and tacit knowledge).

twofish-quant

I think that if the sun goes out people won't be worried too much about factory robotic arms or MRI machines. Given the difficulties involved in merely surviving I don't think there would any energy to do any more than that.

I think people will give up on trying to maintain species diversity and just merely do what it takes to keep a small number of people (100,000 at most) alive. Probably closer to 3000.

Frankly, I don't think there would be much need for neurosurgeons. Anyone that needs neurosurgery would be assumed to be dead already.

I think that all of that would be gone. We'd end up with medieval conditions, with only the bare knowledge needed to maintain life support. Anything and anyone else will be expendable.

Sure. That's why I don't think that we will end up with a high tech civilization. What I envision is a small group of people underground near a geothermal energy source that provides heat. Once you have heat, you can generate enough electric power to electrolyze water so that you can replace oxygen losses. Now if you can replace oxygen, then food, water, and heat are things that don't require a huge amount of high technology to maintain.

Low tech with the KISS principle. Oxygen, water, food, heat, with simple robust technology. I think that anything that requires any sort of specialist technological expertise to fix is going to be non-functional in a year.

twofish-quant

Also, if we have 100 years to prepare, I think it would be a terrible idea to have one settlement. What you really want are thousands of settlements, so that any thing that destroys one settlement doesn't destroy everything. You probably want a settlement that takes a high tech strategy and one that takes a low tech one, so that someone will survive.

Ryan_m_b

I think you're right except for the fact that your entire idea of returning to a quasi-hunter-gatherer state fails in the face of the need for a closed ecosystem. It's nowhere near as simple as just having some heat and oxygen. Have you ever looked into how complex an ecosystem is? You've got to produce one able to healthily sustain a human population for a long time in a small area. That's going to require highly advanced technology to monitor and manipulate at the required level.

The smaller an ecosystem is the less stable it is going to be as there is greater chance for individual or small groups of species to become critical to the food web meaning that when something happens to lower their numbers it sends catastrophic shockwaves. The smaller and more isolated the ecosystem the more disasterous this will be for humans.

This is of course tapdancing past how ecosystems would be build in underground caverns capable of sustaining humans.

twofish-quant

Yes, but since we are creating an artificial one, it's probably best to use the KISS principle and create a minimal surviable system rather than even begin to try to replicate a complex ecosystem. The model I was using was that of a Mars colony or spacecraft to Mars. I can imagine how a spacecraft to Mars with say 50 people would work. I couldn't imagine the complexity of trying to create a spacecraft with a million people, so at least for one of the colonies, I'd suggest not even trying.

Ryan_m_b

The minimum complexity for a redundant, sustainable ecosystem is likely to be huge. Even systems that seem simple have a wealth of hidden complexity; just think of crops and how they rely on soil fauna (all the thousands of species) or insect polinators and then how each of those species requires others etc etc. Mentioning that also makes me think of the human (and all animals for that matter) microbiome and how we'd have to somehow ensure the environment could provide this.

The best idea I can think of would be to investigate some of the most isolated ecosystems that can sustain humans and try to replicate them.
I wasn't using a spacecraft model because they aren't sustainable. You may have some recycling and repair facilities but at the eventually they will run out of their stockpiled resources and die.

Considering the goal here is the continued survival of the species I don't think this action of delaying the innevitable would help.

Maiklas

I have a few ideas...

I like the idea of a steampunk sort of colony. Almost every mine in the world is going to be taken over by refugees. Deep down, the Earth is hot, of course, from its formation and radioactive decay, so refugees are going to look to live in the Goldilocks zone of temperatures, not too shallow or deep. They would drill deeper for hot water and steam to turn to power. With power comes light, which can produce plants, which can produce oxygen and food. Maybe it's all really hard to make this work, and tens of thousands of mining colonies would fail to survive. Still, some colonies could have found a way. I don't think it's so hard as some of the above posters say, as it need not be a truly closed system. They can dig to expand their underground world and resources. They might be able to wear arctic clothing and carry oxygen tanks to go topside for short expeditions. If I were writing the story, I'd alternate the narrative between two underground colonies: a nuclear-powered colony created by a superpower like America, and a steampunk colony founded by miners, like in an African diamond mine or California gold mine. It would be interesting to see the nuclear-powered colony having social problems and the steampunk colony having technical breakthroughs.

Idea #2 is that the underground colonies would have to defend themselves from those still surviving topside. You might get some inspiration from the mysterious Sea People, who invaded/migrated into many of the Mediterranean civilizations circa 1600 B.C. "Coincidentally," around that time there was a major volcanic eruption that probably blocked out the Sun.

Idea #3 is that aliens could be responsible for the calamity. Analogous to how we used gravitational slingshotting to get Voyager and other probes to the outer planets, the aliens could have set up a masterful "billiards shot", perturbing small objects in the Oort cloud that result in more and more powerful interactions that eventually result in the Earth being ejected from the Solar System. There has to be a reason they don't simply send a dinosaur-killer asteroid at Earth, so how about that they want to colonize and they are cold-loving aliens? Maybe cold-fusion based biology or some cold-based biology beyond our current understanding. Their cold-natured ways would explain why they are so darn patient with the decades or centuries that their "billiard shot" would need to play out - they live a very long time and move slowly. The Earthlings would not know about the aliens; it would be just one theory to explain the extraordinary bad luck of a shower of Oort cloud objects destabilizing the orbits of Mercury, Venus, and ultimately the Earth. You can wait to reveal the aliens in the second novel, when, a couple centuries later, colonizing aliens are surprised when Earthlings start popping out of the ground to interfere with their efforts. The aliens would be ill-prepared for conflict, lacking a military, FTL spacecraft, and the speed to react, but they would have their own tricks.

Ryan_m_b

Welcome to the forums Maiklas.
If he's going with realistic science then it's going to be pretty hard to build a sustainable ecosystem with a carrying capacity sufficient for the population. Whilst it doesn't have to be completely closed (waste could be dumped, resources harvested) a lot of the knowledge, techniques and technology is going to be the same. This set up is comparable to trying to set up self-sufficient colony on another planet; you get the resources of the planet but you've got to do a lot of work to use them to keep the ecosystem alive.

twofish-quant

I'm not entirely convinced of that. If this is true, then we are going to be stuffed if we try to colonize Mars.

Submarines and spacecraft.

Now. But any spacecraft that goes out of earth orbit has got to be sustainable for months at a time. If you have a Mars colony or something around Jupiter, it's got to be sustainable indefinitely.

One thing to consider is that if the sun were going out, then it might not make much sense to stay on Earth at all. The missing element is energy. With enough energy anything is possible. So if the sun were going out, it might make more sense to relocate to Io where you have volcanos which are powered by Jupiter's gravity field. Or you could have hydrogen fusion generators with Jupiter giving an essentially infinite source of hydrogen.

Even getting as many people out of the Earth's gravity well as possible would be useful. If you stay in the Earth's gravity well, then you are trapped. Once you get as many people as possible into "deep space" then you can start colonizing as many asteroids and comets as you can to maximize the odds that someone is going to survive.

mfb

Well, this would be a slow effect, slightly reducing solar radiation over the timescale of hundred thousand of years. In addition, solar neutrino observations can directly measure the rate of fusion in the core.

We are talking about something happening decades in the future, and I would expect that a significant amount of working hours can be spent for preparation, assuming the society remains intact. I would expect that roboters can do a lot of mechanical tasks. If you can train a robot to replace one specialist, you can train the robot to replace 10000. Not with the same output as 10000 workers, of course, but you can simply copy the memory to "train" more robots. Those robots would need a significant infrastructure, but (at least in theory) they are able to maintain this, perhaps with the help of humans. You need years of practice for neurosurgery, but if you can build some parts of a car and have a good guide, you might be able to build other parts of it, too.

The alternative would be to implement everything low-tech. Design cars so simple that 10 humans can build them. However, I think this approach will be doomed the day the oxygen runs out, as burning fossil fuels would probably be the only heat/energy source for the whole environment. Fission or even fusion are too complex to maintain.

twofish-quant

Something to point out here is that some of the best science fiction assumes something weird happening and looks at the consequences rather than trying to figure out the cause. One thing that you can do is to say "the sun is going out, and no one knows why." The fact that no one knows why the sun is going out would have some interesting consequences.

Fission reactors would be probably be impossible to maintain, but radiothermal generators could be maintained with minimal skills. The trouble is that I don't know what the energy requirements would be. The energy output of RTG's have been low, but traditionally they have been intended for space use where there are weight requirements.

And I'm not even sure that it would be impossible to design a fission reactor that would be need minimal intervention. Natural managed to create one at Oklo, Gabon.

That actually would be a good place to start. How much *energy* does it take to keep a human alive and how much of that comes from the sun.

Ryan_m_b

Yup.
These are not sustainable isolated ecosystems. Once their food stocks are gone it's game over. Think more along the lines of an ecosystem that cycles from autotrophs to detritivores via enough animals to sustain a human population.
By definition I'd say that a spacecraft is not sustainable. Sustainability is linked to recycling, a biosphere can recycle it's resources potentially indefinitely with constant energy input. A spacecraft cannot, a colony would need to (else it's a dependant outpost).
I don't see why one couldn't just construct solar panels accross swathes of Earth's now frozen surface or use fusion (or any other energy source) on Earth. Moving to space would make the whole endevour hugely more complicated and expensive through the added headache of having to get it there (or designing and shipping equipment to build it all there).
I don't see why moving to space would change any chance of survival. You're going to need precicely the same resources and innovations only if you try for space you have to make it all work there or ship it there.

twofish-quant

I don't see food as a big problem. The fact that we digest plants and vegetable matter is an accident of evolution. It's possible to get all your nutrition injected via an IV, and there are people who end up living for years at a time with all their nutrition supplied that way.

http://en.wikipedia.org/wiki/Parenteral_nutrition

Solar panels won't work. No sun. The thing about Jupiter is its this huge gravity engine which leaks out energy in several different ways, which might be collectable.

Right. But it's best to do it when the lights are still shining.

Also a lot depends on when the lights start to go out. If the sun starts to fade when we already have a solar system infrastructure in place, then what we can do is to use solar power satellites to store as much of the energy of the sun as we can, so that we can tap into it once the lights go out.

More options. Also with the larger planets you get a source of energy. There's also the "now or never" situation. Even in the best case scenario I can't imagine an post-sun earth based civilization *ever* getting the ability to go into space, and if everyone stays on earth, then it's going to be the end sooner or later.

The other thing that could be done is genetic engineering. You could start engineering people that would be most likely to survive the lights going out.

Ryan_m_b

I think you're mistaking the product for the process here. The nutrients that go into IV still have to be produced like regular food. I don't know too much about IV but if it's anything like culture medium then it isn't defined either which is an extra barrier to any artificial synthesis (and if we could synthesise such things we could use it to make in vitro foods if we wanted).
Geothermal or nuclear then. I don't see Jupiter as being a more attractive option given then sheer cost involved in any space endeavour (as well as the extra R&D needed).
Why would it end on Earth sooner or later? Also I don't see any realistic way that this could be accomplished. I know that sounds strange considering the topic of this thread but hear me out: proposing that mankind has the ability to build sustainable underground cities that can house all the ecology, industry and societies we need is one thing considering that all of those things are here on Earth but considering doing it in space (where we would have to seriously ramp up our in-situ resource allocation and fab lab technologies) just adds orders of magnitude of difficulty.
Perhaps though that's so far into the realms of science fiction there isn't much to discuss. Right now if we tried we might be able to swap one allele for another but significant phenotypic engineering is way out there.

Czcibor

When I was playing with a simulation where merely putting an object of size of an underweight star was making havoc in our system. (actually in the simulation that I run the mess wasn't immediate) My idea?

Apocalypse rider: burnt out brown dwarf - massive enough, popular enough, damn hard to detect

Way: it crosses the system and immediately destabilizes orbits. However, the doom on Earth is not immediate it first is moved to much higher orbit/more eccentric. Later it is ejected from the system by interactions with Jupiter.

(so you can get a few decades in which the situation is degrading somewhat)

Possible energy sources: geothermal and nuclear. Iceland becomes surprisingly hospitable ;) Nuclear power plant - the safest place to live ;)

Political system - who got saved? Military? A few rich people and those who they hired? Democratic gov selected? By random from all citizens? By some meritocratic exam?

I would not worry too much about carbon dioxide. If the planet got colder it would freeze at places where temperature would be below -78C.

CCWilson

Guys, I appreciate all the speculation; gets my brain wheels turning. A couple of points.

The story begins just a few years from now, so that the reader can easily imagine himself living it, and the warning is only five or seven years before a black hole passes by, initially with uncertainty as to whether it will sling us into space, so that this generation is the one facing extermination. Forget genetic engineering and traveling to a moon of Jupiter and building fusion reactors and such; not enough time.

One of the issues is going to be maintaining a livable atmosphere underground. Anybody know much about oxygen generators? I do think that geothermal power plants have a lot to recommend them as a semi-permanent source of energy and perhaps a source of water as well; can't forget about water.

You'd want a farm and ranch as part of the bunker city, for dining variety, and the choice of which plants and animals to take underground would be difficult; all others would go extinct, forever.

The economic system would probably be one of central control, at least initially, and a new currency would be established. Your old money is no good here.

The process of selecting underground residents would be wrenching. After choosing scientists and doctors and other technical people, a lottery to give everyone else some small chance? Winners to bring their families? Age restrictions? No one over 40? Would rich people build their own cities underground? Could average citizens band together and survive for a while in caverns?