Imagining a realistic apocalypse - Red Giant cooks world to death, or Tidal Forces turn it into swiss cheese

[Commissioner Tadpole]

I've been imagining a fictional species(three, actually) for writing a story/game(whichever comes first), and a key point for them is that they reside in a world that is on risk of being destroyed by one of three risks - if a risk doesn't end up killing it, the other one(s) will - but are too stubborn to leave it behind. However, I want those to be as realistic as possible, and i'm not sure if I made them to work correctly - I was never that good in physics or chemistry - so, I'd like to discuss whether those disastrous outcomes would actually occur when in the right situation.

• The main risk, and arguably the one who set everything moving foward, is when the planet's star, previously a red dwarf, suddently swelled into a red giant, consuming the inner worlds and causing the surviving ones to be burned into a crisp. The homeworld survived, but its temperature was far higher than normal, its plants have been withering away under the heat, the seas and lakes were drying up, and the ozone layer was being destroyed. In order to stop the chaos from happening, they created a force field to serve both as a makeshift ozone layer, and to hold up against the increased heat. This force field later ends up struggling a lot as the red giant continues to grow bigger.

• Also in a bid to prevent the previous risk, they made artificial plant life to replace the previous one. Made to be far more resistant to the current climate *and* to filter hot air into cold air, they were spread across the entire planet to rebuild. Alas, even though it was a noble attempt, it did little to stop both the next risk and to calm down the population, which agreed that their homeworld was lost and that it'd be better off to just leave. This ends up being the risk that destroys the world, as one of the leaders - there being six in total, due to the government being a technocracy - grows rabid and too attached to his homeworld, and takes control of the plants to "assimilate" those who don't agree with him - at this point being everyone.

• The final risk, while not exactly related to the star, was almost certainly caused by it. By mixing the tidal forces of the star with that of the homeworld's biggest moon, the result wound up being far, far more potent tidal forces storming against the homeworld, causing numerous cracks to open on its surface, releasing both molten lava and abominations which resided deep underground - and as they were primarily adapted to survive in such hostile conditions, the overground was easy prey for them, and became essentially an invasive species, taking over large swatches of land at alarming rates. The ravines also continued to crack open due to the relentless tidal forces, eventually taking down entire cities in the process. The planet was basically becomming swiss cheese.

This all sounds pretty macabre, but my abilities to make characters suffer is not the key point in here - and most of the plot would not take in that world, anyway. Would those apocalyptic scenarios actually work in real life, presented in appropriate circumstances, or they ultimately end up being fantastic and unrealistic?

[Rune]

Hum. The first thing that comes to mind is the the star's swelling to red giant is not something instantaneous. I will be the first to admit that I now next to nothing about the particularities of star evolution, but that seems to be the kind of even that, while happening in the blink of an eye in cosmic timescales, might be quite long on human scales (say, 100,000 years?). So your impending doom might very well be a slowly swelling star, still far from full-fledged red-giant, creating a runaway greenhouse effect, increasing the acidity of oceans, thus killing plankton, which causes the entire biosphere to collapse in short order once some critical isolation level is reached. In the meantime, the climate swings will create plenty of natural disasters like supertornados and that kind of thing. As the oceans slowly evaporate and the rate of atmosphere loss increases, the oxygen content in the atmosphere falls, and CO2 rises. Long before tides can crack the crust (a pretty extreme scenario, BTW), you will have a barren rock of deserts and extremely salty shallow seas. Volcanism would accelerate the greenhouse effect, by releasing trapped gases from underneath the crust.

 

Rune. Unless you also have a huge moon that is coming close to it's Roche limit at the same time... that would be a pretty spectacular Armageddon, with rings and Kessler syndrome involved.

[Scotius]

Red dwarfs do not go through red giant stage - you need a star similiar to our Sun sizewise. Another matter is the distance of the planet - To survive star's expansion stage mostly intact, this planet would have to orbit far away from star's initial habitable zone. For instance Earth will be burnt to cinders by Sun in couple billions of years. Heck! Mars will be a scorched desert then. If initially your star would be a red dwarf, its habitable zone would be tiny, and very close to the star - no way it would survive the expansion. And finally - planet-wide forcefield keeping the planet somewhat habitable while skimming outer layers of red giant's atmosphere? Now that's a feat of engineering that should register on Kardashev's Scale. What is keeping this super advanced civilisation from abandoning the proverbial ship?

[Rune]

1 hour ago, Scotius said:

Red dwarfs do not go through red giant stage

Whoops. As I said, not really great on stellar evolution, THAT would be the first thing to bring up. The "forcefield" I purposely ignored, since it's magic by definition... and as I said, the planet dies in a very short timescale (compared to stellar evolution timescales) when the star's energy output changes by even a small percentage.

If you change the star completely, though, you could make it a big one and then the instability that threatens the civilization could be as simple as solar flares (think Carrington Event every few weeks/months) and a slight increase in energy output. Most big stars are nowhere near as stable as sun-like ones (again, anything star-related happens on long timescales, from a human point of view, even supernovae can last months, and that is the closest to "instantaneous" a star gets), and their radiation bursts would sterilize any accompanying planets... and against radiation, you can use magnetic fields as protection. It would be an astronomical energy expenditure to protect a planet, but perhaps cities can be forgiven by the educated reader (and let's gloss over the fact that dumb mass is a much better radiation shielding than electromagnetic fields).

Yup, a big moon close to its Roche limit + a finicky big star seems to be the best realistic fit to the scenario you seem to want, even though its effects are substantially different than the ones you describe. That would produce, at the same time, big tides, huge climate chanes, runaway greenhouse, increased volcanism, and a big Kessler syndrome when the moon breaks up, plus a lot of meteorite impacts. Very apocaliptic indeed!

 

Rune. Stars can also have radiation bursts when stuff falls into them, IIRC, but it has to be pretty significant stuff.

Edited December 26, 2015 by Rune

[Scotius]

I just don't understand why are you trying to cram so many disasters, at the same time, into one story A single extinction event should be enough to push any civilisation into panic mode (hopefully controlled panic).

[SomeGuy123]

I had a similar idea.  Game needs to be an environment where everything is basically wrecked beyond most recognition and there are a handful of survivors living in a small number of armed, factional groups.

This is because it's possible to actually show in a feasible game.  You could allow players to explore the whole Earth - but the nuke craters and rogue nanotech have erased most signs of human presence and smeared out the geography.  Major cities are just "ruined urban biome" where only fragments of road and building foundations remain.  

The small number of human survivor groups live in camps or space stations or small settlements, with a small enough number of NPCs that you can actually model and show them all, and make the whole station/settlement an explorable place, and they only have 1 leader with a simple government and a simple set of programmatic rules they use to deal with the player.  "halt, turn over your stolen goods, or "this is contraband.  I'm charging you a fine, citizen, and taking all the contraband".  "here's the town message board where various chores that NPCs want doing are listed".  You know the drill.

Anyways, I figured it needed to be multiple causes.  "War never changes".  Some jerks salted the earth with cobalt and other long life radioisotopes, creating lots of hot zones, other jerks released killbots that lie in wait like land mines for anything that moves, yet more jerks released a cloud of nanotech disassembly machines that try to oxidize biological materials.  (and more machines are being made by these self replicating plants, so all humans have to seal themselves away in clean environments or wear space suits outside - even a single breath of dirty air has enough nanomachines to be fatal)

Radioactive salting (some gigantic gigaton class nukes with plates of cobalt metal in the casing) and killbots (think the modern Atlas robot, upgraded, and lying in wait for you with a machinegun) are realistic.  The nanomachines would be these nanoscale things made of diamond that combines organics with oxygen, essentially combusting them, and collect enough energy from the reaction to run themselves.  They get the oxygen by trapping it from the atmosphere.  The machines cannot build anything or self replicate or destroy anything that is not from a list of common organic substances.

 

Edited December 26, 2015 by SomeGuy123

[Commissioner Tadpole]

7 hours ago, Rune said:

Hum. The first thing that comes to mind is the the star's swelling to red giant is not something instantaneous. I will be the first to admit that I now next to nothing about the particularities of star evolution, but that seems to be the kind of even that, while happening in the blink of an eye in cosmic timescales, might be quite long on human scales (say, 100,000 years?). So your impending doom might very well be a slowly swelling star, still far from full-fledged red-giant, creating a runaway greenhouse effect, increasing the acidity of oceans, thus killing plankton, which causes the entire biosphere to collapse in short order once some critical isolation level is reached. In the meantime, the climate swings will create plenty of natural disasters like supertornados and that kind of thing. As the oceans slowly evaporate and the rate of atmosphere loss increases, the oxygen content in the atmosphere falls, and CO2 rises. Long before tides can crack the crust (a pretty extreme scenario, BTW), you will have a barren rock of deserts and extremely salty shallow seas. Volcanism would accelerate the greenhouse effect, by releasing trapped gases from underneath the crust.

 

Rune. Unless you also have a huge moon that is coming close to it's Roche limit at the same time... that would be a pretty spectacular Armageddon, with rings and Kessler syndrome involved.

Ah, biological collapse. I like it. And also lets me keep the plant concept(which is indispensable). And yeah, maybe the tidal forces were over-the-top. I guess they won't occur.

6 hours ago, Scotius said:

Red dwarfs do not go through red giant stage - you need a star similiar to our Sun sizewise. Another matter is the distance of the planet - To survive star's expansion stage mostly intact, this planet would have to orbit far away from star's initial habitable zone. For instance Earth will be burnt to cinders by Sun in couple billions of years. Heck! Mars will be a scorched desert then. If initially your star would be a red dwarf, its habitable zone would be tiny, and very close to the star - no way it would survive the expansion. And finally - planet-wide forcefield keeping the planet somewhat habitable while skimming outer layers of red giant's atmosphere? Now that's a feat of engineering that should register on Kardashev's Scale. What is keeping this super advanced civilisation from abandoning the proverbial ship?

Oh. What a shame. I kind of wanted the star to be red, as it'd give me an excuse to make the plants red without it being unrealistic. And yeah, I was also concerned about the planet-star distance, but I figured it'd end up being answered anyway.

And yeah, this is a pretty advanced civilization - in the Kardashev Scale, they would likely be entering Level 2. Unfortunately, they're too stubborn and don't accept changes, which makes them unwilling to leave their homeworld. This ends up being the moral of the story: "don't be stubborn, and know when to accept change or stick with the old ways".

4 hours ago, Rune said:

Whoops. As I said, not really great on stellar evolution, THAT would be the first thing to bring up. The "forcefield" I purposely ignored, since it's magic by definition... and as I said, the planet dies in a very short timescale (compared to stellar evolution timescales) when the star's energy output changes by even a small percentage.

If you change the star completely, though, you could make it a big one and then the instability that threatens the civilization could be as simple as solar flares (think Carrington Event every few weeks/months) and a slight increase in energy output. Most big stars are nowhere near as stable as sun-like ones (again, anything star-related happens on long timescales, from a human point of view, even supernovae can last months, and that is the closest to "instantaneous" a star gets), and their radiation bursts would sterilize any accompanying planets... and against radiation, you can use magnetic fields as protection. It would be an astronomical energy expenditure to protect a planet, but perhaps cities can be forgiven by the educated reader (and let's gloss over the fact that dumb mass is a much better radiation shielding than electromagnetic fields).

Yup, a big moon close to its Roche limit + a finicky big star seems to be the best realistic fit to the scenario you seem to want, even though its effects are substantially different than the ones you describe. That would produce, at the same time, big tides, huge climate chanes, runaway greenhouse, increased volcanism, and a big Kessler syndrome when the moon breaks up, plus a lot of meteorite impacts. Very apocaliptic indeed!

 

Rune. Stars can also have radiation bursts when stuff falls into them, IIRC, but it has to be pretty significant stuff.

Not really magic, just science so advanced it's indistinguable from magic.

I'm open to changing the star. I suppose a Blue Giant can work(and nicely, since I quite like the colour blue). Could it also influence plant life to get a blue colouration like red stars might make plants reddish? I do like the idea of stellar radiation bursts, and using a magnetic field is more realistic than "lol its a magic barrier in everything but name".

Also, protecting only the cities rather than the entire world is actually a rather good idea, since later on I do pretend to have the main characters return to the world and explore its ravaged wilderness - the cities being the only safe places.

3 hours ago, Scotius said:

I just don't understand why are you trying to cram so many disasters, at the same time, into one story A single extinction event should be enough to push any civilisation into panic mode (hopefully controlled panic).

Well, it was mostly to show how this civilization was so determined to not leave their homeworld behind it'd end up being their death in one way or another. But, looking back at it, I notice I went quite a bit overboard...

Also SomeGuy, your idea seems rather similar to the Fallout series.

Edited December 26, 2015 by Commissioner Tadpole

[KAL 9000]

5 hours ago, Rune said:

Whoops. As I said, not really great on stellar evolution, THAT would be the first thing to bring up. The "forcefield" I purposely ignored, since it's magic by definition... and as I said, the planet dies in a very short timescale (compared to stellar evolution timescales) when the star's energy output changes by even a small percentage.

If you change the star completely, though, you could make it a big one and then the instability that threatens the civilization could be as simple as solar flares (think Carrington Event every few weeks/months) and a slight increase in energy output. Most big stars are nowhere near as stable as sun-like ones (again, anything star-related happens on long timescales, from a human point of view, even supernovae can last months, and that is the closest to "instantaneous" a star gets), and their radiation bursts would sterilize any accompanying planets... and against radiation, you can use magnetic fields as protection. It would be an astronomical energy expenditure to protect a planet, but perhaps cities can be forgiven by the educated reader (and let's gloss over the fact that dumb mass is a much better radiation shielding than electromagnetic fields).

Yup, a big moon close to its Roche limit + a finicky big star seems to be the best realistic fit to the scenario you seem to want, even though its effects are substantially different than the ones you describe. That would produce, at the same time, big tides, huge climate chanes, runaway greenhouse, increased volcanism, and a big Kessler syndrome when the moon breaks up, plus a lot of meteorite impacts. Very apocaliptic indeed!

 

Rune. Stars can also have radiation bursts when stuff falls into them, IIRC, but it has to be pretty significant stuff.

Stellar core collapse happens in a fraction of a second.

[problemecium]

^ Well sure. But a supernova (the result of said core collapse) would hit the planet like a baseball bat against a Christmas ornament, and with no more than a few minutes of warning, tops. We want to actually have a post-apocalyptic wasteland to roam ;P

As for suggestions, try a meteor bombardment a la the Permian Extinction (or at least one of the leading theories). Say the planet's moon has for a long time been in an unstable orbit that, due to multi-body gravitational interactions, has been gradually sinking closer to the planet. One day it hits the Roche limit and breaks up, turning over the course of a few weeks into a cloud of debris, some of which finds its way to the planet and wreaks havoc. We get big craters, charred wastelands, and in the case of the bigger chunks seismic disturbances. Perhaps the artificial plants were made in expectation of a nuclear winter resulting from the dust kicked up from the many impacts.
Through the haze of dust, sunsets will turn blood-red and, if it gets bad enough, the sun as visible from the surface will have blurred edges fading to red as if it's a big burning ember. Sound cool enough?

[fredinno]

18 minutes ago, parameciumkid said:

^ Well sure. But a supernova (the result of said core collapse) would hit the planet like a baseball bat against a Christmas ornament, and with no more than a few minutes of warning, tops. We want to actually have a post-apocalyptic wasteland to roam ;P

As for suggestions, try a meteor bombardment a la the Permian Extinction (or at least one of the leading theories). Say the planet's moon has for a long time been in an unstable orbit that, due to multi-body gravitational interactions, has been gradually sinking closer to the planet. One day it hits the Roche limit and breaks up, turning over the course of a few weeks into a cloud of debris, some of which finds its way to the planet and wreaks havoc. We get big craters, charred wastelands, and in the case of the bigger chunks seismic disturbances. Perhaps the artificial plants were made in expectation of a nuclear winter resulting from the dust kicked up from the many impacts.
Through the haze of dust, sunsets will turn blood-red and, if it gets bad enough, the sun as visible from the surface will have blurred edges fading to red as if it's a big burning ember. Sound cool enough?

It would hit relatively softly, though.

[Scotius]

I hate to be a spoilsport again, but blue giant won't work either (as long as you want to stick to somewhat realistic and scientifically accurate scenario). Glue giants are very hot, pretty to look at (from distance) and unfortunately short lived. Generally the bigger and hotter a star is, it will age and die faster. For G class yellow dwarfs like our Sun lifespan is measured in tens of billions of years. Blue giant will go Supernova in a fraction of that time - way too short for advanced life to evolve.

[Rune]

10 hours ago, KAL 9000 said:

Stellar core collapse happens in a fraction of a second.

And yet novae shine for weeks, or months, even the ones caused by gravitational collapse. But it is nice to see that apparently FTL is doable... because if it really happened "in a fraction of a second", that's the kind of speed the outer layers of the core would have as they fall inwards. Stars are BIG, with radius on the order of hundreds of thousands, or millions of kilometers even for puny sol-type stars, never mind the blue giants that do suffer gravitational collapse. Not that it has anything to do with the discussion, though.

14 minutes ago, Scotius said:

I hate to be a spoilsport again, but blue giant won't work either (as long as you want to stick to somewhat realistic and scientifically accurate scenario). Glue giants are very hot, pretty to look at (from distance) and unfortunately short lived. Generally the bigger and hotter a star is, it will age and die faster. For G class yellow dwarfs like our Sun lifespan is measured in tens of billions of years. Blue giant will go Supernova in a fraction of that time - way too short for advanced life to evolve.

It doesn't have to be a blue supergiant, man. We can probably even come up with a spectral type that will be stable-ish on timescales of... tens of millions of years to give life enough time? But that is still less stable than the small stars. There must be a spectral type for that, I'm sure.

 

Rune. No stellar evolution guys in the audience?

[Scotius]

Why go for a giant anyway? If you want a stable star with decent lifespan, you should use K - G main sequence dwarfs. For example: Alpha Centauri B is a K5 class dwarf - it's slightly smaller and cooler than the Sun, and appears more orange than yellow.

[YNM]

I suppose you can actually have the star problem real. You want them to be Kardashev type II - judging from another website, you'd need the civilization to harvest (or, requires) the energy output of a star. The smallest star that can goes huge is about 0.4 solar mass, which means early M-class star could easily fit in (say, M0). The planet would then most likely being tide-locked ; this can be their advantage early, though, because the larger the planet means it's easier for them to collect more from the star. Let's say a super-Earth with thick atmo, light farm at dayside and most other things being on the other side, most of the wealthy lives at the terminator. The need for heating can be massive - this justifies their power needs. The war can broke up after an SAD - related problem. Nukes flies off at the night side, causing things to be really cold. As the war ends most inhabitants live at the terminator again, unaware (or well, struggling) of their impending doom or such. I don't know, sounds weird indeed.

[Scotius]

Yeppers. Stars don't go unstable at the drop of a hat. And stars unstable from the beginning, create a harsh environment for the life's development. Also, stars on the smaller end of the main sequence type have small ecospheres hugging close to their surfaces. Which means even relatively minor instability can become catastrophic with little warning. It's hard to imagine a civilisation able to survive on the surface of the planet from the hunter\gatherer stage to space age in such conditions.

[SomeGuy123]

I think having the star be the problem is just a bad direction to go in.

It's not much of an apocalypse if it's predictable for millions of years, more than enough time to do something.

My "salt the earth with cobalt bombs" proposal could happen, start to finish, in about an hour, from the moment the order is given to the moment all the nukes have exploded.

[Rune]

55 minutes ago, SomeGuy123 said:

I think having the star be the problem is just a bad direction to go in.

It's not much of an apocalypse if it's predictable for millions of years, more than enough time to do something.

My "salt the earth with cobalt bombs" proposal could happen, start to finish, in about an hour, from the moment the order is given to the moment all the nukes have exploded.

Yeah, but that would change the whole direction of the story. The OP clearly states that the intent of the story is to show that a rigid society that refuses to cope with a changing universe is screwed... your idea is basically "people are jackasses and they will screw up a perfectly fine planet if you give them the chance". Don't get me wrong, it's a perfectly valid story, just not the one the OP is after. And maybe a bit too often used? The OP's, OTOH, is pretty novel IMO... and scarily accurate, look at climate change.

 

Rune. We have been seeing it coming since the sixties-seventies, after all.

Edited December 27, 2015 by Rune

[SomeGuy123]

I suppose.  Part 2 of my "story" is that the surviving humans, who live in various space stations and underground vaults, are each ruled by an autocratic or corrupt government that stalls recovery.  You know, the usual, some dictator dude makes sure all the resources that might have gone to developing solutions to the problems they face goes instead to more champagne and parties for himself.  So the "space stations" and "underground vaults" are these ramshackle things that barely hold together, and since minimal resources go to education, the people running it are mostly technicians who can barely hold it together at all.

Naturally, the protagonist is someone with a real engineering degree who's been cryogenically frozen for the past ~100-200 years.  He gets awoken by Plot Events and he's someone who has to Fix Things.  He has "forgotten more than he knows" which is why the Player of the video game can make mistakes and come up with fairly sad and not all that clever designs and yet it's of course better than anything the NPCs have stock.  

Hey.  It's not gonna win a Hugo award for story but it's self consistent and could make for a fun game or a fun light read.

[charfa]

Regarding plant colors. Plants don't pick up their color after the color of the star - after all plants of Earth are not yellow  If anything they pick the complementary color. Plants on Earth contain chlorophyll that absorbs red and blue and reflect green. You can invent other substance plants will use in photosynthesis on your planet, but it would make sense if it absorbed wavelengths that are most abundant in star's light, and reflected others.

[Scotius]

I heard about theory saying that "foliage" on planets orbiting red dwarfs should be black. It would increase the effectiveness of infrared waves absorption - which those stars radiate a lot..

[More Boosters]

Really massive stars lose mass like it is going out of fashion which doesn't do any favors for planetary formation. Red dwarf going red giant isn't something we have observed yet so we can really only theorize. The universe will be awfully old by then, and expansion of space means our norms for what a solar system for a given star type may not be the same after those trillions of years.

[YNM]

9 hours ago, Scotius said:

Yeppers. Stars don't go unstable at the drop of a hat. And stars unstable from the beginning, create a harsh environment for the life's development. Also, stars on the smaller end of the main sequence type have small ecospheres hugging close to their surfaces. Which means even relatively minor instability can become catastrophic with little warning. It's hard to imagine a civilisation able to survive on the surface of the planet from the hunter\gatherer stage to space age in such conditions.

Yeah. And the fact that most red dwarfs are flare stars - that's really bad news...

Quite hard to think of a legit story for dying star - related problem. Apart from living inside an open cluster I suppose ? But that'd be Nightfall... Anyway, what about planets that orbits a red giant already ? Their problem can be the fact that the star could go off at any time...

[Just Jim]

As far as exploding red giants go, I have a confession to make.  Every evening in the winter, when I go outside, I will look up to the stars, find Orion and yell, "Boom" at it, hoping Betelgeuse will here me.  I'm serious!  Odds are it could blow anytime now.... which could mean tomorrow or in three hundred years..... stars are like that... lol.  But there is actually a halfway decent chance it could go supernova in our lifetimes.  And if what I read is correct, it would be far enough away not to do any real damage... I hope... but close enough to turn night into day!  I would dearly love to see a supernova in my lifetime!

As far as an Armageddon scenario, if you want my opinion, what is much more realistic, much closer to home, and scares me much more than a nearby star going supernova, is the idea of asteroid mining.  Especially some of the wilder ideas of moving one into Earth orbit to mine it... yeah right!  This isn't KSP people!!! 
Screwing around with a floating mountain in space is just asking for disaster. 
And knowing us stupid humans, we would find a way to really, really screw it up...  just my opinion.  

Edited December 28, 2015 by Just Jim

[Scotius]

Welcome to the club I too check on Betelgeuse every night we can actually see the stars here. Chance of it becoming a Supernova right now are small, but weirder things happened.

[kerbiloid]

Beware!

Betelgeuse is 640 light years from us, and we can't know exactly if it still exists: maybe it has blown 500 years ago.

It's a Schroedinger star for us: with some probability it exists, with some probability - no.

And your observations decrease the indeterminancy of Betelgeuse state and with 50:50 chance not in desired direction...