24
$\begingroup$

The people of Magical Almost-Earth needed the Chosen One to be brought from our world. Now that the day has been saved, Chosen One would have liked to stay, marry some royal sibling and enjoy life in a whimsical world where magic exists and people are grateful to have been saved.

Alas, this was not to be: something in Almost-Earth makes it uninhabitable for Earth humans. Maybe some isotopes are different, or the chirality of some molecules is inverted, or some physical constant is different?

Whatever it is, it slowly causes health problems that will result with death unless brought back to Earth. Symptoms should ideally become significant after a few years, but not yet irreversible if Chosen One returns to Earth at that point.

What could cause slow but inevitable and ultimately lethal health problems to a normal Earth human in this world?

Magic exists (part of the world's charm), but is out of scope in this question. Simply consider it as another type of technology in this context. Local medical science is in effect as advanced as ours: if we don't know how to prevent it, neither can they. They cannot sort isotopes or similarly high-tech, extremely expensive operations of the kind.

Earth is basically inaccessible, apart from a one-time round-trip for taking Chosen from (and back to) Earth. So they cannot simply, say, grab special food once a week from Earth to solve a particular health problem.

Similarly, local environment and ecosystem are similar enough for a human to survive without problems until those symptoms start. Some fauna and flora can even be shared or closely related. And the cause should not be obvious to an average human with higher education, until symptoms are starting. (It can be obvious to a specialist, with Chosen One simply not being specialist in this particular field.)

It must also be one-way only: Chosen One doesn't cause significant health problems to the inhabitants of Almost-Earth (though draconian quarantine and the local equivalent to vaccines and decontamination were applied to avoid a plague apocalypse).

$\endgroup$

closed as too broad by RonJohn, StephenG, Cyn, elemtilas, JohnWDailey Jun 16 at 11:17

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 5
    $\begingroup$ If you narrow down what kind of death you want it's pretty easy to find a long-term debilitating disease for that with associated cause. What system/s in the body are you looking to shut down? No illness is non-specific. Work backwards from the symptoms. $\endgroup$ – kleer001 Jun 7 at 17:47
  • 1
    $\begingroup$ Please read our meta posts about high concept questions and open-ended questions. The problem with questions like this is they are broad, not objective and you've provided no criteria for judging a best answer. We need to convert this from an off-topic infinite list of things to an on-topic finite list of things. Until then, VTC OT:POB. $\endgroup$ – JBH Jun 7 at 19:09
  • $\begingroup$ Do you want the medical condition that "true human" develops to be completely reversible, or it's just hopeful that he'd get better? $\endgroup$ – Alexander Jun 7 at 19:43
  • 2
    $\begingroup$ @Eth, I get it. The problem is that, as written, there's no way to judge a best answer. Per our help center, "To prevent your question from being flagged and possibly removed, avoid asking subjective questions where … every answer is equally valid." I'm happy to retract my VTC - it only requires you to provide a description of what makes a best answer. Something like a goal or specific expected result, or limitations/restrictions in the process. As written, any and all answers are the best answer, and that's no bueno. $\endgroup$ – JBH Jun 8 at 20:52
  • 2
    $\begingroup$ Why remove "magic" from the scope ? Isn't more simple and elegant to have the main difference between the two earth being the reason for the departure instead of bringing in weird science facts like chirality ? $\endgroup$ – Echox Jun 9 at 10:21

11 Answers 11

37
$\begingroup$

Several Options:

Ionizing Radiation: Maybe the magic gives it off. Maybe the rocks do. But it's such a small amount that you don't get ARS (Acute Radiation Syndrome). Over time, however, you start to have problems. Long-term exposure to ionizing radiation, even at doses too low to produce any symptoms of radiation sickness, can induce genetic mutations and cancer. This is the biggest risk facing survivors of the Fukushima disaster—the accident emitted a fraction of the radioactive material released at Chernobyl. But the most recent estimates predict the fallout may still cause more than a thousand deaths from cancer. If you were living in a constant Fukushima you'd be playing cancer roulette every day--and the only way to get out of it would be to seek treatment on earth.

I'm not sure why almost-humans would survive--maybe their cell organization is like a ginkgo or their magicalness protects them in some way (I mean, it is energy), but that is definitely a reason why you'd want to go back to earth.

Heavy Metal Contamination: If your world's rocks had a high content of lead, then so would the water. Much like the Flint Water Crisis, that water would be something you did not want to drink. There are species that are unbothered by such things--like your hypothetical almost-humans--but the standard earth human isn't one of them. Sure you could filter your water, drink only bottled stuff, but eventually it would still get to you because it's also in the crops, the dust, the very air... Lead poisoning isn't fun.

Not The Right Stuff: All ideas so far have been things added to the environment, what about things that have been taken away. Humans require a lot of compounds to survive, and so do plants. Nitrogen (N) Potassium (K) Phosphorus (P) Calcium (Ca) Magnesium (Mg) Sulphur (S) Iron (Fe) Manganese (Mn) Copper (Cu) Zinc (Zn) Molybdate (Mo) Boron (B) Chlorine (Cl) are all necessary to life. (in small amounts for some of them) Maybe the plants on this world don't need Potassium to survive. The humans don't either. You do, however, and after a while you're going to have a problem there because the food isn't healthy for you. If Potassium or one of the other listed things was really hard to get, you'd run into a bit of a problem once you'd run through your natural stores.

Blue Blood: Along the same lines as the last option. If your almost-humans had hemocyanin instead of hemoglobin in their blood, then they would need a lot less iron and a lot more copper to survive. Basically the numbers for Iron and Copper in your diet would be switched.

Unfortunately for the chosen one, eating too much copper is a Problem, because it's toxic to regular humans in high amounts, so finding food would be a hassle (assumably the livestock are hemocyanin based as well, and the plants have their levels adjusted--this would be a change across the full ecosystem.) They'd also run into the problem of you being ridiculously anemic all the time, which isn't something anyone needs. Copper poison and anemia would definitely necessitate a trip to an earth hospital (and grocery store)

Disease Biome: Different planets, different diseases. Presumably all the health services on planet Magic are based off of magic. But maybe it doesn't work on us regular earth muggles, so your Chosen One can't get the proper vaccines, and has no access to any kind of medicine. No antibacterial medicine or vaccines means that poor Chosen One person needs to go home and take a sick day.

Cheers, and there's definitely more, but I think adding X toxin to the air so Y happens has already been covered quite well. Have fun writing.

$\endgroup$
  • 10
    $\begingroup$ I must say, your answer is very appreciable. The haemocyanin vs. haemoglobin really makes it stand out. $\endgroup$ – William R. Ebenezer Jun 8 at 16:39
  • 4
    $\begingroup$ Interesting ideas there, I really like Not The Right Stuff and Blue Blood. That one would even be a good excuse to unearth the Blue (not-)Space Elves trope that is becoming so uncommon nowadays (aaah, nostalgia)... $\endgroup$ – Eth Jun 8 at 20:00
  • 1
    $\begingroup$ Looking at your answer, there is a simpler, but related solution. Vitamins, its in the name. Sailors used to die in droves due to a lack of Vitamin C in their diet, but it would take months. The condition was called Scurvy. $\endgroup$ – Aron Jun 10 at 2:05
  • $\begingroup$ Not the right stuff includes germs (specifically bacteria though there is also evidence that we also depend on some viruses - bacteriophages - to be healthy). People who've accidentally completely eliminated almost all germs from their guts often need a fecal transplant (yes, they need someone do donate shit for their guts) $\endgroup$ – slebetman Jun 10 at 8:48
  • 1
    $\begingroup$ @Aron For slower onset of health problems insufficient intake of vitamin C is enough. For years British sailors got their vitamin C intake by consuming lime juice. It wasn't until explorers on land tried the same thing that we discovered that lime juice isn't enough to prevent scurvy (apparently the supplemental food sailors got at ports was enough to top up their vitamin C intake) $\endgroup$ – slebetman Jun 10 at 8:52
30
$\begingroup$

It's not the length of time that matters, it's the date

Snodgroo flowers only bloom once every 13 years. But they're everywhere, and the all bloom all at once. For Almost-Earth residents, this means a month of severe hay-fever, and constantly cleaning all the surfaces. It's annoying at best, but not particularly dangerous.

Unfortunately, the pollen causes severe allergic reactions in Earth dwellers. Even the tiniest bit causes fatalities in minutes.

They've tried putting heroes in clean rooms before to wait it out, but the pollen really does get everywhere. Food becomes inedible and water becomes undrinkable for over year. No one is willing to risk the hero of the world when the entire world is instant death for them.

$\endgroup$
  • 2
    $\begingroup$ Could there not be an easy way to eliminate this species of flowers? And additionally, I can imagine earthlings protecting themselves in hazmat suits. $\endgroup$ – William R. Ebenezer Jun 8 at 16:36
  • 7
    $\begingroup$ @WilliamR.Ebenezer Oh, because we've been so successful at eliminating aggressive plant species on Earth (coughkudzucough). Besides, they're more important to the ecosystem than the hero is. Hazmat could work, if you're willing to live in a suit for a year or more, eat only canned food, and accept the risk that if you leave slightly too early, or containment breaks you might die anyways. $\endgroup$ – Arcanist Lupus Jun 8 at 16:49
  • 4
    $\begingroup$ This has a nice ring - it could work in a story where Chosen One has to ultimately choose between staying with True Love despite the chronic extreme inconvenience and risk of death (and knowing that some day, even the best protections won't be enough, or a tiny but fatal mistake will be made), or not risking the life of Chosen One/inflicting such a burden upon True Love, and be sent/going back to Earth. $\endgroup$ – Eth Jun 8 at 19:49
  • $\begingroup$ You're assuming living in suits. Instead, build a facility to retreat to. It's stocked with everything needed for the year, including air. Air feeds from the tanks, it's maintained at a positive pressure. The risks are leaving too early and that nobody can enter no matter what--think of medical issues. $\endgroup$ – Loren Pechtel Jun 9 at 5:33
  • $\begingroup$ That's the thing exactly, making a perfect clean room is totally doable with our technology. I mean, doing it based on stored air rather than filtration might be necessary if we go for something crazy, but if that's what it takes that's totally doable. $\endgroup$ – David Mulder Jun 10 at 8:39
12
$\begingroup$

I like your thought about molecule chirality. Almost-Earth could have opposite handedness of essential amino-acids; the deficiency would lead to the hero more-or-less wasting to death.

Similar option a missing (or incompatible) vitamin: good candidates would be C, B1 or B3.

Both of these have the narrative benefit of being A. slow-acting and B. unpleasant. However much the hero would like to stay, their loved ones would rather send them home than watch them suffer.

$\endgroup$
  • 5
    $\begingroup$ The vitamins idea seems like a pretty good one, but having the handedness of just a few amino-acids seems a bit more dubious. If they were all flipped of course, the protagonist would probably die of malnutrition in short order. $\endgroup$ – Starfish Prime Jun 8 at 20:32
  • $\begingroup$ Much too fast a killer. $\endgroup$ – Loren Pechtel Jun 9 at 5:35
  • $\begingroup$ The handedness of amino acids was a plot point in a short story in which the progagonist went through some kind of FTL drive that left him as the mirror image of himself. His heart was on the right side of his body, and everything looked backwards to him. He was slowly dying of malnutrition and someone had the brilliant idea to have him use the drive again to get flipped back again. $\endgroup$ – Monty Harder Jun 10 at 15:38
9
$\begingroup$

You're going to have to induce a minor biological change to almost-humans on almost Earth. Sure, hypothetically, it could just be a disease unique to almost-Earth, except that it offends my senses as a writer to have your Chosen One be able to catch diseases, but not give them.

Now, if memory serves correct, carbon monoxide poisoning is pretty bad in humans. It's also irreversible, because the way it functions is that the carbon monoxide permanently bonds to the hemoglobin in your blood cells. (Irreversible in the sense there's no antidote, meaning that once you get it, you have to wait for your body to generate more blood cells. Inhaling a whiff of the stuff won't kill you.)

Almost-Earth can have a mild background level of carbon monoxide in the air, produce from some natural source (possibly a by-product of a flora-based reaction?). The natural citizens of almost-Earth have some means of countering or avoiding this (not sure how, I'd guess some system in the lungs which draws in carbon monoxide and then excretes it as a waste product). This will lead to slow carbon monoxide poisoning. The balance is tricky, to be sure, because you need the subject to build up poisoning faster than the body can replace cells, but not so fast that it kills your Chosen one in a few months.

$\endgroup$
  • 1
    $\begingroup$ Carbon monoxide poisoning does reverse. The binding of CO with Hemeglobin is strong but not unbreakable. CO will preferentially bind, but given O2 and that CO is removed, the CO is eventually displaced. $\endgroup$ – cmm Jun 7 at 18:27
  • 2
    $\begingroup$ Not sure why one-way transmission of disease offends you as a writer, as there are examples in both literature (War of the Worlds) as well as real life (decimation of Native American populations by European diseases). A single individual in a foreign environment could be exposed to many new potential diseases, while the foreign environment can only be affected by whatever that one individual happens to bring with him. $\endgroup$ – Nuclear Wang Jun 7 at 20:00
  • 3
    $\begingroup$ Carbon monoxide poisoning isn’t slow — it will kill you in hours or not at all. $\endgroup$ – Mike Scott Jun 8 at 6:59
  • 4
    $\begingroup$ @NuclearWang The problem with diseases is that having Chosen One being an apocalyptic Typhoid Mary would make for a very different story (though having Chosen One been actually chosen by/to be the Pestilence Horseman would make for another interesting story). So if we want to keep the ecosystems and denizens close enough from Earth and humans, they need to know about it and how to handle it. But then it also means that the reverse has to be true, or Chosen One will not only risk catching a local bug, but also returning it to Earth and unleashing plagues there. Easier to avoid it entirely. $\endgroup$ – Eth Jun 8 at 20:05
9
$\begingroup$

Visitors to Almost Earth have insomnia.

When the visitor lays down to go to sleep he is back up an hour or two later. He cannot go back to sleep: he is up. Sometimes he only sleeps 10 minutes.
This would serve well for a story because it will be immediately obvious something is happening with the protagonist, who is up in the middle of the night. The middle of the night when everyone else is asleep is a good time for narrative too. The protagonist will be able to get by with little sleep for many days while he saves the world, but chronic sleeplessness takes its toll in a well characterized and maddeningly frustrating way.

Medical professionals in the alternate earth will make well meaning recommendations about avoiding caffeine and screen time before bed. Heavy drugs might be able to knock out your protagonist but it will take more and more of them.

You do not need to explain why Alternate Earth is doing this. Sleep is not well understood as it is, and insomnia even less so. Thinking about the end where your protagonist returns to Earth in a bad way and wakes up after 10 refreshing hours - I am craving my own bed!

$\endgroup$
6
$\begingroup$

Allergens

"Almost-Earth" has something in its air that true Earth doesn't have. Maybe it's some pollen, maybe some chemical, but it is causing allergic effect in true humans, and this effect is compounded over time. There is no known remedy for this allergy, except for completely removing true humans from Almost Earth. If left untreated, allergy eventually kills true humans.

With high tech level, true human may be able to live in a bubble, but this is still risky, and what kind of life is that, after all?

Once true human returns to Earth, allergic effects are gradually dissipating until the health is completely restored.

$\endgroup$
6
$\begingroup$

(...) death unless brought back to Earth. Symptoms should ideally become significant after a few years, but not yet irreversible if Chosen One returns to Earth at that point.

The food and the water there are too salty.

CO will have high blood pressure. That will cause a load of symptoms, ranging from frequent headaches to a sense of suffocation. But mostly he will tire easily, be sexually impotent at a younger age and have trouble concentrating. He will also have liquid retention.

Depending on his personality and will, he may end up leading an unhealthy lifestyle which will cause other problems.

Whether the damage is permanent or not will depend a lot on genetics. At some point CO will have kidney stones. Those may or may not damage his kidneys irreversibly. Just handwave it that he has small, passable stones. That wway the damage is not permanent.

By the way, it is not hard to find people living like that in our own real world. If you know people who never drink water, having Coke, Pepsi or something similar instead... CO will be just like them in Almost-Earth.

$\endgroup$
  • 5
    $\begingroup$ Oh god kidney stones. For what I've heard, it's literally one of the most painful things ever. That would certainly work... $\endgroup$ – Eth Jun 8 at 20:48
  • $\begingroup$ As someone who's heard they put salt in g5n cakes just because it makes you eat more of them - I'm sorry, "too salty" might as well be a serious health issue, but it's no way unique to AE. Also, it wouldn't take several years before CO begins to notice something is off. It would happen as soon as they get a plate full of potato chips for dinner third day in a row. $\endgroup$ – John Dvorak Jun 10 at 9:37
  • $\begingroup$ @JohnDvoram at least in original Earth you can choose not to eat salt in excess. $\endgroup$ – Renan Jun 10 at 11:48
  • $\begingroup$ Hero could just distill their water (even solar distillation in a pinch, although in a civilized area there are better ways, even a couple of gallons a day should be no problem). $\endgroup$ – user3067860 Jun 10 at 19:25
  • $\begingroup$ @user3067860 good luck distillig your food, though. $\endgroup$ – Renan Jun 10 at 21:08
4
$\begingroup$

High levels of deuterium (heavy hydrogen) are poisonous to most eukaryotes (but not bacteria). The mass difference between normal hydrogen and deuterium interferes with delicate biochemistry. If the hydrogen/deuterium in Almost-Earth is just over the poisonous level (about 25%), then it will take a while for levels inside the humans to reach poisonous levels. Organisms native to Almost-Earth will be adapted to the high levels of deuterium.

Calculating how long it will take to affect humans is left as an exercise for the interested reader.

$\endgroup$
  • 4
    $\begingroup$ Unfortunately, it is very hard to explain high deuterium levels planet-wide. There isn't much of it in the universe. $\endgroup$ – Ross Millikan Jun 8 at 18:31
  • 6
    $\begingroup$ I think that having super high levels of deuterium in the solar system would have a lot of quite spectacular knock-on effects, like the sun's lifetime being dramatically reduced, its output being somewhat greater and maybe even weirdness like jupiter being a brown dwarf instead of a gas giant. $\endgroup$ – Starfish Prime Jun 8 at 20:35
  • $\begingroup$ @RossMillikan It doesn't have to be in our universe, which is what let me allow messing with physical constants if need be. Deuterium had been my first thought, but I thought it would be too fast-acting. With levels just over the poisonous level, how long would it take for symptoms (and death) to appear? $\endgroup$ – Eth Jun 8 at 20:35
  • $\begingroup$ @StarfishPrime Good point, this would require some work getting the solar system/universe to work at an astrophysics level... $\endgroup$ – Eth Jun 8 at 20:36
3
$\begingroup$

The Chosen One has political views that are unacceptable to the ruling class.

The poster's question suggests the world is ruled by some sort of nobility (reference to "marry a princess".) Assuming:

  1. The CO is expressing views on things like "Democracy" and "Human Rights" that endanger the position of the currently ruling class.
  2. The CO is highly popular with the general population.

This is a situation that is likely to cause severe (probably terminal) health problems. The ruling powers will want the SO gone (one way or another) as quickly as possible.

$\endgroup$
1
$\begingroup$

Lets take a different approach:

There's a chemical present in the almost-Earth biochemistry that is not present in ours--you're not going to be able to eat without encountering it. It's absorbed to some degree by the digestive tract, but our bodies have no way to dispose of it. It is not directly harmful but gets reshaped by our bodies into a form that will stick to itself and build up plaques of it.

Think of how prion diseases kill. This isn't a prion because it's coming from the food rather than our own bodies but the lethal mechanism is the same. Very slow, our bodies have no defense because they don't see it as harmful. And, unlike prion diseases, the effect does not progress without continued exposure to the agent.

$\endgroup$
1
$\begingroup$

How about looking into the core difference between the worlds: Magic!

Living beings on the "almost-Earth" have lived and evolved for all their life in a "magic-rich" environment. The Hero on the other hand lived in a place devoid of this "magic" thing and was only introduced to it after he was summoned. So his body is not actually fit to hold and use magic as good as the natives. For a time it is fine and all the damage done by "magic" is nullified by bodie`s natural restorative systems. May be the hero feels a little discomfort or a slight fever but it subsides in several days only to come back later. But at some point the symptoms start to worsen and magic healing seems to only power them up.

This is actually not my idea - it was introduced in "Mushoku Tensei". The protagonist in that story cures that disease by brewing a special tea that would make the body to excrete extra magic naturally like ammonia and other toxic substances.

$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.