27 KiB
[Q][BST] What would you need to do to convince someone that they were on a spaceship?
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Author: u/alexanderwales Time flies like an arrow*
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URL: https://www.reddit.com/r/rational/comments/3bwwrr/qbst_what_would_you_need_to_do_to_convince/
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Score: 9
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Created: 2015-07-02T20:42:35
Post:
I've been watching a show on Netflix where the premise is basically "there are a bunch of people who have been duped into believing that they're on a colony ship, but really they're underground". The reasons for doing this are a little unclear and/or nonsensical.
Anyway, I like the premise, if not the execution; the space ship is huge, and anyone who knew the first thing about space travel would immediately start wondering how badly the Tsiolkovsky rocket equation was being violated. There's full, Earth-normal gravity, for one thing, which I guess you could do with constant acceleration at a rate of g. But the more I watched, the more I kept thinking that there are a lot of things that would give it away within the first week.
So let's say that it was your goal to convince someone that they were in a spaceship, while actually keeping them in an underground bunker. Assume that they're smart, and know a thing or two about physics. What do you need to do to accomplish that deception? Contrarily, let's say that you're in a spaceship, and you have a creeping suspicion that you never actually left Earth. How do you test it?
Comments:
u/ArgentStonecutter [+17] Emergency Mustelid Hologram (an hour later)
The constant one gee is easy - it's a Heinlein-style generation ship spinning for gravity, or a pair of ships in a "bola" configuration, or something similar.
To test it, you need to make really accurate measurements of the vertical at a distance, along two lines at 90 degrees (ideally, you could do it at a smaller angle).
If the verticals are parallel, you're either in something like a Culture Orbital, they have artificial gravity, or you're on a large planet.
If they converge towards the top, you're in space. You can also measure the size of the vessel (or distance between the heads of the bola) and calculate the rotation rate. Also, you're in a novel by someone like Heinlein or Harrison or Clarke.
If they converge towards the bottom, you're on a small dense planet, or a ship built around a black hole or chunk of neutronium, and you might be in a novel by John Stith or Stanislaw Lem or Greg Egan. Or Stephen Baxter, in which case you're in big trouble.
u/iemfi [+3] (3 hours later)
Well I don't think it would be that hard to sell the idea that a novel means of artificial gravity has been invented. Telling the mark about it and injecting news articles, papers, etc. on this new technology. Unless the mark is a physicist I don't think it would take much to sell this. And even if the mark is a physicist your material just needs to be convincing and bullet proof enough. Same thing with the EM drive turning out to be a huge success. With that out of the way the rest should be easy.
u/FuguofAnotherWorld [+2] Roll the Dice on Fate (12 hours later)
I think it would be a very hard sell. I'd ask you to take me into a room with a gravity generator so I could bounce around on the ceiling and configure a zero-g ball-pit.
u/iemfi [+3] (13 hours later)
Hah, do you think this is star trek? At least read the wiki article on the gravity generator. It requires very careful calibration and immense amounts of energy to start. You can't just turn a dial to change it's strength.
u/FuguofAnotherWorld [+2] Roll the Dice on Fate (15 hours later)
I was briefly insulted, until I realised you were in-character as a denier/confederate. Ignoring for a moment that due to the space-curving nature of gravity a strong uniform field across a small object should be massively harder than a varying one. I'm no physicist, but you'd have to lie about the basics of gravitational theory itself to get me not to realise that, which is more a problem of indoctrination than convincing. So lets say for the sake of not having an argument that we're taking an adult and convincing them instead of raising a child to believe something (which you could totally do, cults manage it all the time).
I can't imagine owning a gravity device and building a colony ship without designating certain areas as lower or higher gravity for convenience sake. Mass transit for example, works so much better in zero-g, as does moving resources and stores.
u/iemfi [+2] (23 hours later)
Hmm, but the idea is that you explain the underlying theory as not allowing for differences in gravitational field and other loopholes like that. Assuming that whoever is dong this has lots of resources and is competent at pulling this off I think you could come up with a very convincing amendment to gravity. At least for me my understanding of advanced physics and gravity in particular is very shallow. I mean you could enter it thinking that a strong uniform field would be very difficult, but if everyone says no, here are all the developments in the last 10 years while you were in a coma, see this stack of papers and this textbook I don't see how I would be able to find flaws in it.
And all my usual avenues for poking holes in such a theory would be doctored/ not available. The possible objections all countered befor
u/FuguofAnotherWorld [+1] Roll the Dice on Fate (2 days later)
That would take a hell of a lot of resources. The atrophy and aging from such a coma would be pretty hard to simulate without sticking someone in an actual coma then starving them.
u/buckykat [+2] (4 hours later)
You could also throw stuff and watch for exaggerated Coriolis forces.
u/ArgentStonecutter [+3] Emergency Mustelid Hologram (13 hours later)
That woudl require a pretty small ship.
But that does suggest you could get good information from a Focault's Pendulum.
u/Chronophilia [+16] sci-fi ≠ futurology (2 hours later)
A: If we're in space, why is there gravity?
B: The ship is spinning to produce a comfortable and healthy amount of gravity.
A: So the ship's a circle? Can I walk all the way around it?
B: You could, but only a small part of it is inhabitable. The rest is storage areas, reaction mass, the nuclear reactor... and it's not airtight, so don't go exploring too far.
A: How come gravity isn't detectably weaker on the top floor than on the bottom floor?
B: We measure the mass of things by putting them on a scale with some lead weights on the other side; you'd need a spring-loaded scale to measure a difference in gravity. Anyway, the effect is too small to notice, gravity is only 3% weaker on the top floor.
A: I measured the floors and they're all the same size. Shouldn't the ones nearer the center be proportionately smaller?
B: You must have measured it wrong. Or perhaps it's just the way the architecture is designed.
A: I found a spring scale, and it says gravity is the same everywhere. Also I built a Foucault pendulum and got some really strange results. Also there's no cosmic radiation.
B: That's impressive, considering you've lived on-ship all your life and we don't teach you about Foucault pendulums or cosmic radiation here. I suspect you are a spy for the Communists/Fascists/Lizardmen; would you please follow me to the interrogation room?
u/noggin-scratcher [+10] I am a happy tree (14 minutes later)
I don't have a great answer worked out, but the question reminds me of this TV show where they faked a space mission.
Their selection criteria seems like a good place to start if your aim is to convince someone at all, rather than someone in particular.
The intention was to obtain a group of Cadets who were highly gullible, conformist, and ignorant about the show's subject matter
Which was quite a necessary condition...
Particularly questioned was how weightlessness, which would be present in a real space flight, would be handled on a ground-based set. The Cadets were told that they would be in "near space" (as opposed to "outer space"), causing only a 30% loss of gravity; which was compensated by "gravity generators" built into the ship. Due to the Cadet-choosing criteria, this profoundly absurd explanation was believed (any object in orbit of another astronomical object will experience free-fall, and thus weightlessness).
u/alexanderwales [+3] Time flies like an arrow (22 minutes later)
Thanks for introducing me to that show; it looks absolutely amazing, and prime "rational" fodder.
u/noggin-scratcher [+4] I am a happy tree (an hour later)
A lot of it felt like an exercise in "How daft can we make this without any of them catching on". So not hugely rational, but it was quite entertaining.
u/BekenBoundaryDispute [+9] (28 minutes later)
What do you need to do to accomplish that deception?
If you have the tech, the easiest, most sustainable way is, of course, a brain-in-a-jar kind of approach. But that's sort of cheating.
With currently existing technology, I'd imagine the most plausible solution would be to put on board a majority of confederates who will continuously assert that it is a spaceship, and systematically deny evidence to the contrary, like the Asch conformity experiments.
Contrarily, let's say that you're in a spaceship, and you have a creeping suspicion that you never actually left Earth. How do you test it?
If possible, get or make a magnetic compass. While the designer can probably easily interfere with this, it is good practice to cover all possible vulnerabilities.
After that, ultrasound, maybe?
u/None [+5] (3 hours later)
If you have the tech
...the easiest, most sustainable way is, of course, a brain implant that prevents the concept of "we're not in space" from becoming encoded in long-term memory.
...the easiest, most sustainable way is, of course, an AI wielding nanobots that hacks any instrumentation or experimental aparatus into "proving" you're in space.
...the easiest, most sustainable way is, of course, to leave their education to a tradition that dissuades investigation and emphasizes adherence to the dictates of the elders.
Saying "if you have the tech" is a bit of a cop-out in my opinion. As you said, sort of cheating.
u/codahighland [+3] (19 hours later)
I would argue that those are neither easier nor more sustainable, even if you do have the tech.
It's one thing to hijack sensory inputs, and another entirely to be able to identify memories in short-term memory and disrupt them before they can be encoded in long-term memory -- we have an idea how to do the former, but the latter is going to run into problems in both figuring out what concepts are involved in a given thought and how to prevent them from being stored without having painfully obvious side effects.
Nanobots would have to be able to identify what apparatuses are relevant to the such an experiment, identify what changes would need to be made to generate a "space" result, and somehow avoid tainting all other experiments in such a way that would raise anomalies.
Education is MORE plausible than the previous two scenarios, and it's certainly easier, but it's hard to say that it's more sustainable.
u/thecommexokid [+3] (5 days later)
At this point, you've reached the point where the easiest, most sustainable way is to actually send them to space and be done with it.
u/trifith [+3] Man plans, god laughs. Like the ant and the grasshopper. (15 minutes later)
Well, as you pointed out, gravity is the biggest giveaway. You're going to have to hand wave that with continuous acceleration, which brings in the fuel/reactor question.
The next one is food supply. A crew needs to eat about 2000 calories per day, each. More people means more food. More food means more mass to accelerate, and more waste to dump.
Actually, food is probably where I'd start looking. Trace the food supply as far back as I can, and trace the waste system as far forward as I could, and see if it doesn't add up. See if I encounter resistance to my search.
u/DCarrier [+6] (an hour later)
The best way to get around the food problem is to actually have it carry its own complete ecosystem. Nobody has done that successfully before, so you might have to fake some of it.
u/None [+2] (19 hours later)
This, I think, is the best answer. It's tempting to reach for physics, but all of that can be hand-waved pretty easily, especially without proper tools and knowledge. Ecology is a lot more intuitive and has way more variables. There's no way they'd be able to construct a genuinely functional and sustainable enclosed ecosystem. Hell, Earth isn't even one of those at the moment.
u/ben_sphynx [+2] (2 days later)
Also interesting is the source of the atmosphere, and of water.
u/clawclawbite [+3] (an hour later)
Test for Coriolis forces.
u/Kerbal_NASA [+3] (an hour later)
Centripetal force! Any ship meant to carry humans for a long time will have to have a spinning ring essentially. Because of the centripetal force, someone inside the ring essentially gets flung into the outer rim of the ring with enough force to equal Earth's gravity. If you tell them they are on a small section of this ring it can work. The bigger you claim the ring is, the shorter the room is in one direction and the shorter the roof the better. Those last two factors are because you'd expect curvature and the Coriolis effect respectively. I'll edit in a diagram later
edit: Ok, here are the diagrams (and yes, my artistic skills are clearly rivalled by none, I am a god of the visuals :p):
So here is a side view of the ring that the tricksters claim these people are in. The red arrows indicate the direction of the force from the perspective of people inside the ring. That force can be just as strong as gravity. As you can see in that picture, I've made the height of the room and the length in one direction relatively small. However the other length can be as large as you'd like, as seen in this isometric view of the same ring. Now if the room was too long in one direction you would expect to either feel gravity to be a little sideways or for the ground to be curved. That's because of how the force always points in the opposite direction of the centre. You can see the effect here. Finally, if you make the roof too tall, the people would expect something dropping to not hit exactly below the drop point (from their perspective). This is because any point on a rotating ring is going to be moving more slowly the nearer the centre it is (since it has less distance to travel for every rotation). That means objects nearer the roof are moving slower (from an outside perspective) than objects near the floor. Which means from the perspective of the people inside the ring, its like there is force pushing things in one direction (that direction being the opposite direction of the rotation at that point). You can see that in this diagram.
u/DCarrier [+2] (an hour later)
That's what I was thinking. There are still a few problems. You'd expect to be able to walk around it. Either there has to be a plausible excuse for only being allowed on a small section, or you have to actually build it into a ring and in addition to hiding the lack of curvature you now have to hide the addition of curvature in another direction.
Instead of a ring, you could claim that there's just two areas circling the ship. Since going from one to the other would be inconvenient, it would be easier to claim that people aren't allowed to move between them. You could also try claiming the ship is lopsided, and there is only one such room, but that would make the rocket more complicated.
There's still the problem of taking off. Depending on how far you're willing to go with the deception, you could actually take off, and then claim that landing was a second burn.
Edit:
You could also fake the take off by actually building it on some kind of pendulum, so you can make it circle faster to add artificial gravity and make it feel like it's taking off.
u/ArgentStonecutter [+3] Emergency Mustelid Hologram (an hour later)
You'd expect to be able to walk around it.
Bola configuration. Two relatively small ships connected by cables spinning around their common center.
u/Kerbal_NASA [+1] (2 hours later)
Sure all of these configurations work, whatever suits the narrative can be used. As for the takeoff, I had assumed they were drugged unconscious during that. Realistically they would be taken in a space elevator to the ship (since it would almost definitely have to be constructed in space). I suppose you could possibly simulate a launch by having the entire room in a super powerful centrifuge (irl) but that would probably be ridiculously expensive. Edit: actually you could just have a smaller room connected to a centrifuge and have it stop when its next to the room which would be vastly cheaper). IMO, its best just to have them drugged and wake up already in "space".
u/DCarrier [+1] (3 hours later)
That's basically what I said. You just explained it better and faster.
u/buckykat [+3] (4 hours later)
Well, they mention an Orion drive powering the ship, so the size is feasable, although the launch could never have been hidden. But the drive should not be constant burn, but a series of explosions. An Orion drive is powered by nuclear bombs, a lot of them.
u/STL [+3] (4 hours later)
Simple math, assuming you're watching Ascension. They were provided with a fake window, through which they could see they aren't rotating. (There would be all sorts of potential ways to try to pierce the window's deception; looking for the CMBR temperature and firing lasers outside come to mind.) So if they know (via their ancestors) that they've been living at 1 g for 51 years, SR tells us (you don't need GR) that v = c tanh(a T / c). This is tanh(52.6459346), which Wolfram Alpha helpfully tells us is 1 - 3.7 * 10^-46. The relativistic kinetic energy of 1 gram of the spaceship would be 270 years of solar luminosity. 30,000 kg going that fast would have 1 foe of energy.
You're not riding a spaceship. You're riding a supernova.
u/alexanderwales [+3] Time flies like an arrow (4 hours later)
Just wanted to point out that on the show, they've got a crew of 600 people. If the average person weighs 69kg (which they do, according to Wolfram Alpha) then that means that they have 41,400kg worth of weight in people alone, even before you start adding in the food, water, animals, reactors, etc.
u/lsparrish [+3] (4 hours later)
The ending episode had some rather ridiculous moments (production of water and oxygen from lithium dioxide and carbon dioxide, not to mention the league of villians and their wootastic xanatos gambit behind the whole experiment). However, the opening was solid and had a lot of promise. I might have liked the real spaceship scenario better, but the fake one was fun too.
My suggestion for gravity is to convince the population that they are under constant uniform acceleration due to atomic bombs exploding behind them at a constant rate. This would be accompanied by an oscillator that causes slight vibrations that can be detected with instruments inside the ship, supposedly dampened by a massive hydraulic spring.
The 1 gee acceleration is too much for the multi-generation story though. They would have to be convinced that the gravity is at least partly from centrifugal force, or fooled into thinking gravity is less than it is with some kind of psychological manipulation.
A longer distance could be chosen, but I'm not sure that does much good (since relativity should kick in and make you need less velocity to travel per unit subjective time, as the universe around you is experiencing lorentzian contraction). Maybe they could get blown off course, miss their destination, and have to head back.
A plausible fuel source is also needed for an accelerator like this. A variant of Bussard Ramjet is probably the most reasonable source, but might not be up to the plausible tech of the time. Maybe (given the threat of being left adrift in space otherwise) the inhabitants could have invented high-strength industrial fibers (with planted scientific data to help them get lucky), enabling them to make really long, thin electrodynamic cables which collect interstellar hydrogen for nuclear fuel while thrusting off of stellar magnetic fields.
There could also be a fake AI, and fake nuclear fusion, as those are things that smart people are often sure should be easy (even though they aren't).
u/ansible [+2] The Culture (an hour later)
Contrarily, let's say that you're in a spaceship, and you have a creeping suspicion that you never actually left Earth.
Cosmic rays are one thing to look for. The Earth's atmosphere protects us from a lot of that. No practical amount of shielding on a human-occupied spaceship is going to provide the same level of protection.
u/ArgentStonecutter [+2] Emergency Mustelid Hologram (an hour later)
Lots of water. You're inside a hollowed out comet a mile across. Or they've just plated the ship in a mile of ice by melting a comet (as in Seveneves).
Parrafin would be better.
Out of curiosity, how are you going to look for cosmic rays.
u/DCarrier [+1] (an hour later)
How do you go about looking for them?
u/ansible [+3] The Culture (an hour later)
Building a cloud chamber isn't that hard:
http://www.amnh.org/education/resources/rfl/web/einsteinguide/activities/cloud.html
u/None [+2] (19 hours later)
The dry ice would be tricky to source. I can't think of a reason to have that on a spacecraft except possibly as a byproduct of freeze separation for CO2 scrubbing.
u/MugaSofer [+2] (a day later)
Ultimately, this is an enormous magic trick. I'm assuming from context that we have to do this with a group taken from contemporary Western society, containing at least one rationalist, and using only current technology?
First, distract the targets. Drug 'em, if possible. Life on the spaceship is tough, so force them through some pretty cultlike/military-style training. The targets are completely isolated from outside media influences, everything is filtered and doctored to twist things our way. (That last bit isn't critical, just a good general principle for this sort of thing - and it should start before they enter training. Break into their houses if you have to.)
The "ship" is small, cramped. It contains ludicrously top-of-the-line IT hardware, and enough tech to provide life-support indefinitely if you don't mind a lot of hard work, and bugger-all else.
So what does the ship look like?
It looks like a goddamn centrifuge, that's what it looks like. A literal centrifuge, underground somewhere. Running 24/7. The budget for this plot is insane, why the hell not do this? Build several vaguely-conventional centrifuges, stack the damn things. Also, personally, I'd be inclined to put in some sort of vacuum chamber thingy, and have one or two stooges be the only people capable of operating the spacesuits.
I actually think you could get away with "we invented a gravity generator", and have a trained magician "demonstrate" it. There are any number of magic tricks you could use for this; levitation is the oldest thing in the book, you can tamper with the instruments, and if worst comes to worst you could sell a literal descending lift as a "low-gravity room" if you had to. But this is the absolute hardest way to do it.
u/Rangi42 [+2] (a day later)
J. G. Ballard wrote a short story, "Thirteen to Centaurus", with a premise like this.
One of the inhabitants of a generation ship performs two tests: he hangs a plumbline from the wall and measures its angle to determine the ship's rotation rate, and times the fall of a known mass to determine the ship's mass.
u/Norseman2 [+2] (10 days later)
It's important to note that any proposed solutions to maintain the deception should be significantly cheaper than actually building a colony ship.
That said, I don't think you'll be able to devise a plausible mock-up of stars on a budget less than building the real thing. Someone could easily go to a window and do trigonometry by hand to show that the 'stars' aren't more than a mile away. Even making a building which is a cube measuring a mile on each side might be expensive enough to make it cheaper to just build a real colony ship.
u/euxneks [+2] (4 hours later)
We are all on a spaceship right now! waves hands
Seriously though, what is your definition of a spaceship? I'm guessing something manufactured that is not the size of a planet?
u/Transfuturist [+4] Carthago delenda est. (6 hours later)
Convince them that they are on a planet/oid purposefully made rogue for interstellar travel. Let them look up out of a very deep shaft.
u/None [+1] (20 hours later)
Tell them so since age four.
It works with religion.
They'll invent the excuses for you.
u/Jiro_T [+1] (3 days later)
Aside from solutions like directly sending input to your brain in a vat, or raising people from age 4 not to question it, I don't think it's possible.
Convincing someone that they're in a spaceship when they're not is a lot like psychics' attempts to explain why psychic powers work, or like any attempt to save a scientific theory that has a lot of evidence against it. You can always add epicycles to any theory--"well, some unbelievers exude a psychic field that keeps experiments from working near them" or "yeah, there's something weird going on that makes a Foucalt pendulum work like it does on the Earth, even though were in space". But enough of those and the most logical explanation is that there's no such thing as psychic powers, not that psychic powers are real but they just happen, for a whole bunch of reasons, not to be detectable.
This is an especially good comparison since there are a number of active psychic fakers. Ask yourself: what could a psychic faker do to convince a rational person that he actually has psychic powers? The answer: Nothing. He can do things that are consistent with real psychic powers, but he can't do things that are unique to real psychic powers. Likewise for fake spaceships.