Meta Notes | The Laws of Physics

Meta Notes | The Laws of Physics


Last December, I posted a video about a dodecagon
world, and one person pointed out that if this thing rotates so quickly all the time,
it will be flinging people off the ground. Which was a good point, so I thought, alright,
it is the sun that goes round and round! Two eels eternally chase each other; the red
one brings the day, and the blue one brings the night. And I suppose the temperature gradient would
look kinda like this, since the sun travels anticlockwise. And since warm air rises, and cold air sinks,
I think this place would have very predictable winds, but I cannot figure out what those
would be. And in any case, how warm is it here compared
to here? Or here compared to here? How quickly does air cool? How quickly does heat dissipate through air? I tried to look it up, but all I found was
crazy maths. so I gave up. Months later, I decided to do some sci-fi
worldbuilding, which was an amateur mistake. At the end of that video, I mentioned that
a child that gets released into space will see the spaceship disappear in a blink of
an eye, but then had it pointed out to me that the child and the spaceship would carry
on travelling through space alongside one another. During acceleration, the ship would eventually
overtake the child, and during deceleration, the child would overtake the ship. But I don’t think the child would ever reach
the destination, because the course of the ship has acceleration and deceleration in
mind, so the child would just become an aimless interstellar object. Or at least that’s what I think, I don’t actually
know. And in a recent video, I mentioned that the
constant growth of the petals that make up my flower-shaped world would make the soil
that sits on top of it crack on a regular basis, but actually… it would not do that? I still cannot wrap my head around that. And I guess you could say: it’s a magical
world; if the laws of physics disagree with you, then you can just change them! But the problem is: if you change one thing,
then you change everything.

Posts created 20953

62 thoughts on “Meta Notes | The Laws of Physics

  1. This is exactly why I decided to re-invent physics alltogether… buuuuuut that turned out to be a "mistake" (That I absolutely don't regret) =P.

  2. I can certainly sympathise – when I'm wordbuilding I find myself having to decide between choices I made in the past and alterations that make more sense based on the reading and learning I've done since first starting my project.
    Sometimes I just decide that it's just a fantasy world and that artistic choices are valid for the sake of my own enjoyment!

  3. I like this new type of video. Its sort of not meant to show us anything, but rather to create a discussion in the comments.

  4. I'm sorry if my (or any similar) comment on the generation ship video caused or contributed to a great deal of stress about this sort of problem! I only meant to idly speculate, but I will try to be more considerate in the future.

    (Unrelated: this actually reminded me of a world idea that your world-on-a-plate idea gave me! Specifically, a world which doesn't natively have gravity, but where the world itself is composed of a single gigantic corkscrew-shape which is eternally spinning at a fixed rate, giving its inhabitants the sensation of living in a world with gravity (albeit, gravity which gets stronger the further away from The Axis you get) and where the entire world, from the perspective of a human too small to see it's true shape, appears to be one, unending slope.)

  5. Especially as someone working on worldbuilding for a story for NaNoWriMo right now, I feel this.
    I very much appreciate your humbleness on this topic, and your awesomeness in general.
    Considerations stemming from our current reality can't be evenly applied to a fantasy world, and in my opinion shouldn't always be.
    It's both fun and frustrating to try making worlds with magical or surrealist elements.
    Being just one person and not knowing everything, there are so many things to juggle, too many really, and it seems there will always be things that don't line up.
    Even if one were to manage (unlikely imo) to make something perfectly aligned to both our current understanding of science, and the fantastically, in 10 years it might become inaccurate as our understanding of our reality changes here and the worldbuilding we did stays static to a past time.

    But the worlds are so fun to make that, even if one might want to not throw up hands and go 'magic!' instead, the rewards for trying to mix in a bit more reality pull at us. We want our worlds to feel like they function, even if differently.
    I suppose in the end we have to bear in mind that there are 'less real' ways to do something, but doesn't make them less fun to build or worse for a story; there is not only one way to balance true realism with the fantastical.

    Also, please don't be hard on yourself. While it is good to try fix up things to be slightly more real, you don't always have to. There are people who will nitpick fantasy to death if given the chance, because they're more focused on the ways it doesn't work than the ways it does.
    The beauty of your settings and stories shines already.

  6. Your point about math is so real!

    But also, it think your concern about physics has a different emphasis depending on what the world you’re building is for. If it’s just a world, than you could get so nitty gritty and not worry. But sometimes something that’s not physically correct makes for a better story. I think your sci-fi world is actually a good example. The image of a child watching the ship leave, at least to me, is more impactful than a corpse floating next to a ship, but of course what really matters are your goals with the project

  7. I struggle with this too. I want my worldbuilding to be logical and rational to a point, but when it comes down to it I care more about the art of worldbuilding than the science of it.

  8. The game Portal breaks pretty much everything about the conservation of energy. But the second you see it used you instantly understand how it works. Good physics breaking tools (including magic systems) keep this in mind.

  9. your assumption about the child never reaching the destination planet is correct (thank goodness, otherwise the child would hit the planet at a good fraction of the speed of light, hitting the planet with comparable energy to an asteroid strike! Of course this depends upon the speed of the child and their mass.)

    The reason for this is that planets don't just stay in one place. So the starship will either have been timed such that it arrives at its destination star in just the right place and time for the planet to be there and the ship to have stopped, OR perhaps more likely the starship stops in orbit around the star and THEN navigates to the planet. Either way, the child will miss the planet and fly through the star system and back out into interstellar space. The interesting thing is that once the ship starts decelerating, sacrifices might actually reach the destination star BEFORE later sacrifices, and at much higher speeds. Perhaps the scientists and leaders aboard the starship will give the child a toy–really a science scanner to gather data from the system. Or perhaps scientists on Earth will have anticipated the need to get data in advance and will have set up space probe launching from the starship at certain intervals to send data back to the ship in advance of its arrival, which the crew and passengers later decided to put their sacrifice aboard.

  10. Another note: the dodecagonal world could be spinning if the world wasn't actually flat, but were instead concave–like a bowl with a weird edge. I'm not sure what the actual shape would be, but I don't think it can be a section of a sphere or ellipse, perhaps a section of a paraboloid. This kind of ruins the idea of making a flat world, of course.

  11. The child’s corpse would only reach the destination if the path was a straight line. The optimal path is probably close to a straight line, but even a curvature that seems negligible would be quite significant in interstellar travel, so you’re probably right. Also, if the child isn’t thrown parallel to the ship’s path, it’ll get further and further away and could get very far quite quickly, depending on the direction and force.

  12. You should just go ahead and take some math classes. If you're going to be doing science fiction you should at least have a basic understanding of astrophysics and calculus. You seem intelligent enough that it wouldn't take too long for you.

  13. Honestly, the ideas you've been sharing with us always had this fairy tale vibe that makes it easy to ignore scientific problems. If anything, it makes it fun and easy to watch your videos. We can focus on the social and cultural implications of a world concept rather than focus too much on why the numbers wouldn't add up.

  14. Thanks for featuring my comment.
    Although I made the nitpick I don't really think you need to worry too much about physics in your worlds, but it can lead to other more interesting ideas. Personally the idea that you could wake up on top of a new small hill is more interesting than waking up over a small crevice. Just make sure you keep it internally consistent and it should be fine.

  15. About the dodecagon world, I don’t think people would fly of.
    If the eels keep ‘swimming’ at the same speed forever, there wouldn’t be any acceleration and not only would no-one fly of, no-one would even feel that they are spinning, just like how we don’t feel the spin of the earth.
    I could be wrong tho

  16. The Petal world is an interesting, and confusing, problem. I'm not sure I agree with the assessment that there are compression forces instead of expansion forces given how you described it, so I'm going to put in my two cents. I'm not a geologist, I'm just applying rudimentary logic and geometry here and seeing what happens.

    I feel like one has to consider where the material is going, in this case. Let's take a single "row" of soil from a single petal, and consider it as it travels. It starts out with a fixed, rather small distance. Let's say it starts out as one mile. As it travels outwards, it comes to a point where it has effectively doubled in length – It's now two miles long. So, what happens to the soil?

    Well, if the only thing that happens to it is splitting apart and creating ravines, then we realize here that we only have one mile's worth of dirt to cover two miles of distance – Ravines have suddenly taken over half the space! And this is only at double the original distance; further out means further separation. This seems rather uninhabitable – And rather unlike the world you were imagining.

    Let's take a step back and consider an alternative or two. We'll get back to the ravines, I promise, we'll just experiment a little here. So let's say that, instead of splitting apart, the petal becomes thinner at the edges, as the material shifts and spreads. If our petal starts out a mile wide and a mile *thick*, at two miles wide, it'll be a half mile thick. This creates another interesting problem – Whatever forces are holding this petal up are likely going to weaken as the soil gets thinner. If it's floating on water or some other liquid medium, we'll eventually see the soil become so thin as to be easily penetrated by normal activity – Meaning that whatever medium is below it, be that air, water, lava, or whatever else, will be exposed, allowing hapless people to fall in. Beyond that, we can expect the petal to break up into clumps, which may fall, float away, or merely provide false land floating on the medium.

    With our example, we get to about 40 feet of thickness at the 128 mile wide mark. This is only 128 miles out from the center of the petal, mind you – Or, something like that at least. That's about the size of Alabama, if we extrapolate that to a radius for a land area estimate. Point is, the petal would need to be very, very thick to become very large. 40 feet implies that building a relatively small basement might be problematic this far out. And imagine when the petal is only five feet thick, or only about a foot thick. The petal might collapse under your weight at those thicknesses, depending on how compacted the soil is. And let's be honest here – The soil being compacted doesn't make much sense when it's constantly spreading, thinning, and shifting. It could happen, but then fracturing becomes much more likely, and so on.

    The third possibility is to simply create land where we need it to keep the petals consistent, but, well… Jut magically creating it where it's needed all the time to keep everything uniform seems a bit boring. Workable, yes, but I think we can do better. One obvious solution – Lava! Volcanoes. Molten earth springing from the ground, dumping nice, fresh rock everywhere. And also possibly setting things on fire. There are many more ideas you could do here – I'll get to that.

    None of these solutions seem workable just by themselves – And frankly, I've been intentionally avoiding the places where they meld together. If we had enormous ravines forming, they'd probably collapse at some point and fill in some of the land, or allow the petal to expand and thin out, thus keeping the ravines relatively closed and not spanning vast distances as in our first example. If the medium the petal is above is lava, then lava would naturally rise in said ravines, creating solid surfaces at their bases as it cools. Lava under enough pressure might even burst out when a ravine first starts forming, filling it in before it even gets a chance to spread very wide.

    So then, naturally, the medium on which our world rests its weight influences what the world is like a lot. If the petals float on seas of magma, this will be a chaotic volcanic world, less so towards the middle. If they're simply hovering over thin air, do loose pieces of land fall, or float on the air? If they fall, this, too, is a dangerous world. Land will, eventually, begin to crumble away at the edges, largely depending on the material properties of the soil and if there is any stronger substrate beneath it. If they float, we have a dangerous, but very interesting world – Floating rocks! They could be used as a means of travel, much like the Edge Chronicles (A must read for worldbuilders; the Edge is an amazing piece of fiction and they explore so, so much of the consequences of their incredibly strange world. It's magnificent.) Or as convenient and portable habitation.

    And then we have water as a medium. This creates an interesting question – What if there are multiple flower-continents on the ocean? What might happen if they got big enough to collide? Probably mountains would eventually form, and we'd get a world with a lattice of mountain ranges dominated by valleys.

    I think that's enough worldbuilding for today, but that was absolutely fascinating for me to chew on, and I hope you all get some good food for thought from it, too. There's a lot of mixing and matching ideas you could do with all of this, for sure. If anyone wants to take what I've put down here and run with it, feel free.

  17. Ewa, don't listen to the dodecagon haters. The centrifugal force (the "flinging outward" force) you would feel at the edge of the world is 5000 times smaller than the force of gravity. When you move closer to the center it gets even smaller. Your little mushroom collectors have nothing to worry about.

  18. I study physics, AND I enjoy Worldbuilding, so I know this problem all too well.
    I imagined a planet with about twice the surface area of earth but with the same composition and surface gravitational acceleration, so I had to change my universe's gravitational constant. However, that meant i couldn't use normal star charts to decide how big and bright and hot my star would be, I had to redo loads of calculations with changed values.
    It's tons of math, which I luckily enjoy, however, we don't yet understand stars all too well so it was kinda hard to find the equations I needed and in the end I had to make some outlandish assumptions just so that it would work.

  19. ah, nitpickers, the bane of any worldbuilding enthusiast. You kinda hate them, but also kinda thankful to them, because an error is an error, even if the result of it being pointed out is you needing to scrap 90% of your setting… X_x

  20. I am a physics student and I enjoy your videos a lot. But like you could build a model for a lot of stuff but sometimes is better to say: it just works

  21. I’m not ashamed to say these videos spurred me to calculate these very things. The practice is one of the benefits I use to justify my worldbuilding addictions…

  22. The way I remedy this issue is to take a single real-world geographic region, isolate it and contort it into a new one, while (trying) to retain its logical soundness, instead of making one completely from scratch. I tend to focus my imagination on applying the ideas of social sciences to made up people and species, much like your river basin.
    Perhaps if I develop a burning interest in physics of geology in the future, or know someone who does, I will be more adventurous on that front.

  23. People wouldn't be flying off the rotating dodecagon world. The radial acceleration that an object experiences following a circular arc with radius r at velocity v is a = v^2/r. Even at the edge this gives us a = (2pi*200km/24h)^2/200km = 13.71 km/h^2 = 0.001058 m/s^2. This is how much outwards acceleration a person living on the flat world would maximally experience due to the rotation. If we assume that the gravity is normally the same as on Earth (g=9.81m/s^2) and that it's perpendicular to the disc everywhere (these have to be handwaved away with "oh the disc is magic", or assuming that the disc is constantly accelerating upwards) we see that the rotation acceleration is just a tiny fraction of the acceleration due to (magic) gravity. Basically this would mean that on the edge the effective gravity would not point exactly towards the ground but a whopping arctan(0.001058/9.81) = 0.006179 degrees to the side.

    For those who are not convinced by math. Think of it this way: you are currently rotating around Earth once every 24 hours, same as on the dodecagon. But Earth is much bigger than the dodecagon world, 200 km vs. 6371 km radius, so the flinging effect should be bigger on Earth as everything is moving faster! Of course Earth is not flat but around the poles the situation should be the same. But no-one has ever heard of an Antarctic expedition tumbling around due to the Earth rotating under them. For comparison, the maximum sideways acceleration felt on Earth is about 0.016845 m/s^2, almost 16 times what is felt on the dodecagon.

  24. The why not just create Gods that constantly argue about what physics should be implemented? That way, any comment that is directed at you is immediately flung at the Gods for screwing up physics.

  25. Well, changing one thing without changing everything else, means their is something that’s doing that, so you have to come up with an explanation for it. Magic works or gods do as well.

  26. I relate with the eel part so much. I've made up a world where there are some floating islands, a ceiling and a floor. Both the ceiling and the floor act like suns. However, I have no idea how hot these should be or how tall should this world be. It gets worse. I want my ficcional inteligent birds to have a temperature measurement system. However, ice melts at different temperatures depending on pressure. But how can I know the air pressure where they live if I don't know how much air there is?

  27. In the void of space or a world with gravity or without. Warm and cold areas would dissipate at alarming levels and that's low levels the earth has been doing this since last Wednesday it started about 4ish pm. The void being over minus two hundred plus degrees, unless your world was like how's receives constant levels from a star of radiation. Also so we have a ball of iron in the centre of our world and once that goes out we're finished no more fish and chips. Some heat is created by a myriad of falling objects particles, rocks hundreds if not thousands of tons per day hitting our atmosphere. As you know to return a spacecraft it generates heat or friction over six thousand degrees in temperature this is not enough to keep our fingers and toes warm and as we spin around the sun we also do so generate friction and heat some say it's measurable and is putting us at risk, but I personally think it happens and the maths is calculable to within a decimal point and I would wager and put up my certificate of thinkology which makes me rather superior to other thinkers. Oh well, they're coming to strap me down to the bed, they don't like me thinking about mathematical problems and physics problems, before they put me to sleep. Free Melanie Shaw and Tommy Robinson and my mate rainbow who's only crime is being he got caught. Be more demanding. STOP smart metres they have microphones in them and they tell burglars when you're in or out of your home and hackers can on switch on your smart devices and watch you through your television and burn down your home by overloading them by Wi-Fi home system and the companies who use your information to make billions from you by spying on what radio and television show's you watch and high radiation levels that comes from your home hub and mobile devices they create damaging environment for your children smart metres some release thousand times the normal background radiation. Missing you already.

  28. As long as things are consistent within your world that's the main thing that matters.
    Why does the colour Cyan make things 70% lighter?, or that the color red makes things faster? no one knows, that's just the way physics works.

  29. I love your world buildning because it's realistic enough to be believable but still super creative and unexpected! But it's nice to see you reflect on the struggle!

  30. I think usually most deviations from real physics can be swept under the rug, just requiring some care as to how it's done. On the spinning disc world, I would have said that the rod generates a non gravitational force which pulls everything toward it, but only very weakly except near the edge of the disk. You could go further and prescribe a specific model for the force, but that would depend on your needs. You'd probably want something that is zero at the center of the disk and sharply increasing near the edge of the disk, peaking a little past it. The source of this force is probably best left nebulous, because uncertainty is plausible while certainty and falsehood should not be.

  31. I think it’s really useful to be able to say “nobody knows.” There are all kinds of weird things that happen in real life that aren’t cleanly predicted by simplified models of how everything works. Like for example, there are places where there are really strange bluffs and depressions in the ground that standard world-building rules wouldn’t have predicted. They eventually figured out that it was because in high enough amounts under high enough pressure, salt doesn’t compress the same way other rocks do, but instead it can flow like a vicious liquid. Nobody know that for most of history, but the geological features were still there. You don’t need to explain everything.

  32. I have a masters in physics and I've tried to make world building by changing some aspects of the laws of physics… I haven't gotten very far

  33. Hey, I totally get you. If you wanna make a totally physically accurate world (which I totally get, being an engineer into worldbuilding that's what I tried to do for 8 years) but eventually I decided it would be easier to make my own laws of physics, and so YukLyd was born. Which I think may be the hardest of hard magic systems ever conceived.

    But I find when worldbuilding it's best to focus on the things you understand, you're never going to end up with something perfectly accurate, and if you did it'd be boring. Just do what you feel is right and interesting. There are always workarounds and you can always explain something as being different in your world.

    Examples: In your sci-fi world, what if space is not a perfect vacuum, but is actually full of some etherial substance that slows things down, that would explain the child getting left behind. In your flower world, what if the soil is of a different composition than found here, or contains some sort of living entity that keeps it moist, and will die of with vibration causing the soil to crack. In your dodecagon world, what if the world is spinning, but there is another force pushing everything in. Or if you want to keep the two eels model, you can make up whatever wind patterns you like, as they will be affected mostly by the terrain and the albedo of the actual world itself.

    Either way, try not to be disheartened, worldbuilding is a struggle and a challenge, sure. But that's what makes it fun.

    – KyuSiik

  34. If you need any references or fact-checking for anything Biology or Chemistry related I‘m your guy, but honestly, unless someone really sits down and does the math to prove their comment correct (and you wrong) then I‘d basically just ignore it. Physics is tricky, especially in a fictional world, but I wouldn‘t get too hung up on it 🙂

Leave a Reply

Your email address will not be published. Required fields are marked *

Begin typing your search term above and press enter to search. Press ESC to cancel.

Back To Top