How to confound a flat-earther

Use the principle of Kook Neutralization. Confront them with a hollow-earther.

Cluff is against the claim made by the flat-Earthers. I don’t know how the flat-Earthers can be so confused. They are obviously wrong. The world is not flat – it’s hollow. They reject all the evidence, he said. Unlike, the flat-Earthers, the hollow-Earthers believe that our Earth is spherical but with a hollow body. Their conspiracy theories also suggest that the moon, the stars, the Sun, and other planets are all hollow bodies.


  1. gijoel says

    Doesn’t work on Alex Jones. He’ll believe anything, no matter how illogical and contradictory.

  2. rossthompson says

    Are they saying that the atmosphere only extends one metre above sea-level? And that the globe has a radius of 16 metres?

    OK, that latter claim might be that the shell of the earth is only 32 metres thick, but I really want to know what he means by the first one, as I pretty certain I can still breaths while standing up…

  3. TheGyre says

    As a boy I read Edgar Rice Burroughs ‘Pellucidar’ novels. They were hollow earth tales written in the early 1900s. As I recall, the explorers flew an airship through an opening in the North pole and descended into a fantastical world of prehistoric animals and Stone Age people. The habitable world itself was on the inner surface of the hollow earth and was lit by the floating, sun-like core (don’t think too hard about how this was possible.) Despite Burroughs sometimes laughablyy bad writing style I loved those stories. At a time long before cable TV, rental videos, the internet and streaming movies this was how a 12 year old kid like me entertained himself on dark winter nights. Looking at the diagram above I am struck by the similarities to Burroughs make-believe world. Did someone read these novels back in the day and they have now forgotten where they got the idea?

  4. rossthompson says

    Ah, they do say that the centre of gravity is 400 miles down, so the shell is 800miles thick. So I have no idea what the 16 metre thing is about.

    Also, isn’t gravity equal in all directions inside a hollow sphere? I think I remember that. So what sticks inside-people to the ground?

  5. says


    No, if you look, the diagram (bottom right on the globe) says you have to go 400 miles to get through half the shell.

    I think this is someone who has no idea what a meter is. On the top right corner, it has 10km. On the top left, the same distance seems to be one meter. So this person thinks one meter is 10 km? Also says height of atmosphere is 200 miles (top left of the sphere).

    But at the bottom left corner, it says 1 meter: 40″ approx. That is, one meter is about 40 inches (which is true). So does this person also not know what 40″ means?

  6. says

    Ah I should have refreshed before I posted!

    As for gravity inside a sphere: it only pulls equally in all directions if you are at the very center. Being on the inside, it would depend on the mass beneath you, and the distance to the greater mass around you. I think it could go either way, depending on the balance of those variables?

  7. Owlmirror says


    Martin Gardner wrote about flat- and hollow-earthers in his book “Fads and Fallacies in the Name of Science”. Cyrus Teed, who posited that the Earth is not only hollow, but that we live on the inside, did so in 1870, long before Burroughs wrote.

    It could also be argued that the earliest “Hollow Earth” ideas came from those who posited that Hell was inside the Earth. Of course, the very earliest may have been thinking that the Earth was flat as well, and that Hell was the bottommost layer.

  8. Zeppelin says

    rossthompson: They’re trying to make an unhelpful analogy, presumably because they think people will have a hard time imagining 160km.
    Look at the picture with the mountains at the top — they’re saying that if you think of 10km as being like 1m (scale on the left vs. scale on the right), then (“in the same scale”) it’s 16m to the centre of the earth (i.e. you have to dig 160km to break through the crust and get to the blue “plastic basalt” layer where the lizard people live in their caves or whatever).

  9. Rob Grigjanis says

    rossthompson @7: Yeah, that’s an example of the beauty of combining Gauss’ law with symmetry arguments. For fields arising from simple electric charge or mass distributions, you can often reduce the calculation time drastically.

  10. leerudolph says

    Re Ross’s and Rob’s comments: note that the hollow sphere with holes at the poles is no longer spherically symmetrical, but (at most) cylindrically symmetrical. Without calculating I presume that, if the holes are large enough (the diagram suggests they’re medium-large) then the most you can expect is for the field to be zero along some part of the axis between the poles, but I admit to a lack of physical intuition (dammit, I’m a topologist, not [really] a geometer, and certainly not a physicist!),

  11. says

    I only have a layperson’s understanding of physics, but wouldn’t a hollow sphere with the radius of the Earth collapse under its own gravity, leaving behind a much smaller sphere?

  12. woozy says

    About the scale: I think there are saying in the scale of the top banner which showers 10 km in the strip (is if the strip is 1 inch wide it’d be 1 in = 10 km) then to the same scale the atmosphere and air will go for 1 meter = 400 km and then center of the earth would be 16 meters = 6400 km.
    Centrifugal (or maybe centripetal) force is more important to hollow earth-ism than gravity.

  13. says

    @derek lactin

    Nah, Poe’s Law applies here. Yes it is ridiculous and funny, I do have a sense of humor, but I don’t see any signs of insincerity. Some people do believe ridiculous things.

  14. aziraphale says

    Computationally, since the gravity inside would be zero if the holes at the poles were filled in, you can regard those holes as possessing negative mass and exerting a gravitational push on anything inside. With that and centrifugal force, anything not nailed down would collect near the equator. The higher latitudes would have no atmosphere – trying to sail through the polar opening would be a very bad move. That’s assuming such a thing could form in the first place.

  15. leerudolph says

    Computationally, since the gravity inside would be zero if the holes at the poles were filled in, you can regard those holes as possessing negative mass and exerting a gravitational push on anything inside.

    Oh, I like that! Very helpful.

  16. whheydt says

    Re: Larry @ #9…
    Ringwold has it’s own problems that Niven missed. To start with, it has neutral orbital stability. Fixing that is what drove writing Ringworld Engineers. The other big problem is the idea that simply being on the Ringworld (opaque to neutrinos…and everything else) will save Teela Brown from the core explosion. Stop and think for a moment how much of the core explosion “fire ball” will be blocked by the overhead arch of the ring, given that the ringworld is 1 million miles (Km?) wide, about 200 million miles across, 30Kly from the center of the galaxy, and the visible explosion is supposed to be about 5Kly in diameter. (Call it one radian for a first approximation.)

    Then there is the problem at the beginning of the first edition of Ringworld spotted by Karen Anderson (wife of Poul). Louis Wu went around the world the wrong way to extend his birthday.

  17. says

    Esoterica in the form of farce, satire, childish whimsey, or (in this case, I think) earnest belief of some kind, seems so often constructed to communicate racial and/or nationalistic or, at the very least, overtly hierarchical doctrines for organizing and governing society.

    Umbert Eco wrote that

    …reflecting upon outlandish theories that were taken seriously for a long time teaches one to distrust many ideas that are accorded full credence in the media, and even in some scientific circles.

    I think that might be too generous. Eco made a literary career out of exploration conspiracy theories and the minds that create them. Don’t they rather teach us to be cynical, too? Eco never explored that part.

    Following the trail of the prominently labelled Agartha (“land of advanced races”) leads one to the idealized purity culture of d’Alveydre, promoting the idea that everything will be perfect when some condition existing in and between people is “replaced”––the mechanism for that isn’t described as far as I know––with order and completeness. Weird ideas about “progress” and “civilisation” from mortals.

  18. jrkrideau says

    @ TheGyre

    And Edgar Rice Burroughs got some of his ideas from Jules Verne (Journey to the Centre of the Earth ) but I think the North Pole entrance was Burroughs. I’d say you are right the ideas are from Burroughs.

  19. John Morales says

    It’s older than that; cf. Bartholomeus Anglicus in C13 and then Athanasius Kircher in C17.

  20. Rob Grigjanis says

    whheydt @24:

    Ringwold has it’s own problems that Niven missed. To start with, it has neutral orbital stability.

    No, a Dyson sphere would have neutral stability; that just means that if it’s knocked off centre there are no increasing forces making it go further off centre*. That would not be the case for a Ringworld; any departure from centrality (in the Ringworld’s plane) would result in further acceleration.

    *A direct consequence of the shell theorem linked to by rossthompson @7.