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Belief is a keyword here. Most of "spherical earthers", alas, also believe what they are told. They happened to pick the right set of beliefs - kudos to them -

Belief is a keyword here. Most of "spherical earthers", alas, also believe what they are told. They happened to pick the right set of beliefs - kudos to them - but there's no critical thinking whatsoever. We watched some time ago a why-do-we-think-earth-is-flat movie with friends and I asked: okay, so what's wrong with their explanation? For an extra credit: how a layman like me can check what is the shape of the earth? And suddenly it turns out that these questions are a bit harder than it seems.

kenjackson 5y ago
When you say, "layman like me can check what is the shape of earth?" Like reviewing satellite footage? I mean this seems ridiculously easy, unless you mean like can you prove it from your front yard.
- eminence32 5y ago
  This is slightly beyond what an average layman can do, but it's not terribly hard or expensive to receive images of our globe from NOAA weather satellites [1]. Generally the most costly part is a ~$120 USD antenna. It's a super fun and rewarding project if this is the kind of thing that interests you. [1] https://en.wikipedia.org/wiki/Geostationary_Operational_Environmental_Satellite https://en.wikipedia.org/wiki/Geostationary_Operational_Envi...
  - NateEag 5y ago
    The problem is that then you aren't verifying it yourself, and a flat earther can claim you're just using one of the propaganda sources created by the government.
  - kavalg 5y ago
    You can also use the ESA earth observation program, which provides free downloads of earth observation data every ~5 days. Look for Sentinel-2. It still won't prove that earth is round though :).
- squeaky-clean 5y ago
  Yeah I think they mean the latter. Satellite footage could be doctored after all, unless you're launched the satellite. It's not really that hard to estimate the circumference of the earth and prove that it has to be spherical. But most methods I know of require quite a bit of driving, or friends that are far away and can take a measurement at exactly the same time. I'm not a flat earther but I do want to do my own measurement of the earth's circumference one day for fun.
  - Const-me 5y ago
    > and prove that it has to be spherical To be precise, the earth is not spherical. It's unfortunately not even an ellipsoid: I live well above the sea level yet my home is like 20 meters below the surface of the WGS84 reference ellipsoid.
- LeifCarrotson 5y ago
  A flat earther would tell you the "satellite" photos are faked, and could provide you with faked photos of their own. The question is how you distinguish the two: always go mainstream? Always counter the old-fashioned ways? Trust the best credentialed person? Distrust credentials achieved during brainwashing, go with independent self-taught thinkers? Independently verify every claim, replicating experiments from first principles?
  - kenjackson 5y ago
    But they can always say anything is faked. They can say that my eyes distort what I see and that math can’t be trusted either. The only way you could really prove it is to define a set of axioms that you some how convince them to agree to. And then get them to agree to logic. And then construct an experiment using those rules whereby if the Earth is round then they die. And see if they are willing to test it. And if they don’t then you win. And if they do it and die then you also win.
- AlexTWithBeard 5y ago
  More like a geometric method used in https://news.ycombinator.com/item?id=29975544 https://news.ycombinator.com/item?id=29975544 The simplest way I could come up with while discussing the issue with my kids, was to call a grandma on the other side of the globe and ask here when did she have a sunset. It still could mean that the earth is a hemisphere, but at least it's not pancake-style flat.
  - kenjackson 5y ago
    Or that there is more than one sun. Once you are willing to throw all science out the window there are a lot of options.
- GTP 5y ago
  There is a simple experiment to show curvature that was actually done by some flat earthers, and it proved curvature, but then they somehow classified it as an interesting but not conclusive result. Here's the experiment: take 3 wood planks, make a hole at the same eight in each of them. Then put them standing in the soil making sure that all have the same height (meaning that the hole is at the same height for all of them). Now use a laser to have a straight line of light (you can observe by other means that a laser beam is a straight line). If the wooden planks are far enough form each other, the laser will not e able to pass trough all 3 holes, despite them being at the same height from heart's surface. This implies curvature.
  - dalmo3 5y ago
    That's too prone to terrain irregularities, and I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere. Further, even if you assume perfect instrumentation, how would one account for gravity?
    - zimpenfish 5y ago
      > I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere Salar de Uyuni - "As a result, the variation in the surface elevation over the 10,582-square-kilometer (4,086 sq mi) area of Salar de Uyuni is less than 1 meter (3 ft 3 in) normal to the Earth's circumference". That's less than 1 in 6371000 - pretty smooth, no? > That's too prone to terrain irregularities Nah, it's still doable, especially on that^ salt flat - if you have two close holes and a 3rd one 55km away, a flat earth will let you line up the laser through all three with less than 2m of adjustment. By my rough calculations, on a spherical earth, the laser will be ~250m above ground at 55km - pretty obviously proving the hypothesis incorrect, no?
      - dalmo3 5y ago
        That's a great example, thanks!
    - GTP 5y ago
CptFribble 5y ago
Laymen can use Eratosthenes of Cyrene's method from the mid 200's BCE. https://www.khanacademy.org/humanities/big-history-project/solar-system-and-earth/knowing-solar-system-earth/a/eratosthenes-of-cyrene https://www.khanacademy.org/humanities/big-history-project/s... For those who don't know it, in brief: Put a vertical pole in flat ground at noon and measure the length of the shadow. The next day, drive an hour or two directly north or south and do the same measurement at noon again. With a bit of trigonometry, you can estimate the earth's circumference - or for our purposes, at least prove to yourself that the earth is not flat, as the shadows will be different lengths with the sun in nearly the same position both times. Of course, there is a separate discussion about whether we should consider light trigonometry within the bounds of what modern laymen should be expected to handle. As the article also states, the ancients observed that as ships passed below the horizon, the hulls disappeared before the masts - this is also within reach of most laymen.
- HideousKojima 5y ago
  >For those who don't know it, in brief: Put a vertical pole in flat ground at noon and measure the length of the shadow. The next day, drive an hour or two directly north or south and do the same measurement at noon again. With a bit of trigonometry, you can estimate the earth's circumference - or for our purposes, at least prove to yourself that the earth is not flat, as the shadows will be different lengths with the sun in nearly the same position both times. Sure, but a flat earther will just argue that the sun is much closer than scientists claim, which explains the difference in shadow length. And again, what's a layman to do? The best experiment to prove the earth is round that I've thought up involves the Coriolis Effect and a rifle fired at different points both north and south of the equator. Unfortunately that requires international travel with firearms, making it legally difficult to try.
  - deleted 5y ago
    [deleted]
  - hervature 5y ago
    Personally, I like multiple Foucault pendulums as this demonstrates rotation and curvature. I think the part that is missing in everyone's explanation is how to prove it is a sphere and not a hemisphere. Obviously, going to the "edge" would immediately shows this is false. But I think the only way to do this without moving too much is to record lunar eclipses and do the math to figure out that you would eventually see straight edges in an eclipse if the earth was not completely spherical.
TameAntelope 5y ago
But here's the problem with this logic; I've never been presented with any credible arguments that suggest Earth is not round, and in fact have been able to use this knowledge of Earth's roundness to understand and accurately predict facts in my real life on a semi-regular basis. * When I see my flight plan, I understand why it's curved. * When I see clouds that a radar says should be a certain distance away, I understand what makes me able to see them. * Where weather is moving, how it's moving, and why certain weather patterns even exist at all. * When I see a landmass on water I can accurately guess how far away it is, and I can understand why moving even a small amount upwards lets me see so much more (and why it was such an advantage on ships to have a vantage point only 20 to 30 feet up in the air). * How stars move in the night sky is predictable. * Why the "north" star exists and is accurate as a directional indicator. * Where constellations are, and how they're different depending on what latitude I'm currently observing the night sky from. * The fact that tides exist, and how they work. * I understand how and what satellites are, when I can see them, and I can predict when I'm going to lose signal from them given certain circumstances. * Every other planet I've observed is round. The moon is round. The sun is round. None of this works if Earth isn't round, and that's just off the top of my head. The point here is that so many things stop making sense if you don't accept the fact that the Earth is round, and so you're constantly failing to predict or understand a whole host of problems that, yes, do come up in my daily life. This isn't about "happening to pick the right set of beliefs", it's about matching what you're told with what you're observing and noting a singular and profound consistency across disciplines, uniformly converging on one single, basic fact; the Earth is round.
- AlexTWithBeard 5y ago
  > * When I see my flight plan, I understand why it's curved. Just came off the plane yesterday. I remember the earth on the flight map was perfectly flat. The path was weirdly curved though...
  - kitd 5y ago
    Yeah lol. Flat-earthers should be suing airlines for flying them further than needed. Make them put their money where their mouth is.
jakelazaroff 5y ago
If you end your sample at N=1, sure, it might seem like “spherical earthers” just happened to pick the right set of beliefs by chance. But if you also consider things like 5G microchips, and chemtrails, and the moon landing, somehow the “spherical earthers” consistently pick the right beliefs. Sure, there’s no critical thinking for a lot of it, in the same way that I don’t think critically about all the physics and engineering before I step on an airplane. The entire point of living in a society is that you don’t have to do everything yourself — you can outsource a lot of that critical thinking to other people who (are paid to) care more than you. You can just go with the flow and actually have a pretty good track record for believing the right things.
- aidenn0 5y ago
  I don't know about flat-earth specifically, but lots of people only believe a few conspiracy theories. There are lot's of "spherical earthers" who believe the moon landing was faked for example. A very large fraction of the US believes in at least one of the major conspiracy theories associated with QAnon (several of which predate QAnon), but a much smaller fraction is actually involved with QAnon.
dools 5y ago
You can check the shape of the earth by replicating the early experiments performed by ancient scientists who discovered the earth was spherical in the first place. Detailed and very easy to follow instructions for this also appear on YouTube
marcus_holmes 5y ago
For me, this was "notice that Orion is upside-down in Australia"
- dalmo3 5y ago
  Draw a 6 on the ceiling, and the person opposite you in the room will see a 9. That doesn't mean the room floor isn't flat.
  - marcus_holmes 5y ago
    Orion isn't directly overhead. In your analogy I'd be drawing a 6 on the wall, and the other person would have to bend over backwards to claim it's a 9. I mean, I guess they could, but they'd clearly be bending over backwards to make a logical fallacy.
    - dalmo3 5y ago
      > Orion isn't directly overhead. Maybe not for you :) In my example the number need not be directly overhead either. It could be drawn in the middle of a very long room where you and the other person are at opposite ends. You're both looking at it at an angle and both still seeing different numbers, although in a very skewed perspective - I don't know how flat earthers account for perspective and projection in their skydome or whatever.
      - marcus_holmes 5y ago
        Well, flat-earthers appearently believe that Australians are all actors paid by NASA to convince everyone the earth is a globe. I'm not going to waste much time listening to them. The Orion-is-upside-down-here thing was the first time I noticed something that drove it home to me that we live on a sphere.
timeon 5y ago
You do not even need to trust the established science. There are experiments done by flat earth believers which proves that earth is actually not flat at all.
darkerside 5y ago
I think this is right, in the same way that you can't ever really "prove" anything. (Direct proof relies on firsthand experience, and human perception and memory are infamously faulty. QED. Alternately, even the strongest experimental conclusion can be chalked up to the most extreme of coincidences.) However, to move forward in life, we must accept certain axioms so that we can be effective and productive. (Prove food is nutritious, prove I won't die in the next 5 minutes, prove my parents are benevolent actors, prove my children are actually mine). At some point, you can litigate anything you want, and the real decision is, what hills are you willing to die on. For me, that's determined strongly by impact to my life, and also partly by interest. What I'm saying is, don't argue that the flat earthers are wrong. Argue that they are useless because what they are arguing about doesn't matter.

kenjackson 5y ago

When you say, "layman like me can check what is the shape of earth?" Like reviewing satellite footage? I mean this seems ridiculously easy, unless you mean like can you prove it from your front yard.

eminence32 5y ago
This is slightly beyond what an average layman can do, but it's not terribly hard or expensive to receive images of our globe from NOAA weather satellites [1]. Generally the most costly part is a ~$120 USD antenna. It's a super fun and rewarding project if this is the kind of thing that interests you. [1] https://en.wikipedia.org/wiki/Geostationary_Operational_Environmental_Satellite https://en.wikipedia.org/wiki/Geostationary_Operational_Envi...
- NateEag 5y ago
  The problem is that then you aren't verifying it yourself, and a flat earther can claim you're just using one of the propaganda sources created by the government.
- kavalg 5y ago
  You can also use the ESA earth observation program, which provides free downloads of earth observation data every ~5 days. Look for Sentinel-2. It still won't prove that earth is round though :).
squeaky-clean 5y ago
Yeah I think they mean the latter. Satellite footage could be doctored after all, unless you're launched the satellite. It's not really that hard to estimate the circumference of the earth and prove that it has to be spherical. But most methods I know of require quite a bit of driving, or friends that are far away and can take a measurement at exactly the same time. I'm not a flat earther but I do want to do my own measurement of the earth's circumference one day for fun.
- Const-me 5y ago
  > and prove that it has to be spherical To be precise, the earth is not spherical. It's unfortunately not even an ellipsoid: I live well above the sea level yet my home is like 20 meters below the surface of the WGS84 reference ellipsoid.
LeifCarrotson 5y ago
A flat earther would tell you the "satellite" photos are faked, and could provide you with faked photos of their own. The question is how you distinguish the two: always go mainstream? Always counter the old-fashioned ways? Trust the best credentialed person? Distrust credentials achieved during brainwashing, go with independent self-taught thinkers? Independently verify every claim, replicating experiments from first principles?
- kenjackson 5y ago
  But they can always say anything is faked. They can say that my eyes distort what I see and that math can’t be trusted either. The only way you could really prove it is to define a set of axioms that you some how convince them to agree to. And then get them to agree to logic. And then construct an experiment using those rules whereby if the Earth is round then they die. And see if they are willing to test it. And if they don’t then you win. And if they do it and die then you also win.
AlexTWithBeard 5y ago
More like a geometric method used in https://news.ycombinator.com/item?id=29975544 https://news.ycombinator.com/item?id=29975544 The simplest way I could come up with while discussing the issue with my kids, was to call a grandma on the other side of the globe and ask here when did she have a sunset. It still could mean that the earth is a hemisphere, but at least it's not pancake-style flat.
- kenjackson 5y ago
  Or that there is more than one sun. Once you are willing to throw all science out the window there are a lot of options.
GTP 5y ago
There is a simple experiment to show curvature that was actually done by some flat earthers, and it proved curvature, but then they somehow classified it as an interesting but not conclusive result. Here's the experiment: take 3 wood planks, make a hole at the same eight in each of them. Then put them standing in the soil making sure that all have the same height (meaning that the hole is at the same height for all of them). Now use a laser to have a straight line of light (you can observe by other means that a laser beam is a straight line). If the wooden planks are far enough form each other, the laser will not e able to pass trough all 3 holes, despite them being at the same height from heart's surface. This implies curvature.
- dalmo3 5y ago
  That's too prone to terrain irregularities, and I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere. Further, even if you assume perfect instrumentation, how would one account for gravity?
  - zimpenfish 5y ago
    > I can't imagine that there's a single area of land on earth that's remotely as smooth as the surface of an sphere Salar de Uyuni - "As a result, the variation in the surface elevation over the 10,582-square-kilometer (4,086 sq mi) area of Salar de Uyuni is less than 1 meter (3 ft 3 in) normal to the Earth's circumference". That's less than 1 in 6371000 - pretty smooth, no? > That's too prone to terrain irregularities Nah, it's still doable, especially on that^ salt flat - if you have two close holes and a 3rd one 55km away, a flat earth will let you line up the laser through all three with less than 2m of adjustment. By my rough calculations, on a spherical earth, the laser will be ~250m above ground at 55km - pretty obviously proving the hypothesis incorrect, no?
    - dalmo3 5y ago
      That's a great example, thanks!
  - GTP 5y ago

CptFribble 5y ago

Laymen can use Eratosthenes of Cyrene's method from the mid 200's BCE. https://www.khanacademy.org/humanities/big-history-project/solar-system-and-earth/knowing-solar-system-earth/a/eratosthenes-of-cyrene https://www.khanacademy.org/humanities/big-history-project/s... For those who don't know it, in brief: Put a vertical pole in flat ground at noon and measure the length of the shadow. The next day, drive an hour or two directly north or south and do the same measurement at noon again. With a bit of trigonometry, you can estimate the earth's circumference - or for our purposes, at least prove to yourself that the earth is not flat, as the shadows will be different lengths with the sun in nearly the same position both times. Of course, there is a separate discussion about whether we should consider light trigonometry within the bounds of what modern laymen should be expected to handle. As the article also states, the ancients observed that as ships passed below the horizon, the hulls disappeared before the masts - this is also within reach of most laymen.

HideousKojima 5y ago
>For those who don't know it, in brief: Put a vertical pole in flat ground at noon and measure the length of the shadow. The next day, drive an hour or two directly north or south and do the same measurement at noon again. With a bit of trigonometry, you can estimate the earth's circumference - or for our purposes, at least prove to yourself that the earth is not flat, as the shadows will be different lengths with the sun in nearly the same position both times. Sure, but a flat earther will just argue that the sun is much closer than scientists claim, which explains the difference in shadow length. And again, what's a layman to do? The best experiment to prove the earth is round that I've thought up involves the Coriolis Effect and a rifle fired at different points both north and south of the equator. Unfortunately that requires international travel with firearms, making it legally difficult to try.
- deleted 5y ago
  [deleted]
- hervature 5y ago
  Personally, I like multiple Foucault pendulums as this demonstrates rotation and curvature. I think the part that is missing in everyone's explanation is how to prove it is a sphere and not a hemisphere. Obviously, going to the "edge" would immediately shows this is false. But I think the only way to do this without moving too much is to record lunar eclipses and do the math to figure out that you would eventually see straight edges in an eclipse if the earth was not completely spherical.

TameAntelope 5y ago

But here's the problem with this logic; I've never been presented with any credible arguments that suggest Earth is not round, and in fact have been able to use this knowledge of Earth's roundness to understand and accurately predict facts in my real life on a semi-regular basis. * When I see my flight plan, I understand why it's curved. * When I see clouds that a radar says should be a certain distance away, I understand what makes me able to see them. * Where weather is moving, how it's moving, and why certain weather patterns even exist at all. * When I see a landmass on water I can accurately guess how far away it is, and I can understand why moving even a small amount upwards lets me see so much more (and why it was such an advantage on ships to have a vantage point only 20 to 30 feet up in the air). * How stars move in the night sky is predictable. * Why the "north" star exists and is accurate as a directional indicator. * Where constellations are, and how they're different depending on what latitude I'm currently observing the night sky from. * The fact that tides exist, and how they work. * I understand how and what satellites are, when I can see them, and I can predict when I'm going to lose signal from them given certain circumstances. * Every other planet I've observed is round. The moon is round. The sun is round. None of this works if Earth isn't round, and that's just off the top of my head. The point here is that so many things stop making sense if you don't accept the fact that the Earth is round, and so you're constantly failing to predict or understand a whole host of problems that, yes, do come up in my daily life. This isn't about "happening to pick the right set of beliefs", it's about matching what you're told with what you're observing and noting a singular and profound consistency across disciplines, uniformly converging on one single, basic fact; the Earth is round.

AlexTWithBeard 5y ago
> * When I see my flight plan, I understand why it's curved. Just came off the plane yesterday. I remember the earth on the flight map was perfectly flat. The path was weirdly curved though...
- kitd 5y ago
  Yeah lol. Flat-earthers should be suing airlines for flying them further than needed. Make them put their money where their mouth is.

jakelazaroff 5y ago

If you end your sample at N=1, sure, it might seem like “spherical earthers” just happened to pick the right set of beliefs by chance. But if you also consider things like 5G microchips, and chemtrails, and the moon landing, somehow the “spherical earthers” consistently pick the right beliefs. Sure, there’s no critical thinking for a lot of it, in the same way that I don’t think critically about all the physics and engineering before I step on an airplane. The entire point of living in a society is that you don’t have to do everything yourself — you can outsource a lot of that critical thinking to other people who (are paid to) care more than you. You can just go with the flow and actually have a pretty good track record for believing the right things.

aidenn0 5y ago
I don't know about flat-earth specifically, but lots of people only believe a few conspiracy theories. There are lot's of "spherical earthers" who believe the moon landing was faked for example. A very large fraction of the US believes in at least one of the major conspiracy theories associated with QAnon (several of which predate QAnon), but a much smaller fraction is actually involved with QAnon.

dools 5y ago

You can check the shape of the earth by replicating the early experiments performed by ancient scientists who discovered the earth was spherical in the first place. Detailed and very easy to follow instructions for this also appear on YouTube

marcus_holmes 5y ago

For me, this was "notice that Orion is upside-down in Australia"

dalmo3 5y ago
Draw a 6 on the ceiling, and the person opposite you in the room will see a 9. That doesn't mean the room floor isn't flat.
- marcus_holmes 5y ago
  Orion isn't directly overhead. In your analogy I'd be drawing a 6 on the wall, and the other person would have to bend over backwards to claim it's a 9. I mean, I guess they could, but they'd clearly be bending over backwards to make a logical fallacy.
  - dalmo3 5y ago
    > Orion isn't directly overhead. Maybe not for you :) In my example the number need not be directly overhead either. It could be drawn in the middle of a very long room where you and the other person are at opposite ends. You're both looking at it at an angle and both still seeing different numbers, although in a very skewed perspective - I don't know how flat earthers account for perspective and projection in their skydome or whatever.
    - marcus_holmes 5y ago
      Well, flat-earthers appearently believe that Australians are all actors paid by NASA to convince everyone the earth is a globe. I'm not going to waste much time listening to them. The Orion-is-upside-down-here thing was the first time I noticed something that drove it home to me that we live on a sphere.

timeon 5y ago

You do not even need to trust the established science. There are experiments done by flat earth believers which proves that earth is actually not flat at all.

darkerside 5y ago

I think this is right, in the same way that you can't ever really "prove" anything. (Direct proof relies on firsthand experience, and human perception and memory are infamously faulty. QED. Alternately, even the strongest experimental conclusion can be chalked up to the most extreme of coincidences.) However, to move forward in life, we must accept certain axioms so that we can be effective and productive. (Prove food is nutritious, prove I won't die in the next 5 minutes, prove my parents are benevolent actors, prove my children are actually mine). At some point, you can litigate anything you want, and the real decision is, what hills are you willing to die on. For me, that's determined strongly by impact to my life, and also partly by interest. What I'm saying is, don't argue that the flat earthers are wrong. Argue that they are useless because what they are arguing about doesn't matter.