I blame facebook. Theres hundreds of these flat earth groups and other junk about vaccines and "gang stalking" .
It's all completely unchecked filter bubbles.
Filter bubbles alone cannot explain an expanding movement (they can explain solidifying and radicalizing within a fixed-size movement, but not growth of the movement.)
> In all fairness though, I don't have good reasons to believe most of consensus science other than appeals to authoritative sources.
In all fairness, flat-earthers do the same thing, they just substitute appeals to authority with denials of authority. Blanket skepticism no more intellectually valid than blind faith.
Also, ironically, while there may be many scientific truths which are difficult for the lay person to understand and verify, the roundness of the earth isn't one of them[0].
That popsci article should really be "10 pieces of evidence that are consistent with the round Earth model". Most of them aren't super easy to reproduce either.
> Blanket skepticism no more intellectually valid than blind faith.
This sounds vaguely like a moral judgement to me. What does "valid" mean here? I find it less inciteful, and more useful, to take a pragmatist approach. Was Newton wrong and Einstein right?
Even if we call Newtonian mechanics "wrong" it's certainly super useful. In the same way, thinking of the Earth as flat is pretty darn useful in daily life. I'd bet a pretty penny that almost everybody operates with an implicit "flat Earth" model in their head for mundane tasks.
On the other hand, the Round Earth model is probably super useful to sattelite engineers. If the Flat Earthers start doing cool space science or something, I'm more than happy to encourage them.
Newtonian mechanics wasn't wrong, it wasn't right enough at certain scales - AFAIK, it correctly predicted the orbits of all of the planets except Mercury, whose proximity to the sun was close enough that relativity had to be taken into account to explain it.
However, flat Earthers aren't "wrong" in the same way that Newton was, they don't simply have an alternative model of reality which is useful in its own peculiar way. Newtonian mechanics and Einstein don't contradict each other, and one doesn't override the other. Flat Earthism, meanwhile, is like the crackpot who denies all this newfangled quantum timespace relativity mumbo jumbo and refuses to believe in anything but Newton, because Newton is simple and obvious. It doesn't refine and augment existing knowledge, it denies its validity altogether.
Thinking of the earth as being flat at human scale is simple and obvious. Thinking of the earth in its entirety as being flat is simple and obvious and wrong in ways that even the ancients could figure out. There's no domain in which that's useful.
> You can trivially deomonatrate that the earth is round using basic tools available 2000 years ago.
It's not actually so trivial. There are simple observations that are consistent with a Round Earth model, but it's pretty difficult to nail things down rigorously and precisely.
Anyway, it's sort of interesting to me that you even bring that up. My comment didn't really claim anything about Flat Earth at all; it was more an open statement about the epistimics of scientific knowledge among non-experts.
The fact that you and one other commenter come to defend Round Earth, seems to suggest a sort of belief tribalism in our current science-oriented zeitgeist.
Questions about rigor and precision are a function of your goal.
The goal is to determine if a Round Earth model is a more useful model than a Square or Disk Earth model.
I've demonstrated it empirically to my own satisfaction.
I've seen the Southern Cross right at the horizon from the Florida Keys, but not visible father north. I've seen that the North Star rises higher in the sky as I've gone north. And in summer I've seen that the daytime is much longer in Michigan than Florida, and how the sunlight in the evening goes through the windows of the north side of buildings, which it doesn't really do in Miami.
I've driven across the US and seen that the sun rises a couple of hours later in the West than the East.
I've been below the Equator, and seen Orion cross the sky upside down, while the Southern Cross and the Magellanic Clouds were high in the sky. I also got confused when driving because it turns out my sense of direction was based on the expectation that the Sun should be in the south at midday, not in the north.
I was once at about 55 degrees north latitude, in early December, and the sun was low in the sky at noon. By measuring the shadow length I calculated the latitude to within a couple of degrees. (This calculation does require knowing the axial tilt, which I have not independently measured.)
These are all consistent with a Round Earth model, and not at all consistent with any description of a Flat Earth model that I've come across.
Now of course it's possible to say that I've not measured the radius of the Earth to sufficient precision, or demonstrated that the diameter between the poles is shorter than the equatorial bulge.
But that's changing the goalposts. I did not have to appeal to any authorities to confirm that the round earth model is a much better fit to my observations than a flat earth one.
Why are you not able to make similar empirical tests? If you are able to carry them out, why are they not enough for you?
The TV series "Ring of Truth" from the 1980s tried to address the question of how you can test things out for yourself. One of the things they did, in such a way that you could reproduce their work, was to drive along a long north-south road and measure the elevation change in a star. From this they could estimate the size of the Earth. They call it the "Van of Eratosthenes." You can see it at https://www.youtube.com/watch?v=yRY2SkMTafc .
Again, there's no reason to trust what the said. Rather, you can use it to reproduce their methods yourself, which is the sort of empirical test you asked about.
Thanks for sharing those stories. It sounds like you pay quite a bit of attention to the sky and stars!
> Why are you not able to make similar empirical tests? If you are able to carry them out, why are they not enough for you?
I'm guessing you meant these as rhetorical questions. They're indeed good for introspection. For clarity though, I'm perfectly satisfied with a globe Earth. Seems to be a pretty good model for my needs.
I was actually hoping sidestep discussions of Flat Earth vs Round Earth since, as you point out, the empirical observations aren't to hard to think up as a lay person. They're not quite trivial enough to be done in your backyard though.
What I'm more interested in, personally, are questions like "What is the structure of the Earth's interior?" I learned an answer from a textbook and am vaguely aware of how seismic data has been used to extrapolate this, but I'm not quite sure how to come up with a Core + Mantle + Crust model myself.
Instead of brute forcing these things, I'd really like to hear some clever reasoning and Fermi estimation capable of rederiving these standard results.
Perhaps easier to answer would be "Does the moon have an atmosphere?" One idea I had was to point a telescope on a line of site tangent to the lunar surface and look for abberations in starlight compared to stars a large angular distance away. This seems doable in your backyard with relatively cheap hardware.
I was responding to your statement "It's not actually so trivial. There are simple observations that are consistent with a Round Earth model, but it's pretty difficult to nail things down rigorously and precisely."
I object to the idea that additional rigor and precision is needed for the specific case you were responding to.
As to your overall topic, one step is to watch that miniseries I mentioned earlier, "The Ring of Truth: An Inquiry into How We Know What We Know". It gives several examples of working things out from scratch. For example, drop a measured and small amount of olive oil onto a still pond. It produces an oil patch. The volume of the oil divided by the size of the patch gives an upper bound for the size of the molecules in olive oil.
What you might not know is that there is a large amount of literature in repeating some of the classic experiments. For example, physics undergraduate lab courses may have the students measure the strength of the Earth's local magnetic field, or the value of the gravitational constant G (not g, which is the acceleration due to gravity), and do so using basic equipment you can gather or make yourself.
Detecting the Earth's structure on your own is difficult. You will need a seismometer, and learn how to interpret it. A quick search shows there are many hobby plans for building your own seismometer, or you can buy ones made for schools. The harder part is to come to trust that P-waves and S-waves are different, that they have different speeds, that one cannot go through liquid, and that observations of many earthquakes from around the world can be combined with an understanding of material science and thermodynamics to produce a model of the interior of the Earth.
If your purpose is to avoid what you consider to be appeals to authoritative sources, you will have to redo from scratch what took others several lifetimes to develop. One of these is Francis Birch, https://en.wikipedia.org/wiki/Francis_Birch_(geophysicist) . Quoting that Wikipedia page, "In 1952 he demonstrated that Earth's mantle is chiefly composed of silicate minerals, with an inner and outer core of molten iron."
Concerning the round earth model, what you can do given limited travel is to create a Foucault pendulum, or visit somewhere which has one set up. In principle this can be done in a backyard, but it required a long pendulum wire and still air - do you have an empty corn silo in your backyard? The time it takes to go around can be used to calculate your latitude.
However, this only shows that you are in a rotating reference frame. You then need to repeat what the ancient Greeks did, and look at lunar eclipses to see that the shadow of the earth is always a circle, no matter where the Moon is in the sky.
These together mean that from your backyard you could (in principle) determine that the Earth is a rotating round object.
Concerning your question "Does the moon have an atmosphere?", the problem is, the Moon does have an atmosphere. It's very thin - https://en.wikipedia.org/wiki/Atmosphere_of_the_Moon . A naked eye view of the Moon is enough to determine that it does not have an extremely thick atmosphere. So with a backyard telescope all you can do is set an upper bound for the thickness of the atmosphere.
But to do that, you need some way to predict what those aberrations might look like. For example, if it had a CO2 atmosphere that was 0.1 bar at the surface, would you be able to detect it? Have you measured the index of refraction of different gasses, or are you willing to trust the measurements of others.
I'm not saying it's impossible, but rather that you have to decide at some point where you can trust the results of others.
Wow. Thank you for you thoughtful and long replies.
> ...you have to decide at some point where you can trust the results of others.
Exactly. My personal attitude in asking is very much in the "hacker spirit"; mainly I point out appeals to authority as an identification of an opportunity to dig deeper.
> Foucault pendulum
Oh! That's a thing I had forgotten. Back in the day, I remeber using several of these and correlating their positions against rotation rates to estimate the Earth's radius. Not quite a backyard experiment though.
> "The Ring of Truth" miniseries
It seems this is on YouTube. Thanks for the pointer! The oil drop experiment sounds really cool.
> Moon does have an atmosphere... all you can do is set an upper bound for the thickness of the atmosphere.
Fair enough. You're speaking more precisely than I. I'm also wondering at what point the variance drops beneath the noise from Earth's atmosphere. This is something that's worth taking a top-down approach by initially trusting our Handbook of Physics and Chemistry and slowly working our way back.
Anyway, thanks again for your in-depth replies. You must be an amazing conversation partner!
I really like everything eesmith wrote. I'm all about understanding on a deeper level how things work and how pieces of the world fit together. I also think re-proving fundamental knowledge with simple experiments is awesome.
For the general question of knowing how we can trust modern knowledge, there is another useful angle. We can look at the technological devices and items in the world, and try to imagine how they work so reliably and precisely.
For example, things like digital cameras, microwaves, mcat machines, gps devices, weather predictions, infrared goggles, sunblock, pneumatic machinery, one-way mirrors, miniature electronics, etc... the list goes on
Why are these things so reliable? How do they work? It's very hard to imagine a world in which these countless devices exist, and yet the corresponding science is not very well-understood or robust, at least without jumping too far off the deep end.
Of course, it's a fantastic exercise to try to research and understand which individual bits of scientific knowledge are required for the various modern technological devices that we encounter.
I know you don't think that the foundations of modern knowledge are shaky. I just thought that your questions were considerate and genuine, and that you might appreciate this additional way of analyzing things.
Edit: Watching the Ring of Truth right now... very cool program. Makes me want to do some observations myself.
He was also a columnist for Scientific American. The only column I remember is when he decided to make bread from scratch. Really from scratch. They grew wheat in a small plot of land near his home in Cambridge, Mass.
He's part of the generation that developed the first atomic bomb. He carried the first core to the Trinity test site in the back seat of his car, and helped load the weapons on the planes that went to Japan.
> There are simple observations that are consistent with a Round Earth model, but it's pretty difficult to nail things down rigorously and precisely.
It's quite possible to both demonstrate that the Earth is round and get an accurate first-order approximation of its size with tools available 2,000+ years ago.
We know this is possible with certainty because it was actually done 2,000+ years ago, by Eratosthenes.
I referenced “round earth” because it is so trivial to demonstrate with tools available to almost everyone. A subset of people are able to directly observe the earths curvarure from ships, aircraft or outer space. There are people in the space station right now who looking at the round earth.
The notion that the earth is flat is absurd to all but the ignorant.
There’s a reason why skeptics target things like round vs. flat earth — it’s a variant of “the big lie” approach used by oppressive political regimes. As humans, we dig into and push back against nuanced arguments. But when you challenge fundamental things, people who are actively ignorant and charismatic have an easier time convincing people about nonsense.
A similar example is the UFO phenomenon of the 80s and 90s, where the military planted or encouraged wacky stories to divert attention from aircraft and cruise missile testing.
Flat earthers have an answer for every scientific question posed. Now suppose NASA Is faking every video etc.. There's no way Americas rivals Soviets, North Korea etc.. who have been or have satellites in space would collude with America to hide such information.
But then they come back and try to say that the Russians are trying to tell them the truth, but the information is getting suppressed before it gets to them (after all, how many of them have personally spoke with a leader in a foreign government, and if so, how do they know that the person they spoke to wasn't a fake planted by the "establishment"?)
I still think that this movement is a big gag, that 99% of the members are in on (something like the Church of the SubGenius).
> "If schools were better at teaching analytical thinking, that might reduce the appeal of conspiracy theories. And it would not hurt if governments were more open and trustworthy."
29 comments
[ 2.8 ms ] story [ 85.0 ms ] threadThe issue itself is, of course, ridiculous. I'd really like to read the actual article, but apparently, I'm not.
It gets me wondering how I could emperically test the things I supposedly know.
In all fairness, flat-earthers do the same thing, they just substitute appeals to authority with denials of authority. Blanket skepticism no more intellectually valid than blind faith.
Also, ironically, while there may be many scientific truths which are difficult for the lay person to understand and verify, the roundness of the earth isn't one of them[0].
[0]https://www.popsci.com/10-ways-you-can-prove-earth-is-round
> Blanket skepticism no more intellectually valid than blind faith.
This sounds vaguely like a moral judgement to me. What does "valid" mean here? I find it less inciteful, and more useful, to take a pragmatist approach. Was Newton wrong and Einstein right?
Even if we call Newtonian mechanics "wrong" it's certainly super useful. In the same way, thinking of the Earth as flat is pretty darn useful in daily life. I'd bet a pretty penny that almost everybody operates with an implicit "flat Earth" model in their head for mundane tasks.
On the other hand, the Round Earth model is probably super useful to sattelite engineers. If the Flat Earthers start doing cool space science or something, I'm more than happy to encourage them.
However, flat Earthers aren't "wrong" in the same way that Newton was, they don't simply have an alternative model of reality which is useful in its own peculiar way. Newtonian mechanics and Einstein don't contradict each other, and one doesn't override the other. Flat Earthism, meanwhile, is like the crackpot who denies all this newfangled quantum timespace relativity mumbo jumbo and refuses to believe in anything but Newton, because Newton is simple and obvious. It doesn't refine and augment existing knowledge, it denies its validity altogether.
Thinking of the earth as being flat at human scale is simple and obvious. Thinking of the earth in its entirety as being flat is simple and obvious and wrong in ways that even the ancients could figure out. There's no domain in which that's useful.
You of course have to trust the math isn’t some conspiracy theory, but the ancient Greeks were able to measure the earth’s circumference.
It's not actually so trivial. There are simple observations that are consistent with a Round Earth model, but it's pretty difficult to nail things down rigorously and precisely.
Anyway, it's sort of interesting to me that you even bring that up. My comment didn't really claim anything about Flat Earth at all; it was more an open statement about the epistimics of scientific knowledge among non-experts.
The fact that you and one other commenter come to defend Round Earth, seems to suggest a sort of belief tribalism in our current science-oriented zeitgeist.
The goal is to determine if a Round Earth model is a more useful model than a Square or Disk Earth model.
I've demonstrated it empirically to my own satisfaction.
I've seen the Southern Cross right at the horizon from the Florida Keys, but not visible father north. I've seen that the North Star rises higher in the sky as I've gone north. And in summer I've seen that the daytime is much longer in Michigan than Florida, and how the sunlight in the evening goes through the windows of the north side of buildings, which it doesn't really do in Miami.
I've driven across the US and seen that the sun rises a couple of hours later in the West than the East.
I've been below the Equator, and seen Orion cross the sky upside down, while the Southern Cross and the Magellanic Clouds were high in the sky. I also got confused when driving because it turns out my sense of direction was based on the expectation that the Sun should be in the south at midday, not in the north.
I was once at about 55 degrees north latitude, in early December, and the sun was low in the sky at noon. By measuring the shadow length I calculated the latitude to within a couple of degrees. (This calculation does require knowing the axial tilt, which I have not independently measured.)
These are all consistent with a Round Earth model, and not at all consistent with any description of a Flat Earth model that I've come across.
Now of course it's possible to say that I've not measured the radius of the Earth to sufficient precision, or demonstrated that the diameter between the poles is shorter than the equatorial bulge.
But that's changing the goalposts. I did not have to appeal to any authorities to confirm that the round earth model is a much better fit to my observations than a flat earth one.
Why are you not able to make similar empirical tests? If you are able to carry them out, why are they not enough for you?
The TV series "Ring of Truth" from the 1980s tried to address the question of how you can test things out for yourself. One of the things they did, in such a way that you could reproduce their work, was to drive along a long north-south road and measure the elevation change in a star. From this they could estimate the size of the Earth. They call it the "Van of Eratosthenes." You can see it at https://www.youtube.com/watch?v=yRY2SkMTafc .
Again, there's no reason to trust what the said. Rather, you can use it to reproduce their methods yourself, which is the sort of empirical test you asked about.
> Why are you not able to make similar empirical tests? If you are able to carry them out, why are they not enough for you?
I'm guessing you meant these as rhetorical questions. They're indeed good for introspection. For clarity though, I'm perfectly satisfied with a globe Earth. Seems to be a pretty good model for my needs.
I was actually hoping sidestep discussions of Flat Earth vs Round Earth since, as you point out, the empirical observations aren't to hard to think up as a lay person. They're not quite trivial enough to be done in your backyard though.
What I'm more interested in, personally, are questions like "What is the structure of the Earth's interior?" I learned an answer from a textbook and am vaguely aware of how seismic data has been used to extrapolate this, but I'm not quite sure how to come up with a Core + Mantle + Crust model myself.
Instead of brute forcing these things, I'd really like to hear some clever reasoning and Fermi estimation capable of rederiving these standard results.
Perhaps easier to answer would be "Does the moon have an atmosphere?" One idea I had was to point a telescope on a line of site tangent to the lunar surface and look for abberations in starlight compared to stars a large angular distance away. This seems doable in your backyard with relatively cheap hardware.
I object to the idea that additional rigor and precision is needed for the specific case you were responding to.
As to your overall topic, one step is to watch that miniseries I mentioned earlier, "The Ring of Truth: An Inquiry into How We Know What We Know". It gives several examples of working things out from scratch. For example, drop a measured and small amount of olive oil onto a still pond. It produces an oil patch. The volume of the oil divided by the size of the patch gives an upper bound for the size of the molecules in olive oil.
What you might not know is that there is a large amount of literature in repeating some of the classic experiments. For example, physics undergraduate lab courses may have the students measure the strength of the Earth's local magnetic field, or the value of the gravitational constant G (not g, which is the acceleration due to gravity), and do so using basic equipment you can gather or make yourself.
Detecting the Earth's structure on your own is difficult. You will need a seismometer, and learn how to interpret it. A quick search shows there are many hobby plans for building your own seismometer, or you can buy ones made for schools. The harder part is to come to trust that P-waves and S-waves are different, that they have different speeds, that one cannot go through liquid, and that observations of many earthquakes from around the world can be combined with an understanding of material science and thermodynamics to produce a model of the interior of the Earth.
If your purpose is to avoid what you consider to be appeals to authoritative sources, you will have to redo from scratch what took others several lifetimes to develop. One of these is Francis Birch, https://en.wikipedia.org/wiki/Francis_Birch_(geophysicist) . Quoting that Wikipedia page, "In 1952 he demonstrated that Earth's mantle is chiefly composed of silicate minerals, with an inner and outer core of molten iron."
Concerning the round earth model, what you can do given limited travel is to create a Foucault pendulum, or visit somewhere which has one set up. In principle this can be done in a backyard, but it required a long pendulum wire and still air - do you have an empty corn silo in your backyard? The time it takes to go around can be used to calculate your latitude.
However, this only shows that you are in a rotating reference frame. You then need to repeat what the ancient Greeks did, and look at lunar eclipses to see that the shadow of the earth is always a circle, no matter where the Moon is in the sky.
These together mean that from your backyard you could (in principle) determine that the Earth is a rotating round object.
Concerning your question "Does the moon have an atmosphere?", the problem is, the Moon does have an atmosphere. It's very thin - https://en.wikipedia.org/wiki/Atmosphere_of_the_Moon . A naked eye view of the Moon is enough to determine that it does not have an extremely thick atmosphere. So with a backyard telescope all you can do is set an upper bound for the thickness of the atmosphere.
But to do that, you need some way to predict what those aberrations might look like. For example, if it had a CO2 atmosphere that was 0.1 bar at the surface, would you be able to detect it? Have you measured the index of refraction of different gasses, or are you willing to trust the measurements of others.
I'm not saying it's impossible, but rather that you have to decide at some point where you can trust the results of others.
> ...you have to decide at some point where you can trust the results of others.
Exactly. My personal attitude in asking is very much in the "hacker spirit"; mainly I point out appeals to authority as an identification of an opportunity to dig deeper.
> Foucault pendulum
Oh! That's a thing I had forgotten. Back in the day, I remeber using several of these and correlating their positions against rotation rates to estimate the Earth's radius. Not quite a backyard experiment though.
> "The Ring of Truth" miniseries
It seems this is on YouTube. Thanks for the pointer! The oil drop experiment sounds really cool.
> Moon does have an atmosphere... all you can do is set an upper bound for the thickness of the atmosphere.
Fair enough. You're speaking more precisely than I. I'm also wondering at what point the variance drops beneath the noise from Earth's atmosphere. This is something that's worth taking a top-down approach by initially trusting our Handbook of Physics and Chemistry and slowly working our way back.
Anyway, thanks again for your in-depth replies. You must be an amazing conversation partner!
For the general question of knowing how we can trust modern knowledge, there is another useful angle. We can look at the technological devices and items in the world, and try to imagine how they work so reliably and precisely.
For example, things like digital cameras, microwaves, mcat machines, gps devices, weather predictions, infrared goggles, sunblock, pneumatic machinery, one-way mirrors, miniature electronics, etc... the list goes on
Why are these things so reliable? How do they work? It's very hard to imagine a world in which these countless devices exist, and yet the corresponding science is not very well-understood or robust, at least without jumping too far off the deep end.
Of course, it's a fantastic exercise to try to research and understand which individual bits of scientific knowledge are required for the various modern technological devices that we encounter.
I know you don't think that the foundations of modern knowledge are shaky. I just thought that your questions were considerate and genuine, and that you might appreciate this additional way of analyzing things.
Edit: Watching the Ring of Truth right now... very cool program. Makes me want to do some observations myself.
You might also be interested in "The Secret Life of Machines". https://en.wikipedia.org/wiki/The_Secret_Life_of_Machines and https://www.youtube.com/watch?v=KDpNQQqdSh8&list=PLByTa5duIo... .
Philip Morrison (from Ring of Truth) is perhaps best known for his powers-of-10 movie. https://en.wikipedia.org/wiki/Powers_of_Ten_(film) .
He was also a columnist for Scientific American. The only column I remember is when he decided to make bread from scratch. Really from scratch. They grew wheat in a small plot of land near his home in Cambridge, Mass.
He's part of the generation that developed the first atomic bomb. He carried the first core to the Trinity test site in the back seat of his car, and helped load the weapons on the planes that went to Japan.
Thanks for the other links, I'll have to check them out!
It's quite possible to both demonstrate that the Earth is round and get an accurate first-order approximation of its size with tools available 2,000+ years ago.
We know this is possible with certainty because it was actually done 2,000+ years ago, by Eratosthenes.
The notion that the earth is flat is absurd to all but the ignorant.
There’s a reason why skeptics target things like round vs. flat earth — it’s a variant of “the big lie” approach used by oppressive political regimes. As humans, we dig into and push back against nuanced arguments. But when you challenge fundamental things, people who are actively ignorant and charismatic have an easier time convincing people about nonsense.
A similar example is the UFO phenomenon of the 80s and 90s, where the military planted or encouraged wacky stories to divert attention from aircraft and cruise missile testing.
I still think that this movement is a big gag, that 99% of the members are in on (something like the Church of the SubGenius).
Two big if's.