The Flat Earth Society
Flat Earth Discussion Boards => Flat Earth Investigations => Topic started by: WellRoundedIndividual on March 21, 2019, 04:50:14 PM
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https://www.researchgate.net/publication/272755423_Modern_replication_of_Eratosthenes'_measurement_of_the_circumference_of_Earth
Found this interesting little duplication of Eratosthenes experiment. It was done with a 3rd city.
Would anyone like to critique this or debunk it?
Here is another website with schools that have uploaded their measurements. A map shows plenty of schools on the same longitude, and therefore we could take that data and compare doing geometry the predicted angles for FE vs RE.
https://eratosthenes.ea.gr/
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FE'ers will rightly point out that the Eratosthenes experiment, in and of itself, doesn't really prove that the earth is round because it assumes that the earth is round as part of its premise (calculating the diameter). If one assumes that the earth is flat and the sun is near, then one can obtain similar results.
https://wiki.tfes.org/Erathostenes_on_Diameter
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That only holds true geometrically if you only use two points. Once, you introduce a 3rd point or more, FE can no longer correctly predict the length of the shadow (or angle).
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My understanding of Eratosthenes experiment is that he was aiming to calculate the circumference of the Earth, not the diameter. Considering how long ago he lived I would say he did a pretty good job.
FE Wiki states...
It's a common misconception that Eratosthenes was measuring the circumference of the round earth in his shadow experiment. Eratosthenes had simply assumed that the earth was a sphere in his experiment, based on the work of Aristotle. He was actually measuring the diameter of the flat earth (distance across), which is a figure identical to the circumference of the round earth (distance around).
If that is true then why is it that the only reference I can find to this claim comes from websites relating to Flat Earth believers? I have checked many other sources which all state that Eratosthenes was assuming that the Earth was a perfect sphere. It was common in ancient times for philosophers, scientists, theologists etc to believe that the Sun, Moon and Earth were perfect spheres and that the Earth was at the centre of the Universe. The sphere was seen as the most perfect of the solids and so it natural to believe that the Earth was a sphere. Close but not quite right.
Eratosthenes realised the Sun was very distant so he also made the assumption that the Suns rays are parallel. So why should the notion that he was measuring a flat surface have entered his mind at any stage? For his experiment to work the way it did if the Earth was flat, Eratosthenes would have had to have been measuring around the edge of the Earth. And that, as the FES states, is somewhere that no one has ever been. It is of course easy to create ones own interpretation of an experiment to suit ones own beliefs.
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That only holds true geometrically if you only use two points. Once, you introduce a 3rd point or more, FE can no longer correctly predict the length of the shadow (or angle).
I made a diagram of this so that everyone could understand this critical point. I chose three locations along the same longitude: Washington DC, Cayo Redondo in Cuba and Lima in Peru (actually the suburb Surquillo because it lined up the best). These are the assumed elevations at the same minute in all three locations (solar noon):
https://www.suncalc.org/#/38.8938,-77.0146,12/2019.03.23/13:15/1/3
https://www.suncalc.org/#/20.2974,-77.0192,16/2019.03.23/13:15/1/3
https://www.suncalc.org/#/-12.1144,-77.012,16/2019.03.23/12:15/1/3
The distances between the locations are 2061.424km for Washington to Cayo Redondo and 3585.03km for Cayo Redondo to Surquillo.
When FE technology gets advanced enough to verify the distances between these locations (there's not too much water so shouldn't be that hard), they'll find that the elevation of the sun measured at all three places points to two different locations in the sky. And the difference is immediately obvious. The reason is because the Earth is not flat.
Here's the diagram so you can check (1 pixel equals one kilometre):
(https://i.imgur.com/kAl3KAq.gif)
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When FE technology gets advanced enough to verify the distances between these locations (there's not too much water so shouldn't be that hard), they'll find that the elevation of the sun measured at all three places points to two different locations in the sky. And the difference is immediately obvious. The reason is because the Earth is not flat.
In other words your argument is a circular one that requires the assumption that the RE map is correct which is precisely what is at question.
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When FE technology gets advanced enough to verify the distances between these locations (there's not too much water so shouldn't be that hard), they'll find that the elevation of the sun measured at all three places points to two different locations in the sky. And the difference is immediately obvious. The reason is because the Earth is not flat.
In other words your argument is a circular one that requires the assumption that the RE map is correct which is precisely what is at question.
One would think that the fact that the RE map is used everyday in the international transportation and shipping industries would be compelling evidence that the RE map in question is, at least, somewhat correct.
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When FE technology gets advanced enough to verify the distances between these locations (there's not too much water so shouldn't be that hard), they'll find that the elevation of the sun measured at all three places points to two different locations in the sky. And the difference is immediately obvious. The reason is because the Earth is not flat.
In other words your argument is a circular one that requires the assumption that the RE map is correct which is precisely what is at question.
One would think that the fact that the RE map is used everyday in the international transportation and shipping industries would be compelling evidence that the RE map in question is, at least, somewhat correct.
You would be incorrect.
https://gis.utah.gov/nad83-and-webmercator-projections/
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When FE technology gets advanced enough to verify the distances between these locations (there's not too much water so shouldn't be that hard), they'll find that the elevation of the sun measured at all three places points to two different locations in the sky. And the difference is immediately obvious. The reason is because the Earth is not flat.
In other words your argument is a circular one that requires the assumption that the RE map is correct which is precisely what is at question.
One would think that the fact that the RE map is used everyday in the international transportation and shipping industries would be compelling evidence that the RE map in question is, at least, somewhat correct.
You would be incorrect.
https://gis.utah.gov/nad83-and-webmercator-projections/
Would you care to explain the relevance of your link to my post?
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When FE technology gets advanced enough to verify the distances between these locations (there's not too much water so shouldn't be that hard), they'll find that the elevation of the sun measured at all three places points to two different locations in the sky. And the difference is immediately obvious. The reason is because the Earth is not flat.
In other words your argument is a circular one that requires the assumption that the RE map is correct which is precisely what is at question.
One would think that the fact that the RE map is used everyday in the international transportation and shipping industries would be compelling evidence that the RE map in question is, at least, somewhat correct.
You would be incorrect.
https://gis.utah.gov/nad83-and-webmercator-projections/
Would you care to explain the relevance of your link to my post?
The summary is in the title:
The Earth is Not Round! Utah, NAD83 and WebMercator Projections
The maps are based on flat earth maps, not round earth maps. Otherwise the title would more accurately be "The Earth is Round!"
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One would think that the fact that the RE map is used everyday in the international transportation and shipping industries would be compelling evidence that the RE map in question is, at least, somewhat correct.
You would be incorrect.
https://gis.utah.gov/nad83-and-webmercator-projections/
Would you care to explain the relevance of your link to my post?
The summary is in the title:
The Earth is Not Round! Utah, NAD83 and WebMercator Projections
I don't think that means what you think it means.
Geographic coordinates use latitude and longitude values to define positions on the 3D surface of the earth, which is of course, best modeled as an ellipsoid, not a sphere. The ellipsoid and its accompanying anchor point that ties it in to the real world, are known collectively as the WGS84 datum. The WGS84 datum is what the constellations of GPS satellites use natively.
The maps are based on flat earth maps, not round earth maps. Otherwise the title would more accurately be "The Earth is Round!"
Interesting. I thought the article was describing the ramifications of dealing with 3 different coordinate systems describing an ellipsoidal earth.
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No. You are wrong. The title is "The Earth is Not Round" and the content of the article reflects that. The article is talking about a globe model that is using the state plane flat maps as their underlying base to get accurate distances. Do your own research on any terms or concepts you find confusing.
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No. You are wrong. The title is "The Earth is Not Round" and the content of the article reflects that. Do your own research in any terms or concepts you find confusing.
Yes, it specifically says that the earth is best described as an ellipsoid and not a sphere. I'm still not sure that I see your point.
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No. You are wrong. The title is "The Earth is Not Round" and the content of the article reflects that. Do your own research in any terms or concepts you find confusing.
Yes, it specifically says that the earth is best described as an ellipsoid and not a sphere. I'm still not siure that I see your point.
It is talking about two models , a flat one and a round one. The round one takes the distances from the flat one, hence the "Earth is Not Round!" title.
Research any terms you find confusing, they are easily found on Google.
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All of this talk about maps and their accuracy has nothing to do with sticking three sticks in the ground and measuring the length of a shadow.
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No. You are wrong. The title is "The Earth is Not Round" and the content of the article reflects that. Do your own research in any terms or concepts you find confusing.
Yes, it specifically says that the earth is best described as an ellipsoid and not a sphere. I'm still not siure that I see your point.
It is talking about two models , a flat one and a round one. The round one takes the distances from the flat one, hence the "Earth is Not Round" title.
Actually, the flat one is projecting small chunks of round coordinates onto a flat Cartesian coordinate system so that distances can be more readily calculated.
Research any terms you find confusing, they are easily found on Google.
Which of those terms suggests that a flat Cartesian coordinate system is the best way to describe the shape of the earth?
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If it was an article telling us that the systems were using round earth distances the title of the article would be "The Earth is Round!," markjo.
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If it was an article telling us that the systems were using round earth distance the title of the article would be "The Earth is Round!," markjo.
Then why does the article state that the earth is best described as an ellipsoid? The article is using "round" to mean "sphere". An ellipsoid is not a sphere.
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Here is further experimental evidence. Peruse at your leisure.
https://core.ac.uk/download/pdf/143365111.pdf
I am still waiting on anyone to tell me if there is something wrong or missing in these experiments.
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Seems pretty clear to me. The only way Eratosthenes could have got a similar result on a flat Earth is if the Sun was a lot (and I mean a lot) closer to Earth than it actually is. We know the distance between the Earth and the Sun very accurately.
As I inferred earlier, Eratosthenes was not and never was setting out to work out the diameter of the Earth as FE Wiki claims. It was widely accepted that the Earth was a sphere in his day so his experiment was to work out the circumference of the Earth and he did that very successfully given the tools available.
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If it was an article telling us that the systems were using round earth distance the title of the article would be "The Earth is Round!," markjo.
Then why does the article state that the earth is best described as an ellipsoid? The article is using "round" to mean "sphere". An ellipsoid is not a sphere.
Only Tom could link to an article which says
3D surface of the earth, which is of course, best modeled as an ellipsoid, not a sphere
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Web Mercator ... has become, and will likely remain for some time, the de facto coordinate system standard for web mapping applications, because, as mentioned above, it works well for maps depicting the portions of the globe we care about most, and because it performs coordinate conversion faster.
And think the article is evidence for a flat earth ???
The article is literally about projections from the real world 3D surface of the globe earth and 2D maps. Were the earth flat you wouldn't need projections, only scale.
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The article clearly describes that those round earth models are pulling values from flat earth planar surveying because they provide more accurate distances. Hence the "The earth is not round!" title.
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Other way round, chap.
It’s talking about the best way to map the real world 3D globe onto a flat surface.
You keep saying there isn’t a map and you don’t have the resources to make one. Now you’re arguing the flat earth maps are more accurate?
???
The article talks about projection.
Why is projection necessary if the earth is flat? Were it so you’d just need scale to make an accurate map. We only need projection because there is no way to represent the curved surface of the globe earth onto a flat map.
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Feel free to look up what NAD84 is, which the article describes as providing more accurate distances. They are flat maps of the earth created through plane surveying.
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You can argue all you want about what the article is using as a reference for distances. It still has nothing to do with the topic of multiple measurements that were taken by schools all over the earth and that verify that the earth is round.
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Feel free to look up what NAD84 is, which the article describes as providing more accurate distances. They are flat maps of the earth created through plane surveying.
First off, there is no such thing as NAD84. There are NAD83 and WGS84 which are geodetic datums.
Because the Earth is curved and in GIS we deal with flat map projections, we need to accommodate both the curved and flat views of the world. In surveying and geodesy, we accurately define these properties with geodetic datums.
We begin modelling the Earth with a sphere or ellipsoid. Over time, surveyors have gathered a massive collection of surface measurements to more reliably estimate the ellipsoid.
When you combine these measurements, we arrive at a geodetic datum. Datums precisely specify each location on Earth’s surface in latitude and longitude. For example, NAD27, NAD83 and WGS84 are geodetic datums.
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Feel free to look up what NAD84 is, which the article describes as providing more accurate distances. They are flat maps of the earth created through plane surveying.
Just for the record so we can dispense with the 'utah' article you periodically bring up because you find the title fetching, for one, it's NAD83. For two, maybe you should free to look up what NAD84 NAD83 is:
North American Datum of 1983
As satellite geodesy and remote sensing technology reached high precision and were made available for civilian applications, it became feasible to acquire information referred to a single global ellipsoid. This is because satellites naturally deal with Earth as a monolithic body. Therefore, the GRS 80 ellipsoid was developed for best approximating the Earth as a whole, and it became the foundation for the North American Datum of 1983.
https://en.wikipedia.org/wiki/North_American_Datum
What is North American Datum 1983 (NAD83)?
The North American Datum of 1983 (NAD 83) is the most current datum being used in North America. It provides latitude and longitude and some height information using the reference ellipsoid GRS80.
https://gisgeography.com/geodetic-datums-nad27-nad83-wgs84/
Now, back to three-point Eratosthenes experiments.
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Now look up what a datum is and think about why that might be necessary for the flat state plane maps and the other globe models to interconnect and exchange data.
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I see you keep ignoring the question about why projection is necessary if the earth is flat :)
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I see you keep ignoring the question about why projection is necessary if the earth is flat :)
It's projecting a spherical coordinate system on to a flat map. The spherical coordinate system is an abstraction used to keep all of the flat maps together and interact with the latitude and longitude requests from GPS receivers, users, etc. The underlying flat maps do not use longitudes and latitudes.
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Here is further experimental evidence. Peruse at your leisure.
https://core.ac.uk/download/pdf/143365111.pdf
I am still waiting on anyone to tell me if there is something wrong or missing in these experiments.
Here's another Eratosthenes-esque experiment that was done by Sly Sparkane and some volunteers. Essentially the experiment teases out how a close-sun doesn't work on a flat earth. A little slow in parts but worth a full view.
https://www.youtube.com/watch?v=V03eF0bcYno
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Flat Earth Theory says that the sun is a projection on the observer's atmospheric dome of vision. Find a video which tests Flat Earth Theory.
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Flat Earth Theory says that the sun is a projection on the observer's atmospheric dome of vision. Find a video which tests Flat Earth Theory.
Which flat earth theory is that? And where is the sun being projected from? And what exactly is an "observer's atmospheric dome of vision"? Sounds fantastical.
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Flat Earth Theory says that the sun is a projection on the observer's atmospheric dome of vision.
Have you ever considered the possibility that Flat Earth Theory might be wrong? Just because something says something, doesn't mean it is right.
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I see you keep ignoring the question about why projection is necessary if the earth is flat :)
It's projecting a spherical coordinate system on to a flat map.
Correct. And this is only needed because the earth isn't flat.
If it were then only scaling would be required
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It's projecting a spherical coordinate system on to a flat map. The spherical coordinate system is an abstraction used to keep all of the flat maps together and interact with the latitude and longitude requests from GPS receivers, users, etc. The underlying flat maps do not use longitudes and latitudes.
Anybody got any idea what Tom is talking about here? Because I certainly can't figure it out. Has it been explained where and what the source of the projection is?
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It's projecting a spherical coordinate system on to a flat map. The spherical coordinate system is an abstraction used to keep all of the flat maps together and interact with the latitude and longitude requests from GPS receivers, users, etc. The underlying flat maps do not use longitudes and latitudes.
Anybody got any idea what Tom is talking about here? Because I certainly can't figure it out. Has it been explained where and what the source of the projection is?
I think he thinks the earth's flat surface has been mapped onto a spheroid then that spheroid projected into a flat map again to show the flat earth (which is massively distorted). Correct me if I'm wrong Tom.
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If it was an article telling us that the systems were using round earth distance the title of the article would be "The Earth is Round!," markjo.
Then why does the article state that the earth is best described as an ellipsoid? The article is using "round" to mean "sphere". An ellipsoid is not a sphere.
So, all the crapola cried by RE is wrong?
Are you admitting you guys have been wrong all this time?
And the spheres depicted in the composites are not spheres?
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The projection of the sun is irrelevant to the shape of the earth. Even if the sun is a projection, using the lengths of shadows from 3 points determines that the earth is a sphere.
Are you part of a new society called SP? Sun Projectionists?
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A spherical coordinate system projected onto a flat map is called a polar coordinate system. The entire azimuthal angle information is lost in the projection. The only other option is to distort the image to preserve the azimuthal information, which results in scale distortions.
This is exactly what happens when a globe is flattened onto a 2D map, Greenland is the notable example of distortion.
Longitudes and latitudes have no existence on a 2D surface - we just call their replacements the x,y coordinates. In spherical coordinates, they count equal measures of polar and azimuth angles.
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Are you admitting you guys have been wrong all this time?
And the spheres depicted in the composites are not spheres?
Wrong about what? It has been long since known that the earth is not a perfect sphere but slightly flattened.
Note the "slightly"
Here's a composite image of the earth from space:
https://upload.wikimedia.org/wikipedia/commons/2/2c/North_America_from_low_orbiting_satellite_Suomi_NPP.jpg
Does that look like a perfect circle? Is it one?
Hint: load that image in a paint package and measure the number of pixels top to bottom and then left to right...
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Are you admitting you guys have been wrong all this time?
And the spheres depicted in the composites are not spheres?
Wrong about what? It has been long since known that the earth is not a perfect sphere but slightly flattened.
Note the "slightly"
Here's a composite image of the earth from space:
https://upload.wikimedia.org/wikipedia/commons/2/2c/North_America_from_low_orbiting_satellite_Suomi_NPP.jpg
Does that look like a perfect circle? Is it one?
Hint: load that image in a paint package and measure the number of pixes top to bottom and then left to right...
Silly you, don't you know your screen resolution will affect the shape? What if you have a widescreen and it flattens the image(!)
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I think he thinks the earth's flat surface has been mapped onto a spheroid then that spheroid projected into a flat map again to show the flat earth (which is massively distorted). Correct me if I'm wrong Tom.
I see. How does that explain what this projection idea is all about. This all sounds like forcing something to fit just to make a particular theory work which is actually clearly wrong in the first place.
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If it was an article telling us that the systems were using round earth distance the title of the article would be "The Earth is Round!," markjo.
Then why does the article state that the earth is best described as an ellipsoid? The article is using "round" to mean "sphere". An ellipsoid is not a sphere.
So, all the crapola cried by RE is wrong?
Are you admitting you guys have been wrong all this time?
And the spheres depicted in the composites are not spheres?
It depends on what you mean by wrong. It's been known and taught for many years that the earth is not a perfect sphere but an oblate spheroid. However, the oblateness so slight that it does not affect our everyday experiences. Earth scientists and pedants are pretty much the only people concerned with the oblateness of the round earth.
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It's been known and taught for many years that the earth is not a perfect but an oblate spheroid
Correct. The slight polar flattening is caused by the Earths rotation. This is evidenced by the fact that the gas giant planets, which rotate faster due to higher mass show the flattening effect more than the Earth does. Therefore the faster a planet rotates the flatter it will become. With a rotation period of 24 hours, the Earth spins far too slowly to become flat.
Geological records in rocks show that the Earth rotated much more rapidly in its early history. That means the flattening effect for Earth would have been more pronounced in the past. So as it slows down, it is getting less oblate spheroid and more spherical.