# Why isn't there a specific Flat Earth model.

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#### JJA

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• Math is math!
##### Re: Why isn't there a specific Flat Earth model.
« Reply #30 on: August 28, 2021, 05:57:52 PM »
Euclidean geometry is not "the geometry of flat surfaces." It is the geometry in which Euclids postulates hold. There is a difference.

Still waiting for a real world example where the angles of a triangle don't add up to 180 degrees.

If you can't provide even a single example, then you have to accept that the Earth as we have measured it is still a ball as you can't show that local space isn't Euclidean. That excuse doesn't hold if you can't show where it diverges.

#### John Davis

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##### Re: Why isn't there a specific Flat Earth model.
« Reply #31 on: August 30, 2021, 02:33:10 PM »
Euclidean geometry is not "the geometry of flat surfaces." It is the geometry in which Euclids postulates hold. There is a difference.
Not really.
Yes, it is the geometry in which Euclid's postulates hold, which includes flat surfaces, as well as other things, such as flat space.

It is often contrasted with spherical and hyperbolic geometry, which are not flat.

Do you have an example of anything that is flat, but non-Euclidean?
Because so far all you have done is appeal to non-flat, non-Euclidean geometries, which in no way helps support the idea that Earth's surface is flat.
Sure. Break any of the first four postulates. Also, it is quite reasonable to describe a geodesic as flat.
« Last Edit: August 30, 2021, 02:56:08 PM by John Davis »
Quantum Ab Hoc

#### John Davis

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##### Re: Why isn't there a specific Flat Earth model.
« Reply #32 on: August 30, 2021, 02:33:52 PM »
Euclidean geometry is not "the geometry of flat surfaces." It is the geometry in which Euclids postulates hold. There is a difference.

Still waiting for a real world example where the angles of a triangle don't add up to 180 degrees.

If you can't provide even a single example, then you have to accept that the Earth as we have measured it is still a ball as you can't show that local space isn't Euclidean. That excuse doesn't hold if you can't show where it diverges.
A triangle formed using a beam of light that is gravitationally lensed and two other vectors.
Quantum Ab Hoc

#### JJA

• 5168
• Math is math!
##### Re: Why isn't there a specific Flat Earth model.
« Reply #33 on: August 30, 2021, 03:24:33 PM »
Euclidean geometry is not "the geometry of flat surfaces." It is the geometry in which Euclids postulates hold. There is a difference.

Still waiting for a real world example where the angles of a triangle don't add up to 180 degrees.

If you can't provide even a single example, then you have to accept that the Earth as we have measured it is still a ball as you can't show that local space isn't Euclidean. That excuse doesn't hold if you can't show where it diverges.
A triangle formed using a beam of light that is gravitationally lensed and two other vectors.

Who performed this measurement, and how far off from 180 degrees did they measure? How large was this triangle and where were the three points? I'd love to read that paper.

Assuming you can answer, that will tell you how big of an effect this could have on the Earth.  Enough to make a flat earth look like a sphere?  Enough to alter a triangle on my desk?  What kind of transformation turns a plane with an edge into a sphere with no edge?

This comes back to what I said earlier. You can't find any measurements we can do on the scale of the Earth that shows it to be residing in non-Euclidian space.  My hair-dryer bends space-time but nobody is going to seriously say that the table it sits on isn't flat, it's actually a torus just because space isn't 100% flat around it.

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#### JackBlack

• 16414
##### Re: Why isn't there a specific Flat Earth model.
« Reply #34 on: August 30, 2021, 04:51:15 PM »
Sure. Break any of the first four postulates. Also, it is quite reasonable to describe a geodesic as flat.
Are you sure that breaking any of the first four postulates will produce a workable geometry? Especially one that can be described as flat?
If so, do you have any evidence at all that such a space exists? Because so far all you have been able to do is appeal to cases where the 5th postulate does not hold, meaning it isn't flat.

And no, it is not reasonable to describe a geodesic as flat. That is because a geodesic is a line, not a surface. That would be described by some as straight not flat.

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#### Cartog

• 530
##### Re: Why isn't there a specific Flat Earth model.
« Reply #35 on: September 05, 2021, 04:56:24 PM »
This thread started with a very valid question.

And the answer is there cannot be a specific FE model because the earth itself is ROUND.  All this flat planet talk is nonsense, and if you start asking questions about what's on the sides or the underside of the flat planet or why no government, even in wartime, announced that the earth was flat, etc., you get vague nonsense from the incels who take FE seriously.