ERATOSTHENES DID NOT PROVE THE EARTH IS A GLOBE!

[Polymath257]

So what you are saying is you don't believe in any absolutes - except there is no way for the earth to be flat.
You don't see that as a self-contradicting statement?
Do you agree with the premise of this thread which states Eratosthenes didn't prove the earth is a globe?

No, Eratosthenes did NOT prove the Earth is a globe. That was well known long before him. Eratosthenes measured the size of that globe.

if you want to know HOW the Earth was shown to be spherical (approximately), then we can do that. But it wasn't Eratosthenes that did that.

 

[Polymath257]

Foucault's pendulum never proved the shape of the earth, if you want we can open another thread and talk about it there.

That's true. Foucalt's pendulum shows that the Earth isn't an inertial reference frame. In essence, it shows that the Earth rotates. It didn't show the shape.

 

[Flat Earth Kyle]

Eratosthenes did NOT prove the Earth is a globe.

Common Ground: you agree with the premise. Argument over.
If you would like to change topics, please open another thread.

 

[Polymath257]

Common Ground: you agree with the premise. Argument over.
If you would like to change topics, please open another thread.

I answered your question: Eratosthenes did NOT show that the Earth is a globe. That was already known. Eratosthenes measured the size of that globe.

 

[Yazata]

 

[Flat Earth Kyle]

Strawman.

 

[Polymath257]

I asked you if you agreed with the premise that Eratosthenes never proved anything about a globe.

He didn't prove the Earth is a globe. That had already been done. He showed how large that globe is, so he did show something about the globe.

You said no - even though you have expressed the belief "science never proves anything."
That appears contradictory to me.

Science never proves general results. It can, and does, show particular facts through observation.

 

[Polymath257]

@Nimos 3 holes are not an issue on the flat earth.
View attachment 79940

Except that this model fails in many other ways.

 

[Polymath257]

1st Your, "clear distinction" isn't very clear.
2nd, you've made a mistake in drawing straight lines. As Neil deGrasse Tyson explained in the OP, the earth has an atmosphere that causes light to bend similar to a straw in a glass of water. Please do feel free to tell me you disagree with Neil deGrasse Tyson. I love it when globe earthers throw him under the bus.
View attachment 79945

OK, how much does the light bend going from water to air? And how does that compare to how much it bends going from a vacuum to air?
Tyson understands that the index of refraction of air is much less than that of water, so that using Snell's law, the amount of bending from the atmosphere is low (except when the sun is low in the sky and there is more time and distance for the refraction to work). The *most* refraction we get from the atmosphere (again, in the late evening) is about 5 degrees. Water typically does MUCH more than that.

By all means, do tell me when and where you claim Eratosthenes took refraction into account. The fact that he didn't take refraction into account is part of what proves him and all his fans wrong.

He wouldn't need to at noon. Refraction from the atmosphere is highest in the evening when there is more atmosphere to go through (because of the angle).

Yes, we *can* measure the amount of reflection during the day and it is insignificant for what Eratosthenes did.

I don't agree to ignore refraction. Acknowledging reality is how my flat earth model works.
Since Eratosthenes did not take refraction into account, do you agree that his results were inaccurate?

The errors due to ignoring refraction are much smaller than those from simple measurement error bars in his case.

 

[Polymath257]

When he claimed the world looked like this?! There comes a time when you need to stop believing whatever your textbook says and start thinking for yourself. P.S. I think there is a rule against profanity on here somewhere...
View attachment 79948

Maps at the time were known to be inaccurate. This is a map, not a detailed description of what the Earth looked like.

Yes, Yes and Yes.

That changes with every passing breeze. As such, when it comes to my model, I document the observation of refraction, describe what I see, experiment with the refraction under different conditions and acknowledge that it is there without worrying about the exact numbers that constantly change.

And what is the largest value for the index of refraction you get? And when do you get it? Not at noon, I assure you.

Here's a good test of the index of refraction from a breeze: Look at something as the wind varies. Does it appear to shift position because of changes in the density of the air? No? Then refraction in the air is insignificant.

I'm not ignoring refraction, I just told you I acknowledge it is there!

But you don't acknowledge how small it is. In particular, is it large enough to affect Eratosthenes' results?

 

[Polymath257]

Zero is the opposite of acknowledging it as being there!

The index of refraction of air is 1.000293. it is the difference from 1 that is significant for how much light is refracted.

The index of refraction for water is 1.333. This changes the *amount* of refraction by a factor of about 1000.

 

[Polymath257]

No, it is not. Zero is a possible value for refraction. We can explain why it was at or very close to zero for Eratosthenes. I doubt if you can support it being different.

Be careful. The index of refraction is a ratio between the speed of light in a vacuum and the speed of light in the medium in question. For air it is very close to *1*, not 0. But it is the difference from 1 that is relevant for the amount of refraction.

 

[Polymath257]

Do you agree that a fish in a fish tank appears magnified due to refraction
and that this still happens at a 90 degree angle?
View attachment 80001 View attachment 80002

That is a misunderstanding. It is the refraction of the off-axis rays that makes the fish look closer, not the refraction of the perpendicular rays.

 

[Polymath257]

View attachment 80006
Note that the light from the fish is travelling from a much denser medium (water) to a less dense medium (air).
The light of the sun would have to travel from a near vacuum to slightly more dense air. I.e. it would appear even less big. (Though with angles of much less than 1° and the refraction index of air it is barely measurable, let alone visible.)

Ouch! This is not a good picture of what happens for refraction from water (or glass). The rays bend outward, not inward, if you go from water to air.

 

[Polymath257]

The astrophysicist Neil deGrasse Tyson directly said light going from the extreme vacuum of space into our atmosphere is going to refract like light going from air into water. Do you disagree with him?

No, I do not disagree. What is said is correct. But the refraction, while *like* that for water, it about 1/1000th that for water. It is the same basic physical process, but for air the amount of bending is less than .1% as much.

The aquarium example better demonstrates my flat earth model since it includes a dense firmament above our heads.
But either way, both my flat earth model and Neil Tyson's globe earth model currently acknowledge celestial refraction.

And how much refraction is there? Give specifics. In particular, we know that the index of refraction is determined by density. So, what is the density of the air?

My main point being just because something appears directly over our heads, that doesn't mean it isn't being refracted.

Well, it means that the amount of refraction is 0. Rays close to perpendicular are those that you should be interested in if you want to discuss magnification. But the amount of refraction for them is minimal.

Do you know Snell's law?

I see the double negative now, you don't disagree with him, which means you agree with him.
So we both agree that refraction still happens at a 90 degree angle above our heads.

No. The amount of bending of a light ray that enters a medium perpendicularly, is 0. For rays close to perpendicular, the angle is approximately multiplied by the index of refraction (which is very close to 1 for air). That means that for air, the amount of bending of the light is very, very small.

 

[Polymath257]

Certainly! But a fair amount of it is like shooting fish in barrel The hope is that at least some of the wrong arguments are worth exploring a bit. The anti-Einstein, one for instance, was not trivial.

Yes, his description of gravity as being equivalent to acceleration needs to be modified to apply only to *local frames*. As with most curvature effects, things fail on a more global scale.

 

[Polymath257]

Strawman.

I don't see how.

 

[Flat Earth Kyle]

He didn't prove the Earth is a globe.

You agree with the premise. Argument over.

 

[Flat Earth Kyle]

I don't see how.

He showed the flat earth existing in a heliocentric universe. That doe not reflect my geocentric model whatsoever.
Also I don't claim we live on a Mercator projection map, nor do I claim the earth is a floating rectangle flying through outer space.

 

[F1fan]

He showed the flat earth existing in a heliocentric universe. That doe not reflect my geocentric model whatsoever.
Also I don't claim we live on a Mercator projection map.

Except we live on a round planet.