Offline Science Supporter

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Size of the Flat Earth
« on: April 10, 2019, 02:31:21 AM »
It is commonly known that Eratosthenes was able to calculate the circumference of the spherical Earth by observing the Sun's rays during summer solstice. He made a slight error in his calculation of only 15%, which was very impressive for the technology they had 2300 years ago. Knowing this, he was also able to calculate the radius of the spherical earth. Knowing the radius, we can accurately calculate the mass of the Earth since we know that g=9.8m/s, and we know the distance between both objects. Which is r^2. (The equation is m=gr^2/G, which is derived from Newton's famous formula.)

For the flat earth, on the Wiki, it gives an estimate of the flat earth radius. I'm not sure if other flat earthers disagree with the mass too. Why haven't experiments been done to calculate the flat earth's radius, and possibly mass too? Am I not looking hard enough?
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Offline Tumeni

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Re: Size of the Flat Earth
« Reply #1 on: April 10, 2019, 11:41:51 AM »
Norwood and the French Geodesic Missions calculated the circumference in the 1600s and 1700s, here summarised by Bryson;

According to Newton’s theory, the centrifugal force of the Earth’s spin should result in a slight flattening at the poles and a bulging at the equator, which would make the planet slightly oblate. That meant that the length of a degree of meridian wouldn’t be the same in Italy as it was in Scotland. Specifically, the length would shorten as you moved away from the poles. This was not good news for those people whose measurements of the planet were based on the assumption that it was a perfect sphere, which was everyone.

For half a century people had been trying to work out the size of the Earth, mostly by making very exacting measurements. One of the first such attempts was by an English mathematician named Richard Norwood. As a young man Norwood had travelled to Bermuda with a diving bell modelled on Halley’s device, intending to make a fortune scooping pearls from the seabed. The scheme failed because there were no pearls and anyway Norwood’s bell didn’t work, but Norwood was not one to waste an experience. In the early seventeenth century Bermuda was well known among ships’ captains for being hard to locate. The problem was that the ocean was big, Bermuda small and the navigational tools for dealing with this disparity hopelessly inadequate. There wasn’t even yet an agreed length for a nautical mile. Over the breadth of an ocean the smallest miscalculations would become magnified so that ships often missed Bermuda-sized targets by dismayingly large margins. Norwood, whose first love was trigonometry and thus angles, decided to bring a little mathematical rigour to navigation, and to that end he determined to calculate the length of a degree.

Starting with his back against the Tower of London, Norwood spent two devoted years marching 208 miles north to York, repeatedly stretching and measuring a length of chain as he went, all the while making the most meticulous adjustments for the rise and fall of the land and the meanderings of the road. The final step was to measure the angle of the sun at York at the same time of day and on the same day of the year as he had made his first measurement in London. From this, he reasoned he could determine the length of one degree of the Earth’s meridian and thus calculate the distance around the whole. It was an almost ludicrously ambitious undertaking—a mistake of the slightest fraction of a degree would throw the whole thing out by miles—but in fact, as Norwood proudly declaimed, he was accurate to “within a scantling”—or, more precisely, to within about six hundred yards. In metric terms, his figure worked out at 110.72 kilometres per degree of arc.


Points to note;

The method used would make no sense on a Flat Earth. Where do you draw the angle of arc?

Separate observations, in differing parts of the world, by different teams, return the same result


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Not Flat. Happy to prove this, if you ask me.
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Nearly all flat earthers agree the earth is not a globe.

Nearly?

Offline jimster

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Re: Size of the Flat Earth
« Reply #2 on: April 11, 2019, 12:46:22 AM »
Before you get too excited about your RE proof, let me list some reasons why your proof doesn't work.

There are many models, so it could be several things
Their calculations might be wrong
How do you know the people in other parts of the world weren't lying
Maybe degrees have a different length in different parts of the world but they measured wrong
Were you there? The entire story could be made up, all the numbers could be lies

There are many ways this could be wrong, so one can still believe FE with so much possibility of dismissal of your idea.

I agree with you, but I expect you will not get an FE to answer and I didn't want you to be disappointed.

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Offline QED

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Re: Size of the Flat Earth
« Reply #3 on: April 11, 2019, 01:19:04 AM »
Before you get too excited about your RE proof, let me list some reasons why your proof doesn't work.

There are many models, so it could be several things
Their calculations might be wrong
How do you know the people in other parts of the world weren't lying
Maybe degrees have a different length in different parts of the world but they measured wrong
Were you there? The entire story could be made up, all the numbers could be lies

There are many ways this could be wrong, so one can still believe FE with so much possibility of dismissal of your idea.

I agree with you, but I expect you will not get an FE to answer and I didn't want you to be disappointed.

The moment when you apply the same standard of skepticism and valuation to the FE wiki, will be the moment when your words gain an incredible power.
The fact.that it's an old equation without good.demonstration of the underlying mechamism behind it makes.it more invalid, not more valid!

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Offline Science Supporter

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Re: Size of the Flat Earth
« Reply #4 on: April 11, 2019, 02:13:43 AM »
There are many models, so it could be several things
This is not about flat earth. This is a proof for a globe earth.
Their calculations might be wrong
They were, with an error of 15%. I said that in my original post. But the fact that they got a somewhat accurate calculation for the technology they had 2300 years ago is impressive.
How do you know the people in other parts of the world weren't lying
That makes no sense. At the time, they didn't know much about the world. So if they found the circumference of earth, this would be a remarkable discovery. Also, he did this by himself.
Maybe degrees have a different length in different parts of the world but they measured wrong
No, he hypothesized that Syene (a city where he did his observations in) was 7 degrees, 14 arcseconds from Alexandria (the other city) on a curved surface. That's around 50 times smaller than a circle, so he multiplied the distance from both cities by 50 to get the circumference of a circle.
Were you there? The entire story could be made up, all the numbers could be lies
"All the numbers can be lies", yet out of a wild guess he got the circumference of Earth with an accuracy of 85%?
There are many ways this could be wrong, so one can still believe FE with so much possibility of dismissal of your idea.
Really?! Can you please explain why?

"We are not here to directly persuade anyone [...] You mistake our lack of interest in you for our absence."
-Pete Svarrior

"We are extremely popular and the entire world wants to talk to us. We have better things to do with our lives than have in depth discussions with every single curious person. You are lucky to get one sentence dismissals from us"
-Tom Bishop

Offline jimster

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Re: Size of the Flat Earth
« Reply #5 on: April 11, 2019, 05:21:27 AM »
I removed your responses and futher clarified why your disproof did not succeed by FE rules. The basic idea is to come up with an explanation for everything, however implausible. Confronting this with RE/regular world expectations made me angry, possibly you if you got blindsided by it. Dorothy, you're not in Kansas any more.

If you think you can patiently educate and lead them through steps to "the world must be round", I and many others have tried. They. Will. Not. Do. That. In fact, they usually don't answer RE posts like yours. They already did, it's in the wiki, etc. If you find the explanation in the wiki flawed, explanations of that: it's not done, it's just one model (some other model may work), it needs work. Generally they seem impatient about convincing you, they want to spend their time explaining to the credulous. or chatting among themselves to develop more FE models. Often, after some brief explanation that you will find unsatisfying, and referal to the wiki, they become exasperated and say they explained it already and leave in a huff.

Here are mine that don't get answered: sextant/latitude/north star, equatorial mount, amsat (amateur radio ioperators build their own repreater satellites and get them launched, multiple proof points), doppler red shift from stars, spacex, maps, amateur radio (multiple proof points, satellites, beam antenna aiming angles, moonbounce), etc etc etc. And good luck getting them to explain how equatorial mount and north star/latitude/sextants work on FE or RE. I had one who was skeptical that the north star angle always equals latitude.

The key thing that most REs find ludicrous is the space conspiracy - all countries space agencies, all astronauts, maybe all astronmers (no way to tell how many are phds cynical liars and how many have been successfully brainwahsed or intimidated. You do have to admit that an astronomer saying the earth is flat may have career consequences.

Here's a fun one: the sun on FE, while actually always above us, seems to be on the horizon vecause of vaniching point and perspective. Good luck explaining what those really mean, but once they knew the phrase "vanishing point", just gotta use that to explain where the sun goes at night, it vanishes!

There are many models, so it could be several things
There might be a flat earth model you don't know about that could explain your observations. You can't prove there is no FE model that explains it. Bear in mind that FE models can have changes to the laws of physics or as yet unobserved features that do things like make comets appear to be somewhere other than they are. A quick example, perhaps silly even for FE, but suppose the dome had a bunch of "wormholes", where things like comets go into the dome and pop out somewhere else after a delay. Since that could all be, you haven't disproved FE.
Their calculations might be wrong
They might have wrongly measured the distance or done the math wrong. There could be a particularly difficult calculation that people are prone to make the exact same error and they all made it. So again, if there is a way to imagine an explanation, you have not disproved FE.
How do you know the people in other parts of the world weren't lying
According to FEs, there is huge money and power in knowing FE but fooling everyone else. Explanations of this are generally vague. Almost all FEs believe NASA is a giant conspiracy created to fool us and kill leakers. It is FE easy to say there could be a conspiracy to hide all things RE, Perhaps NASA knew about the experiment and sent thugs to bribe/threaten them to lie that RE is true. Again, there is a possible way your proof is invalid, so FE lives.
Maybe degrees have a different length in different parts of the world but they measured wrong
You have no way of knowing how long a degree is. You haven't been everywhere. You can't be sure your measuring tool worked, or even that it doesn't work differently. I recently read an FE post that said the only way to know the size of the moon is to go there with a ruler.
Were you there? The entire story could be made up, all the numbers could be lies
85%, that's not 100%. You need 100% for proof.
There are many ways this could be wrong, so one can still believe FE with so much possibility of dismissal of your idea.
Really?! Can you please explain why?

Because they have seen many many many FE videos, each showing them a problem with RE. And I think for various reasons they want FE to be true, mostly 3:

1. they get pleasure from conspiracy
2. they don't want to feel like they are living on a rock spinning wildly every which way, an accident of evolution in some obscure corner of a vast mess. They want to be in a simple place at the center of everything befitting their central place in existence
3. they think the Bible says the earth is flat

Given they have holes in RE, reason to like FE, and you can't prove the earth is flat, carry on with chatting with other FEs in endless speculation of how the world is flat.

And by the way, understand, FE doesn't mean flat necessarily, there are toroid and inverted and dished and bulged, all trying to solve the probems with flat. They have multiple models, you know, if one is wrong, another might be right. FE means not round. The only shape, for whatever reason. they reject. I think thast is more about rejecting the consensus rather than the shape.

I hope I saved you time and aggravation. The challenge of disproving FE is little or nothing outside the FE world. Inside FE, it is impossible to disprove FE on their terms, and they set the terms.

Offline jimster

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Re: Size of the Flat Earth
« Reply #6 on: April 11, 2019, 05:24:08 AM »
Go to "why can't I see the sun at night" and you will see examples of  exactly what I said.