The Flat Earth society

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Mike, I have to ask again, do you actually believe the earth could be flat?

If so, I think the chemtrail exposure has been too much for you. :D
 
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Not quite. Eratosthenes assumed the earth was round, and so calculated its diameter. The shadow difference showed that the sun appeared at a different angle at the two cities. A flat earth and a nearby sun would give the same effect.

But if a person in a third location did the same experiment, it would how the earth to be round.
 
In actual point of fact they are well over the horizon. Again you have to understand that light can and does follow the curvature of the Earth as the atmosphere refracts the light. HOWEVER all common experiences your entire life have taught your brain that light travels in a straight line, i.e., when you see something in front of you and you reach out, there it is exactly where you saw it. Again think of a mirror, you know absolutely that there is nothing behind the mirror yet your brain is totally convinced that there is something there. When light enters the eye our brain interprets this as coming from straight ahead and is coming from a real object. Think of a movie. There is NOTHING ON THE SCREEN the light rays are coming from behind you and bouncing off the screen YET your brain receiving light rays from straight ahead "sees" a image on the screen in front of you.
Hot, less dense air will refract upwards thus you "see" blue puddles of water on the road ahead of you. Cool dense air refracts downward and when the refracted angle exceeds the critical angle we get total internal refraction (like in an optical cable). You can "see" well beyond the curvature of the Earth but your brain insists that the rays reaching your eyes came from STRAIGHT ahead.
NO ONE "SEES" anything we PERCEIVE the world.

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Whatever.

Optical effects can only allow you to see so far, as there are limits to how much refraction there is.

Very large objects, like mountains, can obviously be seen much farther than a boat on the water.

You could argue that on a flat earth there would be less refraction effects, because you would not be looking through layers of the atmosphere. This would allow you to see much further, assuming you had a big enough lens/telescope to zoom into the object.
 
But if a person in a third location did the same experiment, it would how the earth to be round.
No, again, a flat earth and a nearby Sun would give the same effect. It's only if you assume a very distant light source (i.e. the Sun) that a curved surface becomes necessary. If you were to start instead from the assumption that the earth is flat, then the same experimental result, instead of yielding an Earth of radius 6400 km, you give a solar distance of 6400 km.

The point is, that Eratosthenes' experiment let him determine that distance; it wasn't a proof that the Earth is round. The a priori assumption that the Earth is round and the Sun is very distant let him calculate the size of the Earth. Leaving aside the validity of assuming the Earth is flat, if instead he had taken a flat Earth as his a priori, then nothing in his experimental result invalidated that assumption.
 
Whatever.

Optical effects can only allow you to see so far, as there are limits to how much refraction there is.

Very large objects, like mountains, can obviously be seen much farther than a boat on the water.

You could argue that on a flat earth there would be less refraction effects, because you would not be looking through layers of the atmosphere. This would allow you to see much further, assuming you had a big enough lens/telescope to zoom into the object.

Flat or round makes no difference, the refracted ray travels within the layer of air next to the surface

Air is not a perfectly transparent medium being composed of molecules, atoms, and dust. As to refraction again it depends on the medium doing the refracting, with air refraction the temperature and air quality define the limits.
In ultra pure fiber optic cables which utilize total internal reflection the Guinness World record book gives the longest un-regenerated terrestrial fiber optic link is 10,358.16 km (6,436.26 mi) and was achieved by Telstra Corporation (Australia) with their link between Perth and Melbourne, Australia, as verified on 13 February 2015. The signal was successfully transmitted the entire distance between Melbourne and Perth and back again without any regeneration.
Back to air, looking at lines-of-sight a number of factors come into play: For a 6 foot tall person the horizon is about three miles away sans refraction. From the top of Mt. Everest in cold clear air, one can see mountains that are 211 miles (340 Km) distant. Now consider observer height, target height, temperature, air quality, refraction, and nothing to block your sightline. We have the sightline from Mt Dankova in Kyrgyzstan to Hindu Tagh in China a distance of 334 miles (538 km) This is theoretical as no photographs exist but the longest photographed sightline is from Pic de Finestrelles in Spain to Pic de Gaspard in the French Alps a distance of 275 miles (443 km)
 
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No, again, a flat earth and a nearby Sun would give the same effect. It's only if you assume a very distant light source (i.e. the Sun) that a curved surface becomes necessary. If you were to start instead from the assumption that the earth is flat, then the same experimental result, instead of yielding an Earth of radius 6400 km, you give a solar distance of 6400 km.

Two observations could work on a flat earth, from which the altitude of the sun could be calculated.

With a third observation, from a different latitude, the sun's altitude would not match that calculated from the first two points.

Here the experiment was done with people all around the world by a YouTube channel.


"These are the results of a group project which took place during the September Equinox 2017. 23 participants in 9 different countries conducted a simple scientific experiment similar to that of Eratosthenes over 2000 years ago. The test is simple. Using the Latitude of each participant (as Longitude will be either 180° or 0°) The sun's elevation angle was measured during Solar Noon. These angles were then placed across both a Flat Plane and a Sphere to see which model the angles correspond to. "
 
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Flat or round makes no difference, the refracted ray travels within the layer of air next to the surface

Refraction depends on a change in the density of the medium, so if you are looking flat and level through air that is of consistent density you won't observe refraction.


Air is not a perfectly transparent medium being composed of molecules, atoms, and dust. As to refraction again it depends on the medium doing the refracting, with air refraction the temperature and air quality define the limits.

Refraction occurs when the medium changes density. In air there is a gradient from the surface which cause teh refraction. If the air is consistent, there is no refraction.


In ultra pure fiber optic cables which utilize total internal refraction REFLECTION the Guinness World record book gives the longest un-regenerated terrestrial fiber optic link is 10,358.16 km (6,436.26 mi) and was achieved by Telstra Corporation (Australia) with their link between Perth and Melbourne, Australia, as verified on 13 February 2015. The signal was successfully transmitted the entire distance between Melbourne and Perth and back again without any regeneration.

Fibre optic cables are of consistent density, and so there is no internal refraction. Fibre Optics work by reflecting off the walls of the cable.

Refraction
the fact or phenomenon of light, radio waves, etc. being deflected in passing obliquely through the interface between one medium and another or through a medium of varying density.


Back to air, looking at lines-of-sight a number of factors come into play: For a 6 foot tall person the horizon is about three miles away sans refraction. From the top of Mt. Everest in cold clear air, one can see mountains that are 211 miles (340 Km) distant. Now consider observer height, target height, temperature, air quality, refraction, and nothing to block your sightline. We have the sightline from Mt Dankova in Kyrgyzstan to Hindu Tagh in China a distance of 334 miles (538 km) This is theoretical as no photographs exist but the longest photographed sightline is from Pic de Finestrelles in Spain to Pic de Gaspard in the French Alps a distance of 275 miles (443 km)

Mountains can be seen farther away because they are big.

Observing a long distance from Mt. Everest is very much helped by being 8km above MSL, and that the unrefracted line of site is much farther.

Same with those other observations.

The longest photographed sightline was done at a time with rare atmospheric conditions. The vast majority of the time you would not be able to see that far. On a flat earth that observation would surely be more common.
 
Two observations could work on a flat earth, from which the altitude of the sun could be calculated.

With a third observation, from a different latitude, the sun's altitude would not match that calculated from the first two points.
Only if the subtended angle (either to the centre of the Earth, or to the Sun for a flat Earth) is large. For 'small' angles, where a = sin(a) = tan(a) more or less, and for a shadow size much smaller than the result, the result would be the same. From memory, the subtended angle in the Eratosthenes calculation was 7 degrees, which definitely counts as small (0.122 radians, sin(7)=0.122, tan(7)=0.123), and the stick used to create the shadow was much smaller than the radius of the Earth.
 
Yes, 1/50 of a full circle = 7.2°, from the vertical.

So, if the three test sites were close together they may match, within a margin of error. But if the sites are farther apart, they won't.

Small separations in the test sites make for larger errors.

I post this video again, just in case you missed it earlier, to show the experiment done with multiple people in the Northern Hemisphere and a couple in the Southern Hemisphere.

 
Refraction depends on a change in the density of the medium, so if you are looking flat and level through air that is of consistent density you won't observe refraction.
Indeed, but read my statement again. As the ray travels upward the air is changing density and temperature so it is continually bent toward the Earth. Perhaps I should have said "LAYERS"

Refraction occurs when the medium changes density. In air there is a gradient from the surface which cause teh refraction. If the air is consistent, there is no refraction.
Indeed, again re-read my statement I said temperature cold air is denser than warm hence the density increases. By air quality I was referring to particulate matter which would tend to block light rays. However even perfectly pure air is not totally transparent as molecules and atoms are still present

Fibre Optics work by reflecting off the walls of the cable.
You are totally correct here I did indeed use an incorrect term. As the incoming ray's Angle of Incidence changes it approaches and eventually equals the Critical Angle for that material. With the incoming ray AT the Critical Angle the ray is REFRACTED at 90 degrees to the Normal. Exceeding the Critical Angle causes the ray to re-enter the medium and the terminology changes to the Ray being REFLECTED rather than refracted.
Returning to my statement on LOOMING I also made the same terminology error terming it Total Internal REFRACTION when once again I should have termed it REFLECTION. The rest of my statement is correct. The actual ship is well over the curve of the Earth but rays from the ship traveling upward from cold dense air to warmer, higher, less dense air are initially refracted until the refraction exceeds the Critical Angle at which point the ray is Totally Internally REFLECTED within that layer. The air layer is acting like a fiber optic cable

Mountains can be seen farther away because they are big.
Very true BUT the curve of the earth hides more and more of the mountain as distance increases. Pic Finestrelles is 2820 m and Pic Gaspard is 3883 m.
From a height of 2820 m the horizon is 190 km distant and from 3883 m the horizon is 223 km. 190 km + 223 km = 413 km. Now recall that the two peaks are 443 km distant from each other. Continuing Pic Finestrelles UN-REFRACTED line of sight over the Earth bulge puts the line 5.04 km above the ground at 443 km. BOTH calculations show that WITHOUT REFRACTION Pic Gaspard would NOT be visable from Pic Finestrelles.
The photographer himself stated:
To his left, other peaks of the Alps also were to be seen. Refractive favorable circumstances allowed to view some other peaks, even that more distant than the Barre des Ecrins. Pic Gaspard, 443 Km, is what has given us this time the brand new a new world record distance of photograph landscapes of our planet.

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From memory, the subtended angle in the Eratosthenes calculation was 7 degrees,

Actually a bit more 7.2 degrees. Using JUST the two measurements: D / H = tan(7.2) H = D / tan(7.2) H = 5000 stadia (800 km) / 0.126 H = 6330 km to the sun.

Eratosthenes measurement did NOT prove the roundness of the Earth. He made two assumptions, i.e. That the Earth was ROUND and That the sun was at a large distance so all incomming rays were parallel to each other
 
Actually a bit more 7.2 degrees. Using JUST the two measurements: D / H = tan(7.2) H = D / tan(7.2) H = 5000 stadia (800 km) / 0.126 H = 6330 km to the sun.

Eratosthenes measurement did NOT prove the roundness of the Earth. He made two assumptions, i.e. That the Earth was ROUND and That the sun was at a large distance so all incomming rays were parallel to each other

No, Eratosthenes did not try to prove the Earth was round, that theory had already been accepted by scholars in Greece at that time.

He set out to measure the circumference of the Earth.
 
It was only a circumference IF the Earth was indeed round as he ASSUMED. It could juat as easily been a diameter he determined.
 
It was only a circumference IF the Earth was indeed round as he ASSUMED. It could juat as easily been a diameter he determined.

No, he was trying to measure the circumference.

It is possible that he measured the circumference of a flat earth, but only if that circumference was in the plane of Alexandria and Syene.
 
It is possible that he measured the circumference of a flat earth,

Nope on a flat Earth it would have been a diameter. To measure a circumference he would have had to travel around the edge.
Eratosthenes had simply assumed that the earth was a sphere in his experiment, based on the work of Aristotle. He could just as easily been measuring the diameter of a flat earth, which is a figure identical to the circumference of the round earth

.Syene and Alexandria are two North-South points with a distance of 500 nautical miles. Eratosthenes discovered through the shadow experiment that while the sun was exactly overhead of one city, it was 7°12' south of zenith at the other city.

eratosthenes.gif

7°12' makes a sweep of 1/25th of the FE's total longitude from 90°N to 90°S (radius).

Therefore we can take the distance of 500 nautical miles, multiply by 25, and find that the radius of the flat earth is about 12,250 nautical miles. Doubling that figure for the diameter we get a figure of 25,000 miles.
 

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