Please provide your evidence.
I apologise for the length, but you wanted evidence!
There is not much disagreement about the distance from the equator to the north pole being close to 10,000 km.
- That is how Napoleon defined the metre.
- The Wiki says so!
Latitude
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Knowing that as you recede North or South from the equator at equinox, the sun will descend at a pace of one degree per 69.5 miles, we can even derive our distance from the equator based upon the position of the sun in the sky.
Since there are 90° of latitude from the equator to the north pole, the distance must be 90 x 69.5 = 6,250 miles or 10,058 km, close enough for this application. Mind you Napoleon was closer!
The equatorial circumference is where there may be a dispute. The accepted (globe) distance is 40,075 km.
A value very close to this this has been accepted for over 1,000 years. Of the medieval Persian Abu Rayhan al-Biruni (973–1048) it is said:
Al-Biruni
Important contributions to geodesy and geography were also made by Biruni. He introduced techniques to measure the earth and distances on it using triangulation. He found the radius of the earth to be 6339.6 km.
This gives an equatorial circumference of 39,833 km - not far from the current 40,075 km. Note that his methods were some of the earliest examples of Geodetic-Surveying. Al-Biruni is regarded as "the father of Geodetic-Surveying".
I doubt that FE supporters will accept even this evidence, so I have calculated my estimate of the circumference from a couple days travel, on mainly west to east journeys on an "almost round the block trip". Of course the road (even across the Nullabor) is not quite straight. So I actually used the Garmin GPS Map for the distance. Just in case that naughty NASA has been tricking us with the GPS readings I compared used the car's odometer with the map and GPS (the Landcruiser Prado odometer is almost exact). From the point-to-point distances I worked the west-east component of distance, the longitude difference and the average latitude of each of two journeys. From these figures I can calculate the km/degree at the latitude of that journey and hence the (circumference at that latitude) = 360 x (km/degree).
If these figures are accepted, we now have to work out what the equatorial circumference. On the globe that is easy (at least to a good appoximation), where the (equatorial circumference) = (circumference at that latitude)/cos(latitude).
But, for the flat earth we have the problem that no-one seems certain of the accepted map! I will take it as the map on the right on which we should be able to calculate the (equatorial circumference) = (circumference at that latitude)*90/(90-latitude), since on this map the meridians of longitude are straight lines radiating from the north pole.
| The most widely accepted map model of a flat earth. |
I was going to put the detail of calculations in, but it got too large! In summary:
Origin and Destination | "Long Diff" | "at Lat" | "km/deg" | "Circ at Lat" | "Circ at Equ Globe" | "Circ at Equ Flat" |
Balladonia (Western Australia) to Eucla (Western Australia) | 5.264° | -32.01° | 94.5 | 34,021 km | 40,123 km | 31,302 km |
Eucla(Western Australia) to Penong(South Australia) | 4.125° | -31.80° | 94.7 | 34,087 km | 40,108 km | 32,055 km |
The circumference at the equator for the globe reasonably quite well with the "accepted value" of 40,075 km.
The value, however, for the flat earth does not help the flat earth case at all. It is simply based on measured distances, scaled by the ratio of the radiating meridian spacing.
It should be stressed here that the actual distances used were from a (GPS) map, but they were checked against driving distances between the same locations. The driving distances did come out a little larger (eg for the first case 532 km on road, 503 km direct).
It would be good if others could do similar measurements at other locations. We have quite a few long E-W roads, but I imagine USA has similar of better in Texas, Arizona of Nevada.
In summary I contend that the Equator to North Pole is indeed
close to 10,000 km and
the Equatorial Circumference is indeed
close to 40,000 km.
Now, if anyone disagrees, please present your evidence!