The Flat Earth Society

Flat Earth Discussion Boards => Flat Earth Investigations => Topic started by: Bishthebosh on March 14, 2019, 05:21:48 PM

Title: Round Earth proof - comments?
Post by: Bishthebosh on March 14, 2019, 05:21:48 PM
I just watched a beautifully simple experiment on YouTube the link to which is here:

https://youtu.be/YaPa4esJJx4

Any thoughts from FEers?

Warm regards.
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 14, 2019, 06:57:45 PM
Why would the shadows be the same length on a flat earth?

The guy uses highway 33 in Canada.
Quote from: https://leaderpost.com/news/local-news/scientist-pedalling-140km-from-regina-to-prove-the-earth-is-round
Baute will cycle approximately 140km along Highway 33 from Regina to Stoughton

That road isn't north south.
https://www.google.com/maps/place/SK-33,+Saskatchewan,+Canada/@50.0646593,-104.3574711,9z/data=!4m8!1m2!2m1!1scanada+highway+33!3m4!1s0x531e59aad00d09e5:0xb3b578691b9eb1d5!8m2!3d50.0642098!4d-103.7971402

So it is a different local time of day at the two ends of the road. Would you expect a shadow at midday to be the same length as one at sunset?

At least when Eratosthenes did the experiment he took the LOCAL noon time for each location, not at the same generic time of day.
Quote from: https://en.wikipedia.org/wiki/Eratosthenes
He knew that at local noon on the summer solstice in Syene (modern Aswan, Egypt), the Sun was directly overhead.

In the video at 6:23 you can see them counting down to take the exact same real time ... not the same local time.

And you will note from the map that Syene and Alexandria are roughly North South, certainly not 45 degrees off like this guy. (Eratosthenes's done his best being as he has to use the Nile ... travelling the Sahara back then was pretty dangerous and difficult.)
(https://www.researchgate.net/profile/Alok_Kumar23/publication/253596660/figure/fig2/AS:334437452664834@1456747510980/A-map-of-Egypt-The-ancient-city-of-Syene-is-today-known-as-Aswan-Taken-from.png)

This guy doesn't understand the geometry or Eratosthenes experiment. He's just an idiot in cycling shorts. He has proved nothing.
Title: Re: Round Earth proof - comments?
Post by: WellRoundedIndividual on March 14, 2019, 07:15:31 PM
Has anyone taken a look at the data on this website?

http://www.eratosthenes.eu/spip/
Title: Re: Round Earth proof - comments?
Post by: Bishthebosh on March 15, 2019, 11:49:11 AM
Why would the shadows be the same length on a flat earth?

The guy uses highway 33 in Canada.
Quote from: https://leaderpost.com/news/local-news/scientist-pedalling-140km-from-regina-to-prove-the-earth-is-round
Baute will cycle approximately 140km along Highway 33 from Regina to Stoughton

That road isn't north south.
https://www.google.com/maps/place/SK-33,+Saskatchewan,+Canada/@50.0646593,-104.3574711,9z/data=!4m8!1m2!2m1!1scanada+highway+33!3m4!1s0x531e59aad00d09e5:0xb3b578691b9eb1d5!8m2!3d50.0642098!4d-103.7971402

So it is a different local time of day at the two ends of the road. Would you expect a shadow at midday to be the same length as one at sunset?

At least when Eratosthenes did the experiment he took the LOCAL noon time for each location, not at the same generic time of day.
Quote from: https://en.wikipedia.org/wiki/Eratosthenes
He knew that at local noon on the summer solstice in Syene (modern Aswan, Egypt), the Sun was directly overhead.

In the video at 6:23 you can see them counting down to take the exact same real time ... not the same local time.

And you will note from the map that Syene and Alexandria are roughly North South, certainly not 45 degrees off like this guy. (Eratosthenes's done his best being as he has to use the Nile ... travelling the Sahara back then was pretty dangerous and difficult.)
(https://www.researchgate.net/profile/Alok_Kumar23/publication/253596660/figure/fig2/AS:334437452664834@1456747510980/A-map-of-Egypt-The-ancient-city-of-Syene-is-today-known-as-Aswan-Taken-from.png)

This guy doesn't understand the geometry or Eratosthenes experiment. He's just an idiot in cycling shorts. He has proved nothing.

Where are you getting that they are in different time zones? Both are CST.

Also, as long as both sundials are equally oriented (which they easily achieve through the use of compasses and spirit levels) the cardinal direction between the locations is irrelevant - one location still North of the other. You can see on the compass that both sundials are oriented to face North.

Of course the shadows would be the same length on a flat Earth! That is, unless the sun is very very close to the Earth, which it cannot be - there is so much easily observable evidence that the sun is very very very very far away!

Warm regards

(Modified to clarify orientation of sundials)
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 16, 2019, 12:52:47 AM
No, they are in different longitudes ... not time zones. So the LOCAL MEAN TIME (https://www.dictionary.com/browse/local-mean-time) ... ie time determined by position of the sun will be different. Not the exact same. Hence flaw in his calcs.

We are using shadows. We want solar time, not an arbitrarily geographical time zone time.
Title: Re: Round Earth proof - comments?
Post by: stack on March 16, 2019, 01:26:26 AM
No, they are in different longitudes ... not time zones. So the LOCAL MEAN TIME (https://www.dictionary.com/browse/local-mean-time) ... ie time determined by position of the sun will be different. Not the exact same. Hence flaw in his calcs.

We are using shadows. We want solar time, not an arbitrarily geographical time zone time.

According to time and date, Solar Noon today in:

Regina: 1:07
Stoughton: 1:01

So we're looking at a 6 minute difference between the two. The question is, what bearing the 6 minute difference has on the shadow measurements. I don't know. But worth thinking about.

In the vid, at the non-solar time, but same "watch" time, Regina shadow is at 70cm and Stoughton, eastward, is at 66.1cm. Does this make a difference with the solar time? If given another 6 minutes, would Stoughton be at 66.1 like Regina? And does that matter?

I'm trying to work through all of the permutations and I don't know.

Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 16, 2019, 02:58:41 AM
Well 6 minutes is 1.5 degrees of longitude.

And the sun has moved 110km west in that time.

If we know the height of the sticks, the day, work out how far the top of the stick is from the ground ... its a whole lot of maths we might be able to find the answer. But my answer is short. This experiment was botched. Not waiting those 6 minutes screws up the results. Of course shadows get longer and shorter over the course of 6 minutes.
Title: Re: Round Earth proof - comments?
Post by: stack on March 16, 2019, 03:14:17 AM
I kinda think if he had recorded solar time for each location, 6 minutes apart, they would both have been at 66.1 cm shadows. Or at least really close together. If that assumption true, maybe I'm missing something, but I'm not finding the experiment worthy.

What am I missing peoples?
Title: Re: Round Earth proof - comments?
Post by: Balls Dingo on March 16, 2019, 05:21:35 AM
I kinda think if he had recorded solar time for each location, 6 minutes apart, they would both have been at 66.1 cm shadows. Or at least really close together. If that assumption true, maybe I'm missing something, but I'm not finding the experiment worthy.

What am I missing peoples?

Maybe close together but it wouldn't be the same. The simpler experiment is to measure the elevation at solar noon in both of those places. One location is 50.4586825° latitude, the other is 49.6772586°. Difference in kms between those latitudes is 86.89km. If he'd used more precise equipment to measure the elevation at that solar noon at both locations, he should have measured 61.09° at 12:55pm at Regina and 61.87° at 12:49 at Stoughton on 28th May, 2018 (I've reverse engineered to find the most likely day he used from the information in the video but it's not really relevant).

https://www.suncalc.org/#/50.4586,-104.6351,12/2018.05.28/12:55/1/3
https://www.suncalc.org/#/49.6794,-103.0261,16/2018.05.28/12:49/1/3

Based on those values, circumference of the Earth would be 86.89 * (360 / (61.87 - 61.09)) = 40103kms. Very close to accepted value of 40075km.

Or using his measuring device arranged North-South, should have given shadow lengths of 55cm and 53cm, so elevation of 61.19° and 62.08°, and a circumference of 35147kms.

Edit: OK, now that I'm thinking about this, this is a really good experiment after all. Differences in solar noon or differences in latitude and longitude are not relevant to this experiment. The time of 11:15am when he takes the measurement is significant - the shadow has hit both sundial bases which are arranged at the same azimuth at the same time. If you drew a line through both bases, it will go directly to the sun. The shadow should run down the middle of both bases at the moment of measurement. So he can take a relevant shadow measurement at that time and he can use his cycled distance of 138km.
Title: Re: Round Earth proof - comments?
Post by: Bishthebosh on March 16, 2019, 10:01:27 AM
Well 6 minutes is 1.5 degrees of longitude.

And the sun has moved 110km west in that time.

If we know the height of the sticks, the day, work out how far the top of the stick is from the ground ... its a whole lot of maths we might be able to find the answer. But my answer is short. This experiment was botched. Not waiting those 6 minutes screws up the results. Of course shadows get longer and shorter over the course of 6 minutes.

I really can’t figure out your thinking here. The measurement needs to be taken at the same time. If he waited 6 minutes, that would utterly defeat the whole point of the experiment! The shadow length of the second sundial would catch up with the first cancelling out the effect of curvature!

Warm regards
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 16, 2019, 11:53:00 AM
Well 6 minutes is 1.5 degrees of longitude.

And the sun has moved 110km west in that time.

If we know the height of the sticks, the day, work out how far the top of the stick is from the ground ... its a whole lot of maths we might be able to find the answer. But my answer is short. This experiment was botched. Not waiting those 6 minutes screws up the results. Of course shadows get longer and shorter over the course of 6 minutes.

I really can’t figure out your thinking here. The measurement needs to be taken at the same time. If he waited 6 minutes, that would utterly defeat the whole point of the experiment! The shadow length of the second sundial would catch up with the first cancelling out the effect of curvature!

Warm regards
No.

We have too many variables. The sun isn't in the same place regarding the two sticks and the longitude and latitude differ. We have 3 unknowns.

But, if you take two places that are hundreds of miles different NORTH-SOUTH ... but the same longitude and local mean time, now you only have one variable ... latitude. Now you can isolate the shadow length to say the only thing different here is that latitude and you assume the sun to be infinitely far away ... any difference is due to curvature.

I mean FErs will still blow this objection away because we don't think the sun is infinitely far away. But Erastothingy wasn't interested in proving earth round. He already ASSUMED it was and was trying to get a sense of how big the earth was. His experiment is to find the circumference of earth ASSUMING it is round and ASSUMING the sun is infinitely far away. Why round earthers keep suggesting this proves earth round, I have no idea. The experiment was never designed to do that.

But as for the OPs video ... a total waste of time as far as science goes.
Title: Re: Round Earth proof - comments?
Post by: Balls Dingo on March 16, 2019, 01:11:30 PM
Why round earthers keep suggesting this proves earth round, I have no idea.

You don't understand the experiment then. Latitude and longitude are not variables in this experiment. The experiment only works if the bases of the sundials are aligned on the same azimuth. If the shadow runs down the middle of the bases at exactly the same time, then you know that you can draw a line through the sundials and it will point in the direction of the sun. That also means that you can draw a diagram of the experiment from the side with the 1m sundial poles, the shadow lengths, and a distance of 138km between the sundials. You can draw a line from the shadow tips through the tips of the poles and into the sky. Latitude and longitude are not relevant when the experiment is designed this way. You can actually work out the height of the sun on a flat Earth with this experiment. Do you get it yet or do you need a diagram?

So with this experiment you can do two things: if the sun is considered to be far away and it's rays are parallel, you can work out the circumference of the Earth. If you don't consider this, you can do the experiment in other locations and if the height of the sun doesn't match - which it won't - you will know that the Earth is not flat.
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 16, 2019, 01:23:53 PM
Nope. You are wrong. Come on then Mr 33 posts. School me with a diagram.  ::)
Title: Re: Round Earth proof - comments?
Post by: Balls Dingo on March 17, 2019, 01:46:05 AM
Nope. You are wrong. Come on then Mr 33 posts. School me with a diagram.  ::)

OK, let's look at a flat Earth first. The road is at 127° azimuth. So on a flat Earth, I should be able to put the two sundials parallel to the road at the same distance to the road, and when the shadow goes exactly down the middle of the base of one (for example on 1st May, 2018 at 10:30am), it should go down the middle of the base of the other. And at that time, we should be able to get the length of the shadows and thus the elevation.

If the shadow doesn't go down the middle of the base of the second sundial, then FE theory must have some explanation for light bending horizontally. In other words, it must explain why if I'm looking directly at the sun at that time, the atmosphere to the left of the sun has a higher refractive index than the atmosphere to the right of the sun (if bending to the South in my diagram). Assuming this is observed consistently day after day in all seasons and weather conditions, this would be very problematic.

What do you think will be observed and if the shadow doesn't go down the middle of the base of the second sundial, what is your explanation?

(https://i.imgur.com/DGvvkDU.gif)

Edit: Ha! I just realised I made a mistake and drew the experiment the way it would be at a location where I am in the Southern Hemisphere. You'll have to spin the sundials 180° for a Northern Hemisphere experiment. Same logic applies on a flat Earth though for the shadows on the sundials lining up.
Title: Re: Round Earth proof - comments?
Post by: Tumeni on March 17, 2019, 08:58:43 AM
Well 6 minutes is 1.5 degrees of longitude.

1.5 degrees is an angle, isn't it?

Angles are defined by two lines which meet at a point, and the angle is the displacement (?) between the lines at that point.

Indulge us with a diagram of what 1.5 degrees of longitude looks like on a Flat Earth. School us.
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 19, 2019, 05:21:13 PM
Nope. You are wrong. Come on then Mr 33 posts. School me with a diagram.  ::)

OK, let's look at a flat Earth first. The road is at 127° azimuth. So on a flat Earth, I should be able to put the two sundials parallel to the road at the same distance to the road, and when the shadow goes exactly down the middle of the base of one (for example on 1st May, 2018 at 10:30am), it should go down the middle of the base of the other. And at that time, we should be able to get the length of the shadows and thus the elevation.

If the shadow doesn't go down the middle of the base of the second sundial, then FE theory must have some explanation for light bending horizontally. In other words, it must explain why if I'm looking directly at the sun at that time, the atmosphere to the left of the sun has a higher refractive index than the atmosphere to the right of the sun (if bending to the South in my diagram). Assuming this is observed consistently day after day in all seasons and weather conditions, this would be very problematic.

What do you think will be observed and if the shadow doesn't go down the middle of the base of the second sundial, what is your explanation?

(https://i.imgur.com/DGvvkDU.gif)

Edit: Ha! I just realised I made a mistake and drew the experiment the way it would be at a location where I am in the Southern Hemisphere. You'll have to spin the sundials 180° for a Northern Hemisphere experiment. Same logic applies on a flat Earth though for the shadows on the sundials lining up.

Yeah, nice 2d diagram.

Now lets look at it from a side flat earth view.
(http://i68.tinypic.com/xbzul2.png)

You see the sun is closer on flat earth models ... so we also get different shadow lengths ... exaggerated in my diagram above.
Title: Re: Round Earth proof - comments?
Post by: WellRoundedIndividual on March 19, 2019, 05:51:11 PM
It has already been established that the Eratosthenes experiment can be duplicated with similar results on a flat earth with using only 2 points. However, if there are 3 or more points, then results on a round earth will differ from a flat earth. You can go to www.eratosthenes.eu to view schools from around the world posting their results of the experiment. Those data points can then be imported into Excel or whatever you like to use and see if the results point to a flat earth or a round earth. (Or you can google it and find out that someone already did this exact same thing and it points to a round earth). Or you can just yell conspiracy.
Title: Re: Round Earth proof - comments?
Post by: Balls Dingo on March 20, 2019, 03:19:24 AM
You see the sun is closer on flat earth models ... so we also get different shadow lengths ... exaggerated in my diagram above.

So you only want to talk about the second diagram and not what my post was actually about? I know you know that the shadow won't go down the middle of the base of the second sundial - because it's the reason why you said he botched the experiment - even though it absolutely should on a flat Earth.

Let's just simplify the experiment then. Two observers standing right next to that same straight road at either end. They both put sticks in the ground. When the shadow of the stick at the South Eastern end is perfectly parallel with the road, that observer calls up the second observer to ask if their shadow is parallel with the road. If the second observer says no, the Earth is not flat.

You know that the second observer will say no. But let's just ignore that, shall we?
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 20, 2019, 09:35:47 PM
You see the sun is closer on flat earth models ... so we also get different shadow lengths ... exaggerated in my diagram above.

So you only want to talk about the second diagram and not what my post was actually about? I know you know that the shadow won't go down the middle of the base of the second sundial - because it's the reason why you said he botched the experiment - even though it absolutely should on a flat Earth.

Let's just simplify the experiment then. Two observers standing right next to that same straight road at either end. They both put sticks in the ground. When the shadow of the stick at the South Eastern end is perfectly parallel with the road, that observer calls up the second observer to ask if their shadow is parallel with the road. If the second observer says no, the Earth is not flat.

You know that the second observer will say no. But let's just ignore that, shall we?
Well then all you end up with is an argument about whether the road is flat or curved with the shape of the earth ... you are no further forward.

I'm not sure why this is hard for you. The experiment outlined in the OP was first done to show earth's size ASSUMING it is round. It is not to decide what shape earth is. To add insult to injury the guy makes the fundamental mistake of taking the exact same time instead of waiting for the sun to be in the same relative point of the sky for both sticks (local noon). In other words its the wrong experiment and he performs it wrong as well. Double bad-science.
Title: Re: Round Earth proof - comments?
Post by: AATW on March 20, 2019, 10:03:26 PM
The experiment outlined in the OP was first done to show earth's size ASSUMING it is round.
No, it assumes a distant sun.
And you keep saying they needed to take the measurements at different times, that is you just not understanding the experiment that was done.
As has been pointed out, a local sun and a flat earth is a possible alternative explanation for the result - although that is you making an assumption about the shape of the earth - but if you do this experiment at 3 points then you'd expect different results on a FE or a Globe:

https://flatearth.ws/eratosthenes
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 20, 2019, 10:06:53 PM
The experiment outlined in the OP was first done to show earth's size ASSUMING it is round.
No, it assumes a distant sun.
And you keep saying they needed to take the measurements at different times, that is you just not understanding the experiment that was done.
As has been pointed out, a local sun and a flat earth is a possible alternative explanation for the result - although that is you making an assumption about the shape of the earth - but if you do this experiment at 3 points then you'd expect different results on a FE or a Globe:

https://flatearth.ws/eratosthenes
Erastosthenes used two sticks and that's the experiment he failed to recreate in the video. If you read above I already picked out another assumption was distance to the sun.

What we can agree on is that this man has not proved the earth to be round and so Flat Earth gets to jog along for another day.
Title: Re: Round Earth proof - comments?
Post by: AATW on March 20, 2019, 10:38:35 PM
He didn't exactly recreate the original experiment but his version is equally valid and gives the same result.
The version this dude did wouldn't have been possible at the time of the original experiment because it would have been difficult to synchronise over long distances.
But I agree this result doesn't by itself prove the earth is a globe, but the alternative explanation requires a close sun which is problematic for other reasons.
Title: Re: Round Earth proof - comments?
Post by: Balls Dingo on March 21, 2019, 06:24:24 AM
Well then all you end up with is an argument about whether the road is flat or curved with the shape of the earth ... you are no further forward.

I'm not sure why this is hard for you. The experiment outlined in the OP was first done to show earth's size ASSUMING it is round. It is not to decide what shape earth is. To add insult to injury the guy makes the fundamental mistake of taking the exact same time instead of waiting for the sun to be in the same relative point of the sky for both sticks (local noon). In other words its the wrong experiment and he performs it wrong as well. Double bad-science.

I'm not defending the experiment. He botched it. His experiment to measure the circumference of the Earth failed. But he actually did prove the Earth was not flat during the experiment! That is the point I'm trying to make.

He thought the shadows were going to go down the middle of the bases of both sundials at the same time because they were both parallel to a straight road. They didn't. You see it in the video. You've admitted that that is what happened. You've been quite clear that they won't in the experiment as designed. But there's no flat Earth explanation for this. The shadows absolutely should go down the middle of the bases of both sundials at the same time on a flat Earth. Ergo, the Earth is not flat.

What I've proposed is a different, simpler experiment requiring only two mobile phones and two sticks next to that road to prove the Earth is not flat. I've not proposed a different experiment to measure the circumference of the Earth. My apologies for not being clear on this but I though it was obvious from the description of my experiment.
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 21, 2019, 02:00:00 PM
???

But he aligns the sundials with MAGNETIC north. That's the offset. Magnetic north is not some point in the infinite distance. It is a place on earth. If I point my sundial in London to the same place as you point yours in California ... are those sundials aligned parallel, round earth or flat? The guy is in Canada for Pete's sake. That's going to give him quite an offset. He needs to make sure they are pointing to the same place.

Not true north. Not magnetic north. Not grid north. They all bend around to face a point. Pointing with respect to a place infinitely far away in the same direction. He could have line them both up with a star for an instantaneous money shot, for example.

Of course finding a star during the day is going to be a problem ... but its round earth's problem. Maybe you could line them up the night before ... and then do the experiment the next day.

But then I might challenge if the stars are really billions of miles away ... because round earth has the distance of the sun wrong too.
Title: Re: Round Earth proof - comments?
Post by: Balls Dingo on March 23, 2019, 01:41:17 AM
???

But he aligns the sundials with MAGNETIC north. That's the offset. Magnetic north is not some point in the infinite distance. It is a place on earth. If I point my sundial in London to the same place as you point yours in California ... are those sundials aligned parallel, round earth or flat? The guy is in Canada for Pete's sake. That's going to give him quite an offset. He needs to make sure they are pointing to the same place.

Not true north. Not magnetic north. Not grid north. They all bend around to face a point. Pointing with respect to a place infinitely far away in the same direction. He could have line them both up with a star for an instantaneous money shot, for example.

Of course finding a star during the day is going to be a problem ... but its round earth's problem. Maybe you could line them up the night before ... and then do the experiment the next day.

But then I might challenge if the stars are really billions of miles away ... because round earth has the distance of the sun wrong too.

You are right and I am wrong. At 5:40 in the video he says the sundials are lined up with the road and lined up with each other. I assumed that was what he had done but he hadn't. He didn't try to line the sundials up with the road. If he had, he would have found that the compass bearings were different for the reasons you have stated. I humbly submit that I was wrong and consider myself schooled ;)

What I have found though is that you can still do Eratosthenes' experiment if the road is completely straight. But you have to throw away the compass. You don't need an external reference. If the two sundials are perfectly parallel to the road and the shadow goes down the middle of the base of one, it does go down the middle of the base of the other. Not surprising because light from the sun travels in a straight line, at least horizontally. At any time of the year, when this happens next to that road, the difference in elevation is 1.22°. For example, these are two points on that road 135.596km apart (according to GPS):

https://www.suncalc.org/#/50.4229,-104.5336,14/2019.06.23/10:57/1/3
https://www.suncalc.org/#/49.68,-103.0324,16/2019.06.23/10:57/1/3

According to Eratosthenes' formula, this makes the circumference of the Earth:

360 / 1.22 * 135.689 = 40011km.

Very, very close to the accepted number. Unfortunately for me, the shadows go down the middle of the bases at the same time on a round Earth too so my proof of a round Earth, as you already know, is garbage.
Title: Re: Round Earth proof - comments?
Post by: Dr David Thork on March 29, 2019, 05:08:45 PM
???

But he aligns the sundials with MAGNETIC north. That's the offset. Magnetic north is not some point in the infinite distance. It is a place on earth. If I point my sundial in London to the same place as you point yours in California ... are those sundials aligned parallel, round earth or flat? The guy is in Canada for Pete's sake. That's going to give him quite an offset. He needs to make sure they are pointing to the same place.

Not true north. Not magnetic north. Not grid north. They all bend around to face a point. Pointing with respect to a place infinitely far away in the same direction. He could have line them both up with a star for an instantaneous money shot, for example.

Of course finding a star during the day is going to be a problem ... but its round earth's problem. Maybe you could line them up the night before ... and then do the experiment the next day.

But then I might challenge if the stars are really billions of miles away ... because round earth has the distance of the sun wrong too.

You are right and I am wrong. At 5:40 in the video he says the sundials are lined up with the road and lined up with each other. I assumed that was what he had done but he hadn't. He didn't try to line the sundials up with the road. If he had, he would have found that the compass bearings were different for the reasons you have stated. I humbly submit that I was wrong and consider myself schooled ;)

What I have found though is that you can still do Eratosthenes' experiment if the road is completely straight. But you have to throw away the compass. You don't need an external reference. If the two sundials are perfectly parallel to the road and the shadow goes down the middle of the base of one, it does go down the middle of the base of the other. Not surprising because light from the sun travels in a straight line, at least horizontally. At any time of the year, when this happens next to that road, the difference in elevation is 1.22°. For example, these are two points on that road 135.596km apart (according to GPS):

https://www.suncalc.org/#/50.4229,-104.5336,14/2019.06.23/10:57/1/3
https://www.suncalc.org/#/49.68,-103.0324,16/2019.06.23/10:57/1/3

According to Eratosthenes' formula, this makes the circumference of the Earth:

360 / 1.22 * 135.689 = 40011km.

Very, very close to the accepted number. Unfortunately for me, the shadows go down the middle of the bases at the same time on a round Earth too so my proof of a round Earth, as you already know, is garbage.

That is probably the most gracious defeat accepted by anyone on this site for a very long time. I tip my new hat to you (I stole it from Jeppspace's flaccid corpse).
Title: Re: Round Earth proof - comments?
Post by: jimmycrack on April 30, 2019, 05:03:27 AM
1) Gravity - I have yet to see any compelling argument that explains gravity without using Newton's laws of Physics.
2) Stars and Moon - In the northern hemisphere, the moon appears different than it does in the southern hemisphere.  Also there are different stars in the sky.
3) Lunar Eclipse - During a lunar eclipse, you can see the shadow of the Earth on the moon.
4) Day/Night - There is no way that a flat earth model can explain sufficiently how night and day work using a circular light delusion.
5) You cannot see the the Sierra Nevada Mountains from Las Vegas.  It is the driest place in the world and if it was flat, they should be easily seen with a telescope.
6) Satellites - We depend on them daily to get TV signal, GPS services, and communications to remote locations around the world.   
7) Felix Baumgartner.  When he jumps you can see the curvature of the earth easily.  His story cannot be realistically denied.
8) No one has been to the edge of the flat earth.  Not even Steve-O, who is probably the craziest person on the planet. 
9) U2 Spy Plane pilots can see the curve of the earth.  I knew an air force pilot that flew the SR71 and asked him if he could see it, and he said yes.  It was like he was in space. 
10) 536 Astronauts have been to space.  Also the columbia space mission in 2003 is a well documented mission to space that ended in tragedy. It was videoed until their last minutes they were alive on Feb 1st 2003.
11) There is no world map that does not have distortion.  Only a globe can be reliably used to measure distances to anywhere in the world.
12) Many explorers traversed across Antarctica bearing the bitter cold. The latest trip took 53 days and was well documented. https://www.nationalgeographic.com/adventure/2018/12/explorer-completes-historic-antarctic-trek/ 

I am sure I could go on, but I think that basically until I see a flat earth map that shows an Antarctica that can be traversed, that shows a 50% light/darkness ratio, and no distortion of the land masses, I am not buying flat earth. These things are all easily able to be shown with a Globe and from my experience, usually the simplest solutions are the best solutions.

Title: Re: Round Earth proof - comments?
Post by: rodriados on April 30, 2019, 08:15:16 PM
Why would the shadows be the same length on a flat earth?

The guy uses highway 33 in Canada.
Quote from: https://leaderpost.com/news/local-news/scientist-pedalling-140km-from-regina-to-prove-the-earth-is-round
Baute will cycle approximately 140km along Highway 33 from Regina to Stoughton

That road isn't north south.
https://www.google.com/maps/place/SK-33,+Saskatchewan,+Canada/@50.0646593,-104.3574711,9z/data=!4m8!1m2!2m1!1scanada+highway+33!3m4!1s0x531e59aad00d09e5:0xb3b578691b9eb1d5!8m2!3d50.0642098!4d-103.7971402

So it is a different local time of day at the two ends of the road. Would you expect a shadow at midday to be the same length as one at sunset?

At least when Eratosthenes did the experiment he took the LOCAL noon time for each location, not at the same generic time of day.
Quote from: https://en.wikipedia.org/wiki/Eratosthenes
He knew that at local noon on the summer solstice in Syene (modern Aswan, Egypt), the Sun was directly overhead.

In the video at 6:23 you can see them counting down to take the exact same real time ... not the same local time.

And you will note from the map that Syene and Alexandria are roughly North South, certainly not 45 degrees off like this guy. (Eratosthenes's done his best being as he has to use the Nile ... travelling the Sahara back then was pretty dangerous and difficult.)
(https://www.researchgate.net/profile/Alok_Kumar23/publication/253596660/figure/fig2/AS:334437452664834@1456747510980/A-map-of-Egypt-The-ancient-city-of-Syene-is-today-known-as-Aswan-Taken-from.png)

This guy doesn't understand the geometry or Eratosthenes experiment. He's just an idiot in cycling shorts. He has proved nothing.

If you take the measurements at different moments, in each point's exact local noon, then you'd need a North-South difference to have any results. This one experiment, though, as both measurements are taken at the same time, it can also catch any East-West difference as well. Thus, you are not debunking his proof.
Title: Re: Round Earth proof - comments?
Post by: spherical on May 11, 2019, 03:57:43 PM
I post a similar but easier experience, a single pole on Quito Equator, and kindly request Tom Bishop to answer.
I know he is very busy, but I am sure he will be glad to answer.

https://forum.tfes.org/index.php?topic=14748.0 (https://forum.tfes.org/index.php?topic=14748.0)