The Flat Earth Society
Flat Earth Discussion Boards => Flat Earth Theory => Topic started by: Tontogary on April 20, 2018, 02:40:15 AM
-
I have just thought of a pretty foolproof way of measuring angular distance to the horizon.
We use sextant on board my ship, and these cam measure an arc up to 130 degrees.
So an easy way to MEASURE the angle from one horizon to the next is to take an altitude of the sun or other body that is above 60 degrees from the horizon is to measure the suns lower limb on the closest horizon, and then use the same limb on the opposite horizon. This will give us the total distance from one horizon to the next, through the Zenith.
The remaining part will be the earth below us.
If the Measured arcs add up to more than 180 degrees, the remaining part, ie the earth MUST be be less than 180 degrees, PROVING the horizon does not rise to meet the eye level.
If the sun is high enough today i will give it a go. Should be interesting.
-
Plus with an understanding of perspective, the horizon NEVER rises to eye level... Your line of site is either towards the ground, level with the ground, or above the ground... but in terms of perspective, then we only consider an imaginary line "parallel" with the ground... as the ground gets further and further away, then the angle towards that point gets less and less as it approaches "0" i.e. NEARLY the same angle as the line parallel with the ground... But obviously it can never reach zero: or mathematically speaking it reaches the "limit" when the ground is an infinite distance away... (i.e. impossible, but mathematically expressible)
So when drawing the horizon, we draw it at the point level with the eye, to represent that theoretical "zero" limit. It never reaches it, no object ever reaches it, they just get really really close. And obviously on a curved earth, it's dropping away at each point, but very slowly.
Obviously as you climb higher, the distance to even get close to that "zero" point increases... because the parallel line from your eye is higher. So yeah the horizon appears to rise level with your eye. But it's not: again it's just really really close. If the world was flat and infinitely wide then yeah, there would be a horizon line perfectly level with your eye at all times from all heights (assuming there's no atmosphere for the ground to start disappearing in to)
On the glove earth, once you reach a certain height, although the horizon appears to be rising with you most of the way, before too long, when you get really really high, it's obvious the horizon is curving away out of site, until eventually you're literally staring at a big giant sphere.
I think i've said this before somewhere: perspective is like a frog trying to cross the river. It can jump half of the way with each jump. It never reaches the shore. Even when there's only 1mm to go, it jumps .5mm etc... Although people can draw diagonal "perspective lines" on drawings, in reality, the objects described as such never reach the point of intersection... they get closer and closer each time, but jump smaller and smaller amounts each time. The flat earth understanding of perspective is COMPLETELY wrong, they draw diagonal lines and infer meaning out of nowhere with no relation back to how your eye or light works.
-
Ok its after meridian passage here where we are, and that is the best time to do this experiment/measurement, as the sun stops rising, and for a minute or 2 there is hardly any change of altitude.
So today i measured the upper limb on the Northern horizon and it was 58 41.1’ , and the same limb (which became the lower limb) on the opposite horizon was 121 44.5’
Now the instrument error measured and checked is 2 minutes to be subtracted from the readings.
This makes the corrected readings to be 58 39.1’ and 121 42.4’
Now adding the 2 together gives us the arc of the sky above the horizon, which is 180 21.5’ and the sea/ground below must be 179 38.5’
As can be seen the sky is a larger arc than the ground.
Now the dip of the horizon as tabulated and that we use for our current hieght is 10.6, and as this is both horizons, north and south, the dip of the horizon combined should be 0 21.2’
This correlates closely with our measurements, and PROVES that the horizon dips with altitude of the observer. IT Cannot rise to the eye level, and thus is another nail in the coffin of the FE.
The FE arguments seem to be getting debunked here, like skittle pins falling down, one by one by one.
I would really love for someone to explain to me how my measurements and observations can be innacurate, or in any way can be taken to prove the horizon rises to meet the observers eye level.
-
So yeah the horizon appears to rise level with your eye. But it's not: again it's just really really close.
This is the difference Tom doesn't understand. He seems to think that empiricism is just about what you can discern, which isn't necessarily the same as what you can measure. You can't discern that the horizon dips at "normal" altitudes, but you can measure it to show that it does.
Close to eye level is NOT the same as at eye level - even the quote Tom posted when trying to back up his assertion that the horizon is at eye level said it was "practically" at eye level. Which is true, it is. But it is not AT eye level and the dip of the horizon is measurable. This is now the 3rd way which has been posted recently to show that.
It's a subtle difference but it's a very important one. Tom didn't understand the experiment with the boat and the laser because he didn't understand the difference between where the laser hits the boat (the laser is parallel to the ground and the ground curves away so the laser hits the boat higher as it gets further away) and how much of the boat you can see from a certain viewer height (you look slightly down and over the horizon so can see more of the boat than if you looked straight ahead like the laser does).
He declared the experiment a fraud because he didn't understand it. He didn't understand it because of the horizon dip thing. He has now been shown 3 different ways of measuring that but has done nothing to explore this himself. I question how serious he is about actually doing any research or finding out the truth for himself.
-
The only time it's not at eye level is if there's hills mountain's on the horizon. Go up in a plane, the horizon matches your eyes. Look straight ahead, it remains at eye level. The sea? Level. Dr Rowbotham was able to explain this.
-
The only time it's not at eye level is if there's hills mountain's on the horizon. Go up in a plane, the horizon matches your eyes. Look straight ahead, it remains at eye level. The sea? Level. Dr Rowbotham was able to explain this.
And this is why people think you're a troll.
3 different experiments have been posted recently, all use different methods, all show the same result - the horizon is not at eye level and the angle below eye level it is at increases with altitude. Your retort is simply "IS TOO!". You're going to have to do better than that. If you want to do an experiment yourself and show the results on here for review then that would be better. Just restating something which isn't true and has been proven not to be true doesn't make it true.
PS: I am actually flying next week, it will be dark on the way there but on the way back it will be during the day, if it's clear on that flight and the horizon is clear I will try to get a cup of water or something - so I can be clear about what is level - and see if I can get a picture of it compared to the horizon (can't actually remember if I have a window seat so this may be tricky).
-
The only time it's not at eye level is if there's hills mountain's on the horizon. Go up in a plane, the horizon matches your eyes. Look straight ahead, it remains at eye level. The sea? Level. Dr Rowbotham was able to explain this.
So how did i make a mistake then? I wish you can explain? EnaG does not explain the results of my experiment, other than if you look you will see this, etc.
Sextants were around in his time, so why didnt he do the experiment I did, oh yeah, the results wouldn’t have fitted in with his way of thinking, awkward.
-
The only time it's not at eye level is if there's hills mountain's on the horizon. Go up in a plane, the horizon matches your eyes. Look straight ahead, it remains at eye level. The sea? Level. Dr Rowbotham was able to explain this.
Yet ... most every photo I see from a commercial airliner has the passenger looking DOWN to the wing, which in most designs is physically below the passenger compartment, with the horizon BELOW that wing ...
So doesn't that mean the horizon is BELOW eye level?
-
It's a pity airlines won't let someone take a rig like this on a plane ....
https://www.youtube.com/watch?v=NqOQ_BCtqUI
Parallax - have you actually TRIED anything like this, to actually MEASURE what 'level' means in varying situations?
-
You do NOT understand. Surveying is always in error. Always. Every angle and vertical and position needs to be finely positioned. And even when it is to the best of our ability, there is still lens error.
http://whistleralley.com/surveying/theoerror/
As any surveyor should understand, all measurements are in error. We try to minimize error and calculate reasonable tolerances, but error will always be there. Not occasionally; not frequently; always. In the interest of more accurate measurements, we look for better instruments and better procedures.
An amateur off-the-cuff or hand-held surveying demo is not going to cut it. The tolerances are extremely sensitive, and there are many ways it can be wrong. Slight angles and positions will create different results.
I'm not going to perform hand held surveying experiments by holding a water device in one hand and a camera in the other, as I try to get everything to line up with a line a few inches away from my sight, because that is not a legitimate way to survey. If Parallax did this experiment and showed that the horizon lined up, it would mean very little, because the method is invalid.
Surveyors don't hold their measuring equipment in their hands to line up angles. Surveyors use carefully calibrated tripods and carefully measured angles, and even then they are still in error, as the above link tells us, for many reasons.
-
I'm not going to perform hand held surveying experiments by holding a water device in one hand and a camera in the other, as I try to get everything to finely line up with a point, because that is not a legitimate way to survey. If I showed that the horizon lined up it would mean very little, because the method is invalid.
Define your own method then.
You have been shown 3 different ways of proving that the horizon is below eye level. They all clearly give the same results. So you're suggesting the errors of all 3 are exactly the same?
That's convenient. You are free to devise your own method though.
But the fact you don't understand the difference between something starting parallel to the ground (the ground curves away so the laser hits the boat higher) and someone looking slightly down at the horizon (how much of the boat you can see) is the root of you not understanding that experiment.
-
You do NOT understand. Surveying is always in error. Always. Every angle and vertical and position needs to be finely positioned. And even when it is to the best of our ability, there is still lens error.
http://whistleralley.com/surveying/theoerror/
As any surveyor should understand, all measurements are in error. We try to minimize error and calculate reasonable tolerances, but error will always be there. Not occasionally; not frequently; always. In the interest of more accurate measurements, we look for better instruments and better procedures.
An amateur off-the-cuff or hand-held surveying demo is not going to cut it. The tolerances are extremely sensitive, and there are many ways it can be wrong. Slight angles and positions will create different results.
I'm not going to perform hand held surveying experiments by holding a water device in one hand and a camera in the other, as I try to get everything to line up with a line a few inches away from my sight, because that is not a legitimate way to survey. If Parallax did this experiment and showed that the horizon lined up, it would mean very little, because the method is invalid.
Surveyors don't hold their measuring equipment in their hands to line up angles. Surveyors use carefully calibrated tripods and carefully measured angles, and even then they are still in error, as the above link tells us, for many reasons.
1) Surveying is looking for specific angles, and are indeed looking to be as precise as possible. Thus the need/desire for precision. The error involved was stated and accounted for by Tontogary when he did his. As a maritimer of 20 years, are you attempting to claim he doesn't have the experience required to use his device?
2) The water level experiment is NOT about measuring the angle. Everything you've posted in regards to that can thus be ignored. All the water experiment does is show that, when looking at the straight and level line between the two points of water, the horizon drops below it. Noticeably in some instances. This is proof the horizon does NOT rise to eye level. We don't care about how much it does or doesn't, this is all about looking for a drop *at all*.
3) You have yet to give any sort of valid method yourself. If you insist on proclaiming everything we do as 'invalid' you must have SOME idea of what must be done to BE valid. Describe it. Even if you can't or won't do it, I'm sure we've got someone about who would be more than willing to.
-
I ask why the experimenter in the water video did not first align the furthest spout of water with the horizon, and then attempt to align the closest spout with that line? Maybe because it might show something that is contrary to what he was trying to show?
The best method would be to find an obstacle of a known height, set it a distance away, and then set the height of your camera to the height of the top of the obstacle. The camera, object, and horizon should make a straight line. The further the objects are located from each other, the better. The horizon should line up with to top of the object, and there would far fewer surveying errors since everything is set on the ground rather than being dependent on aligning angles in a device of unknown calibration or holding everything in your hands.
The experiment would be similar to the demonstration GlobeBusters gives here, although I am sure a better one can be designed.
https://youtu.be/vvPxGPKTlBQ?t=1m16s
-
You do NOT understand. Surveying is always in error. Always. Every angle and vertical and position needs to be finely positioned. And even when it is to the best of our ability, there is still lens error.
http://whistleralley.com/surveying/theoerror/
As any surveyor should understand, all measurements are in error. We try to minimize error and calculate reasonable tolerances, but error will always be there. Not occasionally; not frequently; always. In the interest of more accurate measurements, we look for better instruments and better procedures.
An amateur off-the-cuff or hand-held surveying demo is not going to cut it. The tolerances are extremely sensitive, and there are many ways it can be wrong. Slight angles and positions will create different results.
I'm not going to perform hand held surveying experiments by holding a water device in one hand and a camera in the other, as I try to get everything to line up with a line a few inches away from my sight, because that is not a legitimate way to survey. If Parallax did this experiment and showed that the horizon lined up, it would mean very little, because the method is invalid.
Surveyors don't hold their measuring equipment in their hands to line up angles. Surveyors use carefully calibrated tripods and carefully measured angles, and even then they are still in error, as the above link tells us, for many reasons.
The instrument error in my readings is quantifiable, measurable and can be corrected for. I cklearly showed this. The final reading i produced were able to be cross checked and verified to within an accptable range.m I did NOT make an error in taking my sextant angles. As the cross checking proves.
It is so much more accurate than the water gauge, but dont take my word for it, do it yourself.
If you think i am buying the diagrams and so called witness sestimony from third hand sources printed in Enag, to prove i am sitting in the low point of a bowl of water which rises all around me, then sorry, I will trust to my measured angles, and fact that millions of positions have been taken from ships, and they all account for dip of the sea horizon. FACT.
-
The best method would be to find an obstacle of a known height, set it a distance away, and then set the height of your camera to the height of the top of the obstacle. The camera, object, and horizon should make a straight line. The horizon should line up with to top of the object, and there would far fewer surveying errors since everything is set on the ground rather than being dependent on aligning angles in a device of unknown calibration or holding everything in your hands.
The experiment would be similar to the demonstration Globe Busters gives here:
https://youtu.be/vvPxGPKTlBQ?t=1m16s
That is completely wrong, we have highly accurate equipment and measurements. If I did this measurement of yours at 100m and 200m high the horizon would be at the same height for both observations?
Interesting you and your friends are not prepared to carry even one experiment.
-
I ask why the experimenter in the water video did not first align the furthest spout of water with the horizon, and then attempt to align the closest spout with that line? Maybe because it might show something that is contrary to what he was trying to show?
The best method would be to find an obstacle of a known height, set it a distance away, and then set the height of your camera to the height of the top of the obstacle. The camera, object, and horizon should make a straight line. The further the objects are located from each other, the better. The horizon should line up with to top of the object, and there would far fewer surveying errors since everything is set on the ground rather than being dependent on aligning angles in a device of unknown calibration or holding everything in your hands.
The experiment would be similar to the demonstration Globe Busters gives here, although I am sure a better one can be designed.
https://youtu.be/vvPxGPKTlBQ?t=1m16s
Wow, some real issues in his video. He's on the balcony of a 7 story building, and comparing it to the top of the 7 story building. The top should be ABOVE the height of his eye. But let's roll with this. How much 'dip' should we see to the horizon? I'll give him 80 feet up, as we don't get anything more accurate, and the building clearly needs to be above sea level by some amount. Some numbers and a bit of math later:
Distance to horizon: 11 miles
Height: 80 feet
Angle to horizon: 0.079°
Nah, there's no way you could see this with the naked eye anyway. The top of the building is gonna resolve at at least that sort of angle. This is no proof at all. Your experiment is in fact the worst of the bunch unless you get much higher!
-
I ask why the experimenter in the water video did not first align the furthest spout of water with the horizon, and then attempt to align the closest spout with that line? Maybe because it might show something that is contrary to what he was trying to show?
I have no idea what that means. It's water, you can't align it. The point of the experiment, the bit that makes it certain that you are looking straight ahead, is that the two tubes of water are connected and thus will always be at the same level as each other. Thus so long as it's clear the two tubes are level with each other you can determine whether the horizon is at, above or below that level.
That experiment doesn't measure the angle of horizon dip but it clearly demonstrates there is one.
The best method would be to find an obstacle of a known height, set it a distance away, and then set the height of your camera to the height of the top of the obstacle. The camera, object, and horizon should make a straight line.
Well, the important thing is that the camera and obstacle are the same height. Your video has two problems
1) It's on the 7th floor so the angle down to the horizon would be very slight
2) How is there any calibration there? How do we know that the camera height and the building height are the same? You claim that the experiment with the water tubes is not exact but here you're claiming that the camera height and building height are exactly the same. Are we supposed to take that claim seriously?
Even then, this is a close up still and the horizon does seem a few pixels below the building level.
(https://image.ibb.co/miwXMn/Horizon_Tom.jpg)
-
Nah, there's no way you could see this with the naked eye anyway. The top of the building is gonna resolve at at least that sort of angle. This is no proof at all. Your experiment is in fact the worst of the bunch unless you get much higher!
This exact experiment has been done at higher altitudes.
https://www.youtube.com/watch?v=LWakrkYzPVY
-
Nah, there's no way you could see this with the naked eye anyway. The top of the building is gonna resolve at at least that sort of angle. This is no proof at all. Your experiment is in fact the worst of the bunch unless you get much higher!
This exact experiment has been done at higher altitudes.
https://www.youtube.com/watch?v=LWakrkYzPVY
So, first off this isn't the same experiment. At all. Like, not even close really. Setting that aside however, there are a LOT of possibilities he doesn't discuss in regards to these guys and how they appear that way. But this video and what it discusses is off topic in regards to the horizon and eye level. So if we could please get back to that instead of getting sidetracked, it would be much appreciated.
-
I ask why the experimenter in the water video did not first align the furthest spout of water with the horizon, and then attempt to align the closest spout with that line? Maybe because it might show something that is contrary to what he was trying to show?
The best method would be to find an obstacle of a known height, set it a distance away, and then set the height of your camera to the height of the top of the obstacle. The camera, object, and horizon should make a straight line. The further the objects are located from each other, the better. The horizon should line up with to top of the object, and there would far fewer surveying errors since everything is set on the ground rather than being dependent on aligning angles in a device of unknown calibration or holding everything in your hands.
The experiment would be similar to the demonstration GlobeBusters gives here, although I am sure a better one can be designed.
https://youtu.be/vvPxGPKTlBQ?t=1m16s
He is standing in HIS seventh floor room, and horizon i aligned with THE TOP of seventh floor of the other building.
How high was he holding the camera?
With this setup you can any slope declare horizontal.
With water level you can't manipulate horizontal line like this.
Or water level is "globe concept" like longitudes and latitudes?
-
Are you saying the horizon is horizontal to you, whatever your altitude? That cannot work from multiple locations.
-
I'm not going to perform hand held surveying experiments by holding a water device in one hand and a camera in the other,
What if this is done with the water level and camera both on tripods and steady with the camera centered vertically on the water level?
-
In theory Tom's experiment of a building being the obstacle between you and the horizon would be a good test of horizon dip but there are two problems
1) Buildings are, in general, not that tall. And significant horizon dip can only be seen and a fairly high altitude
2) The experiment only works if the building and camera are EXACTLY the same height. And how can you accurately determine that?
This is where the water level experiment wins because you can take the equipment to any height and because the two tubes are connected you can be sure that they are the same level as each other. So long you're looking across them so the level in the two tubes match up you know you're looking straight ahead and can determine whether the horizon is the same level or higher or lower.
The only reasonable objection to the video of the water experiment is that it's hand held and thus harder to see the result, but it's still clear enough as these stills show:
(https://image.ibb.co/i9H7Kn/horizondip.jpg)
This is proof which there is no reasonable objection to.
Tom's real objection is that it clearly shows a result which he doesn't believe in so he has to dismiss it. Which is weird as horizon dip is not a matter of belief, it's something which can be clearly shown and measured. He isn't serious about investigating the truth or taking his own empirical measurements. He could easily reproduce this experiment at minimal cost. If his objection is that the camera and tubes are hand held then put the camera on a tripod, keep the water tubes still somehow. You'll get the same result.
He's only interested in empirical measurements which appear to back up the dogma he chooses to believe in. It's confirmation bias writ large.
-
He is standing in HIS seventh floor room, and horizon i aligned with THE TOP of seventh floor of the other building.
How high was he holding the camera?
That's not the only issue:
There's no evidence, that these two buildings are same hight.
- The hight of the floors maybe different. A seven floor building does not need to have the same hight as another seven floor building
- The ground the buildings are build on, may have different elevation
-
I ask why the experimenter in the water video did not first align the furthest spout of water with the horizon, and then attempt to align the closest spout with that line? Maybe because it might show something that is contrary to what he was trying to show?
It's water. It always "finds its own level" as all the best YouTube flat earthers keep saying. The rig is two vertical, connected tubes, and you can see that the single body of water occupies the two vertical and one horizontal tube between them by the way it sloshes about as the operator moves the rig.
Whatever angle the rig is held at, the water always finds a level - unless you disagree with this most basic of concepts?
....far fewer surveying errors since everything is set on the ground rather than being dependent on aligning angles in a device of unknown calibration or holding everything in your hands.
There's no need to align the rig at any particular angle. All that's needed is to hold it such that there's at least some water in each vertical tube. These two columns will form a level.
THEN move the camera to be LEVEL with this.
-
You either align your eye or the camera so the two water levels are the same and you’re looking across the top of them, that’s what happens in that video and you can clearly see the horizon is below that level at altitude and the amount below it increases with altitude. Or you align your eye/the camera with the first tube and the horizon and then see whether the other tube appears at the same level. It’s logically the same thing although the first is more intuitive.
-
The only time it's not at eye level is if there's hills mountain's on the horizon. Go up in a plane, the horizon matches your eyes. Look straight ahead, it remains at eye level. The sea? Level. Dr Rowbotham was able to explain this.
What part of what I said are you disagreeing with? Try this... look at a point on the ground 1.5 meters in front of you... your heads at about a 45 degree angle yeah? Now look at the ground about 3 meters infront of you... whats that, about 30 degrees below eye level? Now 10 meters... now 50 meters...
Do you understand now? The angle to the ground NEVER reaches zero, just gets really really close to it... if it was "zero" then it wouldnt be below you would it, it would literally be infront of you. This is also essentially how perspective works. [Edit: I'm really just arguing a technicality here, not the "core" argument... and i'm describing perspective on an infinite flat plane. I think it's important FE understand how perspective works so they can understand exactly what it means when they say "the horizon rises to eye level" and exactly why that happens, but that's essentially a seperate debate, i'll shutup now lol. That video with the two tubes of water is brilliant... there's really no arguing your way out of that, clearly shows the curve of the earth]
-
You either align your eye or the camera so the two water levels are the same and you’re looking across the top of them, that’s what happens in that video and you can clearly see the horizon is below that level at altitude and the amount below it increases with altitude. Or you align your eye/the camera with the first tube and the horizon and then see whether the other tube appears at the same level. It’s logically the same thing although the first is more intuitive.
OR
Do the experiment with a single body of water, rather than two connected tubes.
(https://dijf55il5e0d1.cloudfront.net/images/na/4/8/6/48621_1000.jpg)
Turn a tray like this upside down, set it on a firm support, introduce a few cms of water, wait for it to settle, and sight the camera along the level of the water.
-
Yes, that would work. As discussed I'm flying today - but it might be dark by the time we get to altitude.
Will be daytime when I come back and I don't have a window seat but if I can get a cup of water and can see the horizon clearly I can try and take a photo.
Have a feeling I won't be able to, will try and get a window seat next time!
-
Here are six simple ways for measuring whether the horizon is at eye level or not:
1. Use a professional theodolite. Eye level is where the crosshair is:
(https://www.metabunk.org/attachments/screenshot-178-png.29725/)
2. Download and properly calibrate a theodolite app. Eye level is where the crosshair is:
(https://www.metabunk.org/data/MetaMirrorCache/2280a2eb67935d369dbdac8a06ed4097.jpg)
3. Make your own theodolite using a spirit level. Eye level is level with the top of the spirit level, when you're sighting along it:
(https://www.metabunk.org/attachments/diy-theodolite-jpg.26429/)
www.metabunk.org/posts/204999
4. Use parallel lines to find the vanishing point (which is always at eye level):
(https://www.metabunk.org/attachments/wtc-lines-jpg.28259/)
5. Take a picture of some actual eyes, with the camera at eye height, and see where the horizon is:
(https://www.metabunk.org/attachments/wtc1-jpg.27470/)
6. Use a homemade water level. Eye level is where the surfaces of the water are aligned:
(https://www.metabunk.org/attachments/horizon-level-liquid-test-jpg.27615/)
-
Nah, there's no way you could see this with the naked eye anyway. The top of the building is gonna resolve at at least that sort of angle. This is no proof at all. Your experiment is in fact the worst of the bunch unless you get much higher!
This exact experiment has been done at higher altitudes.
https://www.youtube.com/watch?v=LWakrkYzPVY
First of all, the buildings in Hawaii 'experiment':
1. Are we sure the buildings are the same design and dimensions?
2. Are we sure that they're exactly the same height above sea level (e.g., could one be a little bit downhill from the other)?
3. As shown, does anyone really think 7 storeys is high enough to tell whether eye level is at or above the horizon?
4. In actual fact, there's no real difference between this and the homemade water level experiments - other than the water level experiments are much better.
Now on to the Jon McIntyres 'Mountain of Evidence' video:
1. When done properly, it's a very good experiment, and a foolproof way of demonstrating the shape of the earth.
2. The problem with this one is that it wasn't done properly: in a nutshell, he had his viewing position and observer elevation wrong, which messed up his results (very easily verifiable, as shown here: www.metabunk.org/posts/191401 (http://www.metabunk.org/posts/191401)).
3. Tom, are you aware that Jon himself has refuted the video, having realised his error?
4. Inspired by this experiment, I devised a method to use any suitable mountain range where observer location and elevation is known to figure out the shape of the earth. It's perhaps a little complex for most, but absolutely undeniable once understood: www.metabunk.org/posts/207142 (http://www.metabunk.org/posts/207142).