I'm often giving Flat Earthers a bit of a hard time. 'Bit' maybe an understatement :)
So, for a change of pace, I'm going to give Jon McIntyre a shout out for admitting error and at least seemingly being one actually looking for the truth of the matter.
Jon first posted a video called "Flat Earth... A Mountain of Evidence" that purports to show a bunch of 'missing' curvature by looking at mountain peaks in the Nantahala National Forest, southwest of Asheville, North Carolina.
|Left to right: Bald Knob, Pinnacle, Graybeard, Fryingpan|
You might want to watch both the original video (can skip to about 44 minutes in) and Sly Sparkane's video response and review (Jesse Kozlowski also did an analysis video but it's less to the point and misses some of Jon's errors).
Long story short: the measurements are wrong, his location was wrong (shows view from Tennent mountain but was actually closer to Frying Pan mountain near Grassy Cove), his altitude was wrong, his camera was tilted, and once corrected everything lines up as expected and shows pretty good evidence of Earth's curvature.
The key observation, starting at 6:38 in Sly's video, is that the camera being tilted, has tilted the horizontal plane about 1 so when you correct for that you find that Bald Knob (1640 m) APPEARS below a horizontal plane when drawn from the peak of the closer and shorter Fryingpan Mountain (1621 m). If the Earth were flat in between then the observation from 1643m would not show Bald Knob below the horizontal plane off Fryingpan Mountain.
Fryingpan Mountain is only about 8.7 km away from the view while Bald Knob is about 66.4 km. The 'drop' due to curvature over these distances is 19.5 feet and 1135.1 feet respectively. That shaves off a difference of 1115.6 feet from Bald Knob.
The angular size of g=1115.6 feet high at r=66.4 km (217847.8 feet) distance is:
α = 2*arctan(g/r/2) = 2*arctan(1115.6/217847.8/2) = 0.2934°
This is exactly what we see in the video - a VERY SMALL angular difference between the horizontal line off Fryingpan Mountain and the peak of Bald Knob despite Bald Knob being taller. If the Earth was flat then the peak of Bald Mountain would be above that horizontal line.
But I think Jon has admitted his error and that's a good thing to be able to do.
Here is an excerpt from his post:
I am neither in allegiance with "flat earth believers" nor opposed to "globe earth believers". I am simply a neutral arbiter. If you do not believe this then please hear me when I say that my observation and video PROVE NOTHING. That is the end of all potential argument and debate with me. The work I did is riddled with potential for inaccuracies but at least I got off my duff and went out and did the work instead of fighting endlessly in front of my computer, which leads absolutely NOWHERE.
I will say this though. Regardless of how much potential error I factor in for my observation I believe I still do not generate enough curvature to match the the curvature that should be there. In my opinion it does appear as though there is "missing curvature".
Understanding the bolded portion is critical for all of us. Observational work is always subject to inaccuracies. We have to work together openly and share our methodology and data so it can be reviewed. The problem is that most Flat Earthers want to immediately point and say "LOOK, LOOK, it's FLAT!" and be done with it and refuse to listen when you point out all the, usually, egregious errors in their "proof".
Note: the observation ground point was at ~1640 meters on Jon's GPS (actual ground is 1638) which showed location as:
Loading up the actual viewpoint on PeakFinder (kind of like a 'sketch' version of Google Earth Street View) we find very good agreement with the observation Jon actually made.
Anyway, wanted to share this as I think it's very educational and, in the end, is actually good evidence for the curvature of the Earth.
|PeakFinder view - dotted line is LEVEL from observer|