So this is happening this weekend...
In a nutshell: flat earthers of the UK - including Dave Murphy - are off to the Bedford Levels to recreate Rowbotham's famous experiment. Will be interesting to see what they come up with.
Rowbotham did use a boat moving away from him, so they did recreate this part of the experiment.External Quote:
They did not recreate Rowbotham's experiment.
They've got the cameras set up on the bridge at the Welches dam pumping station instead of 8 inches above the water surface as Rowbotham did. Rowbotham's formula (8 inches per mile squared) is only useful at surface level. When you are 10 feet above the surface you have to use an entirely different formula. On top of that, they are only guessing that the camera is 10 feet above the water instead of measuring.
At 10 feet above the water surface the horizon would be 3.87 miles away. But at 5.5 miles only the bottom 21 inches of the kayak would be hidden by the horizon, leaving the man completely visible.
If the camera was 12 feet above the surface only the bottom 12 inches of the kayak would be hidden. At 13 feet above the surface only the bottom 9 inches of the kayak would be hidden. Which shows how important it is to know exactly how far above the surface the camera is. Did anyone use a measuring tape?
Is the bridge 10 feet above the surface? Then if the camera is 4 feet above the deck of the bridge then the camera is 14 feet above the surface, isn't it? Did anyone think of that?
And, as far as I can see, they are just guessing that the kayak was 5.5 miles away. That first bridge is the Ely-Peterborough line railway bridge 2.6 miles distant. I'm guessing that they just made an estimate of how far the kayak was beyond the bridge instead of measuring the distance. (In their heart it was 5.5 miles, but how far was it really?) Did anyone use any definite method to determine distance?
And what's the point of the kayak slowly paddling away anyway? Why not just place a stationary target at the 6 mile point? That way you wouldn't be surprised by the weather turning bad and you would know exactly how far away the target is. The target could have horizontal bars of different colors, each a foot high. That way you could really be sure of what is hidden and what is not.
What this really means is open to interpretation.External Quote:The bridge was one third of the way there. Everyone viewing past the kayak past the bridge on the p900 could see it at 5 and a half mile no problem, unilt bad weather and thermals reduced current visibility and previous visibility
Rowbotham's formula (8 inches per mile squared) is only useful at surface level.
He then goes into a math tutorial, coming up with a new formula.External Quote:
dmurphy25: The trolls and detractors will point out that because we were observing Matthew [the man in the kayak] from the bridge, we wouldn't see the 16 feet of curvature anyway. But I would like to add in some of the latest and very fine work from Jeranism; who has correctly pointed out that the calculation of 8 inches per mile squared is actually wrong.
Jeranism: You guys told us that it's 8 inches per mile squared, but it's only good up to a quarter of the globe. So how can that be the the correct formula for curvature of the entire earth?
External Quote:dmurphy25: So according to this new information, Matthew should have disappeared under 1.7 miles of curvature, not 16 feet.
Apparently the earth is now no bigger than an asteroid.
"only good up to a quarter of the globe"? How far away do they think the kayak is?External Quote:You guys told us that it's 8 inches per mile squared, but it's only good up to a quarter of the globe.
FE fans unanimously confuse curvature "dropoff," with bulge height, as they only cling to the simple "8 inches per mile squared" as the be-all and end-all of bulge calculation. I use this diagram to clearly illustrate their mistake without going into the trig they have no patience for, which has been working wonders for getting thru to them.
A slope?
Apparently the earth is now no bigger than an asteroid.
In a nutshell: flat earthers of the UK - including Dave Murphy - are off to the Bedford Levels to recreate Rowbotham's famous experiment. Will be interesting to see what they come up with.
How can you guys so thoroughly do the wrong experiment and use the wrong math?
#1 you did not even reproduce Rowbotham - he shot at 8" over the water and THAT was PROVEN by Wallace to neglect refraction and thus is wrong
#2 wrong experiment - you need to reproduce Wallace's experiment of shooting at 13 + feet over the water looking at CAREFULLY CALIBRATED survey posts placed half-way and then at the end so you can MEASURE exactly how much is obscured.
#3 use the correct equations and don't ignore refraction. The height of a distant object obscured by the curvature of the Earth is given by:
h₁ = √[(d₀ - (√h₀ √[h₀ + 2 R]))² + R²] - R
The geometry behind this is very simple - two right triangles: https://pbs.twimg.com/media/CncAmBKUIAApAip.jpg
Let's say observer elevation is 3m, we want to know what we can see 9659m (6 miles) away, and estimating 20% Earth curvature for refraction (VERY common over water)
√[(d - (√h √[h + 2 R]))² + R²] - R, d=9659, h=3, R=6371000*1.20 = only half a meter would be expected to be obscured at the base of the distant bridge - which is less than the visual acuity of your optics I'll wager.
Your experiment was a complete bust.
If you want to do it right:
Hire some professional surveyors with professional equipment
Don't wait for some dude to ROW all the way down, that was utterly useless
Have them place leveling posts at BOTH ends and one in the middle (professionally calibrated)
AT LEAST do one pair of sightings above 13 feet over the water -- Ideally ALSO do one at 8" and one up higher and compare & contrast
Get the Closure Error by sighting BOTH directions
http://www.aboutcivil.org/errors-in-levelling.html
http://www.aboutcivil.org/curvature-and-refraction.html
And watch them laugh at you for wanting a 6 mile long sighting but just keep promising you aren't a crackpot?