Flat Earth Follies: White Cliffs of Dover from Boulogne

Another extremely clever Flat Earth 'proof' the Earth is Flat...

Run these numbers please, Dark Star pic.twitter.com/dyBRcEaCKd

— Think For Yourself (@ThinkForYourse5) November 12, 2017

Ok...

/Google for source image/

Original by Dave Cawkwell on Blogspot

Confirms it is from Boulogne, France -- Dave Cawkwell says he is about 10 meters up, I think a little higher but I'll go with 10 meters (32 feet).

Based on the position of the wall we appear to be somewhere very near the location marked below, which puts us 29.5 miles away -- not 31 miles away -- and 2 feet higher than the Meme.

What else?  Oh yeah, those are the Cliffs West of Dover which puts them up as high as 437 feet, not just 350 (and this area is 142 meters high)

And once we account for Refraction, completely ignored in the original.

So I find that we expect about 252 feet of the Cliffs to be hidden leaving about 185 exposed.

I also see a small band of an inferior mirage line running along the bottoms of the cliff so the true horizon is likely obscured by the mirage effect by some amount (few pixels worth here).

We don't have the exact camera and lens details to get Field of View but we can estimate the angular size of the Cliffs by finding their angular size at 29.5 miles:

2*arctan(437/2/(29.5*5280)) = 0.1607°

And looking at this and this we get a good estimate of the height of the walls to around about 20' high (from the walkway where the people are fishing to the top) and we know the end is about 1.3 miles away from the camera position - which gives us an angular size of about 0.1669° -- very close to the angular size of the whole Cliffs of Dover at 437' high!

Very good match.

And putting all this together, here is a Meme version you can use for debunking.