Forumite Members › General Topics › Other Stuff › Flat Earth
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Ed P.
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August 28, 2017 at 1:42 pm #11245
I just watched a Flat Earth video… it was very good. But before I become a convert I want to check it for myself. I’m about to go to the beach where I will be able to see cliffs about 17km east across the water. That’s about 0.15 degree angle on the earth circumference if I got it right. How do I calculate the gap between the triangle and the circle’s surface at the thickest point? I could do it with the triangles etc but there probably is an easy way?
I’m off to the beach now. My entire future depends on this answer ?
August 28, 2017 at 2:53 pm #11251Determined, inspired lunacy, with an attempt to use mathematical proof. That’s just what we need on a boring Bank Holiday Monday.
One question: When you look out to sea from a fixed point on land, irrespective of the height of that fixed point, why is the horizon an arc of a circle?
Then there’s this:
http://www.popsci.com/10-ways-you-can-prove-earth-is-round
But thanks for brightening up my day.
When the Thought Police arrive at your door, think -
I'm out.August 28, 2017 at 3:44 pm #11254Bob, don’t blame me God made Earth flat. And it looks like he/she did a pretty crap job too. I went for a swim and as I looked at the sailing boats in the distance I could see only maybe three quarters of the sails. Waves are negligible as I could see other swimmer’s heads 1-2 km. Clearly it isn’t that flat…
August 28, 2017 at 4:16 pm #11258The Earth IS flat, didn’t we all play marbles as kids, if the Earth was round they wouldn’t have stayed where they were put. ?
The more you meet people the more you understand why Noah took animals instead of humans
August 28, 2017 at 5:47 pm #11263The Earth IS flat, didn’t we all play marbles as kids, if the Earth was round they wouldn’t have stayed where they were put.
I had my doubts at first but when the flatearthers used corialis effect to argue one of their points that completely sold it to me. ?
August 28, 2017 at 5:49 pm #11264Determined, inspired why is the horizon an arc of a circle?
Look at the link you provided. The pic in the point six shows it.
August 28, 2017 at 5:50 pm #11265Up next, why Scientology isn’t nuts. ?
August 28, 2017 at 5:55 pm #11267Up next, why Scientology isn’t nuts.
I used to live in East Grinstead and a few of my friends are Scientologists so lets not go there. I have only good things to say about them.
August 29, 2017 at 10:44 am #11285They are called flat earth ‘truthers’ for a reason ?
August 29, 2017 at 4:15 pm #11290The Earth IS flat, didn’t we all play marbles as kids, if the Earth was round they wouldn’t have stayed where they were put.

I once lost a half-crown in 1956 on an errand for me mam. It rolled away until I couldn’t find it, cost me several smacks around the head. Proof positive!
Tadka, the fact that your Scientology friends are good people, does not mean that their beliefs are not dumb. Next door to me is a guy who was well on his way to an obese death: alcoholic, heavy smoker, lost the use of his legs. Had a visit from a Mormon a couple of years ago, became a convert. He is now several stones lighter, dresses smartly and goes out regularly. That does not obscure the fact that a religion built upon some guy finding golden tablets in an American mountain cave, is preposterous and plain silly.
The Earth is not Spherical: it is orange-shaped, being slightly flattened at the Poles. It is an oblate spheroid.
When the Thought Police arrive at your door, think -
I'm out.August 29, 2017 at 8:57 pm #11300I heartedly suggest a trip into space, and then look back.
Arch Linux, on a Ryzen 7 1800X, 32 GB, 5 (yes -5) HDs inc 5 SSDs, 4 RPi 3Bs + 1 RPi 4B - one as an NFS server with two more drives, PiHole (shut yours), Plex server, cloud server, and other random Pi stuff. Nice CoolerMaster case, 2 x NV GTX 1070 8GB, and a whopping 32" AOC 1440P monitor.
August 29, 2017 at 9:41 pm #11301Don’t know about a flat earth but i may be able to help with the maths.
Just draw a line from the middle of your line of sight to the center of the earth to form 2 right angle triangles.
Now use the pythagarus sum of the squares rule to get the length of your new line.
Subtract the length of your line fron the radious of the earth and bingo.
I get 6 meters on my calculator ?
August 30, 2017 at 11:56 am #11311I heartedly suggest a trip into space, and then look back.
Book now with Virgin Galactic!
When the Thought Police arrive at your door, think -
I'm out.August 30, 2017 at 12:36 pm #11314Your question prompted me to check on WikiHow. Interesting little site it taught me a new (rough) formula for the horizon distance.
Square root[Height of your eyes in feet x1.5 ]= horizon distance in miles
i.e roughly 3 miles at sea-level for most adults
August 30, 2017 at 2:27 pm #11319Don’t know about a flat earth but i may be able to help with the maths. Just draw a line from the middle of your line of sight to the center of the earth to form 2 right angle triangles. Now use the pythagarus sum of the squares rule to get the length of your new line. Subtract the length of your line fron the radious of the earth and bingo. I get 6 meters on my calculator
I found some website where you enter whatever data you have on a triangle and it gives you the rest. I made two tringles and a line in the middle to divide them so basically 4 triangles. Then I worked it all out in a somewhat more longwinded way. But I got 44m. Sounds like a bit too much of a curve there but I kept making mistakes so it’s probably wrong.
August 30, 2017 at 4:03 pm #11320Don’t know about a flat earth but i may be able to help with the maths. Just draw a line from the middle of your line of sight to the center of the earth to form 2 right angle triangles. Now use the pythagarus sum of the squares rule to get the length of your new line. Subtract the length of your line fron the radious of the earth and bingo. I get 6 meters on my calculator
I found some website where you enter whatever data you have on a triangle and it gives you the rest. I made two tringles and a line in the middle to divide them so basically 4 triangles. Then I worked it all out in a somewhat more longwinded way. But I got 44m. Sounds like a bit too much of a curve there but I kept making mistakes so it’s probably wrong.
Yep your calculation is wrong. Just a simple thought experiment tells you that your calculation is way out.
Imagine you and someone your height are on either side of a big lake (roughly 3 miles across). at the point you can only see their eyes (binoculars allowed!)you have a line between your eyes that just scrapes the earth’s surface in the middle. The chord meanwhile goes from your feet to his feet and the difference between them (i.e. the ‘bulge’) is your height ~2 metres.
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