The Bedford experiment and refraction of light.

I have just finished reading about the Bedford experiment in "The Earth not a Globe" and out of curiosity I decided to Google it, I found that the experiment is quite legitimate and has been repeated several times, by sceptics and supporters of FET and the results have allways been favourable for FET but then I came across a Wikipedia page and it says that light can refract and 'bend' in the air close to the surface thus creating an illusion of a flat earth. I cannot find any other references or scientific information about this but it has made me a little doubtful of FET. What weight does this actually hold?

This sort of surface level refraction is well known in surveying.

Refraction isn't some weird theoretical voodoo like Superstrings - it's the physical phenomena that makes spectacles work. 

Refractive index of air depends on temperature.  On a still day, you can get quite a temperature gradient in the few feet above the ground or above water, and that will play tricks with your line of sight.  Surveyors routinely need to account for this.

http://en.wikipedia.org/wiki/Bedford_Level_experiment

Notice that repeats of the experiment sighting at water level produce Earth curvature measurements anywhere between that expected values & concave, depending on atmospheric conditions.

Notice also from the Wiki article that until photos of Earth from space, a properly performed Bedford Levels experiment was used in textbooks to demonstrate the curvature of the planet

The idea that this was surface refraction was invented for the sole reason of discrediting the experiment. Faced with the evidence that the Earth was flatter than a pancake, magical bendy refraction was invented to explain it away. Refraction certainly exists, but your bendy refraction does not.

Refraction happens at sheer angles. To get the refraction you're speaking of, the light would have to bend in a uniform curve, which is nonsense. Furthermore you can't get a concave view, as the light would be bending straight into the ground.

The idea that this was surface refraction was invented for the sole reason of discrediting the experiment. Faced with the evidence that the Earth was flatter than a pancake, magical bendy refraction was invented to explain it away. Refraction certainly exists, but your bendy refraction does not.

Refraction happens at sheer angles. To get the refraction you're speaking of, the light would have to bend in a uniform curve, which is nonsense. Furthermore you can't get a concave view, as the light would be bending straight into the ground.

Oh dear....

A tangent to a curve IS a sheer angle.

http://en.wikipedia.org/wiki/Mirage#Superior_mirage

It's not magic - it's refraction.  They didn't invent it just to annoy Flat Earthers

Oh dear....

A tangent to a curve IS a sheer angle.

http://en.wikipedia.org/wiki/Mirage#Superior_mirage

It's not magic - it's refraction.  They didn't invent it just to annoy Flat Earthers

If light moved in tangent to a round Earth, then the ground would not appear flat. You're contradicting yourself now.

I have just finished reading about the Bedford experiment in "The Earth not a Globe" and out of curiosity I decided to Google it, I found that the experiment is quite legitimate and has been repeated several times, by sceptics and supporters of FET and the results have allways been favourable for FET but then I came across a Wikipedia page and it says that light can refract and 'bend' in the air close to the surface thus creating an illusion of a flat earth. I cannot find any other references or scientific information about this but it has made me a little doubtful of FET. What weight does this actually hold?

Here's what I witnessed and photographed looking the same distance (12 miles to hillside, 9 to bridge) across water from two different elevations.


More explanation, debating, etc,  here regarding ENaG and this picture- http://www.theflatearthsociety.org/forum/index.php/topic,56472.0.html

If light moved in tangent to a round Earth, then the ground would not appear flat. You're contradicting yourself now.

Exactly!  The ground doesn't appear flat.  Ships disappear over the horizon - the sun sets in the evening, and the Bedford Levels experiment - properly performed - was used to demonstrate the curvature of the planet in old textbooks. 

But under certain conditions, refraction creates mirages by effectively bending the light, making the horizon appear higher than it should.

Just try re-doing Rowbotham's experiment on an overcast day when there is a stiff breeze blowing.  See what result you get.

The ground doesn't appear flat. 

Yes it does, else you wouldn't have tried using bendy refraction to explain it away.

Ships disappear over the horizon - the sun sets in the evening, and the Bedford Levels experiment - properly performed - was used to demonstrate the curvature of the planet in old textbooks. 

None of that demonstrates curvature. You've simply been told to think it does.

But under certain conditions, refraction creates mirages by effectively bending the light, making the horizon appear higher than it should.

Well do you think it looks flat or do you not? It appears you can not make up your mind even in the same post.

Just try re-doing Rowbotham's experiment on an overcast day when there is a stiff breeze blowing.  See what result you get.

Sounds pretty dreary and unpredictable. I guess RE'ers like to do their experiments incorrectly.

Rushy is right, round-earthers couldn't answer this damning experiment so they simply made up a solution.

Pongo, are you saying that there are absolutely no circumstances where refraction could make a round earth look flat?

Rushy is right, round-earthers couldn't answer this damning experiment so they simply made up a solution.

How many examples of this used by FET do I need to come up with? I could. Please see the FAQ for a list.

Pongo, are you saying that there are absolutely no circumstances where refraction could make a round earth look flat?

No, but this experiment have been repeated many times and is demonstrable proof of a flat-earth.

Quote from: markjo on December 11, 2012, 12:52:29 PM

Pongo, are you saying that there are absolutely no circumstances where refraction could make a round earth look flat?

No, but this experiment have been repeated many times and is demonstrable proof of a flat-earth.

It's been repeated several times with various results which can easily be explained when you account for the refractive properties of air with a temperature gradient.  This isn't proof.

With all these experiments performed at Bedford, did anyone ever bother to do a view down low close to the water, and then move the equipment up higher to get a view from a different elevation?  If so, what were the results?