## Monday, 1 February 2016

1. “The horizon always appears perfectly flat 360 degrees around the observer regardless of altitude. All amateur balloon, rocket, plane and drone footage show a completely flat horizon over 20+ miles high. Only NASA and other government “space agencies” show curvature in their fake CGI photos/videos.”

Here is an useful explanation about how to check this for yourself. No need to rely on Nasa!

# How to Take a Photo of the Curve of the Horizon

https://www.metabunk.org/how-to-take-a-photo-of-the-curve-of-the-horizon.t8859/#post-207697

Here is an a example where the curve has been deliberately and openly exaggerated by 4 times in order to prove that it is there (alsthough hard to see from this height..

Passengers have seen a curved horizon from Concorde (Concorde flew higher than most airliners, which don’t much higher than 40,000 feet, not high enough). Of course, if you are a conspiracy theorist you can always dismiss anyone's account as "part of the conspiracy". Which is why such theories are irrational and unscientific - they protect themselves from any possibility of falsification.
Here is some more photo evidence – amateur images at http://spacephoto.tumblr.com/

Mr Dubay’s photos don’t help him.

However, Daimonie, I’m afraid I have to say that the other video you post is not convincing; there is too much clear barrel distortion caused by the wide angle lens – at around 2.50 and again towards the end we see very strong curvature almost at ground level, which must be an artefact. Moreover, at just 3.18 we get momentary concave horizon as the camera bobs up and down.

However, the thread for Metabunk I mentioned above shows how to avoid this distotion, so anyone can have a go for themselves.

For example
Center and Level the Horizon - Distortion happens concentrically around the middle of the image. So if a line goes through the middle of the image it will be lengthened or shortened slightly, but it will not be bent.
Image Source: https://millerprosthetics.com/2016/08/25/nancy-settles-in-her-rio-apartment-and-its-amazing/
Use a Straight Edge - If you put a known straight edge very close to the horizon, then you can compare the horizon against the straight edge. If the lense is distorting things then the straight edge will be curved too. Then we can see if the horizon curves more than the straight edge, which will indicate the horizon is actually curved.
(This image discussed in more detail here: https://www.metabunk.org/measuring-the-curvature-of-the-horizon-with-a-level.t7832/ )
Take pictures above and below the center - Move the camera so the horizon is first above the center line, then at the center line, and then below the center line. If it curves in the same direction all three then it's definitely curved. If not then we need to account for this.
Here is a paper examining when it is possible to see curvature, based on both calculation and observation by the author and others: http://thulescientific.com/Lynch%20Curvature%202008.pdf

This shows why Mr Dubay’s photos don’t help him. The one at ground level shows a sharp horizon, but the high altitude horizon is too blurred to let us measure any curvature.

On page H41 the author writes: “2. Visually Detect the Earth’s Curvature I first examined the horizon from commercial jet aircraft. While there was a general sense of the horizon, actually identifying the horizon’s location was difficult. It was a very low-contrast boundary in a region of the sky where there were much higher-contrast changes. There were almost always clouds on the horizon that prevented accurate horizon location. When the horizon was clear, detecting curvature from around 35; 000 ft was relatively easy, providing that a wide, unobstructed FOV was available. With a horizontal FOV of 90° or more, the curvature was subtle but unmistakable. Under similar conditions with a FOV smaller than about 60°, the curvature was not discernible. Thus, visually detecting the curvature would seem to depend on both the actual curvature and the FOV.”

There is a discussion about what Lynch says here
https://www.metabunk.org/are-lynchs-horizon-calculations-correct.t7877/#post-189357

It contains a lot more than this graphic:

Warning - there is some mathematics in that thread!

Another good mathematical description of why Dubay’s claim is wrong is here

Have alook at this video for more details, too.

1. For this reference: http://www.travelscholar.com/concorde/page03.html, don't you think that the windows made the curve?

1. No, the windows do't cause a curved appearance. Here is the evidence:
https://youtu.be/ZOsxgGeABGM
Wolfie6020, a long distance pilot posted this: Show me the Curvature... Here it is and don't blame the window - read comments before posting

No the curvature is not being caused by the window and here is proof.

The curve you see is a result of the Earth being a Globe and matches the globe prediction perfectly.

It has been independently verified.

https://postimg.org/image/c5ntic3d1/

https://imgur.com/a/E60OZ

This video clearly shows the Horizon curvature I see at high altitude.
We fly significantly higher than most commercial aircraft.

We operate above 45,000 ft routinely. Airliners operate typically Mid to High 30's. (35,000 to 39,000 ft)

The aircraft below and ahead of us is a Qantas jet traveling in the same direction.

There is NO distortion in the Cockpit window and no fish-eye effect in this camera - you can see this at the end of the video when it shows the top of the flight instruments are perfectly straight at 0:38."

2. Earth curvature and the curve of the horizon are two different things. You can't see earth curvature from an airplane at 30,000ft because the horizon is only about 220 miles out. About the size of a U.S. quarter placed on a 16 inch globe. The curve is the circle of the horizon, not earth curvature.

My comment on another forum where a poster said that Neil deGrasse Tyson stated that in an airplane you can't see the curve of the earth.

***************************

Neil is correct. At 30,000ft the horizon is about 220 miles away. If you were able to see a full 360° around the plane what you're seeing isn't the curvature of the earth but the circle of the visible horizon. Facing forward, if you turn 10° right the horizon is still about 220 miles. Turn 90°, still about 220 miles. Everywhere that you look at the horizon it's roughly 220 miles. Turn completely around you've made a circle but it's not earth curve that you're seeing.

This is why at the beach, the horizon looks straight. Look straight ahead, look left as far as you can at the ocean, now look right, every point on the horizon that you see is roughly three miles out. The reason it looks level is because the horizon that you're seeing is only about 4 or 5 miles of a much larger circle that you'd be able to see if the land to the sides and behind you didn't block it.

If you were able to stand on the ocean 50 miles out with a calm sea, at six feet tall your horizon would be about three miles. Turn completely around, you've made a full 360° circle and every point on the horizon that you see is about 3 miles out. You're not seeing earth curve, you're seeing the circle of the visible horizon.

In fact, if you take a 16 inch globe and a U.S. quarter place the quarter anywhere on the globe, trace a circle around the quarter, that's actually a little bigger than what you'd see from a plane if you could see 360°around it. That circle you traced is the horizon that you'd see, not the curve of the earth.

Kevin McMillen