[Tintagel]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

[Tintagel]

As for stellar parallax, the ancient Greeks surmised correctly that there isn't enough stellar parallax observed to show that the earth is moving. 

Were these the same ancient Greeks who surmised that flies spontaneously emerge from rotten meat?

Indeed, and also surmised the earth was a sphere, but they got a few things right.

[markjo]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

I love it when you guys cherry pick from that article.  Did you even read the conclusions?

Summary and Conclusions
In view of the agreement between the visual obser-
vations, measurements of the photographs, and the
theoretical curvatures, it seems well established that
the curvature of the Earth is reasonably well under-
stood and can be measured from photographs. The
threshold elevation for detecting curvature would
seem to be somewhat less than 35;000ft but not as
low as 14;000 ft.  Photographically, curvature may be
measurable as low as 20;000 ft.

[Antonio]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

That's a bold assumption. Can you give the maths for this "perspective" phenomenon and some relevant data about airplane windows lensing ?

[Tintagel]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

That's a bold assumption. Can you give the maths for this "perspective" phenomenon and some relevant data about airplane windows lensing ?

Maths?  It's just a trick of perception, darling.  Look at this.



See the lovely, flat horizon behind them?  Now imagine you are one of those skydivers.  That horizon wraps all the way around you, 360 degrees.  Look to your left, more horizon.  Look to your right, still more horizon.  It extends in a circle around your point of view, and that can cause the illusion of curvature. 

[Rama Set]

It extends in a circle around your point of view, and that can cause the illusion of curvature. 

I think this is what he is asking you to substantiate.  Why would it not just appear to be a straight line that encircles you?

[Tintagel]

a straight line that encircles you?

a straight line that encircles you?

a straight line that encircles you?

Yes.

[Rama Set]

a straight line that encircles you?

a straight line that encircles you?

a straight line that encircles you?

Yes.

Are you alright?  Maybe save the trolling for down below?

[Tintagel]

a straight line that encircles you?

a straight line that encircles you?

a straight line that encircles you?

Yes.

Are you alright?  Maybe save the trolling for down below?

Apologies, that was snarky but you did illustrate my point rather well in your attempted rebuttal.

[Rama Set]

I did?  I guess we have different interpretations of what I said. You can be encircled by a line that has no apparent curvature in any axis.

[Antonio]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

That's a bold assumption. Can you give the maths for this "perspective" phenomenon and some relevant data about airplane windows lensing ?

Maths?  It's just a trick of perception, darling.  Look at this.
(...)
See the lovely, flat horizon behind them?  Now imagine you are one of those skydivers.  That horizon wraps all the way around you, 360 degrees.  Look to your left, more horizon.  Look to your right, still more horizon.  It extends in a circle around your point of view, and that can cause the illusion of curvature.

Well, we were talking about vision through plane windows,  barely 30-40° for a passenger and perhaps 180° for a pilot. We are far form this outdoor 360° situation. Other than this lovely picture, you didn't give any scientific explanation to you assertion (not to mention windows lensing).

BTW, from my little skydiving experience, I've never seen some horizon curvature when jumping at 10 000+ ft

[Tintagel]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

That's a bold assumption. Can you give the maths for this "perspective" phenomenon and some relevant data about airplane windows lensing ?

Maths?  It's just a trick of perception, darling.  Look at this.
(...)
See the lovely, flat horizon behind them?  Now imagine you are one of those skydivers.  That horizon wraps all the way around you, 360 degrees.  Look to your left, more horizon.  Look to your right, still more horizon.  It extends in a circle around your point of view, and that can cause the illusion of curvature.

Well, we were talking about vision through plane windows,  barely 30-40° for a passenger and perhaps 180° for a pilot. We are far form this outdoor 360° situation. Other than this lovely picture, you didn't give any scientific explanation to you assertion (not to mention windows lensing).

BTW, from my little skydiving experience, I've never seen some horizon curvature when jumping at 10 000+ ft

Pilots will tell you that no curvature is visible on a commercial flight, yet many airline passengers (and many visitors here) claim to have seen the curvature of the earth from a jet.  They are wrong, and your own experience backs up my assertion, since you've never seen curvature while skydiving.  My point is that some people fool themselves into believing they see curvature where there is none.  It isn't a measurable effect, it's just people thinking they see something when they really don't.  (See also: ghosts.)

You keep asking for math to back this point up, when all I need to back that up is to point at the many many people who claim to have seen curvature from commercial flights or skydiving experiences, when even round earthers assert that they are mistaken. 

[inquisitive]

Maths here - http://thulescientific.com/Lynch%20Curvature%202008.pdf

[Tintagel]

Maths here - http://thulescientific.com/Lynch%20Curvature%202008.pdf

And your point is where?

[Rama Set]

At the end of the linked paper. It explicitly disagrees  with your assertion that curvature  is not measurable.

5. Summary and Conclusions
In view of the agreement between the visual obser- vations, measurements of the photographs, and the theoretical curvatures, it seems well established that the curvature of the Earth is reasonably well under- stood and can be measured from photographs. The threshold elevation for detecting curvature would seem to be somewhat less than 35;000ft but not as low as 14; 000 ft. Photographically, curvature may be measurable as low as 20; 000 ft.

[Antonio]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

That's a bold assumption. Can you give the maths for this "perspective" phenomenon and some relevant data about airplane windows lensing ?

Maths?  It's just a trick of perception, darling.  Look at this.
(...)
See the lovely, flat horizon behind them?  Now imagine you are one of those skydivers.  That horizon wraps all the way around you, 360 degrees.  Look to your left, more horizon.  Look to your right, still more horizon.  It extends in a circle around your point of view, and that can cause the illusion of curvature.

Well, we were talking about vision through plane windows,  barely 30-40° for a passenger and perhaps 180° for a pilot. We are far form this outdoor 360° situation. Other than this lovely picture, you didn't give any scientific explanation to you assertion (not to mention windows lensing).

BTW, from my little skydiving experience, I've never seen some horizon curvature when jumping at 10 000+ ft

Pilots will tell you that no curvature is visible on a commercial flight, yet many airline passengers (and many visitors here) claim to have seen the curvature of the earth from a jet.  They are wrong, and your own experience backs up my assertion, since you've never seen curvature while skydiving.  My point is that some people fool themselves into believing they see curvature where there is none.  It isn't a measurable effect, it's just people thinking they see something when they really don't.  (See also: ghosts.)

You keep asking for math to back this point up, when all I need to back that up is to point at the many many people who claim to have seen curvature from commercial flights or skydiving experiences, when even round earthers assert that they are mistaken.

Sorry, but you started explaining that this observation can be explained by windows lensing - unsupported claim - , perspective issue, - still unsupported claim- or an illusion , directly contradicted by my own experience.

Unfortunately, even if I flew Concorde once during a small supersonic loop trip, I could'nt see myself a curvature as I was located at the aisle seat, (and because these windows were awfully small !)
A close relative was a former Concorde flight engineer. He claims he routinely saw earth curvature at cruise altitude. I tend to believe his experience, and the link provided seems to agree with him.

[Tintagel]

Commercial airplanes don't fly high enough to see the curvature of the Earth if it is curved.

commercial aircraft sel-
dom exceed altitudes of 40; 000 ft (1 ft 1⁄4 0:3048 m).
Interviews with pilots and high-elevation travelers
revealed that few if any could detect curvature below
about 50; 000 ft.

Exactly.  If you think you have seen the curvature of earth from a commercial flight, you are mistaken, and have been a victim of either perspective or lensing.  This was my point.

That's a bold assumption. Can you give the maths for this "perspective" phenomenon and some relevant data about airplane windows lensing ?

Maths?  It's just a trick of perception, darling.  Look at this.
(...)
See the lovely, flat horizon behind them?  Now imagine you are one of those skydivers.  That horizon wraps all the way around you, 360 degrees.  Look to your left, more horizon.  Look to your right, still more horizon.  It extends in a circle around your point of view, and that can cause the illusion of curvature.

Well, we were talking about vision through plane windows,  barely 30-40° for a passenger and perhaps 180° for a pilot. We are far form this outdoor 360° situation. Other than this lovely picture, you didn't give any scientific explanation to you assertion (not to mention windows lensing).

BTW, from my little skydiving experience, I've never seen some horizon curvature when jumping at 10 000+ ft

Pilots will tell you that no curvature is visible on a commercial flight, yet many airline passengers (and many visitors here) claim to have seen the curvature of the earth from a jet.  They are wrong, and your own experience backs up my assertion, since you've never seen curvature while skydiving.  My point is that some people fool themselves into believing they see curvature where there is none.  It isn't a measurable effect, it's just people thinking they see something when they really don't.  (See also: ghosts.)

You keep asking for math to back this point up, when all I need to back that up is to point at the many many people who claim to have seen curvature from commercial flights or skydiving experiences, when even round earthers assert that they are mistaken.

Sorry, but you started explaining that this observation can be explained by windows lensing - unsupported claim - , perspective issue, - still unsupported claim- or an illusion , directly contradicted by my own experience.

Unfortunately, even if I flew Concorde once during a small supersonic loop trip, I could'nt see myself a curvature as I was located at the aisle seat, (and because these windows were awfully small !)
A close relative was a former Concorde flight engineer. He claims he routinely saw earth curvature at cruise altitude. I tend to believe his experience, and the link provided seems to agree with him.

So you're saying you've never seen curvature on a flight, even on a high-altitude flight on the Concorde.  Thanks for your contribution.

Many people claim to have seen curvature on flights.  I believe they have not.  I'm not one to call anyone a liar, so I like to try to find alternative explanations.  You seem to be villainizing me for that.  I never made the definite claim that there is measurable curvature due to perspective, lensing, or illusion, but apparently because I'm ostensibly a "flat-earther" anything I say is a statement of irrefutable fact needs to be supported by maths and peer reviewed studies. 

The appearance of curvature at higher altitudes, a la the concorde, is actually where I wanted this discussion to go, so thank you for bringing it up.  Many sources cite measurable curvature at these altitudes, which I think is fascinating, really.

[Rama Set]

So are you just going to ignore the source that demonstrated the measurability of curvature?

[Antonio]

Sorry, but you started explaining that this observation can be explained by windows lensing - unsupported claim - , perspective issue, - still unsupported claim- or an illusion , directly contradicted by my own experience.

Unfortunately, even if I flew Concorde once during a small supersonic loop trip, I could'nt see myself a curvature as I was located at the aisle seat, (and because these windows were awfully small !)
A close relative was a former Concorde flight engineer. He claims he routinely saw earth curvature at cruise altitude. I tend to believe his experience, and the link provided seems to agree with him.

So you're saying you've never seen curvature on a flight, even on a high-altitude flight on the Concorde.  Thanks for your contribution.

Many people claim to have seen curvature on flights.  I believe they have not.  I'm not one to call anyone a liar, so I like to try to find alternative explanations.  You seem to be villainizing me for that.  I never made the definite claim that there is measurable curvature due to perspective, lensing, or illusion, but apparently because I'm ostensibly a "flat-earther" anything I say is a statement of irrefutable fact needs to be supported by maths and peer reviewed studies. 

The appearance of curvature at higher altitudes, a la the concorde, is actually where I wanted this discussion to go, so thank you for bringing it up.  Many sources cite measurable curvature at these altitudes, which I think is fascinating, really.

No I'm saying that during my single Concorde experience, I was not in a position allowing me to see curvature, nothing more, nothing less. From my perspective, it's inconclusive.

Your alternative explanations are always welcome, and I'm sorry if you feel villainised, but you should agree that this kind of statement :

Perspective and lensing through airline windows causes the apparent curve viewed on commercial flights at 30,000 feet or so

sounds quite like an irrefutable fact, whatever your favourite earth shape is.

Anyway, if we agree that some curvature is seen during 50 kft+  flights, let's dig a bit, why do you find it fascinating ?

[aston240]

Im Back,

I didn't say commercial airliners. I said corporate aircraft like the gulfstream V or Falcon900.
Both aircraft that fly higher than normal commercial aircraft. 51,000ft.

T