Why The Earth Appears Curved at a High Altitude.

  • 295 Replies
  • 42454 Views
*

Pongo

  • Planar Moderator
  • 6753
Why The Earth Appears Curved at a High Altitude.
« on: June 01, 2010, 01:22:10 AM »
Here is something that everyone has seen many times.  A round-earth believer, or shape denier as I will call them from here on out, posts a pic from high altitude or makes the statement that in a plane you can see the curvature of the earth.  And indeed, the pictures of the shape deniers do look compelling.  However, it's all an optical illusion.

At ground level, if you look out the window of a plane every flat-earth believer and every shape denier can agree that the earth looks flat.  However, at extreme altitudes, it appears that there is a curvature.  This is well documented and understood.  Now, a shape denier will point to this and ignorantly proclaim, "Ah hah!  We've got you!  Another win for RET!!!"  Seems like a solid claim on the surface, lets look deeper.

The traditional response to this is that they are seeing the outline of the sun's spotlight, and at very very high altitudes or close to dawn/dusk this is true.  However, some pictures are taken at noon, or at the center of the spotlight at altitudes that shouldn't show curvature.  So what's going on?

The real reason that the earth looks curved is due to air pressure.  In order to keep passengers and personnel comfortable, and alive, a plain must maintain a certain atmospheric pressure.  Once a plain gets so high, the pressure outside the fuselage is lower than it is on the inside.  This causes the windows to bow outwards and give objects in the distance a curved look.  As the horizon is the only thing viewable that spans the length of a window, and at a sufficiently far distance, it appears to be curved.  

This optical illusion has fooled many people the world over, but it will no longer deceive you!  The next time you are on an airliner and a kid points out the window claiming to see the curvature of the earth, you can educate him or her on what is really going on and hopefully open their eyes to truth of the shape of this flat earth.
« Last Edit: November 25, 2010, 12:41:25 AM by Pongo »

*

WardoggKC130FE

  • 11842
  • What website is that? MadeUpMonkeyShit.com?
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #1 on: June 01, 2010, 04:17:53 AM »
This is all true. 

*

spanner34.5

  • 4634
  • feck arse drink
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #2 on: June 01, 2010, 06:07:00 AM »
Both Wardogg and myself have looked out of an open aircraft window/door at varying altitudes.

To my knowledge neither of us has seen any evidence of a round Earth.
My I.Q. is 85. Or was it 58?

*

markjo

  • Content Nazi
  • The Elder Ones
  • 38206
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #3 on: June 01, 2010, 06:09:48 AM »
Both Wardogg and myself have looked out of an open aircraft window/door at varying altitudes.

To my knowledge neither of us has admitted to seeing any evidence of a round Earth.

Fixed.
Science is what happens when preconception meets verification.
Quote from: Robosteve
Besides, perhaps FET is a conspiracy too.
Quote from: bullhorn
It is just the way it is, you understanding it doesn't concern me.

?

General Disarray

  • Official Member
  • 5039
  • Magic specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #4 on: June 01, 2010, 06:35:33 AM »
Another troll for FET!

Airplanes don't just suddenly start being pressurized at high altitudes, they are pressurized from ground level.
You don't want to make an enemy of me. I'm very powerful.

*

markjo

  • Content Nazi
  • The Elder Ones
  • 38206
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #5 on: June 01, 2010, 06:51:00 AM »
Another troll for FET!

Airplanes don't just suddenly start being pressurized at high altitudes, they are pressurized from ground level.

Not true.  Airliner cabins are typically pressurized to an altitude of about 6000 - 8000 feet at cruising altitude.
http://en.wikipedia.org/wiki/Cabin_pressurization
Science is what happens when preconception meets verification.
Quote from: Robosteve
Besides, perhaps FET is a conspiracy too.
Quote from: bullhorn
It is just the way it is, you understanding it doesn't concern me.

?

General Disarray

  • Official Member
  • 5039
  • Magic specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #6 on: June 01, 2010, 07:05:29 AM »
Another troll for FET!

Airplanes don't just suddenly start being pressurized at high altitudes, they are pressurized from ground level.

Not true.  Airliner cabins are typically pressurized to an altitude of about 6000 - 8000 feet at cruising altitude.
http://en.wikipedia.org/wiki/Cabin_pressurization

I stand corrected, but according to the article "Visually discerning the curvature of the Earth" by David K. Lynch,

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

Curvature cannot be measured as low as 6-8000 feet anyway. So my point that airplane cabins are pressurized well below the altitude that curvature can be measured stands.
You don't want to make an enemy of me. I'm very powerful.

*

WardoggKC130FE

  • 11842
  • What website is that? MadeUpMonkeyShit.com?
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #7 on: June 01, 2010, 07:58:44 AM »
Both Wardogg and myself have looked out of an open aircraft window/door at varying altitudes.

To my knowledge neither of us has admitted to seeing any evidence of a round Earth.

Fixed.

I swear on all that is holy, I have never seen a curvature in all my flight hours.


Curvature cannot be measured as low as 6-8000 feet anyway. So my point that airplane cabins are pressurized well below the altitude that curvature can be measured stands.

You are missing the point.  When an airplane pressurizes the pressure inside the airplane is greater than that outside the airplane.  In a Herk its about 7.5 psi at altitude.  An airliner probably runs about 9 psi ( At least the GIVs did)  Anyways that pressure pushes out on the hull of the airplane causing it to bow a little.  That is his point.  Not that the cabin is actually at 6-8K.  So if you have a 40 foot long by 8 fot wide by 12 foot tall cargo compartment.  How much total pressure is pushing out against the skin of that airplane?

?

Thermal Detonator

  • 3135
  • Definitively the best avatar maker.
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #8 on: June 01, 2010, 08:07:26 AM »
The original post is a massive failbag of trollness. If Wardogg thinks it's true it either means he's not really a pilot or if he is, he understands the machines he flies so poorly that he should be immediately grounded. Of course, he might be a troll too...  ::)
Gayer doesn't live in an atmosphere of vaporised mustard like you appear to, based on your latest photo.

*

Parsifal

  • Official Member
  • 36114
  • Bendy Light specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #9 on: June 01, 2010, 08:09:15 AM »
The original post is a massive failbag of trollness. If Wardogg thinks it's true it either means he's not really a pilot or if he is, he understands the machines he flies so poorly that he should be immediately grounded. Of course, he might be a troll too...  ::)

I wasn't aware that understanding the physical properties of windows was a requirement for competent handling of an aircraft.
« Last Edit: June 01, 2010, 08:26:41 AM by Parsifal »
I'm going to side with the white supremacists.

*

WardoggKC130FE

  • 11842
  • What website is that? MadeUpMonkeyShit.com?
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #10 on: June 01, 2010, 08:11:20 AM »
The original post is a massive failbag of trollness. If Wardogg thinks it's true it either means he's not really a pilot or if he is, he understands the machines he flies so poorly that he should be immediately grounded. Of course, he might be a troll too...  ::)

Hmmmm i feel an experiment is in order.  I will report back the results tomorrow.

?

Thermal Detonator

  • 3135
  • Definitively the best avatar maker.
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #11 on: June 01, 2010, 08:15:15 AM »
The original post is a massive failbag of trollness. If Wardogg thinks it's true it either means he's not really a pilot or if he is, he understands the machines he flies so poorly that he should be immediately grounded. Of course, he might be a troll too...  ::)

I wasn't aware that understanding the physical proprties of windows was a requirement for competent handling of an aircraft.
Have you forgotten your ban on participating in discussions involving aviation?
You clearly don't understand my grounds for concern, so stop trying to join in.
Gayer doesn't live in an atmosphere of vaporised mustard like you appear to, based on your latest photo.

*

markjo

  • Content Nazi
  • The Elder Ones
  • 38206
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #12 on: June 01, 2010, 08:19:20 AM »
Both Wardogg and myself have looked out of an open aircraft window/door at varying altitudes.

To my knowledge neither of us has admitted to seeing any evidence of a round Earth.

Fixed.

I swear on all that is holy, I have never seen a curvature in all my flight hours.

Says the man that works for a known agency of the conspiracy.
Science is what happens when preconception meets verification.
Quote from: Robosteve
Besides, perhaps FET is a conspiracy too.
Quote from: bullhorn
It is just the way it is, you understanding it doesn't concern me.

*

WardoggKC130FE

  • 11842
  • What website is that? MadeUpMonkeyShit.com?
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #13 on: June 01, 2010, 08:26:36 AM »
Both Wardogg and myself have looked out of an open aircraft window/door at varying altitudes.

To my knowledge neither of us has admitted to seeing any evidence of a round Earth.

Fixed.

I swear on all that is holy, I have never seen a curvature in all my flight hours.

Says the man that works for a known agency of the conspiracy.

Shhhh...dont tell them that.  They will never believe me now.

*

Parsifal

  • Official Member
  • 36114
  • Bendy Light specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #14 on: June 01, 2010, 08:28:28 AM »
Have you forgotten your ban on participating in discussions involving aviation?
You clearly don't understand my grounds for concern, so stop trying to join in.

Your grounds for concern constitute Wardogg agreeing with the OP, which makes no claims regarding aviation, only a fairly obvious effect on the windows of aircraft.
I'm going to side with the white supremacists.

?

Thermal Detonator

  • 3135
  • Definitively the best avatar maker.
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #15 on: June 01, 2010, 09:04:35 AM »
Have you forgotten your ban on participating in discussions involving aviation?
You clearly don't understand my grounds for concern, so stop trying to join in.

Your grounds for concern constitute Wardogg agreeing with the OP, which makes no claims regarding aviation, only a fairly obvious effect on the windows of aircraft.

You understand nothing, as revealed by this post.
Gayer doesn't live in an atmosphere of vaporised mustard like you appear to, based on your latest photo.

Re: Why The Earth Appears Curved at a High Altitude.
« Reply #16 on: June 01, 2010, 09:12:36 AM »
The pressure differential between an aircraft and the outside atmosphere is not nearly enough to cause a noticeable elastic deformation of the sort of glass used in aircraft windows.

I thought you guys were up on your physics?

Really feeble attempt, you should be ashamed

*

WardoggKC130FE

  • 11842
  • What website is that? MadeUpMonkeyShit.com?
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #17 on: June 01, 2010, 09:31:23 AM »
Well an average window is about 9"x12.5" so that give us an area of  112.5 inches.  Now lets use the known psi of a Herk, 7 psi, that would give us 787.5 pounds of force on each of the windows in a cabin.  Obviouly being the weak point of the fuselage.  Do you not think that the fuselage bows out in flight because of it?  AIrliners are probably running about 9 psi...and many more windows.  It makes you wonder, even an inch would effect the view somewhat.

?

General Disarray

  • Official Member
  • 5039
  • Magic specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #18 on: June 01, 2010, 09:37:20 AM »
 ??? Why has no one bothered to cite an analysis of what material airline windows are made of and their thickness or tolerance to pressure? Without any data to show what level of deformations would be caused by the pressures in an aircraft, this all seems pretty unfounded.
You don't want to make an enemy of me. I'm very powerful.

Re: Why The Earth Appears Curved at a High Altitude.
« Reply #19 on: June 01, 2010, 09:50:07 AM »
Well an average window is about 9"x12.5" so that give us an area of  112.5 inches.  Now lets use the known psi of a Herk, 7 psi, that would give us 787.5 pounds of force on each of the windows in a cabin.  Obviouly being the weak point of the fuselage.  Do you not think that the fuselage bows out in flight because of it?  AIrliners are probably running about 9 psi...and many more windows.  It makes you wonder, even an inch would effect the view somewhat.

A 9*12.5 glass window deflecting an inch in the middle? You're hilarious.

I'm crunching some numbers. Back shortly

Re: Why The Earth Appears Curved at a High Altitude.
« Reply #20 on: June 01, 2010, 09:55:24 AM »
Right, assuming your window is 12.5 inch by 9 inch, and a very pessimistic quarter inch thick.

With 7 psi acting, and a Youngs modulus of 9*10^6 lbf/in^2 (bog standard borosilicate glass) you'll get a deflection in the middle of your plate of....

0.025 inches.

0.6mm

Essentially f*ck all.

*

markjo

  • Content Nazi
  • The Elder Ones
  • 38206
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #21 on: June 01, 2010, 10:00:35 AM »
Right, assuming your window is 12.5 inch by 9 inch, and a very pessimistic quarter inch thick.

With 7 psi acting, and a Youngs modulus of 9*10^6 lbf/in^2 (bog standard borosilicate glass) you'll get a deflection in the middle of your plate of....

0.025 inches.

0.6mm

Essentially f*ck all.

Actually, most aircraft windows would most likely made out of some sort of acrylic in order to save weight and provide some flexibility (borosilicate glass would likely be too brittle).
Science is what happens when preconception meets verification.
Quote from: Robosteve
Besides, perhaps FET is a conspiracy too.
Quote from: bullhorn
It is just the way it is, you understanding it doesn't concern me.

?

General Disarray

  • Official Member
  • 5039
  • Magic specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #22 on: June 01, 2010, 10:17:17 AM »
Jet airliner cabin windows are usually acrylic, and consist of three layers of material for redundancy and safety.

You don't want to make an enemy of me. I'm very powerful.

?

Thermal Detonator

  • 3135
  • Definitively the best avatar maker.
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #23 on: June 01, 2010, 10:19:11 AM »
??? Why has no one bothered to cite an analysis of what material airline windows are made of and their thickness or tolerance to pressure? Without any data to show what level of deformations would be caused by the pressures in an aircraft, this all seems pretty unfounded.

If you know what they're made of, Mr Smartypants, why didn't you?
Gayer doesn't live in an atmosphere of vaporised mustard like you appear to, based on your latest photo.

?

General Disarray

  • Official Member
  • 5039
  • Magic specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #24 on: June 01, 2010, 10:20:08 AM »
??? Why has no one bothered to cite an analysis of what material airline windows are made of and their thickness or tolerance to pressure? Without any data to show what level of deformations would be caused by the pressures in an aircraft, this all seems pretty unfounded.

If you know what they're made of, Mr Smartypants, why didn't you?

Because I'm not the one making the claim that deformations in airplane windows cause apparent curvature on the horizon.

Anyone making such a claim should provide evidence to back it up, which would include what the windows are made of, their thickness, and the degree of deformation under standard cabin pressures.

An optical ray diagram would also be helpful because it could show exactly how rays of light would appear to show a curved horizon if the OP's assertions were true.
« Last Edit: June 01, 2010, 10:33:02 AM by General Disarray »
You don't want to make an enemy of me. I'm very powerful.

?

Thermal Detonator

  • 3135
  • Definitively the best avatar maker.
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #25 on: June 01, 2010, 10:30:30 AM »
??? Why has no one bothered to cite an analysis of what material airline windows are made of and their thickness or tolerance to pressure? Without any data to show what level of deformations would be caused by the pressures in an aircraft, this all seems pretty unfounded.

If you know what they're made of, Mr Smartypants, why didn't you?

Because I'm not the one making the claim that deformations in airplane windows cause apparent curvature on the horizon.

Yes, so by default if you take the sceptical stance to that claim you are making the counterclaim that this deformation does not happen.
Gayer doesn't live in an atmosphere of vaporised mustard like you appear to, based on your latest photo.

?

General Disarray

  • Official Member
  • 5039
  • Magic specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #26 on: June 01, 2010, 10:34:03 AM »
??? Why has no one bothered to cite an analysis of what material airline windows are made of and their thickness or tolerance to pressure? Without any data to show what level of deformations would be caused by the pressures in an aircraft, this all seems pretty unfounded.

If you know what they're made of, Mr Smartypants, why didn't you?

Because I'm not the one making the claim that deformations in airplane windows cause apparent curvature on the horizon.

Yes, so by default if you take the sceptical stance to that claim you are making the counterclaim that this deformation does not happen.

I never said that I claimed such deformations did not happen, and I should not be required to prove a negative in any case.
You don't want to make an enemy of me. I'm very powerful.

Re: Why The Earth Appears Curved at a High Altitude.
« Reply #27 on: June 01, 2010, 12:08:03 PM »
And how do you account for such pictures taken outside of an aircraft, i.e skydivers?


*

Parsifal

  • Official Member
  • 36114
  • Bendy Light specialist
Re: Why The Earth Appears Curved at a High Altitude.
« Reply #28 on: June 01, 2010, 01:23:00 PM »
The horizon only appears curved relative to the skydiver, whose body is curved in the opposite direction due to wind resistance.
I'm going to side with the white supremacists.

Re: Why The Earth Appears Curved at a High Altitude.
« Reply #29 on: June 01, 2010, 01:36:56 PM »
The horizon only appears curved relative to the skydiver, whose body is curved in the opposite direction due to wind resistance.

1. Wind resistance does not curve light.
2. What about someone in a windowless helicopter?