Explain the horizon

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tehsolace

Explain the horizon
« on: March 13, 2007, 12:39:08 PM »
If you've ever taken an airplane and gone to a considerable height, you can clearly see the horizon (with no obstructions) and the effect made from a round Earth, whereas the land appears to 'end' at some far distance.  Also to note: the higher you ascend, the farther you out you can see. 

If the Earth were flat, then there would be a clearer view of the distance the higher you ascend, and (even at a relatively low flying altitude) you should be able to see all the way to the ends of the Earth.

I'm posting here with an open mind, so please indulge my curiosity for your explanations of this.

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TheEngineer

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Re: Explain the horizon
« Reply #1 on: March 13, 2007, 12:56:58 PM »
I fly all the time and have yet to witness this 'curvature'.


"I haven't been wrong since 1961, when I thought I made a mistake."
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tehsolace

Re: Explain the horizon
« Reply #2 on: March 13, 2007, 01:48:47 PM »
If you took the time to read more carefully, you may notice that I never once mentioned being able to see any 'curvature'.

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Miss M.

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Re: Explain the horizon
« Reply #3 on: March 13, 2007, 02:42:38 PM »
I fly all the time and have yet to witness this 'curvature'.
To be fair, at a certain point, you're flying through cloud.

I have a problem cause where I am, from my second floor window, it looks kinda curved on the horizon...could be due to slight hills though.

What about the fact that the sky seems to be a sort of dome shape?
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Re: Explain the horizon
« Reply #4 on: March 13, 2007, 04:05:25 PM »
Hello, I am a 3rd year physics student, and I'm here to put and end to this discussion...

The reason why earth looks round from up in the sky is as follows. I'm sure you all have seen that when you put a pencil halfway in a glass of water, it appears to be broken. This is because water is denser than air and light rays bend when the density of the medium changes. This is known as the Snell Law.
Have you ever seen on airplanes' info channels the outside temperature? It goes all the way down to a few degrees, because atmosphere gets colder as you ascend. Cold air is denser than hot air - this is actually why hot air balloons fly! So, when you are looking down from a plane to the surface of the earth, you're looking through the atmosphere that gets warmer (and therefore less dense) as you descend. This causes light rays from the earth to bend and makes the surface look curved - just like the pencil in the water getting broken. It's not a sharp break as in the pencil example but a smooth curve, because the temperature and so the density changes gradually, not suddenly.

This was one of the things that fooled our ancestors into believing earth is round.  The so called "fact" really shook the religious world because it was against what was believed so far. Then, when the scientists realized they were wrong, they just decided to play along with the whole scam because if they revealed their mistake, religion would get back its power and they would lose the eternal battle. Please, think about it, it's all out there, it's the biggest scam on earth's history!

Re: Explain the horizon
« Reply #5 on: March 13, 2007, 04:08:46 PM »
So explain to me with your 3rd year physics knowledge how light bending towards the Earth reduces our veiwing distance?
« Last Edit: March 13, 2007, 04:18:39 PM by kasroa »

Re: Explain the horizon
« Reply #6 on: March 13, 2007, 04:14:11 PM »
Oh, and about the sky being kind of dome-shaped...

Please search google images about "fish-eye" cameras. Due to the spherical shape of the corneas of their eyes, they see everything around as extremely spherical. I will not explain in detail why, but if you're interested, please google (or wiki) "spherical abberation".

Now, guess what the HUMAN cornea is shaped like? Although not as much as fishes, human cornea is also spherical, which most obviously causes spherical abberation. This problem doesn't occur in daily life because it's not effective in short distances, but when you look to the horizon or to the skies, due to the long distance, they look spherically curved...

Any other questions?

Re: Explain the horizon
« Reply #7 on: March 13, 2007, 04:23:09 PM »
Ok now.

I dont want to lay all the scientific stuff out here, but there is an angle called "the brewster angle" in optics. It's the highest angle of incidence on a surface where refraction (or passing through) is possible. In real life examples, face a fishtank and move to a side. You'll observe that after some angle to the glass, you can't see through it! You cant see the fishes in the tank although you can see the side as if it was a mirror. This is that angle I was telling you about.

Now, back to the earth. Looking to earths surface, you can see up to some angle. But after that, the gradually increasing atmosphere density causes the same affect with a fishtank, and starts reflecting. After that point, you just see the reflected sky...
If interested, study "mirages". They occur in hot places. They are actually reflections of the sky. Pretty much the same thing...

Re: Explain the horizon
« Reply #8 on: March 13, 2007, 04:24:58 PM »
Light bending towards the surface would let you see further.

Re: Explain the horizon
« Reply #9 on: March 13, 2007, 04:25:52 PM »
So you're saying that the atmosphere can cause total internal reflection with no medium barrier?

Re: Explain the horizon
« Reply #10 on: March 13, 2007, 04:31:04 PM »
of course

mirages are the perfect example...

http://www.goalfinder.com/product.asp?productid=40
http://www.phys.ufl.edu/~avery/course/3400/atmosphere/mirage_inf_diagram.gif

as you can see, too much heat gradient can actually do that. A medium barrier is not necessary if the heat difference is high enough.

and another link for fisheye view:
http://images.google.com/images?svnum=10&hl=en&gbv=2&q=fisheye&btnG=Search


Re: Explain the horizon
« Reply #11 on: March 13, 2007, 04:34:48 PM »
Light bending towards the surface would let you see further.

and as hotter means less dense, light is actually bending away from the surface... eventually reflecting completely...

Re: Explain the horizon
« Reply #12 on: March 13, 2007, 04:34:57 PM »
Still doesn't change the fact that light bending down causes us to see further not less further.

Re: Explain the horizon
« Reply #13 on: March 13, 2007, 04:50:42 PM »
Still doesn't change the fact that light bending down causes us to see further not less further.

just look a few posts up... It doesnt bend DOWN it bends UP..
or actually, light comes FROM the earth TO the plane in which it bends UP and never reaches the plane unless it's source is close to the plane...

Re: Explain the horizon
« Reply #14 on: March 13, 2007, 04:52:52 PM »
you talk about the observation of the earth from a human eye point of view, still though, what about ships passing through the horizon and their hulls disappearing first? does this have to do w/light refraction as well? because .. it doesn't lol
With no south pole, there is no electromagnetism, giving us no protection from the sun's harmful radiation--we'd all be dead right now.
The ice wall, supposedly made up of antartica lies around the edge of the earth, why no one has recorded it, who knows

Re: Explain the horizon
« Reply #15 on: March 13, 2007, 05:02:48 PM »
you talk about the observation of the earth from a human eye point of view, still though, what about ships passing through the horizon and their hulls disappearing first? does this have to do w/light refraction as well? because .. it doesn't lol

oh thats just simple illusion. Like in those tricky drawings such as:
http://mathworld.wolfram.com/images/eps-gif/CafeWallIllusion_1000.gif

and scientifically:
Every observation instrument (eye, cameras, even telescopes) have a "resolution" based on the "raleigh criterion" (not sure about the spelling).  It tells about the minimum angular separation the instrument can resolve. It is not related to the magnification or anything, but because of "diffraction" occurring in the instrument (i.e in the pupil of the eye or the diaphragm of the camera). It prevents us from separating two things too close to each other.
When the ship is far enough, You can't separate its body from the sea because they're too close together, but you can separate its top from the sea. That's basically it...

Re: Explain the horizon
« Reply #16 on: March 13, 2007, 05:09:56 PM »
i'm sorry but it's not an illusion .. you have no base for it .. and just because the ship is at teh EXACT point of being far enough away for our eyes to deceive us, this ultimately has to be the explanation of why the hull disappears before the mast ?? it's not an illusion, it steadily sails away and disappears just as slowly
« Last Edit: March 13, 2007, 05:11:39 PM by WasteofHumans »
With no south pole, there is no electromagnetism, giving us no protection from the sun's harmful radiation--we'd all be dead right now.
The ice wall, supposedly made up of antartica lies around the edge of the earth, why no one has recorded it, who knows

Re: Explain the horizon
« Reply #17 on: March 13, 2007, 05:18:23 PM »
Light bends towards Earth as it passes through the atmosphere. The denser the air the more it bends. Even in the least dense of air it will still bend towards Earth.

Re: Explain the horizon
« Reply #18 on: March 13, 2007, 07:03:24 PM »
Oh, and about the sky being kind of dome-shaped...

Please search google images about "fish-eye" cameras. Due to the spherical shape of the corneas of their eyes, they see everything around as extremely spherical. I will not explain in detail why, but if you're interested, please google (or wiki) "spherical abberation".

Now, guess what the HUMAN cornea is shaped like? Although not as much as fishes, human cornea is also spherical, which most obviously causes spherical abberation. This problem doesn't occur in daily life because it's not effective in short distances, but when you look to the horizon or to the skies, due to the long distance, they look spherically curved...

Any other questions?

With all due respect, I don't think you've ever seen a picture taken by a fish-eye camera.  We don't see anything like them, regardless of distance.  Please gtfo nao.

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Franc T., Planar

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Re: Explain the horizon
« Reply #19 on: March 14, 2007, 05:59:50 AM »
If you've ever taken an airplane and gone to a considerable height, you can clearly see the horizon (with no obstructions) and the effect made from a round Earth, whereas the land appears to 'end' at some far distance.  Also to note: the higher you ascend, the farther you out you can see. 

If the Earth were flat, then there would be a clearer view of the distance the higher you ascend, and (even at a relatively low flying altitude) you should be able to see all the way to the ends of the Earth.

I'm posting here with an open mind, so please indulge my curiosity for your explanations of this.

Believing is seeing. I don't see any horizon.
Broadcasting live from the Republic of Canada!
 
They say death and taxes are the only two absolutes. Actually, they're only half right.


Re: Explain the horizon
« Reply #20 on: March 14, 2007, 06:00:19 AM »
what makes you think that you're in any way better than a FISH? The similarity is even more obvious with you...

I didnt say it's exactly like them, I said its similar to that... Just google spherical abberation and you'll see.
Dont confront me without knowing any science! Gosh!

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Wendy

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Re: Explain the horizon
« Reply #21 on: March 14, 2007, 06:59:29 AM »
I fly all the time and have yet to witness this 'curvature'.

True. I flew once too, and I did not see a large difference in altitude, but, I did not see an 'ice wall' either.
Here's an explanation for ya. Lurk moar. Every single point you brought up has been posted, reposted, debated and debunked. There is a search function on this forum, and it is very easy to use.

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TheEngineer

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Re: Explain the horizon
« Reply #22 on: March 14, 2007, 08:44:09 AM »
I fly all the time and have yet to witness this 'curvature'.

True. I flew once too, and I did not see a large difference in altitude
It's amazing your plane did not crash into anything!!


"I haven't been wrong since 1961, when I thought I made a mistake."
        -- Bob Hudson

Re: Explain the horizon
« Reply #23 on: March 14, 2007, 08:46:49 AM »
I fly all the time and have yet to witness this 'curvature'.

True. I flew once too, and I did not see a large difference in altitude, but, I did not see an 'ice wall' either.

Are you sure you flew and were not just, like, in a car?

Re: Explain the horizon
« Reply #24 on: March 14, 2007, 09:14:10 AM »
If you've ever taken an airplane and gone to a considerable height, you can clearly see the horizon (with no obstructions) and the effect made from a round Earth, whereas the land appears to 'end' at some far distance.  Also to note: the higher you ascend, the farther you out you can see. 

If the Earth were flat, then there would be a clearer view of the distance the higher you ascend, and (even at a relatively low flying altitude) you should be able to see all the way to the ends of the Earth.

I'm posting here with an open mind, so please indulge my curiosity for your explanations of this.

Believing is seeing. I don't see any horizon.



You said this in another topic somewhere. But seriously just think about what you're saying for a minute there. You're saying that if we believe in something then we can see basically anything we like... This is heavilly going against the laws of science.

We see stuff because the photons are reflected off it and into our eyes. Our brain processes them and we can see stuff. Just because you want to see something can't change the light that you see.

(Yes, I know this isn't very well explained but you see what I mean.)

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Franc T., Planar

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Re: Explain the horizon
« Reply #25 on: March 14, 2007, 06:16:04 PM »
If you've ever taken an airplane and gone to a considerable height, you can clearly see the horizon (with no obstructions) and the effect made from a round Earth, whereas the land appears to 'end' at some far distance.  Also to note: the higher you ascend, the farther you out you can see. 

If the Earth were flat, then there would be a clearer view of the distance the higher you ascend, and (even at a relatively low flying altitude) you should be able to see all the way to the ends of the Earth.

I'm posting here with an open mind, so please indulge my curiosity for your explanations of this.

Believing is seeing. I don't see any horizon.



You said this in another topic somewhere. But seriously just think about what you're saying for a minute there. You're saying that if we believe in something then we can see basically anything we like... This is heavilly going against the laws of science.

We see stuff because the photons are reflected off it and into our eyes. Our brain processes them and we can see stuff. Just because you want to see something can't change the light that you see.

(Yes, I know this isn't very well explained but you see what I mean.)

Obviously the fact that our beliefs interfere with proper evaluation has nothing to do with the fact that photons reach our eye. Thanks for the physics 101 course, though. I needed a refresher, you know, given that I had FIVE YEARS OF PHYSICS.
« Last Edit: March 15, 2007, 03:03:52 AM by Francois Tremblay »
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Re: Explain the horizon
« Reply #26 on: March 15, 2007, 01:39:36 AM »
your beliefs blatantly won't interfere with what you see. Plenty of people believed Santa Claus was real until they sat up all night and didn't see him.

Re: Explain the horizon
« Reply #27 on: March 15, 2007, 06:14:06 AM »
your beliefs blatantly won't interfere with what you see. Plenty of people believed Santa Claus was real until they sat up all night and didn't see him.

and what about all those who really believed in santa and actually saw him that night?
Are you denying that the only reason adults can't see santa is because santa becomes invisible to those who dont believe in them?

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Wendy

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Re: Explain the horizon
« Reply #28 on: March 15, 2007, 06:36:27 AM »
your beliefs blatantly won't interfere with what you see. Plenty of people believed Santa Claus was real until they sat up all night and didn't see him.

and what about all those who really believed in santa and actually saw him that night?
Are you denying that the only reason adults can't see santa is because santa becomes invisible to those who dont believe in them?

Althoug I don't believe in santa  (::)) or the flat earth, I have to agree with phys boy over there. I know some christians who are so set into their beliefs that they actually believe that they saw God on one occassion or another.
« Last Edit: March 15, 2007, 08:05:58 AM by The cookie theory »
Here's an explanation for ya. Lurk moar. Every single point you brought up has been posted, reposted, debated and debunked. There is a search function on this forum, and it is very easy to use.

Re: Explain the horizon
« Reply #29 on: March 15, 2007, 08:44:14 AM »
I fly all the time and have yet to witness this 'curvature'.
try staying awake and don't watch the crappy movie.