[Venus]

Okay I agree that curvature of the horizon from left to right is not visible from the surface of the earth.
What I am wondering is what sort of curvature would you expect to see... would it be in a north south direction? An east west direction?

If you expect to see curvature what happens when you are in the middle of the ocean (or somewhere else where you could see the horizon in all directions) and turn around 360 degrees? Would you expect to see the horizon at a lower level when you have turned 180 degrees and then rise up again as you complete your 360 degree rotation?

Just wondering what the flat earth believers expect to see when they look at the horizon and declare "It's flat, no curvature there". But especially what would you expect to see if you could turn around 360 degrees and see the horizon in all directions. Isn't a flat horizon as you rotate around 360 degrees what you would expect to see if the earth is a sphere?

Because the flat horizon is the major point which seems to persuade people that the earth is flat. But it seems illogical to me that people would expect to see a curve down to either side when eg viewing a picture of the horizon.
Yet in reality there is curvature, but just not side to side as we look toward the horizon, instead the earth curves away from you - in every direction - as you look toward the horizon and rotate 360 degrees. And the fact that you could climb the crows nest of a ship and see further is irrefutable - after all isn't that why they had crows nests in the first place? "Land Ahoy!" So that they could see further over the horizon to see other ships coming or land in the distance. And also the curvature over the horizon is the reason lighthouses are built very tall?

[geckothegeek]

Okay I agree that curvature of the horizon from left to right is not visible from the surface of the earth.
What I am wondering is what sort of curvature would you expect to see... would it be in a north south direction? An east west direction?

If you expect to see curvature what happens when you are in the middle of the ocean (or somewhere else where you could see the horizon in all directions) and turn around 360 degrees? Would you expect to see the horizon at a lower level when you have turned 180 degrees and then rise up again as you complete your 360 degree rotation?

Just wondering what the flat earth believers expect to see when they look at the horizon and declare "It's flat, no curvature there". But especially what would you expect to see if you could turn around 360 degrees and see the horizon in all directions. Isn't a flat horizon as you rotate around 360 degrees what you would expect to see if the earth is a sphere?

Because the flat horizon is the major point which seems to persuade people that the earth is flat. But it seems illogical to me that people would expect to see a curve down to either side when eg viewing a picture of the horizon.
Yet in reality there is curvature, but just not side to side as we look toward the horizon, instead the earth curves away from you - in every direction - as you look toward the horizon and rotate 360 degrees. And the fact that you could climb the crows nest of a ship and see further is irrefutable - after all isn't that why they had crows nests in the first place? "Land Ahoy!" So that they could see further over the horizon to see other ships coming or land in the distance. And also the curvature over the horizon is the reason lighthouses are built very tall?

If you were in the middle of the ocean,  you would be  in the middle of a circle.
The distance to the horizon is the same in all directions.
If you were in a lifeboat just above the level of the sea, the distance to the horizon would be about 2 1/2 or 3 miles and you would be in the middle of a  circle with a diameter of about 5 or 6 miles.
If you were in a crow's rest on s ship , 100 feet above the sea. you would be in a circle about 25 miles in diameter.
Certain radar antennas are also placed on the highest masts so that they can "see" the greatest distance.
The curvature of the earth must also be taken into account for the maximum spacing of certain microwave relay statiions.
But flat earth says that you would never see the horizon no matter how low or high you were, but you would only see "a blur which fades away at some indefinite distance."
This is just one of many of the most glaring and most obvious fallacies of flat earth fallacies.

[Venus]

Okay I agree that curvature of the horizon from left to right is not visible from the surface of the earth.
What I am wondering is what sort of curvature would you expect to see... would it be in a north south direction? An east west direction?

If you expect to see curvature what happens when you are in the middle of the ocean (or somewhere else where you could see the horizon in all directions) and turn around 360 degrees? Would you expect to see the horizon at a lower level when you have turned 180 degrees and then rise up again as you complete your 360 degree rotation?

Just wondering what the flat earth believers expect to see when they look at the horizon and declare "It's flat, no curvature there". But especially what would you expect to see if you could turn around 360 degrees and see the horizon in all directions. Isn't a flat horizon as you rotate around 360 degrees what you would expect to see if the earth is a sphere?

Because the flat horizon is the major point which seems to persuade people that the earth is flat. But it seems illogical to me that people would expect to see a curve down to either side when eg viewing a picture of the horizon.
Yet in reality there is curvature, but just not side to side as we look toward the horizon, instead the earth curves away from you - in every direction - as you look toward the horizon and rotate 360 degrees. And the fact that you could climb the crows nest of a ship and see further is irrefutable - after all isn't that why they had crows nests in the first place? "Land Ahoy!" So that they could see further over the horizon to see other ships coming or land in the distance. And also the curvature over the horizon is the reason lighthouses are built very tall?

If you were in the middle of the ocean,  you would be  in the middle of a circle.
The distance to the horizon is the same in all directions.
If you were in a lifeboat just above the level of the sea, the distance to the horizon would be about 2 1/2 or 3 miles and you would be in the middle of a  circle with a diameter of about 5 or 6 miles.
If you were in a crow's rest on s ship , 100 feet above the sea. you would be in a circle about 25 miles in diameter.
Certain radar antennas are also placed on the highest masts so that they can "see" the greatest distance.
The curvature of the earth must also be taken into account for the maximum spacing of certain microwave relay statiions.
But flat earth says that you would never see the horizon no matter how low or high you were, but you would only see "a blur which fades away at some indefinite distance."
This is just one of many of the most glaring and most obvious fallacies of flat earth fallacies.

I've seen so many photos of horizons both here and on YouTube ... with the claim "Looks flat to me ... no curvature there"
I just can't understand how anyone would expect to see the earth curve from left to right in a photo of the horizon.
It's just completely illogical to think it would curve downwards from one side to the other.
Why can't people understand that the curvature is away from the viewer in every direction?
Am I expecting too much of peoples' intelligence?
If it curved from left to right then we would be living on a cylinder ... but of course if you rotated yourself 180 degrees the horizon would then appear straight and curve away from you.

I'd really like to see a flat earther's response to this ... anyone out there

[rabinoz]

Why can't people understand that the curvature is away from the viewer in every direction?
Am I expecting too much of peoples' intelligence?

I'd really like to see a flat earther's response to this ... anyone out there

Yes, and no.

Flat Earthers will never face up to simple little things that might pierce their comfort zone.

[geckothegeek]

Why can't people understand that the curvature is away from the viewer in every direction?
Am I expecting too much of peoples' intelligence?

I'd really like to see a flat earther's response to this ... anyone out there

Yes, and no.

Flat Earthers will never face up to simple little things that might pierce their comfort zone.

What I would really like to see  would be a flat earther who could honestly say that he had ever been to sea or stood on the shore and looked out to sea (on a clear day) in the first place.
And if he had if he could honestly say that he couldn't see the horizon but could honestly say that all he could see was "an indistinct blur......et cetera, et cetera, and so forth."

Tom Bishop, are you out there ?

[SimonC]

Okay I agree that curvature of the horizon from left to right is not visible from the surface of the earth.
What I am wondering is what sort of curvature would you expect to see... would it be in a north south direction? An east west direction?

If you expect to see curvature what happens when you are in the middle of the ocean (or somewhere else where you could see the horizon in all directions) and turn around 360 degrees? Would you expect to see the horizon at a lower level when you have turned 180 degrees and then rise up again as you complete your 360 degree rotation?

Just wondering what the flat earth believers expect to see when they look at the horizon and declare "It's flat, no curvature there". But especially what would you expect to see if you could turn around 360 degrees and see the horizon in all directions. Isn't a flat horizon as you rotate around 360 degrees what you would expect to see if the earth is a sphere?

Because the flat horizon is the major point which seems to persuade people that the earth is flat. But it seems illogical to me that people would expect to see a curve down to either side when eg viewing a picture of the horizon.
Yet in reality there is curvature, but just not side to side as we look toward the horizon, instead the earth curves away from you - in every direction - as you look toward the horizon and rotate 360 degrees. And the fact that you could climb the crows nest of a ship and see further is irrefutable - after all isn't that why they had crows nests in the first place? "Land Ahoy!" So that they could see further over the horizon to see other ships coming or land in the distance. And also the curvature over the horizon is the reason lighthouses are built very tall?

If you were in the middle of the ocean,  you would be  in the middle of a circle.
The distance to the horizon is the same in all directions.
If you were in a lifeboat just above the level of the sea, the distance to the horizon would be about 2 1/2 or 3 miles and you would be in the middle of a  circle with a diameter of about 5 or 6 miles.
If you were in a crow's rest on s ship , 100 feet above the sea. you would be in a circle about 25 miles in diameter.
Certain radar antennas are also placed on the highest masts so that they can "see" the greatest distance.
The curvature of the earth must also be taken into account for the maximum spacing of certain microwave relay statiions.
But flat earth says that you would never see the horizon no matter how low or high you were, but you would only see "a blur which fades away at some indefinite distance."
This is just one of many of the most glaring and most obvious fallacies of flat earth fallacies.

I've seen so many photos of horizons both here and on YouTube ... with the claim "Looks flat to me ... no curvature there"
I just can't understand how anyone would expect to see the earth curve from left to right in a photo of the horizon.
It's just completely illogical to think it would curve downwards from one side to the other.
Why can't people understand that the curvature is away from the viewer in every direction?
Am I expecting too much of peoples' intelligence?
If it curved from left to right then we would be living on a cylinder ... but of course if you rotated yourself 180 degrees the horizon would then appear straight and curve away from you.

I'd really like to see a flat earther's response to this ... anyone out there

Just to correct you. If you stood as a very small person on a ball maybe the size of a house you would see curves all round you not just on front of you. The whole ball curves away from you in all directions no matter where you stand on it. Take a tennis ball in your hand and put a little black spot on it anywhere. Now move the ball so the spot is at the top (north) of the ball. And note how it curves away from that spot in every direction including 'down the sides'; not just 'ahead' of you like you suggest happens on the sea shore.

[GoldCashew]

Okay I agree that curvature of the horizon from left to right is not visible from the surface of the earth.
What I am wondering is what sort of curvature would you expect to see... would it be in a north south direction? An east west direction?

If you expect to see curvature what happens when you are in the middle of the ocean (or somewhere else where you could see the horizon in all directions) and turn around 360 degrees? Would you expect to see the horizon at a lower level when you have turned 180 degrees and then rise up again as you complete your 360 degree rotation?

Just wondering what the flat earth believers expect to see when they look at the horizon and declare "It's flat, no curvature there". But especially what would you expect to see if you could turn around 360 degrees and see the horizon in all directions. Isn't a flat horizon as you rotate around 360 degrees what you would expect to see if the earth is a sphere?

Because the flat horizon is the major point which seems to persuade people that the earth is flat. But it seems illogical to me that people would expect to see a curve down to either side when eg viewing a picture of the horizon.
Yet in reality there is curvature, but just not side to side as we look toward the horizon, instead the earth curves away from you - in every direction - as you look toward the horizon and rotate 360 degrees. And the fact that you could climb the crows nest of a ship and see further is irrefutable - after all isn't that why they had crows nests in the first place? "Land Ahoy!" So that they could see further over the horizon to see other ships coming or land in the distance. And also the curvature over the horizon is the reason lighthouses are built very tall?

If you were in the middle of the ocean,  you would be  in the middle of a circle.
The distance to the horizon is the same in all directions.
If you were in a lifeboat just above the level of the sea, the distance to the horizon would be about 2 1/2 or 3 miles and you would be in the middle of a  circle with a diameter of about 5 or 6 miles.
If you were in a crow's rest on s ship , 100 feet above the sea. you would be in a circle about 25 miles in diameter.
Certain radar antennas are also placed on the highest masts so that they can "see" the greatest distance.
The curvature of the earth must also be taken into account for the maximum spacing of certain microwave relay statiions.
But flat earth says that you would never see the horizon no matter how low or high you were, but you would only see "a blur which fades away at some indefinite distance."
This is just one of many of the most glaring and most obvious fallacies of flat earth fallacies.

I've seen so many photos of horizons both here and on YouTube ... with the claim "Looks flat to me ... no curvature there"
I just can't understand how anyone would expect to see the earth curve from left to right in a photo of the horizon.
It's just completely illogical to think it would curve downwards from one side to the other.
Why can't people understand that the curvature is away from the viewer in every direction?
Am I expecting too much of peoples' intelligence?
If it curved from left to right then we would be living on a cylinder ... but of course if you rotated yourself 180 degrees the horizon would then appear straight and curve away from you.

I'd really like to see a flat earther's response to this ... anyone out there

Just to correct you. If you stood as a very small person on a ball maybe the size of a house you would see curves all round you not just on front of you. The whole ball curves away from you in all directions no matter where you stand on it. Take a tennis ball in your hand and put a little black spot on it anywhere. Now move the ball so the spot is at the top (north) of the ball. And note how it curves away from that spot in every direction including 'sown the sides'; not just 'ahead' of you like you suggest happens on the sea shore.

I think that what the Op might also be framing up or challenging is the notion that "if it looks flat than it must be flat." The size of the Earth is so large that using "it looks flat, therefore it must be flat" as a rationale way to make a confident conclusion about the shape of the Earth is likely misleading.

The online example I have seen is that if one were shrunk down to be the size of an atom and placed onto say the surface of a basketball or a football, to that small observer the shape might look flat to them; when in reality the shape is actually a sphere.

             

[SimonC]

Why can't people understand that the curvature is away from the viewer in every direction?
Am I expecting too much of peoples' intelligence?

I'd really like to see a flat earther's response to this ... anyone out there

Yes, and no.

Flat Earthers will never face up to simple little things that might pierce their comfort zone.

But its the round earthers and occasional pilots and frequent fliers that are the ones claiming to see a curve from left to right its they who you should be addressing.

[BillO]

But its the round earthers and occasional pilots and frequent fliers that are the ones claiming to see a curve from left to right its they who you should be addressing.

Frequent flyers and airline pilots that make that claim must have been into the free booze.  Maybe the odd test pilot of hypersonic, experimental ultra high-altitude aircraft might get a glimpse of a curve.

So, the OP's question was to flat earthers.  Flat earthers claim that since they do not see a curvature, the earth must be flat.  On the other side of the fence people say that, since the earth is ginormous and we are tiny, we should not be able to see a curvature.  In essence we are okay and unshaken by that same observation.

Let's say you were out on the middle of the pacific ocean, bobbing up and down in an inner tube, and, for the sake of argument, the world was as science say's it is.  What would you (as a flat earther) need to see that would confirm to you the earth was indeed a sphere 12,742,000 meters in diameter?

[Action80]

But its the round earthers and occasional pilots and frequent fliers that are the ones claiming to see a curve from left to right its they who you should be addressing.

Frequent flyers and airline pilots that make that claim must have been into the free booze.  Maybe the odd test pilot of hypersonic, experimental ultra high-altitude aircraft might get a glimpse of a curve.

So, the OP's question was to flat earthers.  Flat earthers claim that since they do not see a curvature, the earth must be flat.  On the other side of the fence people say that, since the earth is ginormous and we are tiny, we should not be able to see a curvature.  In essence we are okay and unshaken by that same observation.

Let's say you were out on the middle of the pacific ocean, bobbing up and down in an inner tube, and, for the sake of argument, the world was as science say's it is.  What would you (as a flat earther) need to see that would confirm to you the earth was indeed a sphere 12,742,000 meters in diameter?

If you are in the middle of the Pacific, it will mean no difference.

You are somehow under the impression a body of water encompassing that many million square miles is going to remain consistently level across it's length and width?

[AATW]

You are somehow under the impression a body of water encompassing that many million square miles is going to remain consistently level across it's length and width?

Why wouldn't it if the earth is flat?
Water finds its level is the common FE mantra. Obviously there will be waves and so on, but why wouldn't it be roughly level on a FE?

[Action80]

You are somehow under the impression a body of water encompassing that many million square miles is going to remain consistently level across it's length and width?

Why wouldn't it if the earth is flat?
Water finds its level is the common FE mantra. Obviously there will be waves and so on, but why wouldn't it be roughly level on a FE?

Waves, swells, and numerous other things, which you mention.

Just like the ground is wavy, dippy, and other imperfections.

[BillO]

If you are in the middle of the Pacific, it will mean no difference.

You are somehow under the impression a body of water encompassing that many million square miles is going to remain consistently level across it's length and width?

Maybe you simply did not understand the question.  I'm not under any impression.  I know from experience exactly how it looks in the middle of the pacific ocean having been there.  Albeit it was in a large boat, but nonetheless, it looks as flat as piss on a platter.

But you folks claim the earth is flat because it looks flat, right?  You see no curvature.

So, the question is, what would you (or any other flat earther) need to see to be convinced the earth is a sphere rather than flat?

Basically I think we are trying to get our heads around why you would expect to see any curvature looking out over a twelve million, seven hundred and forty thousand meter diameter planet.

[SimonC]

But its the round earthers and occasional pilots and frequent fliers that are the ones claiming to see a curve from left to right its they who you should be addressing.

Frequent flyers and airline pilots that make that claim must have been into the free booze.  Maybe the odd test pilot of hypersonic, experimental ultra high-altitude aircraft might get a glimpse of a curve.

So, the OP's question was to flat earthers.  Flat earthers claim that since they do not see a curvature, the earth must be flat.  On the other side of the fence people say that, since the earth is ginormous and we are tiny, we should not be able to see a curvature.  In essence we are okay and unshaken by that same observation.

Let's say you were out on the middle of the pacific ocean, bobbing up and down in an inner tube, and, for the sake of argument, the world was as science say's it is.  What would you (as a flat earther) need to see that would confirm to you the earth was indeed a sphere 12,742,000 meters in diameter?

In the above scenario there is nothing that could prove the earth is a ball. Very strange and futile question.

[BillO]

In the above scenario there is nothing that could prove the earth is a ball. Very strange and futile question.

Very good observation Simon.  It's not supposed to.

The question is actually quite simple.  Most flat earthers should be able to answer it without any problem.  You claim the earth is flat because you don't see any curvature, right?  The question is, what would you expect to see on this large Earth such that you would say "Hey, now I'm convinced teh Earth is a sphere!"

The thing is, even if the Earth was a sphere 12,742,000 meters in diameter, you still could not see a curvature.  Given that, why do you think the Earth is flat?  What is it you are seeing that you should not see on a spherical Earth 12,742,000 meters in diameter?  If you are confused about the whole meters thing, use 41,804,460 feet.  Would you expect to see a curve standing, or boating, on a sphere 41,804,460 feet in diameter?

[SimonC]

In the above scenario there is nothing that could prove the earth is a ball. Very strange and futile question.

Very good observation Simon.  It's not supposed to.

The question is actually quite simple.  Most flat earthers should be able to answer it without any problem.  You claim the earth is flat because you don't see any curvature, right?  The question is, what would you expect to see on this large Earth such that you would say "Hey, now I'm convinced teh Earth is a sphere!"

The thing is, even if the Earth was a sphere 12,742,000 meters in diameter, you still could not see a curvature.  Given that, why do you think the Earth is flat?  What is it you are seeing that you should not see on a spherical Earth 12,742,000 meters in diameter?  If you are confused about the whole meters thing, use 41,804,460 feet.  Would you expect to see a curve standing, or boating, on a sphere 41,804,460 feet in diameter?

I have already answered your question and stated there is nothing in that scenario that could prove the earth is a ball.
Why not let us know what would convince YOU that the world was a sphere by sitting in a boat in the middle of an ocean with no land in sight?

[SteelyBob]

In the above scenario there is nothing that could prove the earth is a ball. Very strange and futile question.

Very good observation Simon.  It's not supposed to.

The question is actually quite simple.  Most flat earthers should be able to answer it without any problem.  You claim the earth is flat because you don't see any curvature, right?  The question is, what would you expect to see on this large Earth such that you would say "Hey, now I'm convinced teh Earth is a sphere!"

The thing is, even if the Earth was a sphere 12,742,000 meters in diameter, you still could not see a curvature.  Given that, why do you think the Earth is flat?  What is it you are seeing that you should not see on a spherical Earth 12,742,000 meters in diameter?  If you are confused about the whole meters thing, use 41,804,460 feet.  Would you expect to see a curve standing, or boating, on a sphere 41,804,460 feet in diameter?

I have already answered your question and stated there is nothing in that scenario that could prove the earth is a ball.
Why not let us know what would convince YOU that the world was a sphere by sitting in a boat in the middle of an ocean with no land in sight?

Limited to just sitting in a boat in the middle of the ocean, things we can observe are clearly limited. However:

- the existence of a clear, distinct horizon line on days with good visibility means the earth cannot be flat. If the earth was flat, the only occasion where you would see a distinct line like that would be when you were close to the 'edge' itself. If the earth was flat, and you were a long way from the edge, then there would be no clear horizon - you would instead get what we see on poorer visibility days, where there is a blurry, indistinct horizon, caused by particulate matter in the atmosphere limiting how far you can see.

- if you lie in the boat at night, and watch the stars, you will notice that they appear to rotate in a circular manner around a fixed point at a rate of one rotation per day. The fact that they behave in this way, but are clearly 'decoupled' from the sun and moon, gives a strong indication that the surface we are on is rotating somehow, and that the stars are a lot further away from us than the sun and moon. If you add in the fact that that the elevation above the horizon of the centre of the point of rotation (roughly where the north star is, in the northern hemisphere) is directly related to your latitude, then we can start to make deductions about the likely shape of the earth.

[stack]

In the above scenario there is nothing that could prove the earth is a ball. Very strange and futile question.

Very good observation Simon.  It's not supposed to.

The question is actually quite simple.  Most flat earthers should be able to answer it without any problem.  You claim the earth is flat because you don't see any curvature, right?  The question is, what would you expect to see on this large Earth such that you would say "Hey, now I'm convinced teh Earth is a sphere!"

The thing is, even if the Earth was a sphere 12,742,000 meters in diameter, you still could not see a curvature.  Given that, why do you think the Earth is flat?  What is it you are seeing that you should not see on a spherical Earth 12,742,000 meters in diameter?  If you are confused about the whole meters thing, use 41,804,460 feet.  Would you expect to see a curve standing, or boating, on a sphere 41,804,460 feet in diameter?

I have already answered your question and stated there is nothing in that scenario that could prove the earth is a ball.
Why not let us know what would convince YOU that the world was a sphere by sitting in a boat in the middle of an ocean with no land in sight?

Limited to just sitting in a boat in the middle of the ocean, things we can observe are clearly limited. However:

- the existence of a clear, distinct horizon line on days with good visibility means the earth cannot be flat. If the earth was flat, the only occasion where you would see a distinct line like that would be when you were close to the 'edge' itself. If the earth was flat, and you were a long way from the edge, then there would be no clear horizon - you would instead get what we see on poorer visibility days, where there is a blurry, indistinct horizon, caused by particulate matter in the atmosphere limiting how far you can see.

- if you lie in the boat at night, and watch the stars, you will notice that they appear to rotate in a circular manner around a fixed point at a rate of one rotation per day. The fact that they behave in this way, but are clearly 'decoupled' from the sun and moon, gives a strong indication that the surface we are on is rotating somehow, and that the stars are a lot further away from us than the sun and moon. If you add in the fact that that the elevation above the horizon of the centre of the point of rotation (roughly where the north star is, in the northern hemisphere) is directly related to your latitude, then we can start to make deductions about the likely shape of the earth.

Not to mention that if you're out in the middle of the ocean and wish to navigate to a desired land location, you bust out your sextant and start observing. Then using your declination and sightings, making sure there are no collimation errors, log the sighting time, then using the Hilaire method, calculate via triangulation including the sphericity of earth and derive your position relative to your map. And on your way you go.

[SimonC]

In the above scenario there is nothing that could prove the earth is a ball. Very strange and futile question.

Very good observation Simon.  It's not supposed to.

The question is actually quite simple.  Most flat earthers should be able to answer it without any problem.  You claim the earth is flat because you don't see any curvature, right?  The question is, what would you expect to see on this large Earth such that you would say "Hey, now I'm convinced teh Earth is a sphere!"

The thing is, even if the Earth was a sphere 12,742,000 meters in diameter, you still could not see a curvature.  Given that, why do you think the Earth is flat?  What is it you are seeing that you should not see on a spherical Earth 12,742,000 meters in diameter?  If you are confused about the whole meters thing, use 41,804,460 feet.  Would you expect to see a curve standing, or boating, on a sphere 41,804,460 feet in diameter?

I have already answered your question and stated there is nothing in that scenario that could prove the earth is a ball.
Why not let us know what would convince YOU that the world was a sphere by sitting in a boat in the middle of an ocean with no land in sight?

Limited to just sitting in a boat in the middle of the ocean, things we can observe are clearly limited. However:

- the existence of a clear, distinct horizon line on days with good visibility means the earth cannot be flat. If the earth was flat, the only occasion where you would see a distinct line like that would be when you were close to the 'edge' itself. If the earth was flat, and you were a long way from the edge, then there would be no clear horizon - you would instead get what we see on poorer visibility days, where there is a blurry, indistinct horizon, caused by particulate matter in the atmosphere limiting how far you can see.

- if you lie in the boat at night, and watch the stars, you will notice that they appear to rotate in a circular manner around a fixed point at a rate of one rotation per day. The fact that they behave in this way, but are clearly 'decoupled' from the sun and moon, gives a strong indication that the surface we are on is rotating somehow, and that the stars are a lot further away from us than the sun and moon. If you add in the fact that that the elevation above the horizon of the centre of the point of rotation (roughly where the north star is, in the northern hemisphere) is directly related to your latitude, then we can start to make deductions about the likely shape of the earth.

Not to mention that if you're out in the middle of the ocean and wish to navigate to a desired land location, you bust out your sextant and start observing. Then using your declination and sightings, making sure there are no collimation errors, log the sighting time, then using the Hilaire method, calculate via triangulation including the sphericity of earth and derive your position relative to your map. And on your way you go.

And the reason this couldnt be done on a flat earth?

[SimonC]

In the above scenario there is nothing that could prove the earth is a ball. Very strange and futile question.

Very good observation Simon.  It's not supposed to.

The question is actually quite simple.  Most flat earthers should be able to answer it without any problem.  You claim the earth is flat because you don't see any curvature, right?  The question is, what would you expect to see on this large Earth such that you would say "Hey, now I'm convinced teh Earth is a sphere!"

The thing is, even if the Earth was a sphere 12,742,000 meters in diameter, you still could not see a curvature.  Given that, why do you think the Earth is flat?  What is it you are seeing that you should not see on a spherical Earth 12,742,000 meters in diameter?  If you are confused about the whole meters thing, use 41,804,460 feet.  Would you expect to see a curve standing, or boating, on a sphere 41,804,460 feet in diameter?

I have already answered your question and stated there is nothing in that scenario that could prove the earth is a ball.
Why not let us know what would convince YOU that the world was a sphere by sitting in a boat in the middle of an ocean with no land in sight?

Limited to just sitting in a boat in the middle of the ocean, things we can observe are clearly limited. However:

- the existence of a clear, distinct horizon line on days with good visibility means the earth cannot be flat. If the earth was flat, the only occasion where you would see a distinct line like that would be when you were close to the 'edge' itself. If the earth was flat, and you were a long way from the edge, then there would be no clear horizon - you would instead get what we see on poorer visibility days, where there is a blurry, indistinct horizon, caused by particulate matter in the atmosphere limiting how far you can see.

- if you lie in the boat at night, and watch the stars, you will notice that they appear to rotate in a circular manner around a fixed point at a rate of one rotation per day. The fact that they behave in this way, but are clearly 'decoupled' from the sun and moon, gives a strong indication that the surface we are on is rotating somehow, and that the stars are a lot further away from us than the sun and moon. If you add in the fact that that the elevation above the horizon of the centre of the point of rotation (roughly where the north star is, in the northern hemisphere) is directly related to your latitude, then we can start to make deductions about the likely shape of the earth.

So the distinct line you see is the beginning, the top, or the falling away of the curve? Do you not consider that if the earth was a continuous curve there would be no distinct line? Curves dont have distinct lines. Even curves 'fade away'. And if there was a distinct line it would be a different (further or nearer line) for every person of differing heights and stood on different heights above sea level. You cant have an infinite number of 'distinct lines'.
And moving on to your second point if you know of such a person who lay in a boat staring towards the sky at every single star for 24 non-stop hours and mentally noting their continuous shift in positions exactly then I should like to meet this person. And you say that this gives an indication that the surface we are on is rotating - had you not given any consideration to the fact that it could be the stars that are rotating and not the earth?