objections to the roundness of Earth

[Jimmy Higgins]

I have heard about the cattle being thought of as growing as you walked closer.

I also read long ago that before gravity was discovered to exist. People thought things were stuck to the ground not because some force was pulling you down but because the Earth was moving up.

Speaking of gravity.....

If you lived before the discovery of gravity how do you explain that if Earth was a ball why doesn't all of the water fall off.

Why would you need to demonstrate that? Gravity is apparent, maybe not explained, but stuff settles down... for whatever reason. No one would live parallel to the surface of Earth.

A flat earth fellow living before gravity was discovered--

"If you pour water onto a ball 10 to the zillion billionth times the water falls off . Therefore the earth cannot be a ball"

This is way too scientific of an argument. A person that long ago is arguing the earth is flat, because the ground around them is as flat as the eye can see.

Where would one live to have the ground be flat all around them as far as the eye could see?

Kansas.

https://www.aps.org/publications/apsnews/200310/pancake-kansas.cfm

Maybe smooth is a better word. Though, it does give me an idea for Terrible Maps, "State Flatness Compared to a Pancake."

 

[Elixir]

My main objection to the roundness of the earth is it makes it harder to see far away stuff. That sucks.

 

[Shadowy Man]

My main objection to the roundness of the earth is it makes it harder to see far away stuff. That sucks.

Two photos I took of Mount Baker, Washington, seen from about 80 miles away. Placed side by side with the scale of the mountain the same. On the left the mountain is seen from a beach at Port Angeles and on the right as seen from the Morse Creek Overlook, at an elevation around 3000 feet.

I probably don’t need to explain the difference to those of us here, but from the beach it is clear that a substantial amount of elevation is hidden behind the curve of the Earth from sea level.

Flat earth is the stupidest conspiracy theory I’ve ever seen as it is nearly trivially debunked by almost anyone anywhere.

 

[Jimmy Higgins]

My main objection to the roundness of the earth is it makes it harder to see far away stuff. That sucks.

Two photos I took of Mount Baker, Washington, seen from about 80 miles away. Placed side by side with the scale of the mountain the same. On the left the mountain is seen from a beach at Port Angeles and on the right as seen from the Morse Creek Overlook, at an elevation around 3000 feet.

I probably don’t need to explain the difference to those of us here, but from the beach it is clear that a substantial amount of elevation is hidden behind the curve of the Earth from sea level.

Flat earth is the stupidest conspiracy theory I’ve ever seen as it is nearly trivially debunked by almost anyone anywhere.

I still say Flat Earth is the Landover Baptist Church (and subsequent Stop the Landover Baptist Church) of geography.

 

[Shadowy Man]

I still say Flat Earth is the Landover Baptist Church (and subsequent Stop the Landover Baptist Church) of geography.

there’s still a higher chance that Landover is right than the Earth is flat.

 

[Jimmy Higgins]

I still say Flat Earth is the Landover Baptist Church (and subsequent Stop the Landover Baptist Church) of geography.

there’s still a higher chance that Landover is right than the Earth is flat.

I'm saying they are all fake.

 

[Wiploc]

Where would one live to have the ground be flat all around them as far as the eye could see?

Kansas.

https://www.aps.org/publications/apsnews/200310/pancake-kansas.cfm

Maybe smooth is a better word. Though, it does give me an idea for Terrible Maps, "State Flatness Compared to a Pancake."

Let's say Kansas is 400 miles across.

And let's say the circumference of the earth is 2500 miles.

And let's assume that Kansas is perfectly smooth, as smooth, even, as the surface of a spherical cow in a vacuum.

By my math (400 miles / 25,000 miles * 360 degrees) the curvature over that length would be about 6 degrees. (5.84 degrees, if we include insignificant digits.)

So, next, I'd like the answer to a question that's pretty vague in my mind, and that I don't have the math to answer anyway.

Possible phrasings of my vague question:

• How curved is that really?
• How tall would a building on the east border have to be in order for us to see it (from a foxhole that puts our eyes at surface level) from the west border?
• Two people are six foot. And they have little periscopes that raise their lines of sight to exactly six foot. Or they're snails, so their eyes are their highest points. (This is getting needlessly complex.) How far apart can they stand and still be able to see each other?
• How far does the surface of a smooth earth drop away from horizontal (horizontal to a stationary observer over 400 miles?

Or you can phrase the question any other way that will help make the point.

And the point is?

The point is that the earth doesn't really look flat. It is only the irregularities, the unsmoothness, plus our closeness to the ground, that hides the curvature.

 

[steve_bank]

By the well known Quasi Conformal Mapping Jackson-Jones-Smith-Rodriguez theorem spherical is a special case of flat.

 

[Elixir]

Where would one live to have the ground be flat all around them as far as the eye could see?

Kansas.

https://www.aps.org/publications/apsnews/200310/pancake-kansas.cfm

Maybe smooth is a better word. Though, it does give me an idea for Terrible Maps, "State Flatness Compared to a Pancake."

Let's say Kansas is 400 miles across.

And let's say the circumference of the earth is 2500 miles.

And let's assume that Kansas is perfectly smooth, as smooth, even, as the surface of a spherical cow in a vacuum.

By my math (400 miles / 25,000 miles * 360 degrees) the curvature over that length would be about 6 degrees. (5.84 degrees, if we include insignificant digits.)

So, next, I'd like the answer to a question that's pretty vague in my mind, and that I don't have the math to answer anyway.

Possible phrasings of my vague question:

• How curved is that really?
• How tall would a building on the east border have to be in order for us to see it (from a foxhole that puts our eyes at surface level) from the west border?
• Two people are six foot. And they have little periscopes that raise their lines of sight to exactly six foot. Or they're snails, so their eyes are their highest points. (This is getting needlessly complex.) How far apart can they stand and still be able to see each other?
• How far does the surface of a smooth earth drop away from horizontal (horizontal to a stationary observer over 400 miles?

Or you can phrase the question any other way that will help make the point.

And the point is?

The point is that the earth doesn't really look flat. It is only the irregularities, the unsmoothness, plus our closeness to the ground, that hides the curvature.

About 16.5 feet every five miles, on average.

 

[Shadowy Man]

About 16.5 feet every five miles, on average.

That’s the 8 inches per mile squared rule, yes? Technically that’s a parabola, not a circle but it’s pretty accurate for quite some distance. But that doesn’t include refraction, which tends to allow seeing farther.

 

[Wiploc]

Where would one live to have the ground be flat all around them as far as the eye could see?

Kansas.

https://www.aps.org/publications/apsnews/200310/pancake-kansas.cfm

Maybe smooth is a better word. Though, it does give me an idea for Terrible Maps, "State Flatness Compared to a Pancake."

Let's say Kansas is 400 miles across.

And let's say the circumference of the earth is 2500 miles.

And let's assume that Kansas is perfectly smooth, as smooth, even, as the surface of a spherical cow in a vacuum.

By my math (400 miles / 25,000 miles * 360 degrees) the curvature over that length would be about 6 degrees. (5.84 degrees, if we include insignificant digits.)

So, next, I'd like the answer to a question that's pretty vague in my mind, and that I don't have the math to answer anyway.

Possible phrasings of my vague question:

• How curved is that really?
• How tall would a building on the east border have to be in order for us to see it (from a foxhole that puts our eyes at surface level) from the west border?
• Two people are six foot. And they have little periscopes that raise their lines of sight to exactly six foot. Or they're snails, so their eyes are their highest points. (This is getting needlessly complex.) How far apart can they stand and still be able to see each other?
• How far does the surface of a smooth earth drop away from horizontal (horizontal to a stationary observer over 400 miles?

Or you can phrase the question any other way that will help make the point.

And the point is?

The point is that the earth doesn't really look flat. It is only the irregularities, the unsmoothness, plus our closeness to the ground, that hides the curvature.

About 16.5 feet every five miles, on average.

Thanks

 

[Elixir]

That’s the 8 inches per mile squared rule, yes? Technically that’s a parabola, not a circle but it’s pretty accurate for quite some distance

I don't know that rule. 5 miles is just a convenient distance for a human to start seeing curvature on ball of earth size. I somehow memorized that when I was like 8 because I figured I might accidentally end up in low earth orbit some day and need that information, since you'd have to go five miles a second ground speed to maintain altitude. Or so I was told.

 

[BH]

That’s the 8 inches per mile squared rule, yes? Technically that’s a parabola, not a circle but it’s pretty accurate for quite some distance

5 miles is just a convenient distance for a human to start seeing curvature on ball of earth size. I somehow memorized that when I was like 8 because I figured I might accidentally end up in low earth orbit some day and need that information.

It is always good to start planning early.

 

[Shadowy Man]

That’s the 8 inches per mile squared rule, yes? Technically that’s a parabola, not a circle but it’s pretty accurate for quite some distance

I don't know that rule. 5 miles is just a convenient distance for a human to start seeing curvature on ball of earth size. I somehow memorized that when I was like 8 because I figured I might accidentally end up in low earth orbit some day and need that information, since you'd have to go five miles a second ground speed to maintain altitude. Or so I was told.

Sure, but keep in mind it’s not linear, so it’s not 33 feet over 10 miles or 3.3 feet over one mile.

 

[Elixir]

That’s the 8 inches per mile squared rule, yes? Technically that’s a parabola, not a circle but it’s pretty accurate for quite some distance

I don't know that rule. 5 miles is just a convenient distance for a human to start seeing curvature on ball of earth size. I somehow memorized that when I was like 8 because I figured I might accidentally end up in low earth orbit some day and need that information, since you'd have to go five miles a second ground speed to maintain altitude. Or so I was told.

Sure, but keep in mind it’s not linear, so it’s not 33 feet over 10 miles or 3.3 feet over one mile.

Right, by the time you’re on the other side of the planet, every mile brings you closer!

 

[Swammerdami]

Flat earth is the stupidest conspiracy theory I’ve ever seen as it is nearly trivially debunked by almost anyone anywhere.

What portion of Flat-Earthers actually believe the Earth is flat? Aren't many just having fun?

I'm guessing that VERY few people agree that Birds aren't real.

 

[Wiploc]

That’s the 8 inches per mile squared rule, yes? Technically that’s a parabola, not a circle but it’s pretty accurate for quite some distance

I don't know that rule. 5 miles is just a convenient distance for a human to start seeing curvature on ball of earth size. I somehow memorized that when I was like 8 because I figured I might accidentally end up in low earth orbit some day and need that information, since you'd have to go five miles a second ground speed to maintain altitude. Or so I was told.

Sure, but keep in mind it’s not linear, so it’s not 33 feet over 10 miles or 3.3 feet over one mile.

Okay, then. Sixteen and a half feet over five miles, but how far over 400 miles?

My first approximation is 1320 feet, the height of the Empire State Building.
Is that a fair estimate or way off?


* "At its top floor, the Empire State Building stands 1,250 feet (380 meters) tall. Counting the spire and antenna, the building clocks in at a mighty 1,454 feet."

 

[Elixir]

Okay, then. Sixteen and a half feet over five miles, but how far over 400 miles?

How far what? Straight line distance, surface distance, departure from a tangent or something else?
Regardless, you need a trigonometrist.
Don’t worry, it usually doesn’t hurt!

 

[Wiploc]

Okay, then. Sixteen and a half feet over five miles, but how far over 400 miles?

How far what? Straight line distance, surface distance, departure from a tangent or something else?
Regardless, you need a trigonometrist.
Don’t worry, it usually doesn’t hurt!

Good questions! I think I was imagining following the tangent 400 miles, then taking a right angle turn downwards, and measuring the distance to the ground.

Now I'm imagining measuring a curved line that runs from a point 400 miles away on the ground (a ground as smooth as the surface of a spherical cow) to a point 400 miles away on a tangent.

But it won't really make a significant distance, will it? The surface of the earth will only be tilted (if I'm right) about six degrees from the tangent. And all we're trying to do is show that someone standing on an ideally smooth Kansas would not see the world flat all around but would rather see the surface curving away downwards in the distance.

 

[Shadowy Man]

Okay, then. Sixteen and a half feet over five miles, but how far over 400 miles?

How far what? Straight line distance, surface distance, departure from a tangent or something else?
Regardless, you need a trigonometrist.
Don’t worry, it usually doesn’t hurt!

This is a good point. The 8 inches per mile squared is the drop from the astronomical horizon (I.e., tangent line).

What you really want is a curve calculator if you’re interested in things like how much of a distant object is occluded by the intervening curve.

One of the best and easiest to use on the internet is Walter Bislin’s.