Is Earth round or flat ?

[rattlesnake]

6 hours ago, BillyBid said:

 

Whats your point?  

 

It is fairly self-explanatory.

[rattlesnake]

9 hours ago, Mike_Hunt said:

1. Drop Over Distance

A common approximation is:

• Over 1 mile (1.61 km), the Earth's surface drops about 8 inches (20 cm).
• Over 10 miles (16.1 km), the drop is about 66.7 feet (20.3 m).
• Over 100 miles (161 km), the drop is about 6,667 feet (2,032 m).

 

Thanks Mike.

 

@BillyBid, any additional insights?

[0ffshore360]

Is it not possible that a round circle can be flat ? But if the earth is flat what does the "underside" look like?

I am wondering if it would be like someone sitting naked on a glass table ? All revealing like?

 

 

[HotMama]

1 hour ago, rattlesnake said:

8 hours ago, BillyBid said:

Whats your point?  

 

It is fairly self-explanatory.

 

Not really.  There are direct flights between Perth and Johannesburg that go over the ocean and nowhere near Dubai..  Why did you post this???  Did you think there weren't flights?  Seriously, I really don't understand.

 

 

 

[rattlesnake]

13 minutes ago, HotMama said:

 

Not really.  There are direct flights between Perth and Johannesburg that go over the ocean and nowhere near Dubai..  Why did you post this???  Did you think there weren't flights?  Seriously, I really don't understand.

 

 

 

 

Research it and you will see the overwhelming majority of airlines do not offer direct flights, South African Airlines being pretty much the only exception.

[HotMama]

10 hours ago, Mike_Hunt said:

Would you like a specific calculation for a given distance?

 

Sure, give me the calculation for 99% of the radius.  Say 6300km to make it a nice easy round number for you.  What would the drop be for that value?  

 

On a sphere that would very obviously be nearly the same as the radius, but using your formula I get a value of many thousands of times larger than that. 

[HotMama]

9 minutes ago, rattlesnake said:

Research it and you will see the overwhelming majority of airlines do not offer direct flights, South African Airlines being pretty much the only exception.

 

Qantas also flies it.  What a surprise that the only two airlines that fly between south Africa and Australia are Qantas and South African.....

 

 

[richard_smith237]

13 minutes ago, rattlesnake said:

 

Research it and you will see the overwhelming majority of airlines do not offer direct flights, South African Airlines being pretty much the only exception.

 

Please do not make a very basic error in sense and mistake basic economics for the earths 'shape' as the reason certain routes are taken. 

[rattlesnake]

4 minutes ago, richard_smith237 said:

 

Please do not make a very basic error in sense and mistake basic economics for the earths 'shape' as the reason certain routes are taken. 

 

A very astute remark indeed.

[rattlesnake]

10 minutes ago, HotMama said:

 

Qantas also flies it.  What a surprise that the only two airlines that fly between south Africa and Australia are Qantas and South African.....

 

 

 

A possibly valid remark.

 

If this were the only example given, I would agree on its limited relevance. I believe, however, that when there is a body of circumstancial evidence, then it warrants closer observation.

 

There are plenty of examples, I will look into them a bit later.

 

[Stiddle Mump]

1 hour ago, rattlesnake said:

 

A possibly valid remark.

 

If this were the only example given, I would agree on its limited relevance. I believe, however, that when there is a body of circumstancial evidence, then it warrants closer observation.

 

There are plenty of examples, I will look into them a bit later.

 

Why can't a plane fly around the coast of Antarctica? Is it because a plane can't fly 120,000 kms in one go?

 

I've looked, and I can't find any flights.

[HotMama]

34 minutes ago, Stiddle Mump said:

Why can't a plane fly around the coast of Antarctica? Is it because a plane can't fly 120,000 kms in one go?

 

I've looked, and I can't find any flights.

 

And you don't think that maybe you can't find any flights because there are no airports or cities anywhere near the coast of Antartica?

[rattlesnake]

So regarding the flight paths, I found this website which provides all available routes between two airports:

 

https://www.flightconnections.com/

 

I did find some peculiar things, confirmed when checked on flightconnections.com:

 

Why does Buenos Aires - New Delhi not stop over in Africa?

 

 

 

Rio Gallegos - Johannesburg: why the detour via Sao Paulo?

 

 

 

There are also several flights which make seemingly massive detours through Europe (in fact most of them, even if the odd direct flight exists). Example here with Buenos AIres - Johannesburg:

 

 

[rattlesnake]

On 3/13/2025 at 12:13 PM, Stiddle Mump said:

Why can't a plane fly around the coast of Antarctica? Is it because a plane can't fly 120,000 kms in one go?

 

I've looked, and I can't find any flights.

 

Good question. Why indeed?

[rattlesnake]

On 3/12/2025 at 11:32 PM, Mike_Hunt said:

 

The Earth's curvature is typically expressed in terms of drop per distance, radius of curvature, or sagitta (chord height difference). Here are a few ways it's quantified:

1. Drop Over Distance

A common approximation is:

• Over 1 mile (1.61 km), the Earth's surface drops about 8 inches (20 cm).
• Over 10 miles (16.1 km), the drop is about 66.7 feet (20.3 m).
• Over 100 miles (161 km), the drop is about 6,667 feet (2,032 m).

The formula for the drop d due to curvature over a distance x on a sphere of radius R is:

d=R−R2−x2

For Earth, where R ≈ 3,959 miles (6,371 km), you can compute the drop for any distance.

2. Radius of Curvature

The Earth's mean radius is 6,371 km (3,959 miles). This value is used in many geophysical and engineering calculations.

3. Sagitta (Height of Arc Over a Chord)

If you draw a straight line (chord) between two points on Earth's surface, the maximum height h of Earth's curvature above the chord is given by:

h=x22R

where x is half the chord length.

Would you like a specific calculation for a given distance?

 

So how does one explain this?

 

[SillySam]

23 minutes ago, rattlesnake said:

So how does one explain this?

What needs explaining?

[Mike_Hunt]

48 minutes ago, rattlesnake said:

 

So how does one explain this?

 

Anyone who does math should understand.

[rattlesnake]

15 minutes ago, Mike_Hunt said:

Anyone who does math should understand.

 

I don't do math, please explain.

[Mike_Hunt]

1 hour ago, rattlesnake said:

 

I don't do math, please explain.

I can't help you at this point.