Challenge: prove the Earth is round

[OohPooPahDoo]

Mountains are not made out of water.

What does that have to do with it?


BTW - I am editing my reply to your post about the stars in opposite directions.

How does the water form a hill?

I didn't say that water formed a hill. I merely pointed out that disppearing feet first only proves there is curvature, it doesn't prove the specific shape is spherical.

 

[OohPooPahDoo]

That would require the moon, Earth, and sun all to be on the exact same plane, and have circular orbits. That would result in a solar eclipse every 28 days and a lunar eclipse 14 days later. Additionally, all eclipses would be total, there would be no annular eclipses like we had less than two weeks ago right here in California.

Nahh, the moon and Sun could be at very slight inclinations off the equatorial plane. The very same reason we don't get a lunar eclipse every full moon and a solar eclipse every new moon with the real world Earth.

If you look at the shadow cast on the moon during a lunar eclipse, its not very sharply defined. it could easily be an ellipse with low ellipticity, and allowing for a small ellipticity is all that is needed to make eclipse frequency less than 1 per 28 days.

It looks pretty well defined to me.

[ame=http://www.youtube.com/watch?v=XIcOrrFDJIw]Entire Lunar Eclipse Time Lapse 8-28-07 - YouTube[/ame]

Nice.

it is well defined

Its also not perfectly circular.

EDIT: or is it?

 

[Quantum Windbag]

What does that have to do with it?


BTW - I am editing my reply to your post about the stars in opposite directions.

How does the water form a hill?

I didn't say that water formed a hill. I merely pointed out that disppearing feet first only proves there is curvature, it doesn't prove the specific shape is spherical.

You still have to explain why the water is curved. There are some liquids that are convex due to surface tension, but water tends to be concave. That would mean that people on the shore would perceive the ship slowly going downhill as it sailed away, not slowly sailing over the crest of a hill.

 

[OohPooPahDoo]

My goal now is to construct a model that satisfies ALL the evidenece above without a (near) spherical earth.

I will go ahead and concede however, that this model will probably be a bit more complex than a spherical model. Since the spherical model is the simpler model to explain all the evidence above and whatever I come up with the more complex - by Occam's razor, the spherical model will win.

So I lose. The model I present will merely be an encore.

Quantum Windbag + Ernie S. are the winners. The good people of USMB should shower them with positive reps.

 

[Quantum Windbag]

Nahh, the moon and Sun could be at very slight inclinations off the equatorial plane. The very same reason we don't get a lunar eclipse every full moon and a solar eclipse every new moon with the real world Earth.

If you look at the shadow cast on the moon during a lunar eclipse, its not very sharply defined. it could easily be an ellipse with low ellipticity, and allowing for a small ellipticity is all that is needed to make eclipse frequency less than 1 per 28 days.

It looks pretty well defined to me.

[ame="http://www.youtube.com/watch?v=XIcOrrFDJIw"]Entire Lunar Eclipse Time Lapse 8-28-07 - YouTube[/ame]

Nice.

it is well defined

Its also not perfectly circular.

EDIT: or is it?

It is close enough that you can't see the difference. If you continued the arc around the circumference you would end up at the same spot,

 

[Quantum Windbag]

My goal now is to construct a model that satisfies ALL the evidenece above without a (near) spherical earth.

I will go ahead and concede however, that this model will probably be a bit more complex than a spherical model. Since the spherical model is the simpler model to explain all the evidence above and whatever I come up with the more complex - by Occam's razor, the spherical model will win.

So I lose. The model I present will merely be an encore.

Quantum Windbag + Ernie S. are the winners. The good people of USMB should shower them with positive reps.

I actually found a trove of stuff from the Flat Earth Society in the local library when I was in 6th grade, I wrote a paper debunking every one of their arguments.

 

[OohPooPahDoo]

How does the water form a hill?

I didn't say that water formed a hill. I merely pointed out that disppearing feet first only proves there is curvature, it doesn't prove the specific shape is spherical.

You still have to explain why the water is curved. There are some liquids that are convex due to surface tension, but water tends to be concave. That would mean that people on the shore would perceive the ship slowly going downhill as it sailed away, not slowly sailing over the crest of a hill.

Surface tension is only relevant at small scales.

If the Earth were the shape of a pitcher's mound and gravity held stuff to the Earth's surface, the water on the Earth's surface would form the same shape as the mound, just as t
...

I'm going to stop right there and make sure what I'm saying is 100% correct


I've got to go to sleep. I'll revisit all of this sometime in the next few days.

 

[Ernie S.]

Nahh... it can still be flat.

Like a pizza pie from the cosmos

The earth's shadow would only be round in the moon was directly over head at local midnight. Any other time, the shadow would be oval or a narrow bar shape.

Yes yes yes! I like it. Having trouble beating you there. Give me 24 hrs. You will be challenge winner #2 if I can't come up with a good one.

How thick was the Earth when it was flat? I know that way back when, you could fall off the edge, but could you also dig too deep of a hole?

LOL


EDIT:

I would ask that you look at some pictures of lunar eclipses. Pick one out that you think clearly shows the shadow to be circular. You might find you have trouble. Lunar eclipses don't usually have the sharp features that solar eclipses do - it may be hard to tell a slightly elliptical shadow from a circular one.

Granted, the earth's shadow is not very sharp in lunar eclipses, but an event near sunset or sunrise would show enough detail
And when you concede, it won't be to me, but to Syrenn who so brilliantly proposed the argument.
So are you conceding that the moon is roughly a sphere?
Solar eclipses cast very sharp shadows, do they not?
Could you also explain why that pre 20th century, it was easily observable that the Moon, Mars, Saturn and Jupiter were all spherical and we are to assume Earth is not?
One more for you explain: A crescent moon rising; the Earth's shadow would also cast a narrow ovate shadow if it were a disk as you pose, would it not?

 

[Procrustes Stretched]

Challenge (to you):

Prove the Earth is an approximate sphere without using any evidence gathered since and including the 20th century (so a picture of the Earth doesn't cut it)

Challenge (to me):

I will come up with an alternate explanation that does not involved a spherical earth for every piece of evidence presented.

get a life and don't forget to take your meds. otay?

 

[MeBelle]

Uhmmm, haven't heard any news of people falling off the edge...
of the earth that is.

lack of evidince isn't evidence

Did you see the ?

T'was a joke.

 

[MeBelle]

Uhmmm, haven't heard any news of people falling off the edge...
of the earth that is.

lack of evidince isn't evidence

Lack of what?


Sorry, D-I did go there...and it's your fault.

 

[IanC]

it may already have been mentioned-

the force of gravity in large objects easily overcomes the tensile strength of any material and works in such a way as to minimize the distance of any particle of matter and the centre of gravity. the shape with the most volume per surface area is the sphere. in fact the earth is somewhat obloid because it spins and the centripital force opposes the gravitational force. you still 'weigh' the same at sea level at the poles or the equator because you are tens of meters closer to the centre of the earth at the poles compared to the equator.

 

[Procrustes Stretched]

Earth is not round.

 

[KissMy]

Challenge (to you):

Prove the Earth is an approximate sphere without using any evidence gathered since and including the 20th century (so a picture of the Earth doesn't cut it)

Challenge (to me):

I will come up with an alternate explanation that does not involved a spherical earth for every piece of evidence presented.

At sea level the curvature of the earth limits the range of vision to 2.9 miles.

The formula for determining how many miles an individual can see at higher levels is the square root of his altitude times 1.225

The Bible says the Earth is circular.

 

[Truthseeker420]

Muslim are you?

Republican bigot are you?

 

[editec]

When a ship goes out to sea, one sees it slowly disappear over the horizon.

Explain how that does not indicate that the earth is basically a spherical object.

The canard that before Colombus everybody thought the earth was flat is a load of nonsense.

Most people who lived near the ocean were aware that the earth must have been shaped like a sphere.

Some ancient greeks even estimated the size of the shere within 10% of its actual size 2000 years before Chris shipped out to the new world.

 

[Rat in the Hat]

Eratosthenes of Cyrene (Ancient Greek: Ἐρατοσθένης, IPA: [eratostʰénɛːs]; English /ɛrəˈtɒsθəniːz/; c. 276 BC[1] – c. 195 BC[2]) was a Greek mathematician, geographer, poet, athlete, astronomer, and music theorist.

He was the first person to use the word "geography" and invented the discipline of geography as we understand it.[3] He invented a system of latitude and longitude.

He was the first person to calculate the circumference of the earth by using a measuring system using stades, or the length of stadiums during that time period (with remarkable accuracy). He was the first to calculate the tilt of the Earth's axis (also with remarkable accuracy)

Eratosthenes calculated the circumference of the Earth without leaving Egypt. Eratosthenes knew that on the summer solstice at local noon in the Ancient Egyptian city of Swenet (known in Greek as Syene, and in the modern day as Aswan) on the Tropic of Cancer, the sun would appear at the zenith, directly overhead (he had been told that the shadow of someone looking down a deep well would block the reflection of the Sun at noon). He also knew, from measurement, that in his hometown of Alexandria, the angle of elevation of the sun was 1/50th of a circle (7°12') south of the zenith on the solstice noon. Assuming that the Earth was spherical (360°), and that Alexandria was due north of Syene, he concluded that the meridian arc distance from Alexandria to Syene must therefore be 1/50 = 7°12'/360°, and was therefore 1/50 of the total circumference of the Earth. His knowledge of the size of Egypt after many generations of surveying trips for the Pharaonic bookkeepers gave a distance between the cities of 5000 stadia (about 500 geographical miles or 800 km). This distance was corroborated by inquiring about the time that it takes to travel from Syene to Alexandria by camel. He rounded the result to a final value of 700 stadia per degree, which implies a circumference of 252,000 stadia. The exact size of the stadion he used is frequently argued. The common Attic stadion was about 185 m,[9] which would imply a circumference of 46,620 km, i.e. 16.3% too large. However, if we assume that Eratosthenes used the "Egyptian stadion"[10] of about 157.5 m, his measurement turns out to be 39,690 km, an error of less than 2%.[11]

Eratosthenes - Wikipedia, the free encyclopedia

Eratosthenes did not prove the Earth spherical. He measured the circumference of the Earth under the assumption that the Earth is spherical (and that the Sun was far away). The same measurements used by Eratosthenes - the Sun 7.2 degrees from zenith in Alexandria when it was 0 degrees from zenith at Syene - would also be obtained if the Sun were 6400 km directly above Syene at the time of the measurement in Alexandria and the Earth were flat.

So you're saying the Sun is between the Earth and the Moon??

 

[MuadDib]

Easy!

[ame=http://www.youtube.com/watch?v=H1KWtG66lEQ]KAGUYA taking "Full Earth-rise" by HDTV (Apr. 5, 2008) - YouTube[/ame]

 

[IanC]

Earth is not round.

it is rounder and smoother than a billiard ball of proportional size.

 

[The Infidel]

Lunar eclipse.

The earth makes the shadow on the moon.... the shadow is round.

Alternative explanation:
The same shadow would be cast if the earth were a flat, circular, disc whose face is perpendicular to an imaginary line connecting the sun and moon.

Only works at precisely local midnight. FAIL!

Maybe the earth is flt and there are moon being that just display an image on their giant flat screen planet.... maybe an eclipse is just their version of a movie and we are just being peeping toms


Hey, its as good as any of the other theories