On a physical level, it seems to me that flying in a plane around the globe is proof enough that the world is round.

But interestingly enough, on a metaphysical level, 3D space could be constructed from 2D space that has wrapped around on itself. Like a piece of paper being wrapped into a cylinder. In which, case the world is flat. However, even deeper, the 2D space would be likely to simply be a 1D line wrapped around itself. Like a zip tie becoming a circle. In which case, the world is not actually flat, but a single line.

This is a joke right? You realize you can't set up a high powered telescope and see from say NY to North Carolina right? http://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/HorizonDistance.png/600px-HorizonDistance.png

This is observable despite all that scary math.

Yep, nobody ever thought the earth was flat, even in the earliest scraps of pre-history we have evidence people knew we were on a big fucking ball in space.

Out of curiosity, which people thought that (and what evidence)? Thanks in advance. Pretty sure some people thought the world was flat and still do to this day (strangely).

Eratosthenes estimated the circumference of the Earth in Circa 250 B.C

Admittedly this isn't quite as early as my previous post implies but I am pretty sure there's evidence of older civilization being aware of the nature of the earth, I just need to find sources, bear with me :)

For sure, no rush, thanks.

In Egypt they claimed the world was flat - that the sun died at night time in the west and was re-born in the east.. Egyptian society also shows evidence of trade with South America due to the mummies of pharaohs all having cocaine (derived from the cocoa plant in south america) in their bodies. so even though this mystical advanced society who built structure we can't fathom today and traveled half the world for cocaine, they couldn't tell if the world was flat? just an observation

I'm confused about what this proves.. ? i could draw a diagram with a flat earth a telescope and a horizon line too. TO BE CLEAR - I'm not condescending to the theory that the earth is spherical .. or against it..

If you drew this... your view would go on indefinitely if there were no curvature. It would not hit the horizon...

what about mountain ranges, and valleys. plus the fact that we can't see forever? horizon would be a matter of perception.

This has got to be the least intelligent "intelligent discussion" I've ever seen. 13 miles... thats all you need. there are places that are effectively flat. There is data, scans of the earth, that show these places. It's very very observable. You aren't even trying here.

Lol, if you can't prove or disprove it, then i'd say its a pretty spot on 'discussion'.. you can throw all the numbers and scans and equations up that you like. you still haven't provided 100% proof either way, as I said I'm not here saying its flat. I'm simply asking for the best most open concepts of why and how. Theres also data and scans of the middle of the earth claiming we have a molten core, yet no ones been there.. iv also seen pictures of the moon, and jupiter and movies where aliens attack earth. what your saying is that someone else did a scan, you heard about it or have been brought up to believe that this is true and as a result here we are. Have you been to the middle of the ocean to test your theory. if so then fantastic. if not then i accept your ideas and concepts as much as my own, because we both have, for ourselves, unproven and unverified data.

Actually. I've done these scans. I've observed this as well. I work with these data regularly. Not unproven. Wow... just wow.

Wow! as someone who works with data like this regularly, wouldn't you understand that all of science is infact theory not proof. I appreciate your contribution to the discussion, despite your closed mind, it has been helpful in discerning that 13 miles (20.92km) is the distance in which a ship will being to fall under the horizon or 'sink' in the ocean. thus providing evidence towards the concept of a spherical earth.

This is the last you get. There is so much information out there if you look for it. I've done these scans, and I do work with these data regularly. They are called DEMs, or Digital Elevation Models. I do not keep the specifics of the science or math at the tip of my tongue. I learned this over a decade ago, and once I did, I am comfortable using specialized tools and models to do some of that math/science/scary stuff for me. And be careful what you say about close mindedness... I am a believer in many things that you might find crazy. That said, this is one thing that I do know is not worth questioning... hence my contribution.

not being a dick. but actually thank you for contributing

Theory and scientific theory are not the same. Scientific theory is the best form of (confirmed)proof that we have of things. You can test scientific theories yourself, just in case you think something is wrong.

I can appreciate that, the most solid or understandable theory based on the observations we make.. I don't know why everyone is blowing up, all i've seen is a big maths equations which is above my head in terms of physics calculations and the 13 mile horizon information (which actually helps) and all i wanted was a discussion with open ideas, rather than angry reposts at a rebuttal of mine. I think its good to question things in your universe, your world. wherever. NOT BEING SARCASTIC, but i appreciate u/arkham69 and u/rontagosh giving some known scientific basis for the theories in laments terms but remember, a long time ago you would be called an idiot, crazy or even a witch or saying the world was round. science hasn't come far enough to understand the majority of our ocean, theres more life under the crust of the earth than there is above it. these things seem crazy, but are 'true' or 'realistic' according to modern science. if i said that the 'flat earth' was moving upwards at 9.8miles per second, instead of the spherical earth spinning at ground level of 1000 miles per hour, you would think I'm stupid. but both seem crazy at first glance and there is maths that verifies it according to our current understandings of the universe. maybe we got the maths wrong? maybe we didn't.

It proves that the world isn't visibly flat at least. If the world were flat, you'd be able to see from NY to China with a telescope.

How do you know that ?, I understand the theory.. flat world, straight line, no loss of visibility.. but how do you KNOW? its more a question of questioning, rather than to be proven or disproven.. if you haven't been too space or crossed the antactic, then it is likely impossible to prove. One argument against ^{^} above theory ^{^} is that as a sailing ship travels away from another, from human perception it fades into the horizon, however through a telescope the ship can be seen from base to mast, however their should be, after a certain distance, a discernible 'wall of water' in front of the view (even though the telescope) which prevents the base of the ship from being seen.

"How do you know that?" - From direct observation.

If you watch a ship sailing away, telescope or not, you'll see it "sink" into the horizon eventually; If the world were flat, you'd always be able to see it (given the appropriate magnification), no matter how far it goes.

But that could be the limit of your eye-sight.. although if it is 'sinking' it would begin to lend towards a sphere i suppose, rather than continually becoming smaller... interesting observation, the difference between sinking and fading.. any sailors in the house to verify results or shall i put a raft together?

"But that could be the limit of your eye-sight" - Then refer to a telescope.

One thing you could do as a personal project, is goto a harbor, set up a scope, and watch the ships that are going far out. Write down your findings.

could be the limit of your eye site though a telescope.. think of the possibilities

The limit of your eyesight would be the distance between your eye and the telescopes eyepiece. The rest is up to the telescope.

I'm also done here; there's tons of ways you can prove earth curvature or disprove flat earth and I feel I and others have laid out simple experiments to do so. Good luck.

You could only see the base of ship B, if you were high enough up in ship A, as in up on the mast. Again, this is very observable. The distances here are around 13 miles where things would disappear beyond the horizon... telescope or not. Again... try it.

So if I'm high up on ship A i could see the base of ship b ? at what distance would 'sink'? 13 miles?, this is good stuff

This is where your scary math comes in. I'm done though. All of this evidence you asked for is being immediately questioned, though, you can go observe this yourself... or go do this math that you question. Just because you wont go try it, doesn't make it not true.

he wants to test it "with you"... O.O

back off slowly...run as fast as i can

math isn't scary, i just wanted the answers. if 13 miles for curvature is the answer then you've culminated then thank you. Question - have you tested it? can i verify my results when i go to test it with you?

No.

Could the universe be a 3+1d hologram embedded in a 4+1d universe? Absolutely, and it's an absolutely valid theory.

Lunar eclipse shows the shape of earth.

interesting. how so?

The shadow.

the shadow of the moon in front of the sun or the sun in front of the moon shows the shape of the earth how?

...that's not how an eclipse works. You're not crazy to question even the oldest or most 'solid' of ideas about our world, but you have to at least work with the data as it exists, otherwise you're asking whether or not what we observe is 'real', in which case there are new studies that suggest it could all be a hologram written in ASCII, and nothing is actually 'round' .* you can launch your own weather balloon into space and take video and photos (don't use a fisheye lens) for less than $1500 if you are looking for an experiment to try yourself.

People got into little metal ships, flew up into the sky, then circled the Earth and looked down at it. Guess what they saw? An oblate spheroid. They even took pictures of it. How much more evidence do you need?

Well you didn't go up did you? Neither did I. inFact only, 4 now, 5 countries in the world have been into space. all these countries have interconnected space programs and are allies in the field. hence, not really proof.

For sure, no rush, thanks.

It proves that the world isn't visibly flat at least. If the world were flat, you'd be able to see from NY to China with a telescope.

If you drew this... your view would go on indefinitely if there were no curvature. It would not hit the horizon...

Lol, if you can't prove or disprove it, then i'd say its a pretty spot on 'discussion'.. you can throw all the numbers and scans and equations up that you like. you still haven't provided 100% proof either way, as I said I'm not here saying its flat. I'm simply asking for the best most open concepts of why and how. Theres also data and scans of the middle of the earth claiming we have a molten core, yet no ones been there.. iv also seen pictures of the moon, and jupiter and movies where aliens attack earth. what your saying is that someone else did a scan, you heard about it or have been brought up to believe that this is true and as a result here we are. Have you been to the middle of the ocean to test your theory. if so then fantastic. if not then i accept your ideas and concepts as much as my own, because we both have, for ourselves, unproven and unverified data.

Actually. I've done these scans. I've observed this as well. I work with these data regularly. Not unproven. Wow... just wow.

not being a dick. but actually thank you for contributing