Killing Flat Earth

Cool pool, but not flat Earthy at all....

What if there's an Island in the middle?

Thanks for posting the link, and maybe I'm just confused, (again), but wouldn't flat water be impossible on a globe?

Whether a swimming pool or a glass of wine, the globe dictates that all liquid is convex. Seems like an easy prove. Any takers?

So if the Earth was flat you should be able to see to the ends of the Earth, there would be no horizon line because no curvature...

I'm not saying that the earth is flat, just show me how water curves. I'm not setting you up. I truly don't get it. How does water hold it's round shape between the US and the UK? And again...............flat water cannot exist on the globe. The center of a body of water must always be higher than it's shores. Not looking to argue, just show me what I'm missing,

You mean gravity? If I knew how gravity worked, I could counteract it and float around....

Cute. Show me round water and we can consider kramarat dead forever. Nowz the chance to strike. Should be easy......but no rush.

and I ain't talkin bout no raindrop. Show me the curve. Show me the curve on a lake or a damned puddle. You're a smart guy. This is easy.

So.....I've got a pool in my back yard. On a globe model, (granted minute), the water in the center of my pool will always be slightly higher than the edges. Just show me how to prove this. I'm confused as usual.

Lay a straight edge across the water....the center will always touch before the edges....

If your pool was 1 mile across the curvature would be about .0038 feet...

1 mile wide; halfwidth x = 0.5 mile; Radius of earth R = 4000 mi, height at center h

By similar triangles, h/x = x/R; h/0.5 = 0.5/4000; h = .25/4000 = 0.0000625 miles = .33 feet = 4 inches

Yes I screwed that up some how, it is indeed 4"...Total curvature over 1 mile would be 7.98 inches.....

Simple my dear what's on. To prove to yourself that water is higher in the center place a floating object in the center of your pool and watch it travel to the side of the pool puled by gravity acting on the sloping surface of the water.

Gee mum I have finally found a pond with a slope, can I go water skiing?

Will the nay sayers who will chime in with surface tension and electron repulsion and attraction please refrain from disparaging this theory,

There would still be a horizon line, that would be level. And depending on where one was located, it is possible not, to see the end of the earth.

Brilliant!!! I knew I missed this place. Thanks bro

Mercury as a liquid state the meniscus goes down at the edge, unlike normal liquids.... Yes!, I do know that mercury is a metal, but at room temperature it is in a liquid state. ;-}

Not only that, mercury wants to form into a sphere due to surface tension. If you look at a droplet of mercury on a flat piece of glass from a side view you will see the shape of the Greek letter Omega. From the bottom, it appears to flow into a circular shape as if it was a suction cup (which it is not). The principles responsible are all about surface tension and minimal energy state.

Add a little random roughness to the glass and the mercury can not stick like it did. Better yet, try to keep a droplet on a sheet of fine sandpaper. It wants to run away from that kind of surface.

Long time no see--welcome back!

You and SE are right about the curved surface of bodies of water, but it is all but unmeasurable over small surface dimensions.

Next time, boys and girls, we'll have a lesson on why it gets dark at night.

No electricity to run light bulbs then?

I've heard about early problems with laser levelled paddocks. Some were done around 4 mile long and didn't compensate for earth curvature.

The water "ponded" in the middle and would not flow to other end until the centre was quite deeper.

The error was confirmed to be the failure to compensate for curvature with software corrections issued within a year.

Hmm, I vaguely remember some company having problems with software corrections recently.

Can you share a link?

I've seen laser points at a distance .. and they aren't points.

I'm intrested in how this could happen?

Laser levels project a beam of light that can be used as a visual chalk line when a straight and level reference point is needed.

_{I'm familiar with laser leveling techniques over shorter distances. At long distance I've seen the point grow to over a foot in diameter.}

_{I'm interested in the situation, equipment..techniques etc.}

Check <https://en.wikipedia.org/wiki/Beam_divergence> for an explanation.

Divergence. https://en.wikipedia.org/wiki/Beam_divergence

Sorry, no link. Was back in the late '80s. They had a laser at halfway on the edge and scrapered the paddock to level for flood irrigation cotton. The water wouldn't flow through and half the paddock failed. Was in the St George irrigation area in central Queensland of Australia.

Software correction next year, paddock re-surfaced and all was good. The paddocks now actually seem high in the centre by eye, but water flows through properly now. It actually looks like the water is flowing uphill (very slowly).

Similar concerns raised for extended earth walls for water in that part of the world. Some on-farm storages are over 1km square per cell with maybe three cells per set. The altitude here is just on 200m with more than 1000km downstream to the ocean if the river ever gets there.

How big were those horses?

Bigger than a breadbox...

Oooou, dat's really big!

Hello to you and all.

In hindsight the horses maybe weren't that big. Just had a peek at aerial shots of the region where that farm was (Not our place, my brother worked there for a couple of seasons) and the property is barely 2 miles long.

Maybe it was 4 mile round trip on the planter.

My humble apologies for poor or distorted memory.

There's an easy way to calculate for small angle 'a' using similar triangles

Half of paddock length d = 2 miles

Radius of earth R = 4000 miles

h/d = d/R

h/2 = 2/4000 or h = .001 miles = 5.28 feet deeper in the middle than on the ends.

I come up with 2.64 feet

Unless I'm doing something wrong, the Pythagorean theorem comes up with about half your results in post 21 too.

It might be my math I'm pretty rusty.

I think this is a very specious argument.

Once you get a large enough body of water that the curvature of the Earth will make a noticeable difference between level lines won't the wind and tide constantly make a difference in where the highest point of water lies on that body of water. Also if water is flowing into a lake, won't the water level at the inlet river be higher than anywhere else on the lake. Lastly, isn't the reference point for height the center of the Earth. Thus with a large Endorheic lake, at slack tide, and no wind to make waves, the height of the water everywhere not near an inlet will be the same even though a level laser from one shore to another might be at different heights.

Neglecting local anomalies produced by variations in the material between you and the center of the earth, the force of gravity is always pointing toward the center of the earth. The surface of a liquid at rest will always be perpendicular to that vector. Move one minute of arc away from your original position and the direction of the vector has also shifted by one minute of arc. Although that produces a curve in the water surface with an apparent hump halfway between your original and current positions, the water remains "level" with respect to the gravity vectors at every point along your path. The rotating earth introduces some "interesting" twists (or should I say ellipsoidals) by changing the magnitude of the gravity vector.

"Lastly, isn't the reference point for height the center of the Earth."

Exactly, he misunderstood what they told him in school: the edges of the lake, ignoring local interference, are at exactly the same height above sea level (now there's a giveaway) as the centre.

I seem to recall some video and pictures of astronauts spilling water and naturally the water beads 'pulled themselves together' to form a sphere. I also recall reading that the perfect spherical ball bearings can only be achieved in space. But then again, I have to prove that man really went into space! Oh boy...here I am arguing with myself.

Gravity will always bring you down to Earth.

Sorry, but the force of gravity on such a small body (drop of water) is much weaker than the molecular forces.

Stephen Hawking had the answer:

https://www.youtube.com/watch?v=TaVdgNI0os4

NetFlix has a video, "Behind the Curve" in which some Flat Earth Society people try to prove that the Earth is flat using lasers, and prove that it is not spinning using gyroscopes. I don't want to give a spoiler here.

I knew better to wander into this pool of brilliance once again, but I have to wonder what the system is that keeps the nose of the plane down to compensate for the ball, and how did they do it in the old days? Let's ask wiki: https://en.wikipedia.org/wiki/Autopilot Wow! In 1912 they were able to.........travel on a straight plane. Perhaps we should look more deeply into Hitler's "Big Lie". Just a painter that's out of my league. Catch you guys up the road.

It's cool how people fly around the earth from west to east and east to west, but somehow circumnavigation becomes impossible along the longitudinal lines. Why?

I'm guessing it's because longitudinal lines only go half way round: to circumnavigate you'd have to jump to the line (old line ±180^o).

Because if they did, one would fall out of the sky at the edge. There is no sky at the far side of the edge. Just space and lots of it too.

Satellites travel longitudinal lines every day.

In the real make believe world, if you go far enough north, you will be going south and if you go far enough west you will be going east.

I agree with the North then South statement, but the same is not true with the east/west statement. There is no East Pole to travel past.

I 100% agree, they changed it to a mid point, called Greenwich, also called a line, one side of the line is East, the other side is West and 180 degrees away is the other mid point. One short step is all it takes.

There's bad news and good news. The bad news is that CR4 is dominated by a handful of assholes, as we can witness by the "who's online" predator list. Just waiting to jump. The good news? You won! Like a beaten stepchild, I bounce in here expecting some sort of mutual respect.....despite differences. But no. I don't know why I bother.

Now that's a real engineers' discussion :)