Why do people have beliefs that are clearly ridiculous?

@Khenpal1 What do you mean?

@Pambie If you go east or west , you will eventually arrive , its rather hard from north-south.

@Khenpal1 You mean going always E or always W brings you back where you started, but going always N or always S leads you to one of two points?

@SomeMichGuy earth rotates at the angel

@Khenpal1 No, if you travel North and keep going, eventually you'll end up in Antarctica. The Earth is a sphere you know, with our compass directions - N, S, E, W - being purely an invention of ours in order to provide us with some direction upon that sphere.

@Pambie You like polar bears and penguins ?😎

@Pambie Actually you cant , even atomic ice breakers cant and no airplanes can cover distance . Only Santa can 😂

@Khenpal1 That's only because of the geography.

@Pambie

No.

If you travel North, you stop at the North pole. Geographic North doesn't suddenly become South at the North pole.

@SomeMichGuy I said "if you keep going".

@Pambie Ah, so you mean continue along the great circle route:

go N along some longitude line at α degrees E or W until you hit the N pole,

then continue by going along the longitude line which is the supplementary angle in the "other" hemisphere--(180 - α) W or E‐‐toward the S.

I think "go E or W along a constant parallel of latitude and you'll be back where you started", for any point on the planet, is compelling enough...

But the shape of the gravitational potential / force around the earth is compelling, too.

@SomeMichGuy What does gravity have to do with it? Start on any random point on the surface of a sphere - any sphere - and if you keep going in one straight direction, eventually you'll get back to where you started.

@Pambie

Yes, geometry gets you that, just as measuring triangles on the surface of the Earth.

But the shape is the shape of a real object, with mass, and the shape of the mass distribution also affects gravity.

Spherical symmetry -> 1/r^2 dependence

Cylindrical symmetry -> 1/r dependence*

Cartesian "symmetry" (flat plate) -> constant field*

*For infinite cylinders or plates, this holds everywhere. For finite bodies, tjis is most true at the center.

And for any body, if one is "sufficiently close", to the surface, the field is approximately constant (equivalently, the potential surfaces close to the body exactly reproduce the shape of the body).

Of course, the lack of observations of any edge ought to be compelling, but these people aren't into reason.