Polar circumnavigation is complete navigation around Earth through both the North Pole and the South Pole. Several parties have successfully done it, and it is only possible if Earth is a sphere.

Flat-Earthers incorrectly claim that Earth circumnavigation has never been done through both the poles, and they use it to “prove” a flat Earth. In reality, many have successfully done such feats.

## Magnetic Dip

A magnetic compass is less usable near the poles partly due to magnetic dip. One of the Earth’s poles is much closer and affects the needle more strongly than the other pole. As a result, Earth’s magnetic field pulls the needle toward the ground.

Flat-Earthers claim that a compass is unusable only near Antarctica. In reality, the same also occurs near the North Pole. Magnetic dip, as observed on various locations on Earth, can only happen if the Earth is spherical.

## Temperature Differences Between the Equatorial & Polar Areas

Polar areas have a lower temperature than areas closer to the equator because the same amount of solar radiation is dispersed over a larger area, and the surface of ice and snow reflects more sunlight than darker surfaces.

In the spherical Earth model, the distance to the Sun from the poles and the equator is practically the same because the sun is much farther than the distance between any two locations on Earth. Because of that reason, flat-Earthers then claim that the temperature in polar and equatorial areas should be the same. In reality, the distance to the sun is not the only factor that can determine temperature.

## Magnetic Poles

Every magnet has a north pole and a south pole. The opposite poles of the different magnets attract each other, while the same poles of the different magnets repel each other. It is not possible to have a magnet with a single pole.

Flat-Earthers proclaim that Earth cannot be a sphere because if a compass really points to the north pole, then on the equator, it should point 45° downward. They are wrong. A magnet does not only have the north pole, but it also has the south pole which is attracted to the north pole of Earth’s magnetic field. Near the equator, both forces are balanced and pull the compass’ needle to both Earth’s poles at the same time. A perfectly balanced compass will be level near the equator.

## Crossing the Continent of Antarctica

Crossing the continent of Antarctica is a feat that has been achieved multiple times. And it is only possible if Earth is a sphere. If Earth were flat, the expeditions would have to travel impossibly far, all the way to the other side of Earth.

Flat-Earthers claim that no such expedition has been attempted before. They are wrong. Crossing Antarctica has been done numerous times by multiple independent parties and using different methods.

## Admiral Byrd: “An Area As Big As The United States on the Other Side of the South Pole”

According most flat earthers, there’s no such thing as the continent of Antarctica. In their imagination, Antarctica is not a continent, but  a long ice wall enclosing the Earth. Without having anything to prove that assumption, they look anywhere for any quote they can mine and stumbled into this quote by Admiral Byrd:

“Strangely enough, there is left in the world today, an area as big as the United States, that’s never been seen by a human being. And that’s beyond the pole, on the other side of the south pole from Little America.”