## Dip Circle

Earth’s magnetic field does not only align horizontally but also has a vertical component. The closer to the magnetic poles, the steeper the dip angle. A dip circle can be used to measure this dip angle. It is basically a compass for the vertical direction.

Compass points horizontally and flat-Earthers wrongly use it as “evidence” of a flat Earth. In reality, a compass is balanced to counter the effect of magnetic dip. We can use a dip circle to measure the actual dip angle of the Earth’s magnetic field.

## 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.

## Sun Compass and Richard E. Byrd’s Flight Toward the North Pole

In 1926, Richard E. Byrd flew near the North Pole and used a sun compass for navigation. A regular magnetic compass is less usable near the poles because it points toward the magnetic pole, which is different from the geographic pole, and that the needle will point toward the ground due to the magnetic dip.

Flat-Earthers are too fixated on the stories about Richard E. Byrd’s compass being unusable in Antarctica and use it as “evidence” of flat Earth, as if it only happens in Antarctica. They failed to realize that the same thing also occurs near the North Pole, and Richard E. Byrd himself also prepared for it.

## 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.