The circumference of the Antarctic Circle is 15909 km, while one measurement of the perimeter of Antarctica’s ice is 53610 km. The numbers are different because the Antarctic Circle is circular, while the perimeter of Antarctica’s ice has a complex shape.
The circumference of the Equator is 40075 km and the 53610 km figure exceeds it. Flat-Earthers use it as “evidence” of a flat Earth. In reality, the 53610 figure is a measurement of the irregularly shaped Antarctica’s ice perimeter, not the circular Antarctic Circle.
The right diagram shows how a smaller irregular shape (like Antarctica’s ice) can have a much longer perimeter than a larger uniform shape (like the Equator).
The length of a coastline depends on how accurate we measure it. Measuring the coastline in a meter interval is going to give us a longer coastline than measuring it in a kilometer interval. In theory, a coastline can approach an infinite length if we contour every particle of sand.
References
- Pode o perímetro da Antártica ser maior do que o perímetro equatorial da Terra? – CREF
- New Map of Antarctica’s Icy Edge – NASA Earth Observatory
- Coastline paradox – Wikipedia