Today I read an interesting article that I'd like to share with everyone.

https://kevinwang0723.medium.com/shorte ... 3945e6c471

The content discusses the Great Circle Route, which is the shortest path connecting two points on the surface of a sphere.
The author used calculus to verify that the shortest distance between two points on a sphere is the arc length of the great circle (which equals 10.23-red curve), rather than the arc length between the two points (which equals 11.19-black curve).

https://www.geogebra.org/m/judpeqzb?sou ... ----------

From my perspective as a student currently studying basic astronomy, this observation is intriguing.
Isn't the great circle arc length just the equatorial coordinates?
And the arc length is the horizontal coordinates.