If you've ever seen a globe of Earth in a classroom, you'll have noticed that it's tipped over such that the North Pole isn't pointing straight up but is instead canted at an angle: 23.5 degrees, to be specific.
您曾经教室里看过地球仪,您会注意到它是倾斜的,因此北极不是笔直指向上方,而是以一定角度倾斜:具体来说,为 23.5 度。