translation.en: Now that's the Tropic of Cancer in the north and the Tropic of Capricorn in the south, that much I knew, but I was surprised to learn this little fact: Those are not cartographers' lines, like latitude or the borders between nations, they are astronomical phenomena caused by the Earth's tilt, and they change.
translation.zh: 那是北面的北回归线 以及南面的南回归线， 这些是我知道的。 但我很惊讶的学到了这一小个事实： 这些不是制图者的线， 像纬度或国家的边界， 它们代表着地球倾斜造成的天文现象， 而它们一直在改变。