地球是圓的,為什麼人仍覺得自己是直立的?

地球直徑12756公里,這麼大我們看起來當然覺得是直的

因為弧形是由無數直線組成的~

2007-02-03 14:05:08 補充：
所以我站在地平線上看上去便似是平面~

It is because the force of gravity is always directed towards the centre of the earth. Under such situation, your weight is in a direction perpendicular to the ground where you are standing. This is the reason why you feel that you are [standing upright].