十六世紀當麥哲伦探險隊隊員們完成了世界上第一次環球航行、離開祖國幾幾乎三年後又停泊在祖國邊岸的時候,他們驚奇地覺察到一椿自己所不明白的事情。他們回到西班牙的那一天是星期五,而根據他們的計算日期,這一天應該是星期四,並且他們完全相信他們所記載日期的那冊航海日誌並没有錯誤。在航行期間“損失了”的一天,究竟掉到哪里去了呢? 打算回答這個問題,應該敘述,雖則是簡短地敘述:時間是怎樣测定的。 從很古的時候起,測定時間的基礎是地球的自動及公转,就是“平均太陽日”及“太陽年”。 這些彷彿是不變的測時單位,其實是亦有其特性。第一,年的長度下斷變化着,雖则變化的程度極微。第二,一年中所包含的日子,並非整數 When the members of the Magellan expedition in the 16th century completed the world’s first global voyage and left the motherland almost three years later and moored to the coast of the motherland, they were amazed at what they did not understand . The day they returned to Spain was Friday and according to their calculation date this day should be Thursday, and they were completely convinced that the log book they recorded was not mistaken. Where did it fall during the day of “loss” during the voyage? The intention to answer this question should be described, albeit briefly, as to how time is measured. From an ancient time, the basis of measurement time is the Earth’s automatic and revolution, the “average sun” and the “solar year.” These seem to be constant unit of measurement, in fact, also has its own characteristics. First, the length of the year is changing, though the degree of change is minimal. Second, the days included in the year are not integers