地球繞太陽公轉一周不是精確的每年365天5小時48分46秒,每年都有變化,變化還不小的, 以33年為單位進行閏年不一定更準確
https://www.quora.com/Does-the-length-of-the-year-on-Earth-change-over-time-or-has-it-always-been-roughly-365-25-days