送交者: xj 于 2005-1-12, 16:47:46:

回答: 埃拉托色尼妙而准确地测定了地球周长 由 HunHunSheng 于 2005-1-12, 16:39:33:

只要夏至中午在亚历山大测一下影子就可以了。没必要两头跑。

怎么知道是中午？树根杆子，测出最小的影子长度就可以了。

• This works only when they are located at the same longitude - HunHunSheng (71 bytes) 2005-1-12, 16:52:23
  • doesn't matter - wasguru (121 bytes) 2005-1-12, 17:08:27
    • I don't think so. It must be Simultaneously in terms of absolute time - HunHunSheng (296 bytes) 2005-1-12, 17:12:57
      • 混混脑子糊涂了,你的同时也是可以算的,不过就不需要夏至这个概念了. - wangle (43 bytes) 2005-1-12, 17:22:11
        • That is my original question: how to you make sure 同时测定 - HunHunSheng (157 bytes) 2005-1-12, 17:26:33
          • 测量最短距离,就保证它是夏至中午,当然还要测出两地连线和这时影子的角度. - wangle (0 bytes) 2005-1-12, 17:32:21
            • Noon at one city might be ahead of or lag behind the noon at the other city - HunHunSheng (0 bytes) 2005-1-12, 17:34:21
              • It is still possilbe to get simultaneity if you really want it - wasguru (105 bytes) 2005-1-12, 21:29:41

加跟贴