送交者: outsider 于 2005-1-12, 18:07:47:

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:

If the two places are not on the same longitude, then the calculation is not accurate.

If point B is 100 miles from A, but B is not straight north of A, but 45 degree (northwest), then the effective distance along the longitutinal line is only 70.7 mile. So the calculation would be off by 30%.

• Hunhun has pointed this out - 008 (406 bytes) 2005-1-12, 21:58:02
• 同经目的是为了保证两地中午是同时 - HunHunSheng (163 bytes) 2005-1-12, 19:28:58
  • 同经是为了保证两地"直线"距离等于两地所在纬线间的距离. - fagus (100 bytes) 2005-1-13, 04:50:59
  • If the two points are not - outsider (180 bytes) 2005-1-12, 22:56:35
    • Good idea - whiteshark (0 bytes) 2005-1-13, 00:06:20
• 埃及国家的形状狭长，ref: Eratosthenes, Syene, and Alexandria - xj (5095 bytes) 2005-1-12, 18:29:30

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