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距離単位

3 件の記事

The supposed remains of the Golden Milestone, the zero-mile marker of the Roman road network, in the Roman Forum

マイルの定義と歴史国際標準から多様な地域単位まで

マイル長さの単位国際マイル海里
2026年8月11日続きを読む →
Transits of Venus across the face of the Sun were, for a long time, the best method of measuring the astronomical unit, despite the difficulties (here, the so-called "black drop effect") and the rarity of observations.

天文単位（au）とは？太陽系を測る基準となる距離の定義と歴史

天文単位au地球・太陽間距離天文学
2026年8月11日続きを読む →
The yellow shell indicating one light-day distance from the Sun compares in size with the positions of Voyager 1 and Pioneer 10 as of 2008 (red and green arrows respectively). It is larger than the heliosphere's termination shock (blue shell) but smaller than Comet Hale-Bopp's orbit (faint orange ellipse below). Click on the image for a larger view and links to other scales.

光秒（Light-second）とは？宇宙と通信の距離を測る究極の単位

光秒光速天文学通信遅延
2026年8月11日続きを読む →