Empirical Earth · The Sky — Sun, Moon & Stars

Day, night & the terminator — the antipode test

The claim

“A ball can only be half-lit, yet maps show ~70–90% lit at once — day in America and Asia together.”

What is measured

At any instant about half the Earth is in daylight, split by a sharp terminator, a distant Sun lighting one hemisphere of a ball.

What would show this is wrong

simultaneous daylight at true antipodes, or a lit fraction far from ~50% at any instant.

Sources

  1. Solar terminator & illuminated fraction. The day/night line is a great circle dividing Earth roughly in half; a little over half (~50.3–50.5%) is sunlit at any instant, owing to the Sun's an link
  2. Antipodes & the land/water split. Only ~15% of land is antipodal to land (≈4.4% of Earth's surface); New York ↔ Indian Ocean, London ↔ the Antipodes Islands, Beijing ↔ Argentina. The Sun's a link
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