大たい気き光こう

noun

airglow; nightglow

Scientific term for the faint natural light emitted by the Earth's upper atmosphere, visible at night as a very dim glow. Nightglow is a subset of airglow.

• 大たい気き光こうは、夜よ空ぞらが完かん全ぜんに暗くらくならない理り由ゆうの一ひとつです。

  Airglow is one reason the night sky is never completely dark.