See under airglow.
Origin of nightglow
a dim light from the upper atmosphere caused by emissions from atoms and molecules ionized by solar radiation: observed at night (nightglow), during the day (dayglow), and at twilight (twilight glow), with each having slightly different characteristics.
Origin of airglow
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the faint light from the upper atmosphere in the night sky, esp in low latitudes
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
A faint photochemical luminescence in the upper atmosphere caused by the collision of x-rays and charged particles from the Sun with atoms and molecules, especially of oxygen, sodium, and the hydroxyl radical (OH). Airglow is strongest over low and middle latitudes.
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