airglow

noun air·glow \ -ˌglō \

Definition of airglow

: light that is observed especially during the night, that originates in the high atmosphere of a planet (such as the earth), and that is associated with photochemical reactions of gases caused by solar radiation

Recent Examples of airglow from the Web

Dr. Shepherd and Dr. Cho zeroed in on four kinds of zonal waves using images taken from a satellite deployed in the 1990s to measure airglow and other features of the atmosphere.

— joanna klein, New York Times, "Waves Above the Earth May Have Once Caused a ‘Nocturnal Sun’," 23 June 2017
Scientific instruments are sensitive enough to detect it, but not human eyes — until a bright night, when an unexpected alignment of waves in our upper atmosphere amplify that once invisible airglow, making it much brighter.

— joanna klein, New York Times, "Waves Above the Earth May Have Once Caused a ‘Nocturnal Sun’," 23 June 2017
That airglow arises when individual gas atoms—previously created when ultraviolet light blasted gas molecules apart—

— sid perkins, Science | AAAS, "‘Bright night’ glowing sky mystery solved," 21 June 2017
A bright night starts with a dull light called airglow, which is found more than 60 miles above the earth’s surface.

— joanna klein, New York Times, "Waves Above the Earth May Have Once Caused a ‘Nocturnal Sun’," 23 June 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'airglow.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.