Air Glow

  • December 18, 2018

The night sky has an overall background luminosity, we all know the localize sources of lights like stars, planets right .. , but in addition to the astronomical sources there is an overall uniform luminosity originating from the Earth's own atmosphere. We are not normally aware of this airglow because it is so uniform
Actually, It is the combination of astronomical and airglow sources that allows us to see the silhouette of an object held against the "dark" sky on a clear moonless night.

Difference Between Earth Glow and Aurora

Difference AirGlow Aurora
spatial extent global high latitude
luminosity relatively uniform highly structured
energy source solar radiation solar wind

Now that you have understood the difference between these 2 things , let's get into types of Airglow ..

Types of AirGlow

  • Dayglow
  • Twilightglow
  • Nightglow


Dayglow (when entire atmosphere is illuminated by the Sun) is the brightest airglow due to the importance of RESONANT and FLUORESCENT processes but it is overwhelmed by direct and scattered sunlight…


Twilightglow (when only the upper atmosphere is illuminated) is the most readily observable airglow from the ground since the observer is in darkness (and Rayleigh scattering of sunlight by the dense lower atmosphere is absent) while the airglow region of upper atmosphere is still illuminated...


Nightglow (when entire atmosphere is in darkness) is not as bright as dayglow since CHEMILUMINESCENCE is the dominant process; however contributes more light than starlight to the total luminosity of the night sky...