The
Sun may appear blue after volcanic eruptions or major forest fires. This is typically due to
scattering
In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiat ...
by
aerosol
An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be generated from natural or Human impact on the environment, human causes. The term ''aerosol'' co ...
particles. Normal
Rayleigh scattering is caused by particles much smaller than the wavelength of visible light. The scattering which causes the blue sun appearance is due to larger particles whose size is similar to the wavelength of light.
See also
*
Blue moon – a similar phenomenon affecting the Moon
*
Green flash – a phenomenon at sunset, when the last edge of the sun may flash green or even blue
References
Atmospheric optical phenomena
Solar phenomena
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