NIGHTGLOW Meaning and
Definition
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Nightglow refers to the faint illumination of the Earth's upper atmosphere that occurs during the night. This phenomenon is predominantly caused by the presence of residual sunlight that is scattered by the various atmospheric components, such as molecules and ions. Nightglow can occur in several forms, including airglow, aurora, and zodiacal light.
Airglow, a type of nightglow, is a natural light emitted by the Earth's atmosphere. It occurs due to the recombination of atoms and molecules after they have undergone ionization during the day through solar radiation. Although the light emitted during airglow is relatively dim, it can still be observed as a faint glow or a series of bands or patches in the night sky.
Aurora, another form of nightglow, is a stunning natural light display that occurs in the polar regions. It is caused by the interaction of charged particles from the Sun with atoms and molecules in the Earth's upper atmosphere. Auroras often appear as colorful, shimmering curtains or waves of light stretching across the sky.
Zodiacal light, one more type of nightglow, is a faint glow that can be observed in the night sky near the horizon after sunset or before sunrise. It is caused by the scattering of sunlight off cosmic dust particles present in the plane of the solar system. Zodiacal light generally appears as a pyramid-shaped, diffuse glow in the direction of the Sun.
Overall, nightglow describes the various natural forms of faint illumination that occur in the Earth's upper atmosphere during nighttime, including airglow, aurora, and zodiacal light.
Etymology of NIGHTGLOW
The word "nightglow" is a compound word derived from the combination of "night" and "glow".
1. "Night" originated from the Old English word "niht" or "neht", which can be traced back to the Proto-Germanic word "nahts" and the Proto-Indo-European root "*nokt-". The word has had similar forms in various Germanic languages such as German "Nacht" and Dutch "nacht".
2. "Glow" comes from the Middle English word "glouen" or "glowe", which, in turn, can be traced back to the Old English word "glōwan". The word evolved from the Proto-Germanic root "*glō-(a)-" and the Proto-Indo-European root "*ghel-", meaning "to shine" or "to burn".
