The Cause Of The Auroras Solar Borealis Astronomy c90 Y/O Trade Ad Card

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The Cause Of The Auroras Solar Borealis Astronomy c90 Y/O Trade Ad Card
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ORIGINAL c90  YEAR OLD TRADE  ADVERTISING CARD
THE CAUSE OF THE AURORAS
An aurora (plural: auroras),[a] sometimes referred to as polar lights, northern lights (aurora borealis) or
southern lights (aurora australis), is a natural light display in the Earth's sky, predominantly seen in the high
latitude (Arctic and Antarctic) regions.
Auroras are produced when the magnetosphere is sufficiently disturbed by the solar wind that the
trajectories of charged particles in both solar wind and magnetospheric plasma, mainly in the form of
electrons and protons, precipitate them into the upper atmosphere (thermosphere/exosphere) due to
Earth's magnetic field, where their energy is lost.
The resulting ionization and excitation of atmospheric constituents emits light of varying color and
complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent
on the amount of acceleration imparted to the precipitating particles. Precipitating protons generally
produce optical emissions as incident hydrogen atoms after gaining electrons from the atmosphere.
Proton auroras are usually observed at lower latitudes.
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