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Астронет: Астрономическая картинка дня Северное сияние над облаками http://variable-stars.ru/db/msg/1192896/eng |
Credit & Copyright: Dominic Cantin
Explanation:
Aurorae usually occur high above the clouds.
The auroral glow is created when fast-moving
particles ejected from the
Sun impact air molecules high in the
Earth's atmosphere.
An
oxygen molecule, for example,
will glow in a green light when reacquiring an
electron
lost during a collision with a solar particle.
The lowest part of an
aurora will typically occur at 100 kilometers up, while
most clouds usually exist only below about 10 kilometers.
The relative heights of
clouds and
auroras are shown clearly in the
above picture taken last month from near Quebec City,
Canada.
The most likely time to see an
aurora is around midnight.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.