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Астронет: Астрономическая картинка дня Небесные вены http://variable-stars.ru/db/msg/1318308/eng |
Credit & Copyright: P-M Hedén (Clear Skies,
TWAN)
Explanation:
Transfusing sunlight
through a a still dark sky, this exceptional display of
noctilucent
clouds was captured earlier this month
above the island of Gotland, Sweden.
From the edge of space, about 80 kilometers above Earth's surface, the
icy clouds
reflect sunlight even though the Sun itself is below the horizon as
seen from the ground.
Usually spotted at
high
latitudes in summer months the night shining clouds made
a strong showing this July.
Also known as polar mesopheric clouds they
are understood to form
as water vapor driven into the cold
upper atmosphere condenses on the fine dust particles supplied by
disintegrating meteors or volcanic ash.
NASA's AIM mission provides
daily projections of noctilucent clouds
as
seen from space.
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.