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Астронет: Астрономическая картинка дня Небесные вены http://variable-stars.ru/db/msg/1485669/eng |
Credit & Copyright: P-M Hedén (Clear Skies,
TWAN)
Explanation:
Transfusing sunlight
through a still dark sky, this exceptional display of
noctilucent
clouds was captured earlier this month,
reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden.
From the edge of space, about 80 kilometers above Earth's surface, the
icy clouds
themselves still reflect sunlight even though the Sun is below the horizon as
seen from the ground.
Usually
spotted at high latitudes
in summer months the night shining clouds have made
a strong showing so far during the short northern
summer nights.
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.