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Астронет: Астрономическая картинка дня Февраль без солнечных пятен http://variable-stars.ru/db/msg/1460711/eng |
Credit & Copyright: Alan Friedman
(Averted Imagination)
Explanation:
Where have all the sunspots gone?
Last month the total number of spots that crossed our Sun was ...
zero.
Well below of the long term monthly average,
the Sun's surface has become as unusually passive this
solar minimum just like it did 11 years ago during the
last solar minimum.
Such passivity is not just a
visual spectacle, it correlates with the
Sun
being
slightly dimmer, with
holes in the
Sun's corona being more stable, and with a reduced intensity
in the outflowing solar wind.
The reduced wind, in turn, cools and
collapses Earth's outer atmosphere (the
thermosphere),
causing reduced drag on many Earth-orbiting satellites.
Pictured in inverted black & white on the left,
the Sun's busy surface is shown near
solar maximum in 2012,
in contrast to the image on the right,
which shows the Sun's surface last August,
already without spots (for a few days), as
solar minimum was setting in.
Effects of this unusually static solar minimum are
being studied.
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.