MYSTERY IN THE MESOSPHERE: This
summer, something strange has been happening in the mesosphere--a
layer of Earth's atmosphere so high that it nearly touches space. The
mesosphere is the realm of noctilucent clouds, electric-blue glowing forms
that are seeded by meteor smoke. Lately, these clouds have been
glowing more brightly than usual. What's happening up there? Researchers
from the University of Colorado may have found the answer.
A HOLE IN THE SUN'S ATMOSPHERE: A
ragged horseshoe-shaped hole in the sun's atmosphere is turning toward
Earth, spewing a stream of high-speed solar wind toward our planet.
NASA's Solar Dynamics Observatory photographed the structure earlier
today:
This is a "coronal hole," a region in the sun's atmosphere where magnetic fields open up and allow solar wind to escape.
Coronal holes are a primary form of space weather during solar minimum--that is, now. Studies show
that coronal holes not only open more frequently, but also last
longer when sunspots are absent. During the last solar minimum in
2007-2009, one coronal hole stayed open for 27 consecutive solar
rotations. As the sun slowly turned on its axis, that hole
fire-hosed Earth with a stream of solar wind almost once a month for
nearly two years. For comparison, this coronal hole has only been
around twice. It is a youngster.
spacewether.com
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