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Sept. 18, 2009 Â
A new study led by scientists at the National Center for Atmospheric Research (NCAR)
and the University of Michigan, finds that Earth was bombarded last
year with high levels of solar energy at a time when the Sun was in an
unusually quiet phase.
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Scientists previously thought that the streams largely disappeared as
the solar cycle approached minimum. But when the study team compared
measurements within the current solar minimum interval, taken in 2008,
with measurements of the last solar minimum in 1996, they found that
Earth in 2008 was continuing to resonate with the effects of the
streams. Although the current solar minimum has fewer sunspots than any
minimum in 75 years, the Sun's effect on Earth's outer radiation belt,
as measured by electron fluxes, was more than three times greater last
year than in 1996.
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"The Sun continues to surprise us,"
says lead author Sarah Gibson of NCAR's High Altitude Observatory. "The
solar wind can hit Earth like a fire hose even when there are virtually
no sunspots." The study, also written by scientists at NOAA and NASA,
is being published today in the Journal of Geophysical Research. It was
funded by NASA and by the National Science Foundation, NCAR's sponsor.
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When strong solar winds blow by Earth,
they intensify the energy of the planet's outer radiation belt. This
can create serious hazards for weather, navigation, and communications
satellites that travel at high altitudes within the outer radiation
belts, while also threatening astronauts in the International Space
Station.
FULL ARTICLE: http://earthchangesmedia.com/secure/3247.326/article-9162526271.php
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