Solar Cycle Driven By More Than Sunspots; Sun Also Bombards Earth With High-speed Streams Of Wind

When the solar cycle was at a minimum level in 1996, the Sun sprayed Earth with relatively few, weak high-speed streams containing turbulent magnetic fields (left). In contrast, the Sun bombarded Earth with stronger and longer-lasting streams last year (right) even though the solar cycle was again at a minimum level. The streams affected Earth's outer radiation belt, posing a threat to earth-orbiting satellites, and triggered space weather disturbances, lighting up auroras in the sky at higher latitudes.

From Science Daily:

ScienceDaily (Sep. 18, 2009) — Challenging conventional wisdom, new research finds that the number of sunspots provides an incomplete measure of changes in the Sun's impact on Earth over the course of the 11-year solar cycle. The study, led by scientists at the High Altitude Observatory of 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 and sunspots had virtually disappeared.

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