The active Sun has thrown a lot our way lately, including
storms of particles streaming outward in the solar wind and
clouds of plasma which triggered awesome auroral displays. Still, a growing body of
intriguing observations from the LASCO instrument on board the
space-based SOlar and Heliospheric Observatory (
SOHO) indicates material also flows back toward the Sun, starting from over 2 million kilometers above its
visible surface. Relatively hard to detect against the outflowing
solar corona, a dark inflowing cloud's relative motion is tracked above in two highly processed images recorded an hour apart. The solar surface, graphically shown by the yellow quarter circle at the lower right, is blocked from view by a smooth occulting disk. Fighting against a
solar wind outflow of about 120 kilometers per second the cloud seems to be moving inward at 50-100 kilometers per second. Occasionally
appearing as often as once per hour, the clouds, seem to be dragged in by collapsing
magnetic field loops rather than gravity alone. Researchers are now
working to relate this surprising inflow to the solar wind and magnetic
environment of the Sun.