11/4/2011 12:41 PM That solar activity can have an effect on
radio communications is well known. Sunspots, solar flares,
coronal mass ejections and other disturbances 93 million miles
away at the center of the solar system can cause problems for
satellites circling earth as well as for shortwave and other HF
radio broadcasts. When the energy of a solar flare reaches the
Earth, it can temporarily increase the density of the
ionosphere, a phenomenon known as Sudden Ionospheric Disturbance
or the Mögel-Dellinger Effect. That in turn causes HF radio
waves to be more completely absorbed by the ionosphere, creating
short fade outs or even complete blackouts for shortwave
broadcasts that can last for minutes or even hours. Which is all
an excuse to post this picture from NASA’s Solar Dynamics
Observatory (SDO) at Goddard Space Flight Center. The bright
light at the upper left is an X 1.9 Class solar flare, numbered
AR1339, emitted from the Sun yesterday (3:27 p.m. EDT on Nov. 3,
2011). According to NASA, disruptions