Hi Lauren,

I think the understanding of the Sun's magnetism came through a number of different discoveries over the years. A couple in particular -

Edward Walter Maunder along with his wife Annie Maunder were important in establishing the importance of solar magnetic fields and their effects at Earth. That was in the in the 1890's. More about them here: http://www.astro.umontrea...bio/emaunder_e.html, http://www.astro.umontrea.../bio/amaunder_e.html

George Ellery Hale discovered magnetic fiels in Sunspots in 1907 (http://obs.astro.ucla.edu/150_hist.html).

People had suggested the solar magnetic field connection, but were not taken very seriously. I am getting a lot of my info here form a quick scan of Stuart Clark's book The Sun Kings. There were a lot of other people who did important research.

The main way the Sun controls the solar system is through gravity. The second way it though providing heat from the light it emits. I would put magnetic effects behind both of those.

cheers,

Terry