[[http://helioviewer.org/ | NASA HelioViewer]]

http://www.meted.ucar.edu/hao/aurora/txt/t1_ssi5.htm

[[http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html | NASA Sun Fact Sheet]]

[[sunspots | SunSpots]]

[[http://www.sns.ias.edu/~jnb/Papers/Preprints/solarmodels.html | Bahcall - Standard solar models, helioseismology, and solar neutrinos: articles]]