NASA
Nasa: Tour of the Electromagnetic Spectrum: Visible Light
Visible light waves are the only electromagnetic waves we can see. We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. When all...
NASA
Nasa: Solar Data Analysis Center: The Corona
This site provides a detailed overview of the sun's corona. Content includes a focus on research dedicated to the solar corona, and includes numerous images taken during solar eclipses.
University Corporation for Atmospheric Research
Ucar: Coronal Holes in the Sun's Atmosphere
Coronal holes are areas in the Sun's atmosphere that appear dark in X-ray and ultraviolet images of the Sun. View a picture and read a description of coronal holes in this article.
Australian Broadcasting Corporation
Australian Broadcasting Corporation: News in Science: Secrets of the Sun's Sizzling Corona
From ABC News in Science, Larry O'Hanlon's article on the sun's corona covers information related to the inner workings of the sun. Several included topics are "Sound makes heat" and "Reaching the surface."
Other
The Virtual Sun: Between the Sun & Earth
The Virtual Sun by Michiel Berger provides a very brief overview of solar wind.