The term 'solar ring' refers to the outermost layer of the Sun's atmosphere, known as the CORONA. The CORONA is composed of plasma and extends millions of kilometers into space. It is visible during a total solar eclipse, when the Moon blocks out the bright light of the Sun's photosphere. The CORONA is also visible in extreme ultraviolet images taken by satellites. Solar rings are made up of loops of hot gas that are held together by magnetic fields. These loops can be seen in X-ray images of the Sun.