The sun can be divided into layers where different things occur. The center or core of the sun is where nuclear fusion occurs.

The sun normally has an 11-year cycle of activity. When it’s active, scientists see sunspots on the surface where the magnetic field lines exit and reenter the sun.

The Ulysses spacecraft was launched in October 1990 from the space shuttle Discovery on a joint mission of NASA and the European Space Agency.

The sun’s interior resonates low-frequency sounds, like a bell vibrating tones. The loudest of the notes have frequencies around .0003 hertz, which is about one vibration every five minutes.