Sun poster.svg

The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma,[1][2] with internal convective motion that generates a magnetic field via a dynamo process.[3] It is by far the most important source of energy for life on Earth. The Sun is a G-type main-sequence star (G2V) based on its spectral class. It theoretically formed approximately 4.6 billion years ago.[lower-alpha 1][4][5] Solar physics is the branch of astrophysics that specializes in the study of the Sun. Heliophysics is the study of the Sun's influence on planetary magnetospheres.


  1. On a short scale, one billion is 109, or 1,000,000,000.


  1. "How Round is the Sun?". NASA. 2 October 2008. Retrieved 7 March 2011. 
  2. "First Ever STEREO Images of the Entire Sun". NASA. 6 February 2011. Retrieved 7 March 2011. 
  3. Charbonneau, P. (2014). "Solar Dynamo Theory". Annual Review of Astronomy and Astrophysics 52: 251–290. doi:10.1146/annurev-astro-081913-040012. Bibcode2014ARA&A..52..251C. 
  4. Bonanno, A.; Schlattl, H.; Paternò, L. (2008). "The age of the Sun and the relativistic corrections in the EOS". Astronomy and Astrophysics 390 (3): 1115–1118. doi:10.1051/0004-6361:20020749. Bibcode2002A&A...390.1115B. 
  5. Connelly, James N.; Bizzarro, Martin; Krot, Alexander N.; Nordlund, Åke; Wielandt, Daniel; Ivanova, Marina A. (2 November 2012). "The Absolute Chronology and Thermal Processing of Solids in the Solar Protoplanetary Disk". Science 338 (6107): 651–655. doi:10.1126/science.1226919. PMID 23118187. Bibcode2012Sci...338..651C.