Wikipedia:Main Page history/2019 July 24

Sun

The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of plasma, heated by nuclear fusion of hydrogen into helium in its core, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometres (860,000 miles) or 109 times that of Earth, while its mass is about 330,000 times that of Earth. It accounts for about 99.86% of the total mass of the Solar System. Roughly three-quarters of the Sun's mass consists of hydrogen; the rest is mostly helium, with much smaller quantities of heavier elements, including oxygen, carbon, neon and iron.

This false-color photograph of the Sun was taken by the Atmospheric Imaging Assembly instrument on NASA's Solar Dynamics Observatory (SDO) at a wavelength of 304 angstroms, in the extreme ultraviolet region of the electromagnetic spectrum.

Photograph credit: NASA/SDO

Recently featured:

Other areas of Wikipedia

  • Community portal – Bulletin board, projects, resources and activities covering a wide range of Wikipedia areas.
  • Help desk – Ask questions about using Wikipedia.
  • Local embassy – For Wikipedia-related communication in languages other than English.
  • Reference desk – Serving as virtual librarians, Wikipedia volunteers tackle your questions on a wide range of subjects.
  • Site news – Announcements, updates, articles and press releases on Wikipedia and the Wikimedia Foundation.
  • Village pump – For discussions about Wikipedia itself, including areas for technical issues and policies.

Wikipedia's sister projects

Wikipedia is hosted by the Wikimedia Foundation, a non-profit organization that also hosts a range of other projects:

Wikipedia languages