Sun/Old Sun

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 Observation data 
Mean distance from Earth
150,000,000 km]]
Visual brightness
-26.8m
Absolute magnitude
4.8m
 Physical characteristics 
Diameter
1,392,000 km
Relative diameter (dS/dE)
 109 
Surface area
6.09 × 1012 km2 
Volume
1.41 × 1027 m3
Mass
1.9891 × 1030 
 kg
Relative mass to Earth
 333,400
Density
1411 kg m-3
Relative density to Earth
0.26
Relative density to water
1.409
Central density
1.5 × 105 kg m-3
Surface gravity
274 m s-2
Relative surface gravity
27.9 Gs
Surface temperature
5780 K
Temperature of corona
5 × 106 K
Luminosity (LS)
3.827 × 1026 J s-1
 Orbital characteristics 
Period of rotation   
At equator:
27d 6h 36m
At 30° latitude:
28d 4h 48m
At 60° latitude:
30d 19h 12m
At 75° latitude:
 31d 19h 12m
 Photospheric composition 
 Hydrogen 
 73.46 %
 Helium 
 24.85 %
 Oxygen 
 0.77 %
 Carbon 
 0.29 %
 Iron 
 0.16 %
 Neon 
 0.12 %
 Nitrogen 
 0.09 %
 Silicon 
 0.07 %
 Magnesium 
 0.05 %
 Sulphur 
 0.04 %
The Sun, sometimes called Sol, is the star in our solar system. The planet Earth and all of her sister planets, both the other terrestrial planets and the gas giants, orbit the Sun in accordance with Newton's Laws of Gravity. Other bodies that orbit the Sun include asteroids, meteoroids, comets, Trans-Neptunian objects, and, of course, dust.
== Physical and other characteristics ==
The Sun is a main sequence star, with a spectral class of G2, meaning that it is somewhat bigger and hotter than the average star but far smaller than a red giant star. A G2 star has a main sequence lifetime of about 10 billion years, and the Sun is probably about 5 billion years old, as determined by nucleocosmochronology.
At the center of the sun, thermonuclear reactions convert hydrogen into helium. This releases energy which escapes from the surface of the Sun as light. Physicists are able to replicate thermonuclear reactions with hydrogen bombs.
All matter in the Sun is in the form of plasma due to its extreme temperature. This makes it possible for the sun to rotate faster at its equator than it does at higher latitudes, since the Sun is not a solid body. The differential rotation of the Sun's latitudes causes its magnetic field lines to become twisted together over time, causing magnetic field loops to erupt from the sun's surface and trigger the formation of the Sun's dramatic sunspots and solar prominences.
For some time it was thought that the number of neutrinos produced by the nuclear reaction in the Sun was only one third of the number predicted by theory, a result that was termed the solar neutrino problem. When it was recently found that neutrinos had mass, and could therefore transform into harder-to-detect varieties of neutrinos while en route from the Sun to Earth, measurement and theory were reconciled.
Observation of the Sun can reveal such phenomena as:
* Sunspots
* Faculae
* Solar flares
* Solar prominences
** quiescent prominences
** eruptive prominences
(Caution: looking directly at the sun can cause blindness.)
Other terms related to the Sun :
* Solar wind
** Aurora borealis
** Aurora australis
* Photosphere
* Chromosphere
* Corona
* Airglow
* Eclipse
----See also: Sun mythology
Solar system:
Sun - Mercury - Venus - Earth - Mars - Asteroids - Jupiter - Saturn - Uranus - Neptune - Pluto - Comets
* Timeline of solar astronomy
Several newspapers are called The Sun.