Sun

::{{otheruses}} For the astrological significance of the Sun, see Solar system in astrology.

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:"Solar" redirects here; for the superhero by that name, see Solar (comics).

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The Sun is the star at the centre of our Solar system. It is occasionally referred to by its Latin name, Sol, to distinguish it from other "suns". Planet Earth orbits the Sun, as do many other bodies, including other planets, asteroids, meteoroids, comets and dust. Its heat and light support almost all life on Earth.

Related Topics:
Star - Solar system - Sol - Earth - Orbit - Planet - Asteroid - Meteoroid - Comet - Dust - Life

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The Sun is a ball of plasma with a mass of about 2×1030kg, which is somewhat higher than that of an average star. About 74% of its mass is hydrogen, with 25% helium and the rest made up of trace quantities of heavier elements. It is thought that the Sun is about 5 billion years old, and is about half way through its main sequence evolution, during which nuclear fusion reactions in its core fuse hydrogen into helium. In about 5 billion years time the Sun will become a planetary nebula.

Related Topics:
Plasma - Hydrogen - Helium - Main sequence - Nuclear fusion - Planetary nebula

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Although it is the nearest star to Earth and has been intensively studied by scientists, many questions about the Sun remain unanswered, such as why its outer atmosphere has a temperature of over 106 K when its visible surface (the photosphere) has a temperature of just 6,000 K.

Related Topics:
K - Photosphere

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Caution: Looking directly at the Sun can damage the retina and one's eyesight. See below for details.

Related Topics:
Retina - Eyesight - See below

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