Changes

{{Solarsystem}}

{{Solarsystem}}

[[Image:Moooghj.jpg|right|thumb|Sun, the small blue dot on the upper-right corner is Earth.]]

[[Image:Moooghj.jpg|right|thumb|Sun, the small blue dot on the upper-right corner is Earth.]]

The '''Sun''', or [[Sol]] is the star at the center of the solar system, and it accounts for over 99% of the mass of the solar system. By mass, it is composed of 72% hydrogen, 26% helium and 2% trace elements of oxygen, carbon, neon, nitrogen, magnesium, iron, and silicon.<ref>[http://www.nasa.gov/worldbook/sun_worldbook.html World Book Encyclopedia @ NASA]</ref> The eight planets, including Earth, orbit the sun, as do countless other small objects.  

The '''Sun''', or [[Sol]], is the star at the center of the solar system, and it accounts for over 99% of the [[mass]] of the solar system. By mass, it is composed of 72% [[hydrogen]], 26% [[helium]] and 2% trace elements of [[oxygen]], [[carbon]], [[neon]], [[nitrogen]], [[magnesium]], [[iron]], and [[silicon]].<ref>[http://www.nasa.gov/worldbook/sun_worldbook.html World Book Encyclopedia @ NASA]</ref> The eight [[planet]]s, including Earth, orbit the sun, as do countless other small objects.  

It provides the [[Earth]] with light and heat. Astronomers classify it as a [[yellow dwarf]] with a [[spectral type]] of [[G2V]].  

It provides the [[Earth]] with light and heat. [[Astronomy|Astronomers]] classify it as a [[yellow dwarf]] with a [[spectral type]] of [[G2V]].  

The sun has a diameter of about 870,000 miles (1.4 million kilometers); some 1.3 million Earths could fit inside its volume. It is an average-sized, middle-aged star. Its surface temperature is 6000 [[Kelvin|K]], while the temperature of its core is around 13.6 million K. The inner layer of the sun, called the core, is where most fusion takes place. Beyond that is the radiation zone and then the convection zone. Outside that is the photosphere, the visible layer of the sun. It would take anywhere between 17,000 and 50 million years for photons produced in the core to be emitted at the surface, being absorbed and re-emitted countless times. The atmosphere, including the corona, surrounds the photosphere. The sun is located about halfway between the center of the galaxy and its edge, and at the speed at which it is travelling around the galaxy, it would take around 230-250 million years to orbit the galactic center.

The sun has a diameter of about 870,000 miles (1.4 million kilometers); some 1.3 million Earths could fit inside its volume. It is an average-sized star. Its surface temperature is 6000 [[Kelvin|K]], while the temperature of its core is around 13.6 million K. The inner layer of the sun, called the core, is where most [[fusion]] takes place. Beyond that is the radiation zone and then the convection zone. Outside that is the [[photosphere]], the visible layer of the sun. It would take anywhere between 17,000 and 50 million years for [[photon]]s produced in the core to be emitted at the surface, being absorbed and re-emitted countless times. The [[atmosphere]], including the [[corona]], surrounds the photosphere. The sun is located about halfway between the center of the [[Milky Way]] [[galaxy]] and its edge, and at the speed at which it is travelling around the galaxy, it would take around 230-250 million years to orbit the galactic center.

The sun produces a vast amount of energy; the Earth receives only a tiny fraction of this energy, yet it powers practically all life (and industry) on Earth, either directly or indirectly. It is also responsible for Earth's climate and weather. Plants and other organisms capture the energy of the sun in a process called [[photosynthesis]]. Animals and other heterotrophs obtain food and energy from consuming plants or from consuming animals who have consumed the plants. Only a few microscopic organisms obtain energy directly from chemical reactions.

The sun produces a vast amount of [[energy]], only a tiny fraction of which the Earth receives, yet this small amount powers practically all [[life]] (and [[industry]]) on Earth, either directly or indirectly. It is also the main force controlling Earth's [[climate]] and [[weather]]. [[Plant]]s and other organisms capture the energy of the sun in a process called [[photosynthesis]]. Animals and other [[heterotroph]]s obtain food and energy from consuming plants or from consuming [[animal]]s which have consumed the plants. Only a few microscopic organisms obtain energy directly from chemical reactions.

Human civilization, too, is dependent on the sun. Much of humanity's industrial energy needs are obtained through the combustion of fossil fuels, the remains of dead plants and animals. Uneven heating of the atmosphere provides wind power. Also, the sun evaporates water from lower-lying bodies of water; this then falls as rain and flows back down channels, providing hydroelectric power. On a limited basis, solar power is directly utilized. Geothermal energy and nuclear energy are examples of energy sources to which the sun does not directly contribute.

[[Human]] civilization, too, is dependent on the sun. Much of humanity's [[industry|industrial]] energy needs are obtained through the combustion of [[fossil fuel]]s, the remains of dead plants and animals. Uneven heating of the atmosphere provides [[wind power]]. Also, the sun evaporates water from lower-lying bodies of water; this then falls as rain and flows back down channels, providing hydroelectric power. On a limited basis, [[solar power]] is directly utilized. [[Geothermal energy]] and [[nuclear energy]] are examples of energy sources to which the sun does not directly contribute.

== Origins ==

== Origins ==