The Sun is the spectral type G2V yellow star at the center of our solar system. The Earth as well as many other bodies (including other planets, asteroids, meteoroids, comets and dust) orbit the Sun, and it accounts for more than 99% of the solar system's mass. Different latitudes of the Sun rotate at different rates; a point on the equator takes 25 days, while a point at a pole takes 36 days. The resultant torsion upsets the Sun's very strong magnetic field to create an 11-year solar cycle of activity. Heat and light from the Sun have supported almost all life on Earth. Humans use sunlight to grow crops (see photosynthesis) and power solar cells. The Sun is a ball of plasma with a diameter of 1.392 million km (864,950 mi) and a mass of about 2.0 x 10^30 kg, 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. The Sun is about 4.6 billion years old, and is about halfway through its main sequence evolution, during which nuclear fusion reactions in its core fuse hydrogen into helium.

Read the rest of this article: http://en.wikipedia.org/wiki/Sun

_______________________________ Today's selected anniversaries:

1602: The Dutch East India Company was established. (http://en.wikipedia.org/wiki/Dutch_East_India_Company)

1852: Uncle Tom's Cabin, a novel by Harriet Beecher Stowe about slavery in the United States before the Civil War, was first published. (http://en.wikipedia.org/wiki/Uncle_Tom%27s_Cabin)

1883: The Paris Convention for the Protection of Industrial Property, one of the first intellectual property treaties, was signed. (http://en.wikipedia.org/wiki/Paris_Convention_for_the_Protection_of_Industri...)

1987: The antiretroviral drug AZT became the first antiviral medication approved for use against HIV and AIDS. (http://en.wikipedia.org/wiki/Zidovudine)

1995: The Aum Shinrikyo sect carried out a poison gas attack on the Tokyo subway system, killing 12 people and injuring more than 6,000 with sarin. (http://en.wikipedia.org/wiki/Sarin_gas_attack_on_the_Tokyo_subway)

_____________________ Wikiquote of the day:

"The spirit of truth and the spirit of freedom — these are the pillars of society." -- Henrik Ibsen (http://en.wikiquote.org/wiki/Henrik_Ibsen)