The Sun
The Sun is a yellow dwarf star (G2V), about 4.6 billion years old, and the dominant gravitational force in the Solar System. It has a diameter of roughly 1.4 million kilometers and contains around 99.8% of the Solar System’s mass. Nuclear fusion in its core converts hydrogen into helium, producing energy that warms the planets. Above the core lie the radiative and convective zones, followed by the visible photosphere (~5,500 °C), the chromosphere, and the much hotter corona (~2 million °C).
Source: science.nasa.gov
APODs including "The Sun"
Comet Hale-Bopp Over New York City Credit and Copyright:
08/04/1997
What's that point of light above the World Trade Center? It's Comet Hale-Bopp! Both faster than a speeding bullet and able to "leap" tall buildings in its single orbit, Comet Hale-Bopp is also bright enough to be seen even over the glowing lights of one of the world's premier cities. In the foreground lies the East River, while much of New York City's Lower Manhattan can be seen between the river and the comet. Comet Hale-Bopp is now moving away from both the Sun and the Earth. It should, however, should remain visible even in northern cities for at least a month. To find Comet Hale-Bopp, look for the brightest object in the northwest sky just after sunset - or wait for its return in 2400 years.