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"
Lisbon Moonset
24/03/2007
Brilliant Venus, a slender crescent Moon, and lights along the Ponte 25 de Abril glow against the western twilight in this lovely moonset scene from Lisbon, Portugal, recorded on March 20. In fact, such serene views were enjoyed across planet Earth this week, as the young Moon remained near the setting Sun following a partial solar eclipse, and Venus ruled as the evening star. Because of strong Earthshine - light from the sunlit Earth - even the Moon's night side is clearly visible in the picture. The Ponte 25 de Abril is a 2.3 kilometer long suspension bridge across the Tagus river, often compared to the Golden Gate bridge in San Francisco, USA.