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"
Earth During a Total Eclipse of the Sun
18/03/2015
What does the Earth look like during a total solar eclipse? It appears dark in the region where people see the eclipse, because that's where the shadow of the Moon falls. The shadow spot actually shoots across the Earth at nearly 2,000 kilometers per hour, darkening locations in its path for only a few minutes before moving on. The featured image shows the Earth during the total solar eclipse of 2006 March, as seen from the International Space Station. On Friday the Moon will move in front of the Sun once again, casting another distorted circular shadow that, this time, will zip over part of the north Atlantic Ocean.