Sun

 Sun

The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as visible light, ultraviolet light, and infrared radiation. 

Information

Surface temperature: 5,778 K

Distance to Earth: 149.6 million km

Mass: 1.989 × 10^30 kg

Age: 4.603 billion years

Radius: 696,340 km

Spectral type: G2V

Moons: 3122 Florence, 130 Elektra, 90482 Orcus

Dimensions

Radius, diameter & circumference

The mean radius of the sun is 432,450 miles (696,000 kilometers), which makes its diameter about 864,938 miles (1.392 million km). You could line up 109 Earths across the face of the sun. The sun's circumference is about 2,713,406 miles (4,366,813 km).

Composition

The Sun, like other stars, is a ball of gas. In terms of the number of atoms, it is made of 91.0% hydrogen and 8.9% helium. By mass, the Sun is about 70.6% hydrogen and 27.4% helium.

Layers

The layers of the Sun are divided into two larger groups, the outer and the inner layers. The outer layers are the Corona, the Transition Region, the Chromosphere, and the Photosphere, while the inner layers are the Core, the Radiative Zone, and the Convection Zone.

Rotation

The Sun rotates on its axis once in about 27 days. This rotation was first detected by observing the motion of sunspots. The Sun's rotation axis is tilted by about 7.25 degrees from the axis of the Earth's orbit so we see more of the Sun's north pole in September of each year and more of its south pole in March.