Our Sun is a star that the Earth orbits. It is a main sequence star, which means it is a middle aged star. The Sun is alive as long as it has a supply of hydrogen to transform into helium. Once the hydrogen is depleted, the Sun will expand and die, leaving a planetary nebula and the Sun's core. The planetary nebula eventually disperse into space, leaving a white dwarf star. The dwarf star will cool and die.
The Sun has a chaotic surface. There are three layers separating the surface from the core. The inside layers of the Sun are the photosphere, the convective zone and the radiative zone. The photosphere is made of hydrogen at the temperature of 5500°C. Inside the convective zone there are swirling currents taking heat to the photosphere. It is around 140,000 km thick. The core energy passes through the radiative zone, which is around 380,000 km thick. The core is like a massive nuclear reactor where hydrogen is transformed into helium.
There are many things happening on the Sun's surface, such as solar flares, which are large explosions happening in the chromosphere. Solar prominences are huge jets of flaming hydrogen. They are held to the corona by the Sun's magnetic field. Solar prominences can sprout from the Sun at great speeds.They can reach a height of 500,000 km. Looped prominences occur when the solar prominences form an arc. Sunspots occur in the photosphere, and are caused by intense magnetic activity, which prevents heat from the convective zone from traveling to the surface. Sunspots appear to be darker because they are cooler, at only 2,700-4,200 °C.
The Sun constantly gives off charged particles called the solar wind. When the charged particles reach Earth's atmosphere, they interact with gases that causes the particles to emit light. This light is most visible at the Earth's poles, and is known as the aurora borealis, or nothern lights in the nothern hemisphere. In the southern hemisphere they are known as the aurora australis or the southern lights.