Sun animation © SOHO

The Sun is average star, but without its energy we would not exist.

It contains more than 99.8% of the total mass in the Solar System, with the planet Jupiter containing most of the rest. The atmosphere of the Sun is primarily made up of hydrogen (75%) and helium (24%), together with small amounts of oxygen, carbon, neon and iron.

All the energy from the Sun is produced in the core by nuclear fusion. It takes about 50 million years for the Sun's energy to make its way out to the surface, and then another 8 minutes for the light to reach us here on Earth.

Astronomers have calculated that the Sun is around 4,500 million years old and should continue shining for another 5,000 million years or so before running out of fuel and undergoing a relatively peaceful death.

The Sun is a very active place, as you can see from the SOHO animation (see right), and significant variations can be seen from day to day, and year to year. The activity arises from the bending and twisting of magnetic lines within the atmosphere of the Sun, which can lead to sunspots and solar flares.