The Sun, Our Star

The Sun is the star at the very centre of our solar system. It is an enormous ball of hot glowing gas — mostly hydrogen and helium — that has been shining for about 4.6 billion years. Everything in our solar system, from tiny Mercury to distant Neptune, travels around the Sun, held in place by its powerful gravity.

Deep in its core the Sun squashes hydrogen atoms together in a process called nuclear fusion. This releases enormous amounts of energy that travel outwards as light and heat. Without the Sun there would be no warmth, no weather, and no life on Earth. In fact, almost all the energy living things use can be traced back to the Sun.

Here is a surprising idea: the Sun is not actually on fire like a bonfire. A fire needs oxygen to burn, and space has no oxygen. The Sun's heat comes from fusion, not from burning. It is a completely different and far more powerful way of making energy.