Stars

Evolution Stars

Stars Huge balls of glowing gases, which give out all forms of electromagnetic radiation head, light, X-rays, radio waves, etc. The energy comes from thermonuclear (fusion) reactions taking place in the centre of the star, the main reaction being the conversion of hydrogen into helium.

The Sun is a typical medium-size star, classed as a yellow dwarf. Super giant stars are many hundreds of times bigger than the Sun, while white dwarfs are several hundred times smaller. Stars vary in mass from about 10 times the mass of the Sun.

Their surface temperatures vary from about 20,000 Celsius for red dwarfs such as Proxima Centauri. Proxima Centauri is the closest star to the Sun and is about 4 - 28 light-years away. Most information about the stars is obtained by studying the lines in their spectrum. In the heavens two out of three stars have at least one companion star. On a broader scale, star cluster together in space into galaxies.