Institute of Astronomy


Published on 25/02/2011 

What is a star?

A star is a huge sphere of hot, glowing gas. The star produces its own heat and light through a process called nuclear fusion. This process forces lighter chemical elements to become heavier chemical elements. When this happens a large amount of energy is released and this energy is what causes the star to heat up and 'shine'.

Stars come in a range of sizes and colours. Our Sun is a fairly typical yellow or G type star. Stars which are hotter than our Sun tend to look bluer while those which are cooler look red. So the next time you look at the night sky, see if you can see stars of different colours!

Page last updated: 24 June 2013 at 17:53