The word nebula comes from the Latin word for cloud. Early astronomers could see no more than a fuzzy area of colour which looked like a cloud in space. Modern astronomers now know that some nebulas contain planets, stars and galaxies, while some others are the result of the explosion of a star to make a supernova.

Nebulas contain many of the same building blocks of matter that are found on Earth. Elements such as carbon, nitrogen, sulphur, iron and oxygen as well as hydrogen can all be detected.

Note: the plural of nebula is sometimes spelt nebulae.