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Luminous globe of gas, mainly hydrogen and helium, which produces its own heat and light by nuclear reactions. Although stars shine for a very long time – many billions of years – they change in appearance at different stages in their lives (they are said to have a ‘life cycle’). Stars seen at night belong to our galaxy, the Milky Way. The Sun is the nearest star to Earth; other stars in the Milky Way are large distances away (to get to the nearest would take about 4 years travelling at the speed of light).

The smallest mass possible for a star is about 8% that of the Sun (80 times that of Jupiter), otherwise nuclear reactions do not occur. Objects with less than this critical mass shine only dimly, and are termed brown dwarfs.

The most massive stars known are Eta Carinae and the Pistol Star in Sagittarius, each with a mass approximately 150 times that of the Sun – at the limit of what astronomers believe on theoretical grounds to be possible.

The flag uses the pan-Arab colours. The design may have been inspired by the pre-1958 Iraqi flag. Effective date: 24 November 1961. >>