Most stars take many years to die. When a star just like the Sun has burned all of its hydrogen fuel, it expands to become a red giant star . this might be many kilometres across - large enough to swallow the planets Mercury and Venus.
After puffing off its outer layers, the star collapses to make a really dense white dwarf star . One teaspoon of fabric from a white dwarf star would weigh up to 100 tonnes. Over billions of years, the white dwarf star cools and becomes invisible.
Stars heavier than eight times the mass of the Sun end their lives very suddenly. once they run out of fuel, they swell into red supergiants. they struggle to stay alive by burning different fuels, but this only works for a couple of million years. Then they blow themselves apart during a huge supernova explosion.
For every week approximately , the supernova outshines all of the opposite stars in its galaxy. Then it quickly fades. All that's left may be a tiny, dense object – a star or a region – surrounded by an expanding cloud of extremely popular gas.
The elements made inside the supergiant (such as oxygen, carbon and iron) are scattered through space. This stardust eventually makes other stars and planets.
