What is a Supernova?

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A supernova is the result of the violent death of a massive star, larger than the Sun. A star shines as a round ball because of the radiation coming from its centre. When the centre cools down, it collapses producing as much energy in the explosion as a galaxy containing thousands of millions of stars, for a short time. In the first ten seconds of explosion, the star produces 100 times more energy than the Sun has during the whole of its 4.6 billion years lifetime. All that remains of the explosion is an expanding cloud of gas and a neutron star, a few hundred kilometres across.

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