How does a star die?

Stars like the sun take billions of years to die, slowly losing material and fading, ending their lives as a dwarf star. Stars with more than about eight times the mass of the sun end their lives in a much more dramatic way. Once nuclear reaction ceases, the star collapses and blows itself apart in a supernova explosion, leaving only a core behind.

The name supernova comes from the star's sudden change of appearance. The explosion looks like a super, new (nova is Latin for new), bright star in the sky> the future of the core-remains depends on the mass. Those stars with 3 times the mass of the sun continue collapsing until they produc a black hole> those with less mass leave a tiny neutron star. They are so densely packed that a handful weighs billions of tonnes. A rapidly spinning neutron star is called a pulsar, sending out beams of energy, like the rotating beam of a lighthouse. It spins many times a second, and if Earth is in the path of the beam, the star's pulses of energy can be detected.