1. A beginning, middle and end
Life Cycle of Stars
A beginning, middle and end 1

2. Nebula: Massive cloud of interstellar gas and dust; the beginning of a star

3. Protostar: massive. concentration of gas and dust
Protostar: massive concentration of gas and dust that develops into star.

4. Nuclear Fusion: - For million years, core of protostar contracts due to gravity. - Temperature continues to rise. At 15 million degrees Celsius, nuclear fusion begins. - Hydrogen atoms fuse to form helium, which releases HUGE amounts of energy. - the more massive the star, the faster its rate of fusion.

5. The Hertzsprung-Russell Diagram

6. Death of a star: 1. Red giants – star that's smaller or equal to the sun that's in its life's last stages Red supergiants – star that is 10 x larger than the sun in its last stages 2. White dwarfs – small, dim, hot star that is left when a red giant dies – will cool into a black dwarf
Red Supergiant
White dwarf – Sirius

7. Supernovas: - Massive stars that explode at the end of their life, due to the star collapsing under its own gravity and the gases bouncing back, exploding into space -very rare

8. Neutron stars – happens when a large star(10 – 30 times more massive than the sun) explodes into a supernova – the core that the gases leave behind is a neutron star – neutrons packed very tightly – can become pulsars if they spin very quickly and emit high-frequency radio waves which can be seen as pulses on earth

9. Black holes – occurs when a very large star collapses under its own gravity
- so dense and such high gravity that not even light can escape
- emits X-ray radiation that can be detected