Notes

Life Cycle of a star: -Average star, red giant, planetary nebula, white dwarf OR
-massive star, red supergiant, supernova, black hole/neutron star

Nebula:
-A large cloud of gas and dust that spread out in an immense volume. -Gravity can pull some of the gas and dust in a nebula together.

Nebula Theory:
-The sun and planets formed from a rotating disk of dust and gases

Protostar:
-Earliest stage in a star's life
-A star is born when nebula contracts gas and dust and becomes so dense and hot that nuclear fusion starts

A star's mass determines how long it will live,, low mass star uses up it's fuel slowly and evetually becomes a white dwarf. Small-mass stars have much longer lives

Low-mass cycle:
-A low mass star like the sun takes billions of years to use up their nuclear fuel.

Red Gaint:
-As they start to run out of fuel, their outer layers expand becoming red giants

Planetary nebula:
-Eventually the outer parts grow larger and drift out into space forming a glowing cloud of gas called a planetary nebula

White dwarf:
-The blue-white core of the star left behind cools and becomes a white dwarf

High-mass stars:
-High mass stars quickly evolve into brilliant supergiants

Supergiant:
-When a supergiant runs out of fuel, it can explode suddenly into a supernova. The remains become either a neutron star or a black hole

Neutron Stars:
-After a supergiant explodes, some o the materials left from the star form a neutron star
-Neutron stars are the remains of high-mass stars.
-They are smaller and denser than white dwarfs

Black holes:
-A black hole is an object with gravity so strong that nothing, even not light can escape.
-After a very massive star dies in a supernova explosion, the fravity of this mass is so strong that the gas becomes dense and packs.