How are stars born? Galaxies are clouds of dust and gas called nebulae hydrogen gas in the nebula becomes clumped together by gravity cloud begins to spin over millions of years, more hydrogen atoms are pulled into the spinning cloud Collisions between hydrogen atoms become more frequent  hydrogen gases heat up. Temperatures above 15,000,000oC  pressure increases and nuclear fusion (the combining of 2 atoms into 1) 2 hydrogen atoms  helium atom Great heat and light is given off  a new star (protostar)

What is the life cycle of a star? Protostar  nuclear fusion Eventually, the star will run out of hydrogen The helium core shrinks and heats up The outer shell is still composed mainly of hydrogen Heating of the helium  outer shell to expand greatly. As it expands  cools and turns into a red giant.

Depending on the mass of the star, 1 of 2 things can happen to the red giant. Low mass stars turn into white dwarf It shines bright white light before it turns into a dead star (this will be the fate of our sun). High mass stars turn into a nova , then break apart in an explosion called a supernova remnants of a supernova serve as a birth place for stars. a black hole can form

What is a black hole? After a supernova explosion, the core remains so massive, that it collapses into an object smaller than a neutron star. The gravity of the core is so strong that light can’t escape the surface Swallows gases and matter as if it were a vacuum cleaner.

Assignment Life Cycle of Stars Foldables