7.4 The Universe Flashcards
what happened after the big bang
at first the universe was a hot glowing ball of radiation
as it expanded the temp. fell and uncharged atoms were formed
before galaxies and stars were formed what was the universe made of?
a dark patchy cloud of hydrogen and helium
how were stars formed
the dust and gas were pulled together by gravitational attraction this started off nuclear fusion in stars
what is most of the universe made of?
empty space
why do stars in a galaxy stay grouped together?
because of the gravitational attraction
what i sa protostar
a gas and dust cloud n space that can go on to form a star
once nuclear fusion has started in a star what type of star is?
a main sequence star
when a star runs out of hydrogen what happens?
it swells, cools down and turn red
what happens in a star similar in size to our sun (a low mass star) after it has turned red
it becomes a red giant
fusion stops
it becomes a white dwarf
eventually a red dwarf
what happens to a very large star after it runs out of hydrogen?
it becomes a super giant and will eventually explode in a supernova this leaves a neutron star if it is big enough it may become a black hole
