7.4 The Universe

Question 1

what happened after the big bang

Answer 1

at first the universe was a hot glowing ball of radiation

as it expanded the temp. fell and uncharged atoms were formed

Question 2

before galaxies and stars were formed what was the universe made of?

Answer 2

a dark patchy cloud of hydrogen and helium

Question 3

how were stars formed

Answer 3

the dust and gas were pulled together by gravitational attraction this started off nuclear fusion in stars

Question 4

what is most of the universe made of?

Answer 4

empty space

Question 5

why do stars in a galaxy stay grouped together?

Answer 5

because of the gravitational attraction

Question 6

what i sa protostar

Answer 6

a gas and dust cloud n space that can go on to form a star

Question 7

once nuclear fusion has started in a star what type of star is?

Answer 7

a main sequence star

Question 8

when a star runs out of hydrogen what happens?

Answer 8

it swells, cools down and turn red

Question 9

what happens in a star similar in size to our sun (a low mass star) after it has turned red

Answer 9

it becomes a red giant

fusion stops

it becomes a white dwarf

eventually a red dwarf

Question 10

what happens to a very large star after it runs out of hydrogen?

Answer 10

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