16.1+2 14/6/24 Formation of Solar System, Life History of Stars

Question 1

what is a vacuum?

Answer 1

emptiness, a place of no matter

Question 2

what is a nebula?

Answer 2

cloud(s) of dust and gas

Question 3

how do the clouds of dust and gas come together to form a nebula?

Answer 3

pulled together by gravity

Question 4

what did the solar system form from

Answer 4

a nebula

Question 5

what forms at the centre of the cloud of a nebula?

Answer 5

protostar

Question 6

during the formation of a protostar, what are formed from rock and gas further from the centre?

Answer 6

planets

Question 7

what are planets formed from? when are they formed?

Answer 7

• formed during the formation of a protostar
• formed from rock and gas further from centre of nebula (from which the protostar is forming)

Question 8

what does a protostar begin when it eventually becomes hot enough?

Answer 8

nuclear fusion

Question 9

what happens to a protostar at the point at which it begins nuclear fusion?

Answer 9

the protostar becomes a main sequence star

Question 10

how and when is a main sequence star formed?

Answer 10

when a protostar eventually becomes hot enough that it begins nuclear fusio, it becomes a main sequence star

Question 11

what type of star is the Sun?

Answer 11

main sequence

Question 12

describe the life cycle of a star that has a mass greater than that of the sun (when it is a main sequence star)

Answer 12

1. nebula
2. protostar
3. main sequence star
4. red supergiant
5. supernova
   (a) neutron star
   (b) black hole - if mass is high enough

Question 12

when does a main sequence star begin the latter stages of its life?

Answer 12

when it has run out of fuel (such as hydrogen) for nuclear fusion to continue

Question 13

give an example of a main sequence star

Answer 13

the sun

Question 13

Two forces act on the sun that keep it stable. Which two forces and in which direction do they act?

Answer 13

inwards - gravity
outwards - radiation pressure (released during nuclear fusion)

Question 14

describe the life cycle of a star that has a mass less than that of the sun (when it is a main sequence star)

Answer 14

1. nebula
2. protostar
3. main sequence star
4. red giant
5. white dwarf
6. black dwarf

Question 14

why does nuclear fusion begin in a protostar?

Answer 14

(the protostar’s mass gives it gravity)
- gravity pulling things together causes heat
- this causes the protostar to heat up
- its temperature continues to increase until eventually nucear fusion occurs

Question 15

red giants create elements up to ___ ?

Answer 15

iron

Question 16

the ? elements such as uranium are created in a ?

Answer 16

• largest
• supernova

Question 17

what will a smaller supernova (which is still incredibly big) collapse to form?

Answer 17

neutron star - incredibly dense

Question 18

what does a larger neutron star collapse to form?

Answer 18

a black hole

Question 19

what is a black hole

Answer 19

an area of space where the density is so high that even light is unable to escape

Question 20

a cloud of dust and gas

Answer 20

nebula

Question 21

protostar

Answer 21

gravity pulls dust and gas together and heats it up

Question 22

main sequence star

Answer 22

(like our Sun) a stable star with gravity and radiation pressure forces balanced

Question 23

red (super)giant

Answer 23

hydrogen runs out and fusion of heavier elements (up to iron) happens

Question 24

(smaller) white dwarf

Answer 24

the red giant collapses inder gravity, leaving a small, hot, dense star

Question 25

(smaller) black dwarf

Answer 25

- the white dwarf cools - this is the end of its life cycle

Question 26

(larger) supernova

Answer 26

- red supergiant collapses and explodes outwards