P16 - Solar system

Question 1

comets

Answer 1

frozen rocks that move around sun

Question 2

comets orbit

Answer 2

elliptical shape
- squashed circle

Question 3

birth of a star

Answer 3

-nebula becomes increasingly concentrated
- clouds merge to forma protostar
- protostar become denser so temp increases
- hot enough = nuclear fusion = brighter star

Question 4

nebula

Answer 4

-clouds of dust/gas pulled together by gravity

Question 5

protostar becomes denser meaning

Answer 5

particles speed up more and collide more
- transfers energy from gpe to thermal store

Question 6

hotter star =

Answer 6

nuclei of H fuse
- releases energy
- gets hotter and brighter

Question 7

main sequence stars

Answer 7

-radiation from H fusion in core
-main stage of life cycle

Question 8

fusion in core of main sequence star

Answer 8

• keeps it hot
• continues fusion
• gamma flows out steadily from core in all direction

Question 9

star is stable when

Answer 9

-forces within are balanced
- equilibrium

Question 10

forces within a star

Answer 10

• gravity contracts star inwards
  -balanced by outward force of radiation from nuclear fusion
  (to expand)

Question 11

when a star runs out of hydrogen nuclei to fuse

Answer 11

reaches end of the main star sequence stage
-core collapses
- other layers swell out
- become red giants

Question 12

red giants eg

Answer 12

sun

Question 13

red giant

Answer 13

• helium and other light elements fus in core to form heavier element

Question 14

red giant - when fusion stops

Answer 14

• its own gravity = collapses in
• as it collapses, it heats up = white dwarf

Question 15

red giant to

Answer 15

yellow giant to white

Question 16

white dwarf

Answer 16

hot dense white star
much smaller

Question 17

white dwarf then

Answer 17

fades out
-goes cold to form black dwarfs

Question 18

stars bigger than the sun

Answer 18

ends life after main sequence stage
- swell out and become red super giant + collapse

Question 19

red super giant collapse

Answer 19

-matter in star’s ore compresses the core more and more
- supernova

Question 20

supernova

Answer 20

explosion
- can outshine a galaxy for weeks

Question 21

after suprnova

Answer 21

neutron star is formed
- or a black hole

Question 22

when is a black hole formed

Answer 22

after a supernova
-only if there’s enough mass

Question 23

light elements

Answer 23

from fusion in stars
-nuclear fusion

Question 24

red giant fuses

Answer 24

helium and small nuclei = larger nuclei

Question 25

nuclei larger than iron cannot be formed

Answer 25

as that required too much energy

Question 26

heavy elements come from

Answer 26

supernova - enormous force fuses small nuclei into bigger than iron nuclei - scatters elemnts throughout univers

Question 27

debris from supernova

Answer 27

has all elements -pulled together to form new stars

Question 28

neutron star

Answer 28

supernova compresses core into this - very dense + made from neutrons only

Question 29

gravity in black hole

Answer 29

so great noting can escape -formed only if a star is big enough

Question 30

earth orbits

Answer 30

sun in a circular shape

Question 31

moon orbits

Answer 31

in a circular shape

Question 32

orbit

Answer 32

one body orbits a much bigger body always -gravity between them

Question 33

centripetal force

Answer 33

gravity on planet from centre of sun

Question 34

planets velocity

Answer 34

changes by centripetal force

Question 35

direction of motion of a planet is

Answer 35

at a right angle to the direction of the force of gravity

Question 36

planet in circular orbit

Answer 36

-acceleration towards centre of circle from resultant force

Question 37

acceleration

Answer 37

change of velocity per second

Question 38

change of velocity

Answer 38

directed towards the centre -speed doesn't change

Question 39

satellites too close to earth

Answer 39

lose speed fall inwards

Question 40

satellites in circular orbit above earth

Answer 40

moves at a constant height stable orbit

Question 41

to stay in a stable orbit =

Answer 41

particular speed

Question 42

if launch speed is too high

Answer 42

satellite flies into space

Question 43

if launch speed is correct

Answer 43

constant height speed of orbit

Question 44

the further a satellite or planet is in orbit

Answer 44

less speed needed to stay in circular orbit (less gravity) - longer it takes to move around

Question 45

time for each complete orbit =

Answer 45

circumference/ speed

Question 46

if speed changes in stable orbit

Answer 46

radius must change (height of orbit)

Question 47

communications satellites

Answer 47

orbit at 36 000km -period of 24 hrs - orbit same direction as earth's spin (stays above same places as they move) -geostationary

Question 48

monitoring satellites

Answer 48

- fitted with tv cameras - include weather forecasting - much lower in orbit -orbit once every 2/3 hrs

Question 49

wavelength of light increases from

Answer 49

blue to red

Question 50

light waves are stretched if

Answer 50

star/galaxy is moving away

Question 51

red shift

Answer 51

wavelengths increase -moves away

Question 52

blue shift

Answer 52

light waves are squashed -star moving towards - wavelength is reduced

Question 53

dark spectral lines

Answer 53

caused by absorption of light by specific atoms (shows which shift is happening)

Question 54

bigger shift =

Answer 54

the more the waves are squashed/stretched

Question 55

faster the star/galaxy is moving towards you

Answer 55

the bigger the shift is

Question 56

edwin hubble

Answer 56

light from distant galaxies was red shifted - further a galaxy is from earth = bigger the red shift

Question 57

he found that

Answer 57

distant galaxies are moving away from earth

Question 58

greater distance in red shift =

Answer 58

greater speed of recession = greater red shift

Question 59

universe is

Answer 59

expanding - after exploding from small hot dense point

Question 60

big bang theory

Answer 60

space, time, matter created from explosion of small hot dense point

Question 61

cosmic microwave background radiation

Answer 61

EM radiation only explained by big bang theory

Question 62

as universe expands

Answer 62

it has stretched wavelength to microwaves

Question 63

dark matter

Answer 63

missing mass in galaxy -cannot be seen

Question 64

dark matter purpose

Answer 64

-bends light holds galaxy together doesn't emit EM