P16 - Solar system Flashcards

1
Q

comets

A

frozen rocks that move around sun

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2
Q

comets orbit

A

elliptical shape
- squashed circle

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3
Q

birth of a star

A

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

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4
Q

nebula

A

-clouds of dust/gas pulled together by gravity

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5
Q

protostar becomes denser meaning

A

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

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6
Q

hotter star =

A

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

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7
Q

main sequence stars

A

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

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8
Q

fusion in core of main sequence star

A
  • keeps it hot
  • continues fusion
  • gamma flows out steadily from core in all direction
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9
Q

star is stable when

A

-forces within are balanced
- equilibrium

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10
Q

forces within a star

A
  • gravity contracts star inwards
    -balanced by outward force of radiation from nuclear fusion
    (to expand)
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11
Q

when a star runs out of hydrogen nuclei to fuse

A

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

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12
Q

red giants eg

A

sun

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13
Q

red giant

A
  • helium and other light elements fus in core to form heavier element
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14
Q

red giant - when fusion stops

A
  • its own gravity = collapses in
  • as it collapses, it heats up = white dwarf
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15
Q

red giant to

A

yellow giant to white

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16
Q

white dwarf

A

hot dense white star
much smaller

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17
Q

white dwarf then

A

fades out
-goes cold to form black dwarfs

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18
Q

stars bigger than the sun

A

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

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19
Q

red super giant collapse

A

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

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20
Q

supernova

A

explosion
- can outshine a galaxy for weeks

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21
Q

after suprnova

A

neutron star is formed
- or a black hole

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22
Q

when is a black hole formed

A

after a supernova
-only if there’s enough mass

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23
Q

light elements

A

from fusion in stars
-nuclear fusion

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24
Q

red giant fuses

A

helium and small nuclei = larger nuclei

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25
Q

nuclei larger than iron cannot be formed

A

as that required too much energy

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26
Q

heavy elements come from

A

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

27
Q

debris from supernova

A

has all elements
-pulled together to form new stars

28
Q

neutron star

A

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

29
Q

gravity in black hole

A

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

30
Q

earth orbits

A

sun in a circular shape

31
Q

moon orbits

A

in a circular shape

32
Q

orbit

A

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

33
Q

centripetal force

A

gravity on planet from centre of sun

34
Q

planets velocity

A

changes by centripetal force

35
Q

direction of motion of a planet is

A

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

36
Q

planet in circular orbit

A

-acceleration towards centre of circle from resultant force

37
Q

acceleration

A

change of velocity per second

38
Q

change of velocity

A

directed towards the centre
-speed doesn’t change

39
Q

satellites too close to earth

A

lose speed
fall inwards

40
Q

satellites in circular orbit above earth

A

moves at a constant height
stable orbit

41
Q

to stay in a stable orbit =

A

particular speed

42
Q

if launch speed is too high

A

satellite flies into space

43
Q

if launch speed is correct

A

constant height
speed of orbit

44
Q

the further a satellite or planet is in orbit

A

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

45
Q

time for each complete orbit =

A

circumference/ speed

46
Q

if speed changes in stable orbit

A

radius must change (height of orbit)

47
Q

communications satellites

A

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

48
Q

monitoring satellites

A
  • fitted with tv cameras
  • include weather forecasting
  • much lower in orbit
    -orbit once every 2/3 hrs
49
Q

wavelength of light increases from

A

blue to red

50
Q

light waves are stretched if

A

star/galaxy is moving away

51
Q

red shift

A

wavelengths increase
-moves away

52
Q

blue shift

A

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

53
Q

dark spectral lines

A

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

54
Q

bigger shift =

A

the more the waves are squashed/stretched

55
Q

faster the star/galaxy is moving towards you

A

the bigger the shift is

56
Q

edwin hubble

A

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

57
Q

he found that

A

distant galaxies are moving away from earth

58
Q

greater distance in red shift =

A

greater speed of recession = greater red shift

59
Q

universe is

A

expanding
- after exploding from small hot dense point

60
Q

big bang theory

A

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

61
Q

cosmic microwave background radiation

A

EM radiation only explained by big bang theory

62
Q

as universe expands

A

it has stretched wavelength to microwaves

63
Q

dark matter

A

missing mass in galaxy
-cannot be seen

64
Q

dark matter purpose

A

-bends light
holds galaxy together
doesn’t emit EM