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1 SOES1008 earth and ocean systems > cosmology > Flashcards

cosmology Flashcards

1
Q

where did the expression wanderer come from?

A

greek- homer era didn’t realise the earth was a planet. they saw things that moved quickly in the sky, planet means wanderer.

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2
Q

what is the heliocentric universe concept?

A

all heavenly bodies including the earth, circulate around the sun.

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3
Q

what is the geocentric universe concept?

A

the earth sat motionless in the centre of the heavens and all rotated around us

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4
Q

who thought of the heliocentric principle?

A

Copernicus 15th century

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5
Q

what is the Antikythera mechanism?

A

secret machine from ancient greek, the oldest computer, used to predict solar and lunar eclipse and record dates of the ancient olympiad.

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6
Q

when was the Antikythera machine constructed?

A

150-100 BC.

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7
Q

what is the ecliptic plane?

A

the horizontal line which the earth moves in line with

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8
Q

what is the equatorial plane?

A

the plane which expands from the equator, is tilted due to the earth being on tilt.

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9
Q

how many years does it take for the earth to do a full wobble?

A

26,000 years

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10
Q

what ages are we in now?

A

Pisces

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11
Q

why does the position of the sun shift westwards around the sky?

A

because of the slow change in our orientation to the stars, the first day of spring, the sun slowly shifts westwards around the sky.

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12
Q

what is the north star?

A

Polaris, which changes over time. this affects teh earthsp precission, as the nearsest celestial pole changes over time.

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13
Q

when will Polaris next be in the sky?

A

27,800 years and it will be smaller due to the proper motion around the galaxy.

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14
Q

why does the earth wobble?

A

the earth isnt a perfect sphere.

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15
Q

what is newtons first law of motion?

A

objects in motion remian in motion, objects at rest remain at rest.

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16
Q

what is precession?

A

teh earths spin axis isnt fixed, due to the earth being not a sphere and it wobbles.

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17
Q

what did Eratosthenes discover?

A

that the sun lit the base of a deep vertical well precisly at noon on the first day of summer. therefore he calculated the circumference of the earth, which was 2% from complete accuracy.

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18
Q

what is the circumference of the earth?

A

24,421 miles.

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19
Q

how long does it take for ight to hit the earth from the moon?

A

1.3 seconds. therefore it is 13 light seconds away.

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20
Q

what is a light year?

A

is the distance that light travels in one earth year, which equals around 9.5 trillion km.

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21
Q

how mnay stars are there in our galaxy?

A

300 billion

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22
Q

how many galaxies are there?

A

100 billion

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23
Q

how far away is the next galaxy?

A

2.2 billion light years away

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24
Q

what is the doppler effect?

A

when a high frequency seems to get lower when the sound source travels past you. change in freuqnecy.

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25
Q

how does the doppler effect work?

A

sound waves change and compress due to shorter wavelenghts being infront of the moving object, and therefore sound higher in pitch.

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26
Q

what is a red shift?

A

a moving star displays the dopper effect. red means moving away from earth.

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27
Q

what is blue shift?

A

moving towards us in light

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28
Q

how can water waves hold the dopper effect?

A

F = N/T numberof waves and times. as each wave passes, air alternatly compresses, then expands.

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29
Q

what is the expanding universe theory?

A

that the universe is contunously expanding around us. this is due to red light frequencies all around us. thus must be moving away from earth. like a ball of dough rising.

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30
Q

what was in the universe before the big bang?

A

universe was so small and dense, very very hot, as it consisted of entire energy- atoms and smallest subatomic particles couldn’t even exist.

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31
Q

what happened the first second of the big bang?

A

the univesre had decreased by about million billion times the desntiy of water, and then the atoms could form. this happened at the speed of light form.

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32
Q

what is big bang nucelosynthesis?

A

formation of new nuclei by fusion reactions. this happened before the stars existed. after 5 minutes, nucleosynthesis stopped.

33
Q

what happened 5 minutes after the big bang?

A

nucelosynthesis stopped, and the density was 1/10th of waters. atoms were so far apart that they rarely collided.

34
Q

what is large hadron supercollider?

A

the biggest experiment ever, when scientists tried to stimulate the coniditons after the big bang, this proved the existence of the God particle.

35
Q

what is primordial nucleosynthesis?

A

protons and neutrons combined due to conditions. colliding happened very rapidly, and after- anything else can not is made.

36
Q

what happened after nucleosynthesis stopped?

A

the universe consisted of nuclei dispersed in a sea of wandering electrons (plasma). the temperature dropped a few thousand degrees, and netrual atoms could form- therefore molecules aswell. they formed patchy clouds of gas, where atoms and molecules formed.

37
Q

what are quarks

A

what everything is made up of. weak force is able to change the element due to the moving of a weak charge cuasing a proton and electorn to be made.

38
Q

what is electromagnetic spectrum?

A

it is the range of all types of electromagnetic radiation. this is the energy that travels and spreads as it goes.

39
Q

what is in the elctromagnetic spectrum?

A

microwaves, infrared, visible, untraviolet, oxray, gamma rays

40
Q

what does infrared do?

A

helps us map dust between stars in space.

41
Q

what is CMB?

A

cosmic microwave background, patterns of blotches in the sky. can discover new galaxies.

42
Q

what is nuclear fision?

A

when you compress early hydrogen and helium, the first stars formed.

43
Q

why were the first stars short lived?

A

the more hydrogen and helium, the largest the supernova star, and therfore very short lives. when they exploded, began to form more elements.

44
Q

what happens when helium is used up?

A

forms a red giant phase.

45
Q

how do you form protostars?

A

the gravity began to remound the universe, all matter exerts to gravitational pull of its surroundings. the gravitational pull of the dense nebular began to pull in surrounding has, getting richer. gret in mass and density and got more compact, initial swirling of the gases caused an axis to for. due to rotation, condesning nebula evolved a spinning disk- accretion disk.
this gravitational poll became great enough to trigger the collase of surroundign nebulae. the inner fell, then outer-into a great ball. kinetic energy transfromed into thermal. increased tmeperature, and central ball of accretion disc behacme hot enough to glow- and it becomes a rotostar.

46
Q

when was the first star?

A

200 million years AFTER the universe had formed.

47
Q

what happens to the protostar after its made?

A

it coninues to grow, by pulling in more mass until it is very dense. hydrogen nucleii in the protostar join to form helium nuclei. called hydrogen burning.

48
Q

what is hydrogen burning?

A

fusion reactions between hydrogen and helium

49
Q

why are first generation stars very large?

A

due to the nebular of the beginning of the univser containing a lot more matter. the larger the sun the hotter it burns, and the faster it runs out of fuel and “dies”.

50
Q

how large were first generation stars?

A

100x the size of the sun

51
Q

what is frost line?

A

water freezes then other gases. frsom lines form and separate zones where earth-like planets accrete from giant gaseous planets accreting in ice zones.

52
Q

what is a habitable solar system?

A

where water can act as a liquid on the sirface of the planet.

53
Q

how was the moon formed?

A

collsion.

54
Q

what happened when the moon got further away?

A

the days lengthens the seasons.

55
Q

what is neutron capture and decay?

A

neutron sticsk to nucleus of an atom, and causes atomic mass of the nucleus to increase by one. then the neutron “decays”. meaning it transforms into a proton by releasing an electron.

56
Q

what is a planet?

A

sizable solid object orbiting a star. it may itself travel with a moon or many moons.

57
Q

what is a moon?

A

an object in orbit around a planet

58
Q

what are the 4 inner planets

A

mecurty, venus, earth and mars. they are the terrestrial planets.

59
Q

what are terrestrial planets made out of?

A

consist of a shell of rock and surrounding a core iron alloy.

60
Q

what are the next 4 outer planets?

A

saturn, jupiter, uranis and neptune. the Jovian planets

61
Q

what are the inner 2 Jovian planets consists of?

A

elementary composition like the sun- hydrogen and helium.

62
Q

what do the 2 outer Juvian planets consist of?

A

ice

63
Q

how was the solar system formed?

A

the central ball of our protoplanetary dis developed into the protosun and the remainder evolved into a series of rings. due to the protoplanetary disk being hotter towards its center, the inner rings were the warmest. the material surrounding the rings began to accrete and clumped and bound together, to form larger pieces. this depended on the speed of collision. if the collision was too fast then the blocks shatter and produce smaller fragments. gradually, enough blocks formed planetesimals, which pulled other objects into them to increase mass. this caused the to become protoplanets.

64
Q

what happened when the sun ignited for the first time?

A

it generated a strong stellar wind (solar wind), of particles, travelling rapidly in space. the solar wind blew any remaining gases out into the innter proprtion of the newborn solar system. wind was too weak to blow away the atmopsheres.

65
Q

how does the moon generate tides?

A

gravitational pull, when the moon and sun are in complete alignment, then there are more floods.

66
Q

what is retrograde?

A

when the planets move gradually through the stars from west to east, sometimes the planets path amoungst the stars appear to stop and go backwards. this is due to some travelling slower than the earth.

67
Q

what the difference mars and earth speed?

A

mars are slower, therefore it goes around the sun less. 1 mars year is 2 earth years.

68
Q

how did the moon form?

A

Hadean Eon- post moon forming impact. earth was hit by a meteorite, a large collision change the planet and generated the moon. a mars-sized protoplanet hit the earth. when this occurred, the colliding body disintegrated as well as the earth mantle. 65% of the objects melted away and some mass vaporised. a ring of debris formed around the earth and formed the moon.

69
Q

how old is the earth?

A

4.5 billion years old

70
Q

what are the different types of meteorites?

A

iron and nickel alloys, chondrites and carbonaceous chondrites.

71
Q

what are asteroids?

A

small bodies of solid rock or metal that orbit buts of mars and jupiter. they reside in a belt.

72
Q

what are meteorites?

A

the earth collided with and incorporated all the planetesimals and smaller fragments in its path. this was mostly asteroids and comets. some of the material was ejected into space when large objects collided with these bodies. these are meteoroids.

73
Q

how fast are meteoroides?

A

very fast, when they reach an altitude of 150km, they leave a bright streak of glowing gas. the glowing streak shows a flaling star.

74
Q

what are the 3 basic classes of meteoroids?

A

iron made out of nickel iron alloy
stony, out of simicate rock
stony iron, rock embedded in a matric of metal

75
Q

how did hydrogen and helium come to be the dominant elements?

A

due to them being the elements which were synthesised in the big bang.

76
Q

why are Li, Be, Boron relatively much less abundant?

A

they were poorly synthesised in the big bang, and also poorly synthesised in the stars. they were destroyed by the reactions in stars. mostly made out of cosmic ray interactions in the interstellar medium

77
Q

what caused the progressive decrease in abundance with increasing atomic number?

A

it takes combinations of lighter elements to make heavier elements and nuclear fusion in stars stop at Fe. therefore, heavier elements are only produced in supernovae, so they are less abundant.

78
Q

why is there an alteration in the abundance of elements with odd and even atomic numbers?

A

in nuclides with an even atomic number, then the protons can pair up with spins in opposite directions making them more stable. odd numbers attract another proton.

79
Q

what makes iron have an unusally high peak abundance?

A

nuclear fusion can only elease energy up to the mass of 56. after this, the reaction becomes endothermic, and comsumes enerfy.

1 SOES1008 earth and ocean systems (30 decks)

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