physics (s2 exam) Flashcards

earth in space test

1
Q

what are all the planets in order?

A

mercury, venus, earth, mars, jupiter, saturn, uranus, neptune
(mvem jsun)

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2
Q

how many cycles of the moon are there in a single earth year?

A

13.4

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3
Q

what is a day?

A

the amount of time it takes for a planet to orbit on its own axes
(earth = 24 hours)

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4
Q

what is a year?

A

the amount of time it takes for a planet to orbit the sun
(earth = 365.25 days)

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5
Q

why, if a planet is further away from the sun, does it take longer to fully orbit?

A

because it has a larger distance to travel around the sun which causes a longer planet year (longer time)

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6
Q

what planet(s) have the longest/shortest earth days per year

A

shortest: venus earth year is 225 venus days (venus day = 243 earth days)

longest: jupiter 1 earth year = 12 earth years)

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7
Q

what is a month?

A

approximately the amount of time it takes the moon to orbit earth once

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8
Q

what is the light year formula?

A

300,000,000 x 365.25 x 24 x 60 x 60
= 9.5 x 10¹⁵m - {don’t forget units}
x whatever amount of light years needed

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9
Q

what is the life cycle of a star for the 𝗵𝗶𝗴𝗵 𝗺𝗮𝘀𝘀 𝘀𝘁𝗮𝗿?

A
  • stellar nebulae
  • high mass star
  • red super giant
  • super nova
  • neutron star
  • black hole (if 2.5+ solar masses)
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10
Q

what is the life cycle of a star for the 𝗹𝗼𝘄 𝗺𝗮𝘀𝘀 𝘀𝘁𝗮𝗿?

A
  • stellar nebulae
  • low mass star
  • red giant
  • planetary nebula
  • white dwarf
  • black dwarf
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11
Q

what does schwarzschild mean? (to do with black holes)

A

the point of no return (also known as event horizon)

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12
Q

what is a black hole?

A
  • it has a large concentration of matter (packed density)
  • crushes matter to inflate density
  • it recycles space objects
  • stabilizes the formation of the galaxy
  • has to be over 2.5 solar masses or its a neutron star
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13
Q

what is a galaxy?

A
  • our galaxy is the milky way (spiral galaxy)
  • made up of dust, gas, billions of stars and their solar system
  • galaxies are made out of 75% hydrogen, 25% helium
  • universe has 27% dark matter
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14
Q

what are the 4 main types of galaxies?

A
  • peculiar
  • spiral
  • elliptical
  • irregular
    (pesi)
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15
Q

what is red shift?

A
  • measured using a spectroscope
  • used to deduce how far/close objects are from space
  • hubble’s law (the name of the observation of redshifting and how close/far objects are from space)
  • proves the earth is still expanding
  • it is light from galaxies which are redshifting when the galaxies are moving away from the earth
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16
Q

what is the big bang theory?

A
  • the theory of the origin of the universe
  • universe began at just a single point
  • began to expand to become larger
  • is still expanding
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17
Q

why is it warm for us in june?

A

the northern hemisphere is tilted towards the sun which gets more heat energy from the fun for longer (= longer days)

18
Q

why is it cold for us in december?

A

the northern hemisphere is tilted away from the sun which means it gets less heat energy from the sun (= days are shorter)

19
Q

why do we get well defined shadows when it’s a sunny day?

A

because the light can directly travel from the sun

20
Q

why do shadows get shorter as the day progresses (mid-day)?

A

the sun rises in the sky meaning it becomes more directly overhead which causes it to go straight down making the shadow less visible or disappear

21
Q

what happens to shadows as the sun begins to set?

A

shadows slowly become longer (sun angle)

22
Q

how does light travel?

A

in straight lines

23
Q

when is the sun higher/lower, winter/summer?

A

summer : higher
winter : lower

24
Q

what is the closest star to us?

A

proxima centauri - 2.28 light years away

25
Q

refractor telescope

A
  • uses lenses
  • if size increased brighter image (more light reflecting)
  • has 2 lenses that focus an image
  • used to view planets and stars
26
Q

reflector telescope

A
  • uses mirrors
  • focuses the rays of light onto another mirror
  • used to see far away galaxies or objects away
27
Q

what is a satellite
and does it take longer or shorter to orbit the earth if its further away?

A

a satellite orbits a planet or a star, if a satellite is further from the earth it takes longer to make an orbit

28
Q

what are the advantages/disadvantages of using an earth based telescope?

A

advantages: easy to construct and accessible
disadvantages: weather and atmosphere dependant

29
Q

what are the advantages/disadvantages of using an orbit telescope?

A

advantages: able to observe more clearer
disadvantages: expensive to place in orbit and to repair

30
Q

what measurement is used for this universe?

A

light years (l.y)

31
Q

what is the angle of the earth’s axis?

32
Q

how do each the moon and the sun produce light?

A

sun: radiates light
moon: reflects light from the sun

33
Q

what is in our solar system?

A
  • planets
  • star (sun)
  • dwarf planets
  • planets and their satellites
  • asteroids
  • comets
34
Q

what do you need to bring to space with you?

A
  • oxygen supply
  • water supply
  • food supply
  • power supply
  • a system for sanitation
  • a way to keep fit in low gravity
35
Q

what is… an enormous collection of stars held together by gravity?

36
Q

what is… a scientific description for the beginning of the universe?

A

the big bang theory

37
Q

what is… observed when an object gives out light but is moving away from the earth?

38
Q

what is… an object that has such a strong gravitational pull that light cannot escape it?

A

black hole (and you can’t see it but you can see what is floating around it)

39
Q

solar system is…

A

the sun and the planets that orbit them

40
Q

how long does it take for the moon to spin on its axis?

A

27.3 times

41
Q

if you have a supernova, how many solar masses is it to be a black hole or neutron star?

A

less then 2.5 solar masses is a neutron star, if more it is a black hole

42
Q

what is a light year?

A

the distance light travels in a year