(A) Topic 5,6,7,8 wrong Flashcards

1
Q

Explain why we see inferior planets best at the maximum angle of elongation

A

Inferior planets can’t be seen in opposition

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2
Q

Explain the term elongation

A

Angle at which we see an inferior planet

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3
Q

What happens during an occultation?

A

One celestial body obscures and covers the other, blocking its light

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4
Q

When does an opposition occur?

A

When a planet is opposite the Earth from the Sun

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5
Q

Describe the main features of a meteor shower

A
  • can last several hours
  • happens when the Earth passes through a dusty meteoroid stream in the wake of a comet
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6
Q

Define the term meteor

A

Fragments of dust from comets or asteroids that Earth smashes into whilst orbiting the sun

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7
Q

What is a planetary track?

A

Path a planet makes on a star map

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8
Q

What is inclination?

A

Angle between the orbital plane of the object and the plane of the ecliptic

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9
Q

What is the Earth’s inclination?

A

23.5

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10
Q

Devise an experiment to observe the Sun using a paper or card

A
  1. Cut out a small hole in a card paper
  2. Find a smooth surface
  3. Angle the hole so the sun can be seen through it
  4. Look at the Sun (through the projection)
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11
Q

Why are red torches used by astronomers?

A

To ensure they don’t ruin their adapted eye

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12
Q

How does the milky way look from Earth as seen with the naked eye?

A

furry light irregular column

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13
Q

How can we find an observer’s latitude using NCP?

A

Altitude of NCP = Latitude of Observer

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14
Q

Explain why the sky appears to move from east to west when we know the Earth rotates

A

The apparent motion of the sky- we think we are stationary, whereas in reality, we may be standing still but the Earth is still moving

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15
Q

Define circumpolar stars

A

Stars that never set below the horizon: can be seen from one location throughout the year

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16
Q

What two things affect how long we can view the constellations?

A
  • Earth’s titled axis
  • 23.5 degree angle to the ecliptic
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17
Q

What formula determines the circumpolarity of stars?

A

declination >/ (90 - latitude of observers)
observer’s latitude +/- co-declination of stars
declination=co-latitude

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18
Q

Define the term upper culmination

A

Star at its highest point

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19
Q

Define the term lower culmination

A

Star at its lowest point

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20
Q

What other word can be used instead of culmination?

A

transit

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21
Q

What is co-declination?

A

Distance between NCP and stars

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22
Q

What is the formula for co-declination?

A

Co-declination = 90 degrees - declination

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23
Q

When does the upper culmination take place?

A

Takes place when right ascension = LST

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24
Q

Define cardinal point

A

Compass point in space

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25
Q

Define circumpolarity

A

When a star never sets below the horizon from a certain latitude

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26
Q

Define culmination

A

When a star (or another body) reaches the observer meridian

27
Q

Define the term meridian

A

Imaginary line between north and south pole

28
Q

What is an hour angle?

A

Angle between the meridian of the observer and star’s meridian line

29
Q

What is the formula for the hour angle?

A

local sidereal time - RA of stars

30
Q

Define the term Altitude

A

How high an object is above the horizon

31
Q

Define the term Azimuth

A

How far eastwards an object is in degrees

32
Q

When can we work out the Sun’s altitude and use which equation?

A

When the sun is at its highest point in daytime
sun altitude = sun declination + (90 degrees - latitude of observer)

33
Q

Describe other visibility problem that affect astronomers

A
  • Rising and setting of sun + thicker atmosphere
  • Saharan dust + volcanic ash in Upper Earth atmosphere
  • weather conditions
  • landscape
  • other celestial bodies
34
Q

Why are many of the constellations based on Greek Mythology?

A

Ptolemy, a Greek astronomer was responsible for scripting all the constellations

35
Q

What are star maps and charts?

A

Map that gives positions and magnitudes of stars

36
Q

What is a planisphere?

A

Rotating star locator

37
Q

What is the Plough used to find?

A

Polaris and Arcturus

38
Q

What does Orion point to?

A

Sirius the brightest star

39
Q

What does the square of Pegasus point?

A

Andromeda Galaxy

40
Q

Define the term open cluster

A

Group of stars close to each other but form no specific symmetry

41
Q

Define the term globular cluster

A

Groups of stars which are spherical shaped with more stars closer to the nucleus

42
Q

Define the term nebulae

A

Place where stars are born + where they die

43
Q

Define the term supernovae

A

The large explosion which takes place after the death of a star

44
Q

Define the term aurorae

A

The solar wind interacts with the atmosphere which produces light and colour displays in the sky

45
Q

What are binary stars?

A

Stars that orbit around a common center - share a gravitational bond

46
Q

What is another name for binary stars?

A

double stars

47
Q

What are optical double stars?

A

Stars that look close together from Earth but are actually not related to each other

48
Q

How do we know the difference between a star and a planet when viewed from Earth without a telescope?

A

Planets are typically brighter and don’t tend to oscillate

49
Q

Define the term asterism

A

Pattern of stars that may or may not be related to a constellation.

50
Q

Define epicycles

A

Each planet revolves uniformly along a circular path, which revolves around the earth in a larger circular path

51
Q

Who came up with the idea of epicycles?

A

Ptolemy

52
Q

Why were epicycles created?

A

To justify the geocentric theory by solving the inability to explain the imperfect motion of heavenly bodies

53
Q

What is the inverse proportion law?

A

Every body in the Universe attracts another with a force that is directly proportional to the product of their masses and inversely proportional to the square of their distance

54
Q

How is the inverse proportion law related to Kepler’s third law?

A

As an object orbits nearer in an elliptical orbit, there must be an increase in gravitational force between them at that point

55
Q

What is Kepler’s third law?

A

The square of the orbital period of a planet (t) is proportional to the cube of its mean distance (r) from the sun

56
Q

What is the role of mass in Kepler’s third law?

A

Gravitational attraction is dependent on the mass, therefore mass must accounted for

57
Q

What is an orbit?

A

The celestial path of body in space around another body

58
Q

What is Kepler’s first law?

A

Planets move in elliptical orbits around the sun, with the sun at one focus

59
Q

What is Kepler’s second law?

A

An imaginary line from the Sun to a planet sweeps out equal areas in equal intervals of time

60
Q

What is an ellipse?

A

Oval shape with two foci

61
Q

Who introduced the Geo-heliocentric model?

A

Tycho-Brahe

62
Q

What did the geo-heliocentric model suggest?

A

Moon and the Sun orbited Earth but everything else orbited the Sun

63
Q

What did Kepler discover using Tycho’s observations?

A

Planets didn’t follow circular orbits but elliptical