NYU Observational astronomy 2013-2014

2a1046385e6cf8e4d07d590f9821ece5?s=47 federica
June 18, 2015

NYU Observational astronomy 2013-2014

Lecture 3:
-gravity
-the Moon
-other solar system moons

2a1046385e6cf8e4d07d590f9821ece5?s=128

federica

June 18, 2015
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Transcript

  1. lecture 3 gravity, our moon - other moons observational astronomy

    1
  2. lecture 3 gravity, our moon - other moons recap •the

    earth spins on its axis •the earth revolves around the sun 2
  3. lecture 3 gravity, our moon - other moons recap •the

    earth spins on its axis • this causes the changes seen through the night in the skyscape • the alternation of day and night •the earth revolves around the sun • this causes the seasonal changes in the night sky • the alternation of seasons 3
  4. lecture 3 gravity, our moon - other moons recap •the

    earth spins on its axis • this causes the changes seen through the night in the skyscape • the alternation of day and night •the earth revolves around the sun • this causes the seasonal changes in the night sky • the alternation of seasons 4
  5. lecture 3 gravity, our moon - other moons recap the

    solar day lasts 24h. time passing between two transits of the Sun the sidereal day is 23h 56m. time passing between two transits of the same (distant) celestial body 5
  6. lecture 3 gravity, our moon - other moons equator NP

    SUN winter solstice summer solstice the axial tilt of the earth is 23.4 degrees. the misalignment of earth’s spin axis and ecliptic plane cause the season changes because of the different length of the day and angle of incidence of the solar radiation 6
  7. lecture 3 gravity, our moon - other moons equator NP

    SUN winter solstice summer solstice the axial tilt of the earth is 23.4 degrees. the misalignment of earth’s spin axis and ecliptic plane cause the season changes because of the different length of the day and angle of incidence of the solar radiation 7
  8. lecture 3 gravity, our moon - other moons equator NP

    SUN winter solstice summer solstice the axial tilt of the earth is 23.4 degrees. the misalignment of earth’s spin axis and ecliptic plane cause the season changes because of the different length of the day and angle of incidence of the solar radiation A B C 8
  9. lecture 3 gravity, our moon - other moons equator tropic

    of cancer tropic of capricorn antarctic circle arctic circle the declination of the sun at noon changes through the year, with maximum and minimum at 23.4 degrees. SUN 9
  10. lecture 3 gravity, our moon - other moons equator tropic

    of cancer tropic of capricorn antarctic circle arctic circle SUN what is the declination of the sun? Dec -90d 90d 24h 0h RA 10
  11. lecture 3 gravity, our moon - other moons •the earth’s

    moon •other solar system moons 11
  12. lecture 3 gravity, our moon - other moons •concepts of

    classical gravity •the earth’s moon •other solar system moons 12
  13. lecture 3 gravity, our moon - other moons Empirically describe

    the motion of celestial bodies in the heliocentric system kepler’s laws 13
  14. lecture 3 gravity, our moon - other moons kepler’s laws

    Empirically describe the motion of celestial bodies in the heliocentric system 1.The orbit of every planet is an ellipse with the Sun at one of the two foci. 2.A line joining a planet and the Sun sweeps out equal areas during equal intervals of time. 3.The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit. 14
  15. lecture 3 gravity, our moon - other moons concepts of

    classical gravity 15
  16. lecture 3 gravity, our moon - other moons 16

  17. lecture 3 gravity, our moon - other moons 17

  18. lecture 3 gravity, our moon - other moons one force:

    gravity 18
  19. lecture 3 gravity, our moon - other moons one force:

    gravity 19
  20. lecture 3 gravity, our moon - other moons one force:

    gravity lecture 3 20
  21. lecture 3 gravity, our moon - other moons one force:

    gravity lecture 3 21
  22. lecture 3 gravity, our moon - other moons one force:

    gravity 22
  23. lecture 3 gravity, our moon - other moons 23

  24. lecture 3 gravity, our moon - other moons center of

    mass 24
  25. lecture 3 gravity, our moon - other moons center of

    mass 25
  26. lecture 3 gravity, our moon - other moons center of

    mass 26
  27. lecture 3 gravity, our moon - other moons center of

    mass 27
  28. lecture 3 gravity, our moon - other moons center of

    mass 28
  29. lecture 3 gravity, our moon - other moons center of

    mass 29
  30. lecture 3 gravity, our moon - other moons center of

    mass 30
  31. lecture 3 gravity, our moon - other moons center of

    mass 31
  32. lecture 3 gravity, our moon - other moons center of

    mass 32
  33. lecture 3 gravity, our moon - other moons newton’s laws

    Explain the motion of celestial bodies in terms of forces 1. A body in motion tends to maintain its motion 2. 3. 33
  34. lecture 3 gravity, our moon - other moons orbital elements

    planets orbit around sun in an ellipse (first Kepler law) 34
  35. lecture 3 gravity, our moon - other moons orbital elements

    ellipse: locus of points equidistant from two points called foci (plural of focus) 35
  36. lecture 3 gravity, our moon - other moons orbital elements

    ellipse: locus of points equidistant from two points called foci (plural of focus) 36
  37. lecture 3 gravity, our moon - other moons orbital elements

    ellipse: locus of points equidistant from two points called foci (plural of focus) a1 b1 37
  38. lecture 3 gravity, our moon - other moons orbital elements

    ellipse: locus of points equidistant from two points called foci (plural of focus) a1 b1 a2 b2 a1+b1 = a2+b2 38
  39. lecture 3 gravity, our moon - other moons orbital elements

    ellipse: locus of points equidistant from two points called foci (plural of focus) a1 b1 a2 b2 a3 b3 a1+b1 = a2+b2 = a3+b3 39
  40. lecture 3 gravity, our moon - other moons orbital elements

    semimajor axis semiminor axis 40
  41. lecture 3 gravity, our moon - other moons orbital elements

    semimajor axis semiminor axis eccentricity 41
  42. lecture 3 gravity, our moon - other moons orbital elements

    semimajor axis semiminor axis eccentricity apo-center peri-center 42
  43. lecture 3 gravity, our moon - other moons semimajor axis

    semiminor axis eccentricity apo-center peri-center 43
  44. lecture 3 gravity, our moon - other moons semimajor axis

    semiminor axis eccentricity apo-center peri-center inclination 44
  45. lecture 3 gravity, our moon - other moons kepler’s laws

    Empirically describe the motion of celestial bodies in the heliocentric system 1.The orbit of every planet is an ellipse with the Sun at one of the two foci. 2.A line joining a planet and the Sun sweeps out equal areas during equal intervals of time. 3.The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit. 45
  46. lecture 3 gravity, our moon - other moons the earth’s

    moon 46
  47. lecture 3 gravity, our moon - other moons perigee (363,000

    km) apogee (406,000 km) Moon’s orbit is significantly elliptical 47
  48. lecture 3 gravity, our moon - other moons perigee (363,000

    km) apogee (406,000 km) Moon’s orbit is significantly elliptical 48
  49. Moon phases 49

  50. Moon phases 50

  51. Moon phases 51

  52. new full first quarter third quarter waning crescent waxing crescent

    Moon phases waxing gibbous waning gibbous 52
  53. lecture 3 gravity, our moon - other moons Moon phases

    53
  54. lecture 3 gravity, our moon - other moons 5o Moon

    phases 54
  55. lecture 3 gravity, our moon - other moons orbital period

    = 27.3 d synodic period = 29.5 d 55
  56. Moon phases 56

  57. maria 57

  58. highlands (terrae) 58

  59. Tycho Copernicus 59

  60. Tycho Copernicus 60

  61. lecture 3 gravity, our moon - other moons tidal locking

    61
  62. lecture 3 gravity, our moon - other moons 62

  63. lecture 3 gravity, our moon - other moons 1.libration in

    longitude uniform rotation, but elliptical orbit (exaggerated so you can see it) 63
  64. lecture 3 gravity, our moon - other moons 2.libration in

    latitude misalignment of Moon’s axis of spin and rotation 1.libration in longitude 64
  65. lecture 3 gravity, our moon - other moons 3.diurnal libration

    parallax change during day (highly exaggerated; actual amount is typically 8000 km / 400,000 km = 1/50 rad ~ 1 deg) 2.libration in latitude 1.libration in longitude 65
  66. lecture 3 gravity, our moon - other moons 59% of

    the surface of the moon is visible to earth 66
  67. lecture 3 gravity, our moon - other moons 67

  68. lecture 3 gravity, our moon - other moons timeline 4.6

    4.4 surface cools and hardens 4.2 3.9 heavy bombardment 3.8 billion years volcanism 3 ... geological quiescence 68
  69. lecture 3 gravity, our moon - other moons timeline 4.6

    4.4 surface cools and hardens 4.2 3.9 heavy bombardment 3.8 billion years volcanism 3 ... geological quiescence 1968 men on the moon 69
  70. lecture 3 gravity, our moon - other moons 70

  71. lecture 3 gravity, our moon - other moons APOLLO lunar

    laser ranging experiment 71
  72. lecture 3 gravity, our moon - other moons APOLLO collecting

    rocks from the moon 72
  73. lecture 3 gravity, our moon - other moons APOLLO collecting

    rocks from the moon mare Basalts: 3.9 billion years highland Anorthosite: 4.6 billion years Breccias and Lunar Solis from impacts 73
  74. lecture 3 gravity, our moon - other moons science, 2012

    74
  75. lecture 3 gravity, our moon - other moons timeline 4.6

    4.4 surface cools and hardens 4.2 3.9 late heavy bombardment 3.8 billion years volcanism 3 ... geological quiescence 1968 men on the moon 75
  76. lecture 3 gravity, our moon - other moons 76

  77. lecture 3 gravity, our moon - other moons moons of

    jupiter 77
  78. lecture 3 gravity, our moon - other moons moons of

    jupiter 78
  79. lecture 3 gravity, our moon - other moons moons of

    jupiter Io Europa Ganymede Callisto 79
  80. lecture 3 gravity, our moon - other moons moons of

    jupiter Io Europa Ganymede Callisto 80
  81. lecture 3 gravity, our moon - other moons moons of

    jupiter 81
  82. lecture 3 gravity, our moon - other moons moons of

    saturn 82
  83. lecture 3 gravity, our moon - other moons moon formation

    in situ 83
  84. lecture 3 gravity, our moon - other moons moon formation

    in situ impactor capture 84
  85. lecture 3 gravity, our moon - other moons capture 85

  86. lecture 3 gravity, our moon - other moons 86

  87. lecture 3 gravity, our moon - other moons 87

  88. lecture 3 gravity, our moon - other moons 88

  89. lecture 3 gravity, our moon - other moons 89

  90. lecture 3 gravity, our moon - other moons summary 1.

    Kepler’s laws describe the motion of the solar system objects 2. Newton’s law explain the motion of the solar system objects in terms of one force: Gravity 3. Bodies in orbit are permanently free falling 4. Celestial orbits can be described as ellipses with eccentricity, semimajor & semiminor axis (peri- & apo-center), inclination... 5. The moon orbits the earth, synchronously (tidal locking) 6. The moon formed from the impact of a celestial body with the earth from earth material, 4.6 billion years ago. 8. A variety of moons exist in the Solar System, formed through impacts, in situ, or by capture 90
  91. lecture 3 gravity, our moon - other moons reading Kaler

    Chapter 6.2, 9 first half, Chapter 12.1 first half Monday labs: the first outdoors lab -we may go out this week! Wednesday labs: the second outdoors lab - we learn how to use telescopes! The second indoors lab is Starry Night The third indoors lab is the Ecliptic 91