Part One I › Division III III › Section 133 133

The Solar System

Subject Outline

AA survey of the solar system
- 1The Sun [see B., below]
- 2The major planets of the solar system, their surfaces and atmospheres, their satellites [see C., D., and E., below]
- 3Other constituents of the solar system
  - aMinor planets, or asteroids
  - bComets
  - cMeteoroids, meteors, and meteorites
  - dThe interplanetary medium
- 4Regularities of the solar system: the distances of the planets from the Sun, the distribution of natural satellites
- 5Interactions among various bodies in the solar system: gravitational perturbations, actual physical encounters
- 6Theories of the origin of the solar system: origin by an orderly process, origin by catastrophe [see also 131.E.2.C.]
BThe Sun
- 1The Sun's surface layers and their features: the quiet Sun
  - aSolar data derived from observations of the photosphere, the visible luminous surface of the Sun
  - bThe chromosphere, the relatively transparent layer that forms a transition zone between the Sun's photosphere and corona: the flash spectrum, spicules, supergranulation
  - cThe corona, the luminous, high-temperature, rarefied gas envelope of the Sun: form, structure, physical properties; the solar wind
- 2Solar features that occur with increased frequency during the active phase of the solar cycle: the active Sun
  - aCentres of activity: areas of localized strong magnetic fields at the Sun's surface
  - bSunspots: their physical nature, the sunspot cycle of about 11 years
  - cOther features; e.g., faculae, prominences, flares, coronal condensations
- 3The solar interior: energy generation, the evolution of the Sun [see also 132.D.7.]
- 4Solar radiation, including light, radio waves, and particles
- 5Solar-terrestrial relationships and interactions
CThe planets and their satellites
- 1The terrestrial planets
  - aMercury
  - bVenus
  - cEarth [see D., below]
  - dMars
- 2The minor planets, or asteroids [see A.3.a., above]
- 3The giant planets and Pluto
  - aJupiter
  - bSaturn
  - cUranus
  - dNeptune
  - ePluto
DThe Earth as a planet
- 1The distance of the Earth from the Sun: the astronomical unit and solar parallax
- 2The orbital motion of the Earth around the Sun and the rotation of the Earth on its axis: the year, the day, the precession of the equinoxes [see also E.7.a., below]
- 3Effects of the Earth's orbital position and speed on astronomical observations
  - aAstronomical parallax
  - bAberration of light
- 4The Earth's magnetism, temperature, and other physical properties [see 212]
- 5The structure and composition of the Earth's interior [see 213]
- 6The origin of the Earth, its atmosphere, hydrosphere, and surface features [see 232 and 241]
EThe Moon
- 1The shape, radius, mean density, and varying brightness of the Moon
- 2The motion of the Moon
  - aThe apparent motion: the month, or sidereal and synodic periods of the Moon; optical and physical librations [see 7.a.ii., below]
  - bThe actual motion
- 3The mass and gravitational field of the Moon
  - aUnderlying theory: basic gravitational properties of the Moon
  - bDiscovery of lunar mascons: gravity anomalies on the Moon
- 4The physical nature of the Moon
  - aObservations from Earth and from space vehicles: results of remote lunar photography, manned lunar landings, and close-up photography [see also 738.C.]
  - bThe lunar surface features: craters, lineaments (e.g mare ridges, the lunar grid system, rilles), temporary or transient features
  - cTheories of origin of the Moon's surface features: the volcanic and impact theories
- 5The origin and evolution of the Moon
  - aProbable development of the Moon's orbit
  - bEvidence from the composition and physical properties of the Moon
- 6The chemical nature of the Moon
  - aSurface composition: findings of the chemical analysis of lunar rock samples
  - bPossible zonal variations of the interior
- 7The Sun-Earth-Moon system
  - aRelative motions of the Sun, Earth, and Moon
    - iThe geometry of the Sun-Earth-Moon system: the celestial equator, the apparent motion of the Sun along the ecliptic, the inclination of the Earth's axis to its orbit
    - iiMotions of the Sun-Earth-Moon system as the astronomical basis of chronology: the day, month, and year; the Sothic cycle, Metonic cycle, and other complex cycles
  - bEclipses of the Sun and Moon