Part One I › Division III III › Section 131 131

The Cosmos

Subject Outline

AThe structure and properties of the universe
- 1Basic data for the universe
  - aThe estimated chemical composition of the universe [see also 121.D.]
  - bThe large-scale structure and behaviour of the universe: evidence that the universe is expanding, Hubble's law and the theory of the red shift
  - cThe age of the universe
  - dThe clustering of galaxies
  - eCosmic microwave background radiation
  - fThe missing mass problem
  - gSpace-time: a four-dimensional continuum used to describe the universe
- 2Cosmological models: theoretical representations of the original behaviour of the universe [see E.1., below]
- 3The known and postulated components of the universe
  - aDistant galaxies [see 132.A.]
  - bThe Local Group of galaxies [see 132.A.1.C.]
  - cQuasars and related objects, including such hypothetical phenomena as supermassive black holes at the centres of galaxies
  - dNebulae
  - eStars and stellar groups [see 132.C. and 132.D.]
  - fPlanetary systems: solar and extrasolar systems [see also 133.A.]
BGravitation: a universal force of mutual attraction that is postulated as acting between all matter
- 1Development of gravitational theory
  - aEarly concepts: the Aristotelian viewpoint, contributions of Kepler and Galileo
  - bNewton's law of gravity [see also 126.A.3.b.v.]
- 2Interpretation of gravity measurements
  - aPotential theory: mathematical representation of the gravitational fields of irregular mass distributions [see also 10/22.D.2.C.]
  - bEffects of local mass differences: measurement of small gravity anomalies
- 3Modern gravitational theory and its relation to other aspects of physical theory
  - aField theories of gravity and their general properties and predictions
  - bGravitational fields and the general theory of relativity: principles and consequences [see D.2., below]
- 4Acceleration of gravity on the Earth's surface [see 212.A.]
- 5The gravitational constant, G: methods of measurement, possible variation in time and space
CCelestial mechanics [see 126.B]
DProperties of the space-time continuum: the astronomical implications of relativity theory
- 1The special theory of relativity
  - aHistorical background: the search for the ether
  - bRelativity of space and time
  - cConsequences of the special theory
- 2The general theory of relativity
  - aUse of relativity to interpret gravitational phenomena
  - bExperimental confirmation of the theory
  - cImplications of general relativity
EThe origin and development of the universe
- 1The development of the universe as a whole
  - aBig-bang versus steady-state models of the universe
  - bPrimordial nucleosynthesis
  - cThe early universe: extrapolations backward in time to the beginning of the universe
- 2The formation and development of components of the universe: galaxies, stars, the solar system [see also 132.B., 132.D., and 133.A.]
  - aThe origin and development of galaxies: protogalaxies
  - bThe formation and development of stars
  - cThe origin of the solar system
- 3Time scale of the universe: dating of significant events in the history of the universe