Preface
.Acronyms.
1 Time: Pre-Twentieth Century.
1.1 In the Beginning.
1.2 Characterizing Time.
1.3 Calendars.
1.4 Astronomical Observations.
1.5 Timekeeping.
1.6 Time Epochs.
1.7 Time Transfer.
1.8 Rotation of the Earth.
1.9 Beginning the Twentieth Century.
References.
2 Solar Time.
2.1 Apparent Solar Time.
2.2 Mean Solar Time.
2.3 Equation of Time.
2.4 Sidereal Time.
2.5 Washington Conference of 1884.
2.6 Newcomb’s Theory of the Sun.
2.7 Universal Time.
2.8 Coordinated Universal Time (UTC).
2.9 Greenwich Mean Time (GMT).
2.10 Tropical Year.
2.11 Besselian Year.
2.12 Reference System.
2.13 Time Zones.
2.14 Daylight Saving Time.
References.
3 Ephemerides.
3.1 Ephemerides and Time.
3.2 Before Kepler and Newton.
3.3 Kepler and Newton.
3.4 Tables, General Theories, and Ephemerides.
3.5 Lunar Theories.
3.6 The Advent of Computers.
3.7 Numerical Integrations.
3.8 Observational Data.
3.9 Dynamical Reference Frame.
3.10 Time Arguments.
3.11 Astronomical Constants.
3.12 Artificial Satellite Theories.
3.13 Theory of Relativity.
References.
4 Variable Earth Rotation.
4.1 Pre 19th Century.
4.2 Secular Variation.
4.3 Irregular Variations in the Earth’s Rotation.
4.4 Early Explanations for the Variable Rotation.
4.5 Current Understanding of the Earth’s Variable Rotation.
4.6 Consequences.
References.
5 Earth Rotation and Polar Motion.
5.1 Earth Orientation.
5.2 Variations in the Earth’s Orientation.
5.3 Transforming Between Reference Frames.
5.4 Determination of Earth Orientation.
5.5 Earth Orientation Data.
References.
6 Ephemeris Time.
6.1 Need for a Uniform Time Scale.
6.2 Danjon Proposal.
6.3 Clemence’s Proposal.
6.4 Adoption and Definition.
6.5 Observational Determination.
6.6 The Ephemeris Second and Atomic Time.
6.7 Historical DT.
6.8 Problems with Ephemeris Time.
6.9 Relativity.
6.10 Dynamical Time Scales.
References.
7 Relativity and Time.
7.1 Newtonian Reference Systems.
7.2 Special Relativity.
7.3 Lorentz Transformations.
7.4 Coordinate and Proper Time.
7.5 Minkowski Diagrams.
7.6 Time in Special Relativity.
7.7 General Relativity.
7.8 IAU Resolutions.
7.9 Time Scales.
7.10 Relativistic Effects in Time Transfer.
References.
8 Dynamical and Coordinate Time Scales.
8.1 Replacing Ephemeris Time.
8.2 Terrestrial Dynamical Time (TDT) and Barycentric Dynamical Time (TDB).
8.3 Problems with TDT and TDB.
8.4 New Reference System.
8.5 New Time Scales.
8.6 DT and Ephemeris Time Revised.
8.7 Relationships Among Coordinate Time Scales.
References.
9 Clock Developments.
9.1 Introduction.
9.2 Keeping Time in Antiquity.
9.3 The First Mechanical Clocks.
9.4 Pendulum Clocks.
9.5 Quartz Crystal Clocks.
9.6 Clock Performance.
References.
10 Microwave Atomic Clocks.
10.1 Beyond Quartz-Crystal Oscillators.
10.2 Physics of Atomic Clocks.
10.3 General Structure of Atomic Clocks.
10.4 Development of Atomic Clocks.
10.5 Stored Ion Clocks.
10.6 Characterizing Atomic Clocks.
References.
11 Optical Atomic Standards.
11.1 Optical Transition Frequencies.
11.2 Optical Ion Clocks.
11.3 Optical Neutral Atom Clocks.
11.4 Quantum Logic Clock.
11.5 Characterizing Optical Standards.
References.
12 Definition and Role of a Second.
12.1 The Historical Second.
12.2 The Ephemeris Second.
12.3 The SI Second.
12.4 Adopting the SI Second.
References.
13 International Atomic Time (TAI).
13.1 Constructing an Atomic Time Scale.
13.2 History of TAI.
13.3 Formation of TAI.
13.4 Stability of TAI.
13.5 Distribution of TAI.
13.6 Relationship of TAI to Terrestrial Time.
References.
14 Coordinated Universal Time.
14.1 Universal Time Before 1972.
14.2 Coordinated Universal Time After 1972.
14.3 Leap Seconds.
14.4 UT1.
14.5 UTC Worldwide.
14.6 Time Distribution.
14.7 The Future of UTC – Leap Seconds or Not?.
References.
15 Time in the Solar System.
15.1 The Solar System.
15.2 Pursuit of Uniformity.
15.3 Pursuit of Accuracy.
15.4 Time and Phenomena.
15.5 Time and Distance.
15.6 Space Mission Times.
15.7 Proper Times at Planets.
15.8 Pulsars – An Independent Source of Time?.
References.
16 Time and Frequency Transfer.
16.1 Historical Transfer Techniques.
16.2 Time and Frequency Dissemination Modeling.
16.3 Time and Frequency Dissemination Systems.
References.
17 Modern Earth Orientation.
17.1 Terrestrial to Celestial Reference Systems.
17.2 Determination of Earth Orientation Parameters.
17.3 Earth Orientation Data.
References.
18 International Activities.
18.1 Time and International Activities.
18.2 Treaty of the Meter.
18.3 Scientific Unions.
18.4 Service Organizations.
References.
19 Time Applications.
19.1 Time Enables the Infrastructure.
19.2 Positioning and Navigation Services.
19.3 Communications.
19.4 Power Grid.
19.5 Banking and Finance.
19.6 Emergency Services.
19.7 Water Flow.
19.8 Summary.
Reference.
20 Future of Timekeeping.
20.1 Future Needs for Time.
20.2 Modeling the Earth’s Rotation.
20.3 Clocks of the Future.
20.4 Future Time Scales.
20.5 Future Time Distribution.
Glossary.
Index.
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