Time: From Earth Rotation to Atomic Physics

This accessible reference presents the evolution of concepts of time and methods of time keeping, for historians, scientists, engineers, and educators.

Dennis D. McCarthy (Author), P. Kenneth Seidelmann (Author)

9781107197282, Cambridge University Press

Hardback, published 18 October 2018

400 pages
25.3 x 17.8 x 2.3 cm, 0.95 kg

'Why do we add 1 second to our clocks at midnight at the end of some years, or at the end of June in others? Why don't we subtract 1 second sometimes instead? … You will find the answers to these and many more questions in this excellent book, written by two experts who worked on the practical aspects of these topics at the US Naval Observatory … The second edition brings these subjects right up to date, and investigates the possible future developments in timekeeping.' L. V. Morrison, The Observatory

In the twenty-first century, we take the means to measure time for granted, without contemplating the sophisticated concepts on which our time scales are based. This volume presents the evolution of concepts of time and methods of time keeping up to the present day. It outlines the progression of time based on sundials, water clocks, and the Earth's rotation, to time measurement using pendulum clocks, quartz crystal clocks, and atomic frequency standards. Time scales created as a result of these improvements in technology and the development of general and special relativity are explained. This second edition has been updated throughout to describe twentieth- and twenty-first-century advances and discusses the redefinition of SI units and the future of UTC. A new chapter on time and cosmology has been added. This broad-ranging reference benefits a diverse readership, including historians, scientists, engineers, educators, and it is accessible to general readers.

Preface
1. Time: pre-twentieth century
2. Solar time
3. Ephemerides
4. Variable Earth rotation
5. Earth orientation
6. Ephemeris time
7. Relativity and time
8. Time and cosmology
9. Dynamical and coordinate time scales
10. Clock developments
11. Microwave atomic clocks
12. Optical atomic standards
13. Definition and role of a second
14. International Atomic Time (TAI)
15. Coordinated Universal Time (UTC)
16. Time in the solar system
17. Time and frequency transfer
18. Modern Earth orientation
19. International activities
20. Time applications
21. Future of time keeping
Acronyms
Glossary.

Subject Areas: Geographical information systems [GIS & remote sensing RGW], Geophysics [PHVG], Atomic & molecular physics [PHM], Astronomical observation: observatories, equipment & methods [PGG], Astronomy, space & time [PG], History of science [PDX]