Tony Jones, "Splitting the Second: The Story of Atomic Time"
Institute of Physics Publishing | ISBN 0750306408 | 2000 Year | PDF | 1,25 Mb | 199 Pages
Institute of Physics Publishing | ISBN 0750306408 | 2000 Year | PDF | 1,25 Mb | 199 Pages
| “ | As better clocks were built, measurements showed increasingly subtle causes for variations in the length of the day ranging from a non-circular orbit, to tidal effects, to crust movements, and down to atmospheric effects on the rotation rate. All these are covered in detail. The most convenient source of time with nanosecond accuracy is now the GPS satellites. Jones describes how special and general relativity affect their timekeeping and how these effects are compensated. He also goes into great detail about the international organizations responsible for managing UTC and the complex methods used to average the time from the primary standards and hundreds of secondary standards to produce UTC. Jones manages to do this without losing the reader's attention. Although the book avoids any math or advanced physics, it does not condescend in any way, and is directed to the mature reader. There are explanations of cesium and rubidium frequency standards, hydrogen masers, and also the latest developments: laser cooling and cesium fountains. It would have been nice if the author had included a bibliography, but this is compensated by providing the URLs for all the major world timekeeping organizations and also links to a number of web sites devoted to time. | ” |