Time

Resources

• calendars
  • Calendar Reform, Rick McCarty, East Carolina University
  • Calendars and their History, L. E. Doggett, reprinted from Explanatory Supplement to the Astronomical Almanac
  • Calendars Through the Ages, Claus Tøndering
  • Seven Day Week, Ed Stephan, Western Washington University
• clocks (and watches)
  • How Stuff Works, Marshall Brain
    • Alarm Clock
    • Digital Clock
    • Pendulum Clock
  • Quartz Watch, Smithsonian Institution
• clocks, atomic
  • ammonia
    • The Atomic Clock: An Atomic Standard of Frequency and Time. National Bureau of Standards Technical News Bulletin. Vol. 33 No. 2 (February 1949): 17–24. The first atomic clock used ammonia, so it was really a "molecular clock".
    • The Atomic Clock. Harold Lyons. Instruments. Vol. 22 (December 1949): 133–135.
    • Microwave spectroscopic frequency and time standards. Harold Lyons. Electronic Engineering. Vol. 68. (March 1949): 251.
    • Atomic clock. Harold Lyons, Benjamin F. Husten. US Patent 2,699,503 (1955).
  • cesium
    • The atomic clock: a universal standard of frequency and time. Harold Lyons. American Scholar. Vol. 19 (April 1950): 159–168.
  • ytterbium
    • Optical Frequency Measurements Group. Time and Frequency Division. National Institute of Standards and Technology (NIST).
  • An Atomic Clock with 10⁻¹⁸ Instability. N. Hinkley, J. A. Sherman, N. B. Phillips, M. Schioppo, N. D. Lemke, K. Beloy, M. Pizzocaro, C. W. Oates, A. D. Ludlow. Science. Vol. 341 No. 6151 (13 September 2013): 1215-1218.
  • strontium
    • Jun Ye Group. JILA — a joint institute of University of Colorado Boulder and the National Institute of Standards and Technology (NIST).
  • An optical lattice clock with accuracy and stability at the ⁻¹⁸ level. B.J. Bloom, T.L. Nicholson, J.R. Williams, S.L. Campbell, M. Bishof, X. Zhang, W. Zhang, S.L. Bromley, J. Ye. Nature. Vol. 506 (6 February 2014): 71–77.
  • A quantum network of clocks. P. Kómár, E.M. Kessler, M. Bishof, L. Jiang, A.S. Sørensen, J. Ye, M.D. Lukin. Nature Physics. Vol. 10 (August 2014) 582–587.
• History
  • A Walk Through Time. The Evolution of Time Measurement through the Ages.
• Humor
  • New "Time" to Keep Everything from Happening at Once, The Onion, 19 April 2000
  • Mr. Deity and the Really Hard Time, Mr. Deity, 8 February 2010
• length of day
  • International Earth Rotation and Reference Systems Service (IERS)
    • hpiers.obspm.fr
    • www.iers.org
  • NASA Details Earthquake Effects on the Earth['s Rotation]
  • Rotation of the Earth. Nigel Bunce & Jim Hunt. The Science Corner. No. 42 (13 September 1984)
  • Coral Growth and Geochronometry. John W. Wells. Nature Vol. 197 No. 4871 (9 March 1963): 948–950. Growth rings in fossil coral can be used to determine the length of the day in the past (by counting the number of solar days in a year).
• network time
  • NTP: The Network Time Protocol, University of Delaware
  • Network Time Synchronization Project, Dave Mills, University of Delaware. The man who gave time to the Internet.
• sundials
  • Sundials on the Internet, British Sundial Society
• time services
  • France
    • Bureau International des Poids et Mesures (BIPM)
  • UK
    • National Physical Laboratory (NPL)
  • US
    • National Institute of Standards and Technology (NIST)
      • Time and Frequency Division
  • time.gov. The Official NIST US Time.
  • At the Tone. A Little History of NIST Radio Stations WWV & WWVH (1955-2005). shortwavemusic. SoundCloud.
  • NIST-F1. The nation's primary time and frequency standard.
  • United States Naval Observatory (USNO)
    • Time Service Department. The Official Source of Time for the Department of Defense (DoD) and for the Global Positioning System (GPS).