Evolution of Timescales from Astronomy to Physical Metrology

Abstract

Astronomy has provided a means to mark the passage of time throughout history. One of the repeating phenomena that makes this possible is the Earth's rotation. The basic variability in its rotational speed, however, makes astronomical techniques unsuitable for timekeeping with the precision required for modern applications. Physical metrology from the first mechanical clocks to the most sophisticated atomic standards of today has assumed a growing role in timekeeping. Along with this progress in technology, more sophisticated concepts of timescales have appeared to take advantage of those improvements.

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Document Details

Document Type
Technical Report
Publication Date
Jul 20, 2011
Accession Number
ADA548492

Entities

People

  • Dennis D. Mccarthy

Organizations

  • United States Naval Observatory

Tags

Communities of Interest

  • Air Platforms
  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Accuracy
  • Astronomy
  • Atomic Clocks
  • Clocks
  • Coordinate Systems
  • Energy Levels
  • Frequency
  • Frequency Standards
  • General Relativity
  • Measurement
  • Metrology
  • Observatories
  • Periodic Variations
  • Precision
  • Rotation
  • Standards
  • Time Signals

Fields of Study

  • Physics

Readers

  • Control Systems Engineering.
  • Positioning, Navigation, and Timing (PNT) Technology.
  • Systems Analysis and Design