Theoretical Astronomy - Theory of Astronomical Time Keeping

Theory of Astronomical Time Keeping

Until recently all the time units that appear natural to us are caused by astronomical phenomena:

  1. Earth's orbit around the Sun => the year, and the seasons,
  2. Moon's orbit around the Earth => the month,
  3. Earth's rotation and the succession of brightness and darkness => the day (and night).

High precision appears problematic:

  1. amibiguities arise in the exact definition of a rotation or revolution,
  2. some astronomical processes are uneven and irregular, such as the noncommensurability of year, month, and day,
  3. there are a multitude of time scales and calendars to solve the first two problems.

Some of these time scales are sidereal time, solar time, and universal time.

Read more about this topic:  Theoretical Astronomy

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