Theory of Astronomical Time Keeping
Until recently all the time units that appear natural to us are caused by astronomical phenomena:
- Earth's orbit around the Sun => the year, and the seasons,
- Moon's orbit around the Earth => the month,
- Earth's rotation and the succession of brightness and darkness => the day (and night).
High precision appears problematic:
- amibiguities arise in the exact definition of a rotation or revolution,
- some astronomical processes are uneven and irregular, such as the noncommensurability of year, month, and day,
- 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
Famous quotes containing the words theory of, theory, time and/or keeping:
“Could Shakespeare give a theory of Shakespeare?”
—Ralph Waldo Emerson (1803–1882)
“Everything to which we concede existence is a posit from the standpoint of a description of the theory-building process, and simultaneously real from the standpoint of the theory that is being built. Nor let us look down on the standpoint of the theory as make-believe; for we can never do better than occupy the standpoint of some theory or other, the best we can muster at the time.”
—Willard Van Orman Quine (b. 1908)
“A junky runs on junk time. When his junk is cut off, the clock runs down and stops. All he can do is hang on and wait for non-junk time to start.”
—William Burroughs (b. 1914)
“Jealousy is in some measure just and reasonable, since it merely aims at keeping something that belongs to us or we think belongs to us, whereas envy is a frenzy that cannot bear anything that belongs to others.”
—Francois Duc De La Rochefoucauld (1613–1680)