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:
“[Anarchism] is the philosophy of the sovereignty of the individual. It is the theory of social harmony. It is the great, surging, living truth that is reconstructing the world, and that will usher in the Dawn.”
—Emma Goldman (1869–1940)
“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)
“Gifts of one loved me,—
‘T was high time they came;
When he ceased to love me,
Time they stopped for shame.”
—Ralph Waldo Emerson (1803–1882)
“Man seems to be capable of great virtues but not of small virtues; capable of defying his torturer but not of keeping his temper.”
—Gilbert Keith Chesterton (1874–1936)