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:
“The things that will destroy America are prosperity-at-any- price, peace-at-any-price, safety-first instead of duty-first, the love of soft living, and the get-rich-quick theory of life.”
—Theodore Roosevelt (1858–1919)
“The weakness of the man who, when his theory works out into a flagrant contradiction of the facts, concludes “So much the worse for the facts: let them be altered,” instead of “So much the worse for my theory.””
—George Bernard Shaw (1856–1950)
“So little time we live in Time,
And we learn all so painfully,
That we may spare this hour’s term
To practice for Eternity.”
—Robert Penn Warren (1905–1989)
“A father ... knows exactly what those boys at the mall have in their depraved little minds because he once owned such a depraved little mind himself. In fact, if he thinks enough about the plans that he used to have for young girls, the father not only will support his wife in keeping their daughter home but he might even run over to the mall and have a few of those boys arrested.”
—Bill Cosby (20th century)