Talk:Orders of magnitude (time)
From Wikipedia, the free encyclopedia
- 109 years - aeon – 106 years - eon – 103 years - millennium – 102 years - century – 101 years - decade – 100 years - year
- annum (a) - kilo-annum (ka) - mega-annum (Ma) - giga-annum (Ga)
- second (s) - millisecond (ms) - microsecond (μs) - nanosecond (ns) - picosecond (ps) - femtosecond (fs)
[edit] Orders of magnitude
(moved from second)
A millisecond (ms) is equal to one thousandth of a second. It is often used for measuring the duration of speech sounds in phonetics.
- A microsecond (µs) is equal to one millionth (10-6) of a second. It is often used for measuring things like atomic and chemical reactions, which occur in normally imperceptible lengths of time.
- A nanosecond (ns) is equal to 10-9 of a second.
- It is only infrequently put into everyday use. In technical situations it is however a very common unit, especially in computers, telecommunications, pulsed lasers, and some areas of electronics.
- In 1 ns, light travels exactly 299.792458 mm in a vacuum (via the definition of the metre). But the speed of light is slower in materials, indicated by an index of refraction n greater than 1. Thus in air (n = 1.003), light travels about 298.9 mm in 1 ns, but it travels only about 225.4 mm in water (n = 1.33) each nanosecond.
- A picosecond (ps) is equal to 10-12 of a second, or one trillionth in the short scale (ie, one million millionth) of a second.
- The waves of visible light oscillate with a period of about 1 femtosecond.
- An attosecond (as) is an SI unit of time equal to 10-18 of a second.
- The current shortest measurable period of time (as of February 2004) is 100 attoseconds. (BBC News)
- A zeptosecond (zs) is equal to 10-21 of a second.
- A yoctosecond (ys) is equal to 10-24 (one septillionth in the short scale) of a second.
