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Orders of magnitude (time) An order of magnitude of time is usually a decimal prefix or decimal order-of-magnitude quantity together with a base unit of time, like a microsecond or a million years. In some cases, the order of magnitude may be implied (usually 1), like a "second" or "year". In other cases, the quantity name implies the base unit ...
A unit of time is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI), and by extension most of the Western world, is the second, defined as about 9 billion oscillations of the caesium atom. The exact modern SI definition is " [The second] is ...
Symbol. s. The second (symbol: s) is a unit of time, historically defined as 1⁄86400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each (24 × 60 × 60 = 86400). The current and formal definition in the International System of Units (SI) is more precise:
The centimetre (SI symbol: cm) is a unit of length in the metric system equal to 10−2 metres (100m = 0.01 m). To help compare different orders of magnitude, this section lists lengths between 10 −2 m and 10 −1 m (1 cm and 1 dm). 1 cm – 10 millimetres. 1 cm – 0.39 inches. 1 cm – edge of a square of area 1 cm 2.
10−18 s. An attosecond (abbreviated as as) is a unit of time in the International System of Units (SI) equal to 10 −18 or 1 ⁄ 1 000 000 000 000 000 000 (one quintillion) of a second. [1] An attosecond is to a second, as a second is to approximately 31.69 billion years. [2]
A millisecond (from milli- and second; symbol: ms) is a unit of time in the International System of Units equal to one thousandth (0.001 or 10 −3 or 1 / 1000) of a second [1][2] or 1000 microseconds. A millisecond is to one second, as one second is to approximately 16.67 minutes. A unit of 10 milliseconds may be called a centisecond, and one ...
Animation showing the difference between a sidereal day and a solar day. Sidereal time ("sidereal" pronounced / saɪˈdɪəriəl, sə -/ sy-DEER-ee-əl, sə-) is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky.
A leap second is a one- second adjustment that is occasionally applied to Coordinated Universal Time (UTC), to accommodate the difference between precise time (International Atomic Time (TAI), as measured by atomic clocks) and imprecise observed solar time (UT1), which varies due to irregularities and long-term slowdown in the Earth's rotation.