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More exactly, the mean solar day is 86.400 002 ks due to tidal braking, and increasing at the rate of approximately 2 ms/century; to correct for this time standards like UTC use leap seconds with the interval described as "a day" on them being most often 86.4 ks exactly by definition but occasionally one second more or less so that every day ...
2.68 microseconds – the amount of time subtracted from the Earth's day as a result of the 2004 Indian Ocean earthquake. [2] 3.33564095 microseconds – the time taken by light to travel one kilometre in a vacuum. 5.4 microseconds – the time taken by light to travel one mile in a vacuum (or radio waves point-to-point in a near vacuum).
Earth-based: the day is based on the time it takes for the Earth to rotate on its own axis, as observed on a sundial [citation needed]. Units originally derived from this base include the week (seven days), and the fortnight (14 days). Subdivisions of the day include the hour (1/24 of a day), which is further subdivided into minutes and seconds ...
A sidereal rotation is the time it takes the Earth to make one revolution with rotation to the stars, approximately 23 hours 56 minutes 4 seconds. A mean solar day is about 3 minutes 56 seconds longer than a mean sidereal day, or 1 ⁄ 366 more than a mean sidereal day.
Precession of the Earth's axis (about every 25,700 years) 10 −11: 10 pHz ~31.71 pHz: Once per millennium 10 −10: 100 pHz ~317.1 pHz: Once per century 10 −9: 1 nanohertz (nHz) ~1 nHz: Once per generation (about every 30 years) ~2.9 nHz: Average solar cycle (about every 11 years) ~3.171 nHz: Once per decade 10 −8: 10 nHz 11.6699016 nHz ...
For example, glacial rebound shortens the solar day by 0.6 ms/century and the 2004 Indian Ocean earthquake is thought to have shortened it by 2.68 microseconds. [ 29 ] It is a mistake, however, to consider leap seconds as indicators of a slowing of Earth's rotation rate; they are indicators of the accumulated difference between atomic time and ...
A mean solar day is, therefore, nearly 4 minutes longer than a sidereal day. The stars are so far away that Earth's movement along its orbit makes nearly no difference to their apparent direction (except for the nearest stars if measured with extreme accuracy; see parallax), and so they return to their highest point at the same time each ...
One kè was usually defined as 1 ⁄ 100 of a day until 1628, though there were short periods before then where days had 96, 108 or 120 kè. [7] A kè is about 14.4 minutes, or 14 minutes 24 seconds. In the 19th century, Joseph Charles François de Rey-Pailhade endorsed Lagrange’s proposal of using centijours, but abbreviated cé , and ...