Editing Hour (section)

===Modernity===
{{main|Decimal time|Metric system}}
The minor irregularities of the apparent solar day were smoothed by measuring time using the [[mean solar day]], using the Sun's movement along the [[celestial equator]] rather than along the [[ecliptic]]. The irregularities of this time system were so minor that most clocks reckoning such hours did not need adjustment. However, scientific measurements eventually became precise enough to note the effect of [[tidal deceleration]] of the [[Earth]] by the [[Moon]], which gradually lengthens the Earth's days.

During the [[French Revolution]], a [[French Revolutionary units|general decimalisation of measures]] was enacted, including [[decimal time]] between 1794 and 1800. Under its provisions, the French hour ({{langx|fr|{{linktext|heure}}}}) was {{frac|10}} of the day and divided formally into 100 decimal minutes (''{{lang|fr|minute décimale}}'') and informally into 10 tenths (''{{lang|fr|{{linktext|décime}}}}''). Mandatory use for all public records  began in 1794, but was suspended six months later by the same 1795 legislation that first established the metric system. In spite of this, a few localities continued to use decimal time for six years for civil status records, until 1800, after Napoleon's Coup of 18 Brumaire.

The [[metric system]] bases its measurements of time upon the [[second]], defined since 1952 in terms of the Earth's rotation in AD{{nbsp}}1900. Its hours are a secondary unit computed as precisely 3,600 seconds.<ref name=sportsillustrated>{{citation |url=http://www.bipm.org/en/publications/si-brochure/ |title=The International System of Units (SI), ''8th ed.'' |contribution-url=http://www.bipm.org/en/publications/si-brochure/table6.html |contribution=Non-SI Units Accepted for Use with the SI, and Units Based on Fundamental Constants (contd.) |publisher=International Bureau of Weights and Measures |date=2014 |location=Paris }}</ref> However, an hour of [[Coordinated Universal Time]] (UTC), used as the basis of most civil time, has lasted 3,601 seconds 27 times since 1972 in order to keep it within 0.9 seconds of [[UT1|universal time]], which is based on measurements of the [[mean solar day]] at [[0° longitude]]. The addition of these seconds accommodates the very gradual slowing of the [[Earth's rotation|rotation]] of the [[Earth]].

In modern life, the ubiquity of clocks and other timekeeping devices means that segmentation of days according to their hours is commonplace. Most forms of [[employment]], whether [[wage labor|wage]] or [[salaried]] labour, involve compensation based upon measured or expected hours worked. The fight for an [[eight-hour day]] was a part of [[labour movement]]s around the world. Informal [[rush hour]]s and [[happy hour]]s cover the times of day when commuting slows down due to congestion or alcoholic drinks being available at discounted prices. The [[hour record]] for the greatest distance travelled by a cyclist within the span of an hour is one of [[cycle sport|cycling]]'s greatest honours.