mean solar day
noun
: the interval between successive transits of a given meridian of longitude by the mean sun
The confusion wasn't resolved for good until 1884, when an international time conference in Washington, D.C., replaced the old-fashioned solar day with the mean solar day—a legal fiction in which the daily fluctuations are averaged out, enabling us to enjoy the blessings of a uniform 24-hour day all year long.—
Jon Vara
Jon VaraExamples of mean solar day in a Sentence
Recent Examples on the Web
This is actually the mean solar day, which uses the center of the sun’s disk as a reference point and is an average of every day of the year.
—Phil Plait, Scientific American, 23 Feb. 2024
For much of the twentieth century, the second was based on a nineteenth-century standard derived from astronomical calculations: 1/86,400 of a mean solar day.
—Tom Vanderbilt, Harper’s Magazine , 13 Mar. 2023
The mean solar day, to smooth out inconsistencies, is derived from the movement of an idealized, hypothetical sun.
—Tom Vanderbilt, Harper’s Magazine , 13 Mar. 2023
In the 19th century, scientific institutions worked to define the second in astronomical terms, and in the 1940s an international agreement defined the second as 1⁄86,400 of a mean solar day.
—Jay Bennett, Popular Mechanics, 24 Mar. 2017
Phil Plait, Scientific American, 23 Feb. 2024
For much of the twentieth century, the second was based on a nineteenth-century standard derived from astronomical calculations: 1/86,400 of a mean solar day.
—Tom Vanderbilt, Harper’s Magazine , 13 Mar. 2023
The mean solar day, to smooth out inconsistencies, is derived from the movement of an idealized, hypothetical sun.
—Tom Vanderbilt, Harper’s Magazine , 13 Mar. 2023
In the 19th century, scientific institutions worked to define the second in astronomical terms, and in the 1940s an international agreement defined the second as 1⁄86,400 of a mean solar day.
—Jay Bennett, Popular Mechanics, 24 Mar. 2017
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'mean solar day.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
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“Mean solar day.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mean%20solar%20day. Accessed 26 Apr. 2024.
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