solar time
Americannoun
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Time based on the rotation of the Earth with respect to the Sun. Solar time units are slightly longer than sidereal units due to the continuous movement of the Earth along its orbital path. For example, by the time the Earth has completed one full rotation on its axis with respect to the fixed stars, it has also moved a short distance in its orbit and is oriented slightly differently to the Sun, so that it must turn slightly more on its axis to complete a full rotation with respect to the Sun.
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◆ The time it takes the Earth to rotate fully with respect to the Sun is called a solar day. The length of a solar day varies throughout the year due to variations in the Earth's orbital speed and other factors.
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◆ The average value of all solar days in the solar year is called a mean solar day; it is 24 hours long and by convention is measured from midnight to midnight.
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◆ A solar year is the period of time required for the Earth to make a complete orbit with respect to the Sun as measured from one vernal equinox to the next; it is equal to 365 days, 5 hours, 48 minutes, 45.51 seconds. A solar year is also called an astronomical year and a tropical year.
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◆ A solar month is one twelfth of a solar year, totaling 30 days, 10 hours, 29 minutes, 3.8 seconds.
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Compare sidereal time
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
In the summer of 1972, the International Time Bureau for the first time added a leap second to try to resolve a difference between International Atomic Time and the less-precise solar time.
From Slate ● Aug. 9, 2022
Do we just let it fall out of sync with solar time?
From The Verge ● Jul. 26, 2022
Human sleep patterns prefer to be in sync with “solar time,” he said, and standard time is closer to true solar time.
From Seattle Times ● Mar. 10, 2022
With the Industrial Revolution, clock time liberated the workday from solar time and established labor routines organized by schedules — the 9-to-5 job being the ultimate expression of this.
From Washington Post ● Mar. 10, 2017
They are, in truth, elegant and instructive astronomical toys, to say the least of them; and indicate the solar time to the accuracy of about two minutes, when the sun is pretty high.
From Notes and Queries, Number 67, February 8, 1851 A Medium of Inter-communication for Literary Men, Artists, Antiquaries, Genealogists, etc. by Bell, George
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
