LEAP SECONDS Meaning and
Definition
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Leap seconds are defined as the adjustments made to Coordinated Universal Time (UTC) in order to account for the difference between atomic time and Earth's rotation. As the Earth's rotation gradually slows down due to tidal forces, the length of a day, defined as the time it takes for Earth to complete one full rotation on its axis, becomes slightly longer.
Since the introduction of atomic clocks, which are extremely precise and rely on the vibrations of atoms, it has been discovered that Earth's rotation is not a constant rate. This discrepancy, caused by factors such as tidal friction and ice melting, is the reason for introducing leap seconds.
Leap seconds are added to or subtracted from UTC to ensure that it stays within 0.9 seconds of mean solar time, which is determined based on Earth's rotation. Typically, leap seconds are added at the end of June 30 or December 31, and their occurrence is irregular, happening approximately every 18 months on average.
The process of introducing leap seconds is determined by the International Earth Rotation and Reference Systems Service (IERS). However, leap seconds can pose challenges for certain systems and technologies that rely on precise timekeeping, such as satellite navigation and computer networks. To manage these issues, some proposals have been made to eliminate leap seconds altogether and instead rely solely on atomic time, although this raises concerns about the accuracy of astronomical observations and long-term synchronization.
Etymology of LEAP SECONDS
The term "leap seconds" combines two words: "leap" and "seconds".
1. Leap: The word "leap" comes from Middle English "lep" or "leapen", which ultimately derives from Old English "hlēapan". "Leap" refers to a sudden or forceful movement or action, often associated with jumping or bounding forward.
2. Seconds: The term "seconds" in this context refers to units of time. It comes from the Latin word "secundus", which means "following" or "second". In this case, "seconds" refer to the smaller divisions of a minute within the concept of measuring time.
When combined, "leap seconds" implies the addition or subtraction of an extra second to or from Coordinated Universal Time (UTC) to synchronize atomic time with Earth's irregular rotation, ensuring precision in timekeeping.
