diff -u old/leap-seconds.list new/leap-seconds.list --- old/leap-seconds.list 2023-07-04 05:06:27.000000000 -0700 +++ new/leap-seconds.list 2023-12-15 10:50:55.047136064 -0800 @@ -1,69 +1,71 @@ # ATOMIC TIME. -# The Coordinated Universal Time (UTC) is the reference time scale derived -# from The "Temps Atomique International" (TAI) calculated by the Bureau -# International des Poids et Mesures (BIPM) using a worldwide network of atomic -# clocks. UTC differs from TAI by an integer number of seconds; it is the basis -# of all activities in the world. +# The Coordinated Universal Time (UTC) is the reference time scale derived +# from The "Temps Atomique International" (TAI) calculated by the Bureau +# International des Poids et Mesures (BIPM) using a worldwide network of atomic +# clocks. UTC differs from TAI by an integer number of seconds; it is the basis +# of all activities in the world. # # -# ASTRONOMICAL TIME (UT1) is the time scale based on the rate of rotation of the earth. -# It is now mainly derived from Very Long Baseline Interferometry (VLBI). The various -# irregular fluctuations progressively detected in the rotation rate of the Earth lead -# in 1972 to the replacement of UT1 by UTC as the reference time scale. +# ASTRONOMICAL TIME (UT1) is the time scale based on the rate of rotation of the earth. +# It is now mainly derived from Very Long Baseline Interferometry (VLBI). The various +# irregular fluctuations progressively detected in the rotation rate of the Earth lead +# in 1972 to the replacement of UT1 by UTC as the reference time scale. # # # LEAP SECOND -# Atomic clocks are more stable than the rate of the earth rotation since the latter -# undergoes a full range of geophysical perturbations at various time scales: lunisolar +# Atomic clocks are more stable than the rate of the earth rotation since the latter +# undergoes a full range of geophysical perturbations at various time scales: lunisolar # and core-mantle torques, atmospheric and oceanic effetcs, etc. -# Leap seconds are needed to keep the two time scales in agreement, i.e. UT1-UTC smaller +# Leap seconds are needed to keep the two time scales in agreement, i.e. UT1-UTC smaller # than 0.9 second. Therefore, when necessary a "leap second" is applied to UTC. -# Since the adoption of this system in 1972 it has been necessary to add a number of seconds to UTC, -# firstly due to the initial choice of the value of the second (1/86400 mean solar day of -# the year 1820) and secondly to the general slowing down of the Earth's rotation. It is -# theorically possible to have a negative leap second (a second removed from UTC), but so far, -# all leap seconds have been positive (a second has been added to UTC). Based on what we know about +# Since the adoption of this system in 1972 it has been necessary to add a number of seconds to UTC, +# firstly due to the initial choice of the value of the second (1/86400 mean solar day of +# the year 1820) and secondly to the general slowing down of the Earth's rotation. It is +# theorically possible to have a negative leap second (a second removed from UTC), but so far, +# all leap seconds have been positive (a second has been added to UTC). Based on what we know about # the earth's rotation, it is unlikely that we will ever have a negative leap second. # # # HISTORY -# The first leap second was added on June 30, 1972. Until yhe year 2000, it was necessary in average to add a +# The first leap second was added on June 30, 1972. Until yhe year 2000, it was necessary in average to add a # leap second at a rate of 1 to 2 years. Since the year 2000 leap seconds are introduced with an # average interval of 3 to 4 years due to the acceleration of the Earth rotation speed. # # # RESPONSABILITY OF THE DECISION TO INTRODUCE A LEAP SECOND IN UTC -# The decision to introduce a leap second in UTC is the responsibility of the Earth Orientation Center of -# the International Earth Rotation and reference System Service (IERS). This center is located at Paris +# The decision to introduce a leap second in UTC is the responsibility of the Earth Orientation Center of +# the International Earth Rotation and reference System Service (IERS). This center is located at Paris # Observatory. According to international agreements, leap seconds should only be scheduled for certain dates: -# first preference is given to the end of December and June, and second preference at the end of March +# first preference is given to the end of December and June, and second preference at the end of March # and September. Since the introduction of leap seconds in 1972, only dates in June and December were used. # # Questions or comments to: # Christian Bizouard: christian.bizouard@obspm.fr # Earth orientation Center of the IERS -# Paris Observatory, France -# +# Paris Observatory, France # # # +# COPYRIGHT STATUS OF THIS FILE +# This file is in the public domain. +# # VALIDITY OF THE FILE # It is important to express the validity of the file. These next two dates are # given in units of seconds since 1900.0. # -# 1) Last update of the file. +# 1) Last update of the file. +# +# Updated through IERS Bulletin C # -# Updated through IERS Bulletin C (ftp://hpiers.obspm.fr/iers/bul/bulc/bulletinc.dat) +# The following line shows the last update of this file in NTP timestamp: # -# The following line shows the last update of this file in NTP timestamp: +#$ 3897417600 # -#$ 3897417600 -# # 2) Expiration date of the file given on a semi-annual basis: last June or last December # # File expires on 28 June 2024 # -# Expire date in NTP timestamp: +# Expire date in NTP timestamp: # #@ 3928521600 # @@ -111,6 +113,6 @@ # # A hash code has been generated to be able to verify the integrity # of this file. For more information about using this hash code, -# see the README file in the 'sources' directory. +# see . # #h 3c44ec30 4a2e0d1b 1073101d d3fd2655 23c2e293