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TOPIC: leap second 2005


L

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RE: leap second 2005
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Space Timekeeping: NASA's SDO Adds Leap Second to Master Clock

On Dec. 31, 2016, official clocks around the world will add a leap second just before midnight Coordinated Universal Time - which corresponds to 6:59:59 p.m. EST. NASA missions will also have to make the switch, including the Solar Dynamics Observatory, or SDO, which watches the sun 24/7.
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L

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Leap second 2016
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New Year delayed by one second

A "leap second" will be added to this year's New Year's countdown to compensate for a slowdown in the Earth's rotation.
The extra second will occur as clocks strike midnight and a time of 23:59:60 will be recorded, delaying 2017 momentarily.

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Leap second 2015
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'Leap second' added for first time in three years

Midnight will come later tonight as for the first time in three years an extra second is added to the official time set by atomic clocks.
The "leap second" means the last minute of June will have 61 seconds in it.

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L

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RE: leap second 2005
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A Leap second is added at midnight UT, 30th June 2015

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L

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Ocean Mass Redistribution
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Title: Ocean Mass Redistribution & Corresponding Frequency Offsets for Precise Timing Applications
Authors: Scott Czopek

The relativistic timing affects of tidally redistributed ocean mass are investigated. The Sun, Moon, and Earth hurl through space, and their gravitational fields cause the tides which is a slight redistribution of ocean mass. This redistributed mass perturbs the Earth's gravitational potential affecting atomic clocks. The magnitude of this perturbation will be quantified, correcting for this effect. The predicted fractional frequency offset (10^-19) is too small to be detected, but this effect may become visible in the future.

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Date:
Leap second 2012
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NASA Explains Why Clocks Will Get an Extra Second on June 30

June 30, 2012, will be one second longer than the typical day. Rather than changing from 23:59:59 on June 30 to 00:00:00 on July 1, the official time will get an extra second at 23:59:60.
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Ed ~ NASA using Universal Time...



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L

Posts: 129912
Date:
Leap second
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LEAP SECOND JUNE 30, 2012



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L

Posts: 129912
Date:
Leap seconds
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Leap second decision 'postponed'

A decision on whether to abolish the leap second - the occasional, extra second added to the world's time - has been deferred.
Experts at the International Telecommunication Union were unable to reach a consensus, so moved the matter to a meeting in 2015.

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L

Posts: 129912
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Leap second
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Time experts debate whether to abolish the leap second

The future of the world's time is being debated at a meeting in Switzerland.
Experts at the International Telecommunication Union are deciding whether to abolish the leap second.
This is an extra second that is added every few years to keep time measured by atomic clocks in sync with the time based on the Earth's rotation.
Countries such as the United States, France and Germany want to lose the leap second, but the UK, along with China and Canada, wants it to stay.

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Posts: 129912
Date:
Earth's rotation
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First ever direct measurement of the Earth's rotation

A group with researchers at the Technical University of Munich (TUM) are the first to plot changes in the Earth's axis through laboratory measurements. To do this, they constructed the world's most stable ring laser in an underground lab and used it to determine changes in the Earth's rotation. Previously, scientists were only able to track shifts in the polar axis indirectly by monitoring fixed objects in space. Capturing the tilt of the Earth's axis and its rotational velocity is crucial for precise positional information on Earth - and thus for the accurate functioning of modern navigation systems, for instance. The scientists' work has been recognised an Exceptional Research Spotlight by the American Physical Society.
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