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http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2015/06/29/june-will-end-with-a-rare-61-second-minute/
Partial Snip:
We’ll need to wait for July just a shade longer, as the world’s timekeepers have added a leap second June 30 – to officially keep Earth and our precise, atomic clocks in sync.
On Tuesday a leap second will be added to the world’s clocks at 23 hours, 59 minutes and 59 seconds Coordinated Universal Time (UTC, formerly called Greenwich Mean Time). For the Eastern United States, this translates 7:59:59 p.m. Eastern Daylight Time, which is when the extra second will be inserted at the U.S. Naval Observatory’s Master Clock Facility.
Normally, the world’s timepieces go from 23:59:59 to 00:00:00 – the start of the next day. With the leap second insertion, UTC will move from 23:59:59 to 23:59:60 to 00:00:00. Welcome to July.
The rate of Earth’s rotation has slowed an average of about 1.5 to 2 milliseconds per day, per century – mostly due to tidal forces in the Earth-moon system, said Geoff Chester, public affairs astronomer at the Naval Observatory.
More: http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2015/06/29/june-will-end-with-a-rare-61-second-minute/
Partial Snip:
We’ll need to wait for July just a shade longer, as the world’s timekeepers have added a leap second June 30 – to officially keep Earth and our precise, atomic clocks in sync.
On Tuesday a leap second will be added to the world’s clocks at 23 hours, 59 minutes and 59 seconds Coordinated Universal Time (UTC, formerly called Greenwich Mean Time). For the Eastern United States, this translates 7:59:59 p.m. Eastern Daylight Time, which is when the extra second will be inserted at the U.S. Naval Observatory’s Master Clock Facility.
Normally, the world’s timepieces go from 23:59:59 to 00:00:00 – the start of the next day. With the leap second insertion, UTC will move from 23:59:59 to 23:59:60 to 00:00:00. Welcome to July.
The rate of Earth’s rotation has slowed an average of about 1.5 to 2 milliseconds per day, per century – mostly due to tidal forces in the Earth-moon system, said Geoff Chester, public affairs astronomer at the Naval Observatory.
More: http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2015/06/29/june-will-end-with-a-rare-61-second-minute/