Wait a sec for leap into 2006

Sunday, December 25, 2005

Get ready for a minute with 61 seconds. Scientists are delaying the start of 2006 by the first "leap second" in seven years, a timing tweak meant to make up for changes in the Earth's rotation.
The adjustment will be carried out by sticking an extra second into atomic clocks worldwide at the stroke of midnight Coordinated Universal Time, the widely adopted international standard, the U.S. National Institute of Standards and Technology said this week.
"Enjoy New Year's Eve a second longer," the institute said in an explanatory notice. "You can toot your horn an extra second this year."
Coordinated Universal Time coincides with winter time in London. On the U.S. East Coast, the extra second occurs just before 7 p.m. on New Year's Eve. Atomic clocks at that moment will read 23:59:60 before rolling over to all zeros.
A leap second is added to keep uniform timekeeping within 0.9 second of the Earth's rotational time, which can speed up or slow down because of many factors, including ocean tides. The first leap second was added on June 30, 1972, according to NIST, an arm of the U.S. Commerce Department.
High-speed communications systems among other modern technologies require precise time measurements.
Since 1999 until recently, the two time standards have been in close enough synch to escape any need to add a leap second, NIST said.
Although it is possible to have a negative leap second -- that is, a second deducted from Coordinated Universal Time -- so far all have been add-ons, reflecting the Earth's general slowing trend due to tidal breaking.
Deciding when to introduce a leap second is the responsibility of the International Earth Rotation and Reference Systems Service, a standards-setting body. Under an international pact, the preference for leap seconds is December 31 or June 30.

2005年延长1秒钟 快乐新年迟到1秒
2005-12-26
　　根据美国国家标准及技术协会的估计，在格林威治子午线以西地区，今年的十二月三十一日不是只有二十四小时，而是二十四小时零一秒。
　　由于地球过去七年自转的速度变慢了，因此今年就要加上一个闰秒，以配合地球自转的时间。美国与世界各地精确计时的原子钟，在今年的十二月三十一日，都会加上一个闰秒。
　　亚洲与中东地区的居民应该比较快乐些，因为这一个闰秒是加在明年元旦，这一天不用上班上课。
　　美国国家标准暨技术协会指出，加上一个闰秒的过程将从格林威治时间十二月三十一日二十三时五十九分五十九秒开始。校正世界各地标准时间的原子钟，将会显示二十三时五十九分六十秒，然後才是正常的格林威治时间零时零分零秒，这也就是二○○六年一月一日来临的时刻。