Three, Two, One ... One. Happy New Year!!

As time ticks down this New Year's Eve, a rare phenomenon will take place - celebrants must wait one more second to begin their 2006 revelry. This is because a leap second will occur on Dec. 31, 2005, at 23:59:60, adding an extra second to the clock.

Leap seconds are one-second adjustments to Coordinated Universal Time, the widely adopted reference for civil time. In response to the July announcement of the upcoming leap second by the International Earth Rotation Service, Analytical Graphics, Inc. (AGI) initiated a review of its software for land, sea, air, and space analysis to ensure the highest level of accuracy for its users in the national security and space communities. As such, all STK software versions 6.2 and higher - including its recent version 7 release - account for the leap second.

There are two opportunities to insert a leap second each year, on Dec. 31 and June 31. The term "leap second" can also mean the deletion of a second, however, only positive leap seconds have ever been inserted. The most recent was added on Dec. 31, 1998. Although AGI software products operate internally on continuous time scales not affected by leap seconds, some software updates were necessary for proper transformation between internal time scales and the UTC time scale (the default time scale for input and output of dates). Users can find a document detailing best practices for updating AGI products to incorporate the leap second at

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