Credit: EarthSky.org

Leap second

Tonight, just before 8 PM EDT, an extra second will be added to the clock.  This is not a new concept; the last leap second was added on June 30, 2012, and the one before that was December 31, 2008.  You may be wondering why it happens just before 8 instead of at the end of the day (midnight).  Well, technically, 8 PM EDT is the “end” of the day.  The official world clock is kept in Greenwich, England.  The time you see above has UTC written under it.  UTC is an effort for everyone to use time without the…