Jun 26, 2015

Set Your Clocks Back

Tuesday June 30 is the day to adjust your clocks back by one second. At 2359 Greenwich Mean Time on June 30, or 9.59am US EST on July 1, the world will experience a minute that will last 61 seconds. It is called the leap second. That is when timekeepers adjust high-precision clocks so they are in sync with earth’s rotation, which is affected by the gravitational tug of the sun and moon.

The last modification, on June 30, 2012 was disruptive for many internet servers, including Qantas’ online reservation system, which went down for several hours. The leap second is not something that needs to be added to your watch, your stove, the clock on your nightstand, etc.