I wonder if when the new year rang in if the countdown included the extra second that was added to the world clocks. Probably not and while it might not seem like much, the time change is important to our view of the world thanks to our modern technology even if we don’t realize it.
We have added 27 “leap-seconds” to the clock since the practice started in 1972. Read more about adding leap-seconds.
From (mostly) NASA: On Dec. 31, 2016, official clocks around the world added a leap second just before midnight Coordinated Universal Time — which corresponds to 6:59:59 p.m. EST. NASA missions also had to make the switch, including the Solar Dynamics Observatory, or SDO, which watches the sun 24/7.
Clocks do this to keep in sync with Earth’s rotation, which gradually slows down over time. When the dinosaurs roamed Earth, for example, our globe took only 23 hours to make a complete rotation. In space, millisecond accuracy is crucial to understanding how satellites orbit.
“SDO moves about 1.9 miles every second,” said Dean Pesnell, the project scientist for SDO at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “So does every other object in orbit near SDO. We all have to use the same time to make sure our collision avoidance programs are accurate. So we all add a leap second to the end of 2016, delaying 2017 by one second.”
The leap second is also key to making sure that SDO is in sync with the Coordinated Universal Time, or UTC, used to label each of its images. SDO has a clock that counts the number of seconds since the beginning of the mission. To convert that count to UTC requires knowing just how many leap seconds have been added to Earth-bound clocks since the mission started. When the spacecraft wants to provide a time in UTC, it calls a software module that takes into consideration both the mission’s second count and the number of leap seconds — and then returns a time in UTC.