[GreenKeys] Leap Second

[tony.podrasky]

GM OMs;

I watched my 4 WWVB clocks and didn't see a "60" in the seconds field.

As I (just now) glanced at one of them, and wondered "why" - I realized
that they only sync-up with the time signal at 2:00 AM. Other than that
they are free-running. They'd have to be displaying the time directly
from WWVB to show the 60 in the seconds field.

The attached JPEG is not from last December.

UE,
K2EAA - TONY
NNNN
ZCZC


On 12/28/2016 04:22 PM, Craig Sawyers wrote:
>> Leap Second inserted at
>> 23:59:59 UTC on the 31st December, due to the earth slowly slowing down.
>
> Well, no - the earth is not slowing down. On long term average the rotation speed is remarkably
> constant (slowing by less than 2 milliseconds per century). But depending on the detailed mechanics
> of how the earth's core behaves (the core-mantle boundary), and the relative positions of the moon
> and planets, leap seconds are either added *or subtracted* from time to time, every few years, in
> order to align a celestial measurement of rotation speed with UTC.
>
> On shorter averaging time, the earth's speed varies by +/-4 milliseconds.
>

-- 
There is no reason for any individual
to have a computer in their home
-Ken Olsen, President, Digital Equipment,
Convention of the World Future Society, 1977
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