http://phys.org/news/2013-09-world-timek...ing leap second

If you aren't aware of the leap second it is a way of keeping our Earth centered days in sync with the universal time kept by atomic clocks. The problem is that the rotation of the Earth is slowing down. That creates problems with keeping accurate time over long periods of time if you use the Sun as a time keeper. So UTC time was invented. UTC is based on very accurate atomic clocks. Over a period of about 100 years there will be a slippage of about 15 seconds. So they invented the leap second to enable the clocks of the world to be adjusted so that they will stay in step. They add one second whenever the time drifts apart. That usually occurs at midnight on June 30, or Dec. 31. Now they are getting to worrying about the fact that when you adjust all of the clocks you may upset a lot of distributed systems that all have to be adjusted together and have to be in very close sync. So some people want to do away with the leap second and others don't want to.

The first thing that comes to my mind is: If they throw away the leap seconds how do they keep the calendar in sync with the clocks?

Bill Gill

In sync with what Bill?

All you really have is day/night and seasons at a practical level and countries already do daylight saving so if the drift gets to bad you could just adjust like a one off daylight saving.

The deeper question for me is why would you want to lock to drifts to a second when you have no real idea what that lock is against in any real sense.

So I guess I am with the no clock fiddlers unless you can give me a good reason to synchronize clocks.

Well, I guess that is the point of contention among the worlds clock keepers. Essentially people live by the solar day. We (mostly) get up in the morning, work during the daylight, and go to bed at night. Some people want our clocks to match that cycle. Others aren't worried as much about that as they are about keeping systems all over the world very precisely synchronized. And having to go in and tell all those systems that it is time to change is problematic. If they don't all get the word simultaneously then there could be confusion and loss of data. So I guess it is just that some people want to keep the old way, make the clock match the Sun, and some want the new way. Let the Sun go hang.

Now there are some problems with this. I have been working on a calendar program for my computer for the past 6 months. Some calendars are very much based on solar and lunar events such as solstices, equinoxes and moon phases. If we start letting the time drift it might make some problems in calculating the times. Of course there are already problems with that. Calculating those events requires correction for the variability in the length of the day over time. And the drift isn't linear, it is mostly random. It does drift in one direction all the time, but there are random variations because of changes in, among many other things, the shape of the Earth due to tectonic events.

Bill Gill