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Leap Second To Be Added Dec 31, 2008
ammorris writes "Don't be the laughingstock of your friends when you shout 'Happy New Years' a second too early ... The International Earth Rotation and Reference Systems Service has announced that a leap second will be added on December 31, 2008 at 23h 59m 60s, meaning that this year will be exactly one second longer. The last leap second occurred Dec 31, 2005; they are added due to fluctuations in the rotational speed of the earth. You can read all about leap seconds on Wikipedia."
Until 2007 legal time in the US was mean solar time, and that has no leaps, so this is the first leap second for the legal US time. Officially, of course, USNO and NIST were keeping UTC, but that didn't make it legal. The difference shows up in computer time scales.
Yes, yes, that's Nix vs Hedden and it was ruling by the U.S. Supreme Court in 1893. The court ruled that in the common parlance of the time a tomato was seen to be a vegetable and not a "fruit of the vine", working from the assumption that most people at it for a main course instead of a dessert. I think that if you were going to pick up on the ridiculous nature of the case you'd focus on the reason behind the court case — that taxes needed to be paid on imported vegetables and yet not on imported fruit.
XML is like violence. If it doesn't solve the problem, use more.
Those of us in the U.S. will get to celebrate our extra second during a reasonable time of day, as it's in UTC. The local astronomy museum generally has a baloon drop at that time, so that the kids can feel they celebrated New Year's properly.
Bruce Perens.
Haven't they heard of NTP? http://en.wikipedia.org/wiki/Network_Time_Protocol
Yes, but we are talking about interfaces between a lot of different networks, each of which have their own GPS based time reference. An NTP daemon in each network talks to the GPS device, but there is no way to be sure that all the daemons will slew the time at the same rate.
http://michaelsmith.id.au
I'm sorry? Fluctuations in the rotation of the earth? You mean the earth is accelerating and breaking?
Yes, that's exactly what we mean (well, "braking" rather than "breaking"). The earth does not have a constant angular velocity. To conserve angular momentum, as the mass distribution of the earth changes (e.g. due to glacial rebound), the spinning of the earth speeds up and slows down. It also slows down a little due to tidal braking. So a "day", as measured by the rotation of the earth relative to the fixed stars, is not exactly 86400 seconds. It's generally a little more, around 86400.001 seconds at present, and it varies from day to day and from year to year. Now that civil time (UTC) is kept with atomic clocks, this is a genuine problem. Leap seconds are introduced to keep UTC close to UT1 (astronomical time).
It has nothing to do with the fact that a rotation around the sun is not exactly 365.25 rotations around our own axis? hmm...
That's right. Leap seconds have nothing whatsoever to do with that. They don't affect the calendar. That's what leap days are for. Leap days keep the calendar in sync with the seasons (by setting the average calendar year length to 365.2425 days, very close to the vernal equinox year which is currently 365.242374 days).
The UTC second 60 gets added at midnight only at those locations where UTC == local time, i.e. places like England.
For us in the rest of Europe, the leap second will be added an hour after local midnight, i.e. at 01:00:60 CET.
Terje
"almost all programming can be viewed as an exercise in caching"