Every day the Earth spins a little slower than the day before, which means each day is getting longer. It’s a slight change as you might imagine, but nevertheless. It is largely caused by the oceans, which, because they lag behind the motion of the Earth, essentially drag the spinning down. The oceans also get banged around by the moon’s gravity. And by the atmosphere’s failure to keep up (it’s why prevailing winds are west to east.) Poor Earth. I’ve been told that a day took up only 20 hours in the age of the dinosaurs. I suppose that as Earth slows, it will soon need 25 and 26 hours and then someday, like our moon, maybe it won’t spin at all. It will be day on one side and night on the other every day. And boy will that play havoc with the timekeepers on this planet, whoever or whatever they might be.
I mention this because if you’ve been looking forward to this summer in the Hamptons, I am here to tell you that the scientists currently in charge are making a new adjustment in the time to further account for this slowing this summer. One minute before midnight on Tuesday, June 30, right in the middle of the Fourth of July week, time will be added. It won’t be time we have to give back like with Daylight Savings Time. It will be ours to keep. And we can thank an absolute blizzard of time keeping organizations around the world who have, in this new era where computers have to be coordinated one with the other, voted to make that happen.
Don’t get all excited. It’s one second. Exactly. Sort of.
Oh, this is such a mess. The earth actually lurches this way and that as it is slowing, so the slowing is really hard to predict. Besides the ocean tides and the winds, earthquakes and shifting global plates cause slowdowns and speeding up. Changes in mantle convection (whatever that is) affect it. The movement of the Earth’s crust relative to its core changes things. A wobbling of the earth’s angular momentum changes things. Glacial melting has an effect. Scientists think the 2004 Indian Ocean earthquake shortened each day by 2.68 microseconds, for example.
How to keep up and what to do? Other creatures don’t care, but humans do. Ptolemy measured a day in 140 A.D. by using fractions, which worked but was unhelpful. Muslim scholars in 1000 divided the day into the hours, minutes and seconds we use today. But though the concept was good, it eventually got so out of whack, in 1582 Pope Gregory XIII had to take 10 whole days out of the year, never to be heard from again.
The Industrial Age came and people began to have to coordinate time with one another more accurately. Wind-up clocks and watches increased in accuracy. In the early 20th century, people would get together and synchronize their watches if something needed to be attended to together. As a general rule, however, if you were getting together at 9:30, and you’d show up a little late it wouldn’t matter. Others would straggle in. Nobody thought they were getting stood up unless people were more than 20 minutes late.
It wasn’t until about 1960 that people began to make a really serious effort to get things exactly right on the dot around the world. We’d soon send a man to space, and soon we would be sending a man to the moon, but we were still using the time based on the solar spin, and that was not fully accurate. That didn’t matter before. But now, with computers, it did. We needed to get it exact.
Well, we tried. Nineteen-sixty, the year before we sent a man into space, was the year I started Dan’s Papers. I’d read that scientists all over the world were going to meet that year in Sevres, France for a General Conference on weights and measures to create an International System of Units solving this problem once and for all.
I wondered, in writing a story for the paper in anticipation of the conference, how they were going to get everybody to show up on time for that conference since they were meeting
to figure out the right time. But apparently they did.
What came out of this, however, was still flawed. And so, in 1967, they decided that they’d have to agree on something artificial. They found that, remarkably, there was an atom called caesium-133, that, emitted radiation at a rate which, when multiplied by 9,192,631,770 equaled 1 part in 10 to the tenth power of an astronomical second. It was utterly reliable. It did not change. And so, every country on the planet agreed that this throbbing caesium, which any scientist anywhere could find, was the cat’s pajamas. Thus was the Atomic Clock born. And the master caesium, in case anybody lost theirs, would be kept under lock and key somewhere where anybody could adjust to it.
They did know, at that time, that eventually, a second would have to be added to adjust it here and there. You might have to do that every few years. They didn’t consider
that a problem.
How wrong that turned out to be. Since the first leap second in 1972, that second got added 25 times. An outfit called the International Earth Rotation and Reference Systems Service (IERRSS) based in Frankfurt am Main, Germany oversees it. Remember how I told you the earth’s spin lurches and shudders as it adjusts to its cosmic events? Sometimes the IERRSS orders the second added two years in a row, sometimes they go six years without adding it. They have a rule. If the Earth’s time is getting to be 9/10ths of a second slower than Atomic Time, it’s time to shove in the leap second. Increasingly, this slight modification has brought disasters. An entire industry of computer programmers has sprung up to make computers talk to one another in a meaningful way exactly when IERRSS makes its move. Qantas Airways has had problems, so has Reddit, Mozilla and anybody running Linux. Some of Motorola’s software had a glitch, which caused misbehavior if there were no leap second scheduled for 256 weeks. On November 28, 2003, some devices switched to November 29 at midnight for one second, but then switched back to November 28.
IERRSS has tried desperately to make sure everybody gets the message. They only add an extra second on July 1 or December 31, and they always give six months notice. More recently, they have added a “leap second flag,” informing users the leap second is imminent. The leap second has caused problems with navigation, with timestamps, with transport, with astronomic observations. Google thinks it has successfully solved problems with the leap second by using a “leap smear” where they add a sliver of a second every day from the day the upcoming insertion is announced.
In 2001, a proposal was made by scientists in the United States to change the leap second to a leap minute, which would only have to be done every 50 years. From 2008 to today, arguments have raged for and against. At last count the US, Mexico, Japan, Italy, France and Switzerland were in favor of dumping the leap second while Canada, China, Germany and the UK were against. Nigeria, Russia and Turkey, unsure, want more study. A decision on this proposal is scheduled to be made at a World Radiocommunication Conference in Geneva, Switzerland from November 2 to 27.
Hope everybody gets there on time. Meanwhile, here in the Hamptons, enjoy that extra second while it lasts.