Why the U.S. Wants To End the Link Between Time and Sun
online.wsj.com
online.wsj.com
To rebut my own argument, I suppose one could say that noon should always be noon, regardless of how long the day is. The prevalence of daylight-saving time in the US might disagree with that though.
In other words, given a point on Earth (or any planet) and it's angle relative to the sun it orbits, when that point aligns exactly with and faces the center of the sun, it is noon.
Consider this: The way everyone refers to time is "X Units before noon", much like the 24-hour clock (no am/pm), except 0 is noon. The key is that X must be flexible, it should have no maximum, and no minimum.
edit: clarification
More complications arise from the position of the Moon. The Earth's rotation is affected by tides (stronger when the Moon is at perigee), and by the Earth's orbit around the Earth-Moon barycenter. Precession of the Earth's rotational axis is also a factor. And many more astromechanical effects also subtly affect the timing of the apparent position of the Sun.
Locking our timekeeping to the actual position of the Sun actually proves to be an intractable problem. At some point, we need abstractions to simplify and assume that that the relation to the Sun is good-enough. Famously, the Julian calendar was good-enough for millennia until the relation to the sun drifted off true by more than 10 days. So arguing over leap seconds could be seen as rather trivial.
Yes, but by allowing our clocks to go out of sync with the natural time of noon, a relationship controlled by orbits rather than clocks, this proposal would prevent that. Over time noon (highest solar position in the local sky) would drift away from noon as given by a clock.
I especially like the part where this proposal's advocates dismiss those who use a sextant to locate themselves on the ocean. I personally required this clock consistency to navigate my boat during my around-the-world sail, after my hi-tech satellite receiver expired.
This is not to argue that there's only one good argument here -- both arguments are reasonable. Unfortunately, they differ in the most basic way.
If we stick to 86,400 seconds in a day and don't allow leap-seconds, eventually daylight will happen at midnight -- either that or we will require leap-hours or even leap-days (as happened in Europe during the transition from the Julian to the Gregorian calendars).
If we continue to allow leap-seconds, all sorts of chronological record-keeping will continue to be more complex than it needs to be.
As with all truly interesting problems, there's no easy answer.
It does provide a nice discussion point.
Much longer. But the practical difficulties would appear right away, when the time "error" is still measured in seconds. As I said earlier, both sides of this issue have perfectly valid points to make.
Even to get 5 minutes out of sync, that's 300 years. A leap-hour would need thousands of years. I think it's a rather weak argument that we should worry about noon being "out of sync" for thousands of years in the future.
Not if you're on the open ocean and need to know where you are, as I was every day for four years during my around-the-world sail. In that case, "noon" had a very specific, and very important, meaning -- each second of clock error equals 1/4 nautical mile of position error (or 1,519 feet).
I emphasize that both sides of this issue have very reasonable arguments.
And actually, it can easily, very easily, be done by hand, even if we stopped adding leap seconds to UTC. Just keep a log of leap seconds and then apply them to your UTC clock.
Sticking to celestial bodies for time seems pointlessly complicated to satisfy a few edge cases that can be handled in better ways.
edit to add link http://en.wikipedia.org/wiki/Leap_second#Proposal_to_abolish...
We should always be wary of fundamental shifts in the name of "safety", "security", or worse, sloth.
The June leap second wasn't exactly problem-free...
Here's a more recent article posted here a few months ago: http://www.nytimes.com/2012/01/19/science/to-keep-or-kill-lo...
Personally, I wish people would just leave UTC alone. If you don't want to deal with leap seconds, use TAI, which was intended for such uses.
Yes, there are the obvious problems like the uncertainty of scheduling future events in UTC because the insertion of leap seconds aren't known in advance. But such things should be scheduled in TAI, anyway.
Our current way of measuring time is absurd. It starts as base 1000 with milliseconds, then base 60 with seconds and minutes, then 24 for hours, 7 for days, 4.3whatever for months or 28-31 however you want to track it.
I like that China only has one time zone for the entire country. We should all go by UTC times regardless of our geographical position. But we should also change our means of measuring time to work around whole base 10 numbers.
Your idea to go from intuitive measurements of time to abstract measurements sounds awful.
A single timezone for a 3,000 mile wide country sounds awful.
Why must time be be earth centric? Imagine how hard it must have been for Copernicus to convince everyone to use his model. Lazy programmers isn't as compelling argument, but it has similarities. http://en.m.wikipedia.org/wiki/Copernican_Revolution
Non-rhetorical questions: Does the Mars Curiousity rover use leap seconds? Does it have Martian time too?
Both the Mars Curiosity rover, and its operators, use the Mars day duration (which is 24h 39m 35.24409s), but with time measured in "normal" seconds. The JPL people directly responsible for this project even switch to a Mars clock in their personal lives.
Why must time be earth centric?
This downright scary if true - a system that's not robust and fault tolerant enough to withstand a leap second bug without putting lives in danger is going to suffer from other bugs which will put lives in danger. Since software development practices actually tend to be very paranoid when it comes to air travel, I suspect this is really a scare tactic to garner support for abolishing the leap second.
> the U.S. has proposed adding in a "leap hour" every 500 to 600 years, which also accounts for the fact that the Earth's rotation is expected to slow down even further. That would be no more disruptive than the annual switch to daylight-saving time
I'm incredulous. Daylight savings time effectively works by changing your timezone offset from UTC. UTC itself doesn't change. Daylight savings time is actually very disruptive to programs, and the solution is to just use UTC for everything. A "leap hour" would presumably require changing the UTC-equivalent itself. I guarantee you that no one will actually code for such a rare event, which will make it a big and scary flag day which will get postponed repeatedly while everyone prepares (probably by bringing a bunch of legacy programmers out of retirement if software still exists by then). The only thing appealing about this is that we'll all be long dead by then.
Earlier I proposed exactly the opposite. Never change UTC, just redefine your timezone to create an apparent leap hour. Since we already do this twice a year in many countries, it should be less of a problem.
I'm going to use this line a lot in all my future planning meetings.
Isn't this the tail wagging the Dog? Crappy programming leads the UN to redefine TIME for the whole plannet? There are few truly golobal, hitsorical markers of culture shared by human societies. Accross continents, races and millenia. Solar time is one of them.
How about: Don't fix what ain't broke. Fix that which is?
Sorry for the Rant
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Edit:
As pointed out elsewhere in the comments. This proposal was from 2005, and is apparently no longer on the table. Cooler heads appear to have prevailed.
Edited: For levity
We figured it out, and it wasn't too bad. Some good time libraries would go a long way...
I'm not sure what a correct system should be, but I know that it can't be based on the Earth, the sun, or any one galaxy. In order to have accurate time, it must be external to all of these things, like a meter stick is to an object.
The possible problem with this is that there will come a time when "3:00 pm" is in the middle of the night, the time to wake up for work will always "change".
edit: more thoughts
well, one time .. but do you !really! care about how the folks in +600 yrs measure time? I'd guess they invent some kind of "glacial-period-light-saving-time" by then...
Although I still don't fully understand why leap seconds caused such a problem - we can handle leap years and we can handle daylight savings, surely this is just another clock correction action such as these?
[1] https://en.wikipedia.org/wiki/Leap_second#Insertion_of_leap_... (see the chart at the side)
But Einstein's theory of relativity makes that impossible -- there is no absolute time. The larger reason for debates like this is because any timekeeping convention is relative.
As to a "meter stick", that's also relative, and therefore arbitrary, for the same reason -- relativity theory.
So it's not abandoning the shifting so much as putting it off into a larger interval, the leap-hour.
Today, that interval is the second. Today, we don't adjust for partial seconds; this proposal just moves the adjustment interval way out.
Perhaps somewhere in the middle like leap-minutes would be better. This would thus occur every 60-90 years.
Even if one clock were picked, observations of when the clock ticked would vary over the planet as well.
Astronomical distant fixed points are more stable over long time spans than Earthbound clocks or the Earth's rotational and orbital characteristics, and the relative displacement with regard to Earthbound distance is negligible.
Leap seconds are an abomination against nature: they make math not work on time. In chronological (atomic) time, math on time is stateless and referentially transparent. Like math. In sidereal time, it... isn't.
The general use of sidereal time is a gigantic global complexification with trivial cosmetic benefits to one specialized profession - astronomy. Unfortunately, it is also the astronomers who have been put in charge of time standardization, so the disaster will probably continue.
The right way to treat time as a programmer, if you're really serious about time, is to treat sidereal time as a display mode, like a timezone, and work internally in proper chronological time (eg, GPS time). Unfortunately the leap second system is a timezone that varies over time. But at least the complexity is isolated in the presentation layer.