Beta

Slashdot: News for Nerds

×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

The Future of Time: UTC and the Leap Second

CmdrTaco posted about 3 years ago | from the good-bye-gold-standard dept.

News 235

rlseaman writes "UTC ("Coordinated Universal Time") is very close to being redefined to no longer track Earth rotation. Clocks everywhere — on your wall, wrist, phone or computer — would stop keeping Solar time. 'American Scientist' says: 'Before atomic timekeeping, clocks were set to the skies. But starting in 1972, radio signals began broadcasting atomic seconds and leap seconds have occasionally been added to that stream of atomic seconds to keep the signals synchronized with the actual rotation of Earth. Such adjustments were considered necessary because Earth's rotation is less regular than atomic timekeeping. In January 2012, a United Nations-affiliated organization could permanently break this link by redefining Coordinated Universal Time.'"

cancel ×

235 comments

Copypasta (2, Insightful)

Gothmolly (148874) | about 3 years ago | (#36598764)

Taco, all you did is quote the article summary. I can spin up an RSS reader to do that.

Re:Copypasta (2)

machxor (1226486) | about 3 years ago | (#36598790)

And the article isn't even available. I want my click back :-)

Re:Copypasta (2, Funny)

Anonymous Coward | about 3 years ago | (#36598812)

Are you sure he didn't replace himself with a shell script?
That's what I would do if it was my site :-)

Re:Copypasta (5, Funny)

bennomatic (691188) | about 3 years ago | (#36598870)

A taco shell script? Inconceivable!

Re:Copypasta (1)

dainbug (678555) | about 3 years ago | (#36598982)

I wish I had mod points for you!

Re:Copypasta (1)

bennomatic (691188) | about 3 years ago | (#36599488)

Thank you, thank you; I'll be here all week!

Re:Copypasta (0)

Anonymous Coward | about 3 years ago | (#36600836)

Try the fish.

Re:Copypasta (1)

MirthScout (247854) | about 3 years ago | (#36599026)

I'm getting hungry.

Re:Copypasta (1)

2names (531755) | about 3 years ago | (#36599588)

Well played, benno...well played, indeed.

Re:Copypasta (4, Insightful)

csnydermvpsoft (596111) | about 3 years ago | (#36598864)

Do you normally read all American Scientist articles? I don't, so I appreciate this article being brought to my attention (though I'm not planning to pay to read it). The purpose of /. is to point out interesting information so that we can read it further. The summary is supposed to be an accurate summary of the article; since an abstract is already provided, why shouldn't it be used?

Re:Copypasta (2)

93 Escort Wagon (326346) | about 3 years ago | (#36599808)

The summary is supposed to be an accurate summary of the article; since an abstract is already provided, why shouldn't it be used?

Because we can't read the actual article unless we're a paid subscriber to the journal/magazine - that's why.

Re:Copypasta (1, Informative)

csnydermvpsoft (596111) | about 3 years ago | (#36599862)

Because we can't read the actual article unless we're a paid subscriber to the journal/magazine - that's why.

As others have mentioned, it is available - follow the first link and look for a link to the article PDF in the right sidebar. I agree that the /. summary could've mentioned that.

Re:Copypasta (2)

Capt James McCarthy (860294) | about 3 years ago | (#36598920)

Taco, all you did is quote the article summary. I can spin up an RSS reader to do that.

So then why are you on /.? Don't bitch, go sign up for your feed and you've fixed _your_ problem.

Re:Copypasta (1)

MachineShedFred (621896) | about 3 years ago | (#36599048)

Yeah, and then you can't even RTFA if you want to, because it's behind a paywall.

Well done, Taco. Well done.

Membership Required (1)

nemasu (1766860) | about 3 years ago | (#36598808)

The ONE time I try to RTFA, I CAN'T?? Unbelievable. "The content you've requested is available without charge only to active Sigma Xi members and affiliates."

Re:Membership Required (4, Informative)

Tx (96709) | about 3 years ago | (#36598956)

The Download: PDF Only link on the right hand side of the first linked page (Cornell) gives you a PDF of the same article [arxiv.org] .

Re:Membership Required (1)

nemasu (1766860) | about 3 years ago | (#36599018)

Cool. Thanks!

Re:Membership Required (1)

Grishnakh (216268) | about 3 years ago | (#36599268)

Yeah, no kidding. Here I am thinking, "maybe I should stop my regular pattern of opening my big mouth in the comments without bothering to read the article first, and go RTFA first!" And then I find that I can't! What a crock.

Why not call it GMT? (1)

rich_hudds (1360617) | about 3 years ago | (#36598814)

I know there is a difference but they could have just redefined GMT rather than coming up with another name altogether. UTC doesn't even work as an acronym, it's just some French plot to wipe Greenwich from history.

Re:Why not call it GMT? (0)

Anonymous Coward | about 3 years ago | (#36599122)

Because GMT has an astronomical meaning. The new definition of UTC would simply make it something like "number of clicks since T_0". GMT would then be defined from UTC is such a way that GMT maintained its original meaning.

It's been done. (5, Informative)

msauve (701917) | about 3 years ago | (#36599742)

It's called TAI [wikipedia.org] . Redefining UTC is just plain stupid - it was created to track sol. If someone doesn't like the fact that doing so requires occasional adjustments, then they chose to use the wrong time scale. Those who use UTC as intended shouldn't have to live with the problems which will result if it is unlocked from solar time, just to keep those who made a poor choice happy.

(GMT hasn't been in use for a long time, although most people use the term interchangeably with UTC).

Re:It's been done. (1)

thsths (31372) | about 3 years ago | (#36600808)

> GMT hasn't been in use for a long time

Au contraire - it is the official time of GB and Ireland. As such it is subject to Daylight Saving Time (called BST), and very different from UTC. So using GMT could cause never ending confusion...

Funny enough gruve.com made exactly that mistake: it does not support DST for GMT. And support is unable to help.

Anyway, the C in UTC stands for coordinated, so I cannot see how they could redefine it without turning it into a lie.

Mayan Calendar (1)

AwooOOoo (1081997) | about 3 years ago | (#36598822)

I expect this is the trouble the Mayan's ran into with their calendar ending in 2012 and thus the leap seconds leading to the end of the world next year.

Oh no! (0)

Anonymous Coward | about 3 years ago | (#36598834)

If time is kept by atomic clocks that's not synchronized with the Earth's rotation then one day, Midnight could be when the Sun is high in the sky!

We can't have this! Think of the children! They'll learn that Noon is when the Sun is high in the sky only to see it pitch black!

We need to stop this insanity now!

Re:Oh no! (2)

PPH (736903) | about 3 years ago | (#36598888)

We can't have this! Think of the children! They'll learn that Noon is when the Sun is high in the sky only to see it pitch black!

By then, children will no longer venture outside. Thanks to Facebook. And Slashdot.

Think of the Humans (1)

bill_mcgonigle (4333) | about 3 years ago | (#36599014)

If time is kept by atomic clocks that's not synchronized with the Earth's rotation then one day, Midnight could be when the Sun is high in the sky!

We can't have this! Think of the children! They'll learn that Noon is when the Sun is high in the sky only to see it pitch black!

You're right, even if accidentally. Time keeping that is meaningful for most humans is much more important than time that is meaningful for just a handful of computer operators and nuclear scientists. They need to stop being so ego-centric.

Re:Think of the Humans (2)

TheRaven64 (641858) | about 3 years ago | (#36599332)

Yes, think of the humans. The ones wasting millions of dollars a year keeping databases up to date with the leap seconds which, unlike leap years, are not algorithmically predictable, and ensuring that all critical time-dependent software is properly tested and verified.

Leap seconds happen at most twice a year, and typically once every few years. If they happen at their maximum permitted frequency, then in 1000 years the difference between midday and noon will be 2000 seconds, or just over half an hour. In other words, for me the drift due to not living exactly on a time zone boundary line will still be more than the difference due to ignoring leap seconds.

Note that this is a wildly pessimistic prediction. It's more likely that we will drift about 5 minutes over the next thousand years. In 1,000 years, if the position of the sun over Greenwich at 12:00 is still of importance to a significant fraction of the human race, then I'll be very surprised.

Re:Think of the Humans (3, Interesting)

zill (1690130) | about 3 years ago | (#36600004)

Leap seconds happen at most twice a year, and typically once every few years. If they happen at their maximum permitted frequency, then in 1000 years the difference between midday and noon will be 2000 seconds, or just over half an hour. In other words, for me the drift due to not living exactly on a time zone boundary line will still be more than the difference due to ignoring leap seconds.

It's impossible to predict ahead of time how many leap seconds are necessary. Just because it's been historically ±1 second doesn't mean it will always stay like that in the future. As T increases quadratically, we will eventually see leap minutes and leap hours.

That's not even taking into account of the fact that doomsday style meteor impacts could necessitate adding or removing a whole day every year. That pretty much breaks half of the time-related code that I've written.

Note that this is a wildly pessimistic prediction. It's more likely that we will drift about 5 minutes over the next thousand years. In 1,000 years, if the position of the sun over Greenwich at 12:00 is still of importance to a significant fraction of the human race, then I'll be very surprised.

It's not pessimistic at all. T between the 1000AD and 2000AD was 1600 seconds.

In fact, I'd say that's a very optimistic prediction, since T is monotonically increasing, T for the next 1000 years will be much larger than T for the previous 1000 years.

Re:Think of the Humans (1)

TheCycoONE (913189) | about 3 years ago | (#36599406)

But only the handful of computer operators and nuclear scientists use UTC; the rest can use UT1 or more accurately continue to use EST, or MST, or GMT, which will likely track UT1 which will continue to take into account leap seconds.

From the article:

Reprogramming of operational software that already presumes UT1 and UTC are always within a second of
each other would be required, and some space operations and astronomical applications would need to
distinguish between the UTC without leap seconds and UT1.

Re:Oh no! (1)

camperdave (969942) | about 3 years ago | (#36599842)

But noon hasn't been when the sun is highest in the sky for generations.

PDF version (5, Informative)

KenAndCorey (581410) | about 3 years ago | (#36598840)

Here's the full PDF version [arxiv.org] .

Re:PDF version (0)

Anonymous Coward | about 3 years ago | (#36599816)

Thank you kind sir(s).

GMT, PST.... (0, Flamebait)

RdeCourtney (2034578) | about 3 years ago | (#36598848)

So Greenwich Mean Time is GMT, Pacific Standard Time is PST does that mean that Coordinated Universal Time would be CUnT?

Re:GMT, PST.... (0)

Anonymous Coward | about 3 years ago | (#36599286)

I see no 'n' there...

Metric Time (1, Interesting)

Normal Dan (1053064) | about 3 years ago | (#36598856)

As long as we're redoing time I say we convert it to the metric system. This was hard to do before because we kept trying to keep time in line with the rotation/orbit of the earth. But if all that's going out the window, let's just divide everything up into units of 10 and be done with it.

base-12 >> base-10 (2)

bill_mcgonigle (4333) | about 3 years ago | (#36598988)

10 is an arbitrary base and works poorly for time. Earth time works very well in Base-12, which is what we have now.

If you want to think of the children, the Egyptians and Babylonians taught their children to count on the knuckles of their four non-thumb fingers. The 10-finger-number system is just an unfortunate thing that came along with arabic numerals, which are very useful.

I saw we adopt something from the UNICODE set to mean eleven and twelve. Say, they're not 1-teen and 2-teen, are they?

Re:base-12 base-10 (1)

aardvarkjoe (156801) | about 3 years ago | (#36599292)

10 is an arbitrary base and works poorly for time. Earth time works very well in Base-12, which is what we have now.

Why would it work more poorly for time than for distance or anything else?

Although one thing I do find amusing about the whole metric vs. traditional units is that one of the primary arguments for moving to metric units is that it makes conversion between units easier. The only problem is that about the only units that I convert between on a regular basis is ... time, which is not handled in base 10. (I do think that we'd be better off switching to metric, but ease of unit conversion is a pretty minor point).

Re:base-12 base-10 (2)

residieu (577863) | about 3 years ago | (#36600064)

The ease of conversion is more when converting compound units. A newton is a kg m/second^2. A Joule is a Newton applied over a meter = kg m^2/second^2. A Watt is a Joule used every second = kg m^2/second^3.

American units have the pound, which is a slug foot /second^2. Except no one uses the slug, so it has to be pound-force = pound mass * 32.2 ft/second ^2. Energy? Sometimes they use foot-pound which is easy enough, but other areas we use kilowatt-hour, or BTU (defined from the heat capacity of water). Power is defined in either kilowatts or horsepower (defined via watts). Air conditioners are rated by BTU (actually BTU/hour, but that's not the way they're advertised).

Re:base-12 base-10 (1)

aardvarkjoe (156801) | about 3 years ago | (#36600326)

The ease of conversion is more when converting compound units. A newton is a kg m/second^2. A Joule is a Newton applied over a meter = kg m^2/second^2. A Watt is a Joule used every second = kg m^2/second^3

Oh, I understand the principle. The thing is that I haven't had any reason to do those types of unit conversions since I got out of school, and I'm willing to bet that goes for almost everyone else. Those who do (scientists and engineers, mostly), ought to be using metric in their work, no argument there, but the customary units that are used in other contexts doesn't matter all that much.

I am aware that in some fields of engineering they still use traditional units. And yes, that's beyond stupid.

Re:base-12 base-10 (1)

w_dragon (1802458) | about 3 years ago | (#36600514)

Hate to tell you, but metric is the 'customary' system pretty much everywhere but the USA and Libya.

Re:base-12 base-10 (0)

Anonymous Coward | about 3 years ago | (#36599712)

Say, they're not 1-teen and 2-teen, are they?

In Chinese, basically they are.

Re:base-12 base-10 (1)

Twinbee (767046) | about 3 years ago | (#36599876)

I'm one of the biggest advocates for the base 12 (or 16) number system, but if we have to keep with base 10 for now, then it would obviously make sense to have time as base 10 also to keep things standard.

Re:base-12 base-10 (1)

nschubach (922175) | about 3 years ago | (#36600184)

I agree, 10 doesn't work so well, but 1 works great for time if you consider one rotation of Earth. At .500000 Greenwich would be through one half rotation. If you told someone to meet up in 2 and a half days you know how many time units it is already... (hint: 2.5)

I actually wrote a JavaScript clock for my desktop that uses UTC time converted to decimal for Earth rotations.

I will disagree that 12 is a reasonable number though. Sixteen I can see, but twelve does not evenly halve out to a round number. 12/2 = 6/2 = 3/2 = 1.5

Re:base-12 base-10 (1)

Phleg (523632) | about 3 years ago | (#36600478)

Being a power of two is not of as much use as is being an even multiple of 2, 3, 4, and 6, giving you many possible factors to divide evenly by.

Re:base-12 base-10 (1)

nschubach (922175) | about 3 years ago | (#36600794)

But what's the point of dividing a day into three or six parts? I can see 2 and 4 (half and quarter day) but I don't know many people who think in third or sixth of days.

Re:base-12 base-10 (0)

Anonymous Coward | about 3 years ago | (#36600938)

People deal with money every day, decimals are not out of the ordinary or overly complex to divide:
1/2 = $.50
1/4 (Quarter) = $.25 (Opposed to one quarter hour which is now 15 minutes ... that's just odd in a "base 10 world." 1/4 == .25)

Re:base-12 base-10 (0)

Anonymous Coward | about 3 years ago | (#36600916)

16 is perfect, because it fits in nicely with Time Cube theory: Cubed Earth has 4 Days within simultaneous rotation!

Re:base-12 base-10 (1)

transami (202700) | about 3 years ago | (#36600366)

"We know that the human race is not sufficiently advanced because they have not yet converted to a base-6 system of enumeration."

Re:base-12 base-10 (1)

Normal Dan (1053064) | about 3 years ago | (#36600616)

Now that you mention it, I've always considered base-2 or 16 to be rather useful for dealing with computers. As long as we're rearranging things, let's pick a base and put everything in it. I say 16. We can learn to count on our non-thumb knuckles and toes. We'll be a race of super geniuses, etc.

Re:Metric Time (1)

chuckugly (2030942) | about 3 years ago | (#36599250)

Better to stop using decimal and convert everything to base 12. It's a wonderfully evenly divisible number.

Re:Metric Time (5, Informative)

gstrickler (920733) | about 3 years ago | (#36600598)

The metric system is originally based upon an earth derived measurement called the meter. 1m ~ 1/10,000 the distance from the equator to the poles, 1g = the weight of 1cc of pure water at STP, etc. That all the measurements are base 10 is not what makes it "metric", it's that they're derived from the (originally) earth centric meter. Our time system is also derived from earth centric measurements, called day and year.

Base 10 time would be a huge adjustment for society. While using a 100,000 "MetSec" day and a 100 "MetSec" "MetMin" would produce units fairly close to the existing second and minute measurements, a "MetHour" would be much longer or much shorter than an hour, either 14.4 minutes (100 MetHours/day), or 2.4 hours (10 MetHours/day). And that doesn't do anything to address the leap second issue, nor does it alter the ~ 365.25 MSD year.

The bottom line is that as long as we maintain the concept of a day and year and all the associated stuff (seasons, equinoxes, solstices, etc.), all of which are critical to agriculture and survival, there has been no system of time keeping proposed that is significantly better than what we have. The universe is not going to arbitrarily adapt it's cycles to make it easy for our minds and computers to keep track of time.

And that's without considering relativistic time dilation. While most people never have to worry about time dilation effects, the atomic clocks that create UT1 and GPS satellites have to compensate for relativistic differences caused by differences in local gravity and speed, both of which are affected by altitude.

Perhaps Douglas Adams said it best, "Time is an illusion, lunchtime doubly so."

Captain's Log.... (1, Offtopic)

MoldySpore (1280634) | about 3 years ago | (#36598876)

<Kirk Voice> Stardate.....65500...My...solar TIME, clock...seems to be...malFUNCTIONing...perhaps Coordinated....UniversalTime...is finally...UPON us. <\Kirk Voice>

I don't care about CUT (0)

Anonymous Coward | about 3 years ago | (#36598900)

I really don't care about coordinated universal time or time that has to be regular. I care about the real rotation of the Earth and the Earth's orbit around the sun. So, what we see in the sky is always gonna matter most to me and not what humans create :) It doesn't matter to me if it's irregular.

Re:I don't care about CUT (1)

Guy Harris (3803) | about 3 years ago | (#36599080)

I really don't care about coordinated universal time or time that has to be regular. I care about the real rotation of the Earth and the Earth's orbit around the sun. So, what we see in the sky is always gonna matter most to me and not what humans create :) It doesn't matter to me if it's irregular.

And you're going to notice a small number of seconds difference?

Relativistic Reference Frames? (3, Interesting)

bill_mcgonigle (4333) | about 3 years ago | (#36598940)

In 2012, a new definition of time that is only relative to the Earth's reference frame falls short.

Re:Relativistic Reference Frames? (0)

Anonymous Coward | about 3 years ago | (#36599314)

Which frame would you prefer?
You can only pick one.

It's about time (1, Insightful)

Dolphinzilla (199489) | about 3 years ago | (#36598952)

Seriously this has been an issue for along time - GPS time does not include leap seconds and I am tired of having to write software that let's user adjust for the variable amount of leap seconds - nobody really cares if the earths rotation is synchronized with " UTC"

Re:It's about time (5, Informative)

gdshaw (1015745) | about 3 years ago | (#36599120)

Seriously this has been an issue for along time - GPS time does not include leap seconds and I am tired of having to write software that let's user adjust for the variable amount of leap seconds - nobody really cares if the earths rotation is synchronized with " UTC"

Those who doesn't care about synchronisation already have the option to use TAI. They should use that instead of redefining UTC.

Re:It's about time (0)

Anonymous Coward | about 3 years ago | (#36600614)

No, we don't have this option. See CCTF/09-27 [bipm.org] which was submitted to ITU-R SG7A in 2007-09 and which said
                The CCTF realizes that some misunderstanding exists regarding
                the scope of application of the various time scales. It
                stresses that TAI is the uniform time scale underlying UTC,
                and that it should not be considered as an alternative time
                reference.

Re:It's about time (3)

kaiser423 (828989) | about 3 years ago | (#36599542)

?

Leap seconds is already included in the GPS stream. So, with the GPS stream you get GPS time, and UTC time. Most GPS receivers output GPS time until they've received the NAV or other message that has the leapseconds count in it, and then correctly updates to UTC time. It seems like a simple, solved problem. Am I missing something with respect to your leap year stuff?

Re:It's about time (1)

kaiser423 (828989) | about 3 years ago | (#36599592)

err, leap year in the last sentence should be *leap second*

Re:It's about time (0)

Anonymous Coward | about 3 years ago | (#36599764)

Yeah, now all you will have to do is write software to make all those same adjustments between UTC and local time. That will be so much easier for sure, definitely...

Re:It's about time (2)

msauve (701917) | about 3 years ago | (#36599812)

" I am tired of having to write software that let's user adjust for the variable amount of leap seconds"

You're doing it wrong.

No it's pointless. (1)

pavon (30274) | about 3 years ago | (#36600312)

Time conversion is complicated because the universe is complicated. The time it takes to orbit around the sun isn't a nice even multiple of the amount of time it takes for the earth rotate, or any subdivision of that day. It isn't even constant as the drag of the moon and the shifting of the tectonic plates all affect the rate at which the earth rotates.

Over time we have developed many different ways of measuring time, each of which have their own advantages and disadvantages depending on the application. TIA and GPS time are both useful for applications where having a continuous scale is more important that exact accuracy. UTC was devised to keep the time in sync with the motion of the earth. That is it's purpose. By removing the leaps seconds, you remove any advantage it provides over TIA, and it becomes a redundant pointless time system.

Furthermore, it won't make software easier, because it will still have to account for the times in the past where leap seconds were inserted. More so, all local times are based on UTC and they add their own discontinuities, which have to be tracked using databases, so it's not like you are removing the need to maintain such databases; you just eliminated one entry in it.

As Einstein said, "Everything should be made as simple as possible, but no simpler". This is a case of oversimplifying for no good reason.

Re:It's about time (0)

Anonymous Coward | about 3 years ago | (#36600406)

... nobody really cares if the earths rotation is synchronized with " UTC"

Wrong. Astronomers care deeply. And "average" people will start to care when the sun is shining at midnight (and they don't live above the Arctic Circle).

The point is? (1)

Nethemas the Great (909900) | about 3 years ago | (#36599002)

Even if we don't manage to exterminate ourselves in the interim we won't be getting off this rock in any meaningful way for several more generations on even the most optimistic forecasts. What is the point of divorcing UTC from humanity's relationship to our day to day on earth?

Re:The point is? (1)

tom17 (659054) | about 3 years ago | (#36599150)

So what we need to do is leave it as is for now and when we start real space travel, we can have Space Time.

Space Time, a fusion between the concepts of space and time, brought forward into one four dimensional continuum. Yeah man. I love that shit right there.

While we're at it (4, Insightful)

vegge (184413) | about 3 years ago | (#36599006)

... could we also get rid of Daylight Savings Time?

And time zones! (0)

Anonymous Coward | about 3 years ago | (#36599190)

The world is a lot smaller place than a hundred years ago. Time zones especially when combined with daylight savings time add nothing to our society and make for a royal PITA. The old term midnight is the only issue. Who cares if you work from 01:00 to 09:00 or 08:00 to 17:00.

Re:And time zones! (0)

Anonymous Coward | about 3 years ago | (#36599482)

Exactly, so why should I have to change my watch for a farmer?

Re:While we're at it (1)

EvanED (569694) | about 3 years ago | (#36599376)

As someone who lives at a crappy place in terms of daylight, I have a better idea: make DST year-round. Gets rid of the clock change while still having the benefits (not getting dark at 4:30pm for as much of the year) of DST.

Re:While we're at it (2)

msauve (701917) | about 3 years ago | (#36599856)

Why don't you just work, say, 8-4 instead of 9-5? It's not like DST really saves time, you know.

Re:While we're at it (0)

Anonymous Coward | about 3 years ago | (#36600020)

As someone who lives at a crappy place in terms of daylight, I have a better idea: make DST year-round. Gets rid of the clock change while still having the benefits (not getting dark at 4:30pm for as much of the year) of DST.

Or maybe we could split the difference (moving ahead or back 1/2 hour to the middle between the two endpoints) and keep that year round. Then we'd have half of our previous daylight savings to please people that like it for environmental or whatever reasons, and not shift times around for people like me who don't readjust very well or just plain hate daylight savings.

Re:While we're at it (1)

Pope (17780) | about 3 years ago | (#36599404)

No thanks. PS. it's Daylight Saving Time, there's no "s".

Re:While we're at it (1)

vegge (184413) | about 3 years ago | (#36600244)

Thank you for the correction.

Re:While we're at it (1)

compro01 (777531) | about 3 years ago | (#36599560)

Of course not. Studies utilizing questionable methodologies say it saves energy.

Besides, not having to run in circles every time Congress decides to twiddle the dates would put people out of work and that's the last thing we need in this economy.

Re:While we're at it (2)

epine (68316) | about 3 years ago | (#36600674)

Besides, not having to run in circles every time Congress decides to twiddle the dates would put people out of work and that's the last thing we need in this economy.

Congratulations, you've just won a contract valued at 4 weeks of "running in circles" paying $100 per hour next time Congress twiddles the dates. This will spare you having to take out a second mortgage for the expanded deck and hot tub. Hope your spouse is the patient type and accepts that you'll be in good coin any day now for the big splurge, where any day now is some four digit year beginning most likely beginning with 2.

A watched politician never twiddles the desired knob.

This is great! (0)

Anonymous Coward | about 3 years ago | (#36599028)

Leap seconds are a disaster. Rare and seemingly unimportant enough that software don't handle them, important enough to break stuff.

From now on, a UTC "day" will always correspond to exactly 86400 seconds. To correct for the slowing of earth, time zones can simply be adjusted by an hour, every time we'd otherwise have had 3600 leap seconds. (This will happen the first time around year 2500.)

How long is year anyway? (3, Informative)

scorp1us (235526) | about 3 years ago | (#36599042)

We say 365 days.
We observe 365.25.
The tropical year (equinoxes+solstices) is closer to 365 solar days, 5 hours 49 minutes 19 seconds
The sidereal year is 1.0000385 tropical years (365.256363004 ) (20m24.5128s longer than tropical year)

So may times...

Re:How long is year anyway? (1)

Anonymous Coward | about 3 years ago | (#36599540)

We say 365 days.
We observe 365.25.

As long as we're being pedantic, it's actually 365.2425 under the Gregorian calendar. Years ending in 00 are only leap years if divisible by 400.

Aw, jeezus (2)

jra (5600) | about 3 years ago | (#36599064)

This has been *progressing*?

This is possibly the stupidest idea in history. Their stated goal: taking complexity out of time handling code -- *cannot happen*: it will *still* have to account for all the years we did this.

And it will break *lots* of stuff.

Re:Aw, jeezus (0)

Anonymous Coward | about 3 years ago | (#36599928)

It won't break anything if they just stop adding seconds.
The added seconds are being decided in the months preceeding they are added so nothing will break by no new leapseconds being added.

Re:Aw, jeezus (1)

SandorZoo (2318398) | about 3 years ago | (#36600852)

What's it going to break? The only systems that will know or care are those that know what the GMT time is, because they will see UTC drifting further and further from GMT. Currently UTC and GMT are not supposed to differ by more than a second or so.

I deal with lots of system that pass time-stamped packets around, and care about their accuracy. Different systems deal with leap seconds in different ways - jump, adjust slowly (over 10 minutes), adjust quickly (under a minute). Accurate time stamps stop working for the 10 minutes or so after a leap second, so our usual solution is to just stop critical operations during leap seconds. They are a PITA. One solution proposed else-thread is to use TIA, but not many time distribution systems support this, as far as I know.

Also, leap seconds make it is impossible to calculate delta times accurate to the second into the future. How many seconds will there be between 1-Feb-2012 16:32:21 UTC and 22-Jun-2016 17:42:31 UTC? Nobody knows.

I'm fully in support of binning leap seconds, but my understanding is it has been proposed several times before (mostly by America) and shot down every time (mostly by Europe). I don't have much hope this time around.

Arghhh! (1)

SETIGuy (33768) | about 3 years ago | (#36599082)

You have no idea how much code I'll have to look through to make sure that it doesn't assume |UTC-UT1| < 1.

Oh... (1)

jra (5600) | about 3 years ago | (#36599090)

and TFA is apparently only available to Sigma Xi members. Great work there, Slashdot editor.

tl;dr? (1)

caturday (1197847) | about 3 years ago | (#36599106)

Since the summary is direct copypasta of the terrible abstract, does anyone have a tl;dr on this?

They are preparing for asteroid 2004 MN4 (1)

www.sorehands.com (142825) | about 3 years ago | (#36599158)

This is in preparation for the impact of asteroid 2004 MN4 (Apophis). Once that happens there will be no life on Earth. Without UTC, we will have to leave a person on Earth so if we want to know the time, we will have to call him -- like the old telephone time service.

Re:They are preparing for asteroid 2004 MN4 (1)

fuego451 (958976) | about 3 years ago | (#36599884)

"like the old telephone time service." Ah, UL3-1212. Haven't thought about that in a long...um...time. For the 'new-time' perhaps we could use: U812 or Fi1U12.

Horrors! (0)

Anonymous Coward | about 3 years ago | (#36599358)

Horrors! in 5000 years we might get to the point where the sun reached its height at 3 in the afternoon....

Wall clocks (4, Insightful)

bugs2squash (1132591) | about 3 years ago | (#36599366)

will simply ignore UTC and continue to show the time based on the earth's rotation. All this means is that UTC loses any small shred of relevance that it once may have had to the common man. So go ahead, redefine UTC and we can all just go back to using GMT for our reports, syslog messages, traps etc. that all have far more to do with the time as experienced by users than the time as experienced by a cesium atom. I expect that soon after the decision is made someone will start gmt.pool.ntp.org and utc.pool.ntp.org and we'll have a choice.

Re:Wall clocks (1)

NixieBunny (859050) | about 3 years ago | (#36599726)

Wall clocks don't know anything about the earth's rotation. They're typically driven by the mains frequency, which is in the process of being disconnected form 60 Hz in the USA. And GMT is no solution - it didn't handle the earth's rotation rate change very gracefully. Do you want the version that changed the definition of a second based on the last few years' observed day lengths?

Re:Wall clocks (1)

bugs2squash (1132591) | about 3 years ago | (#36600210)

In general, people will want clocks that pretty much point to noon at the sun's zenith where they live, where it gets dark at around the wall-clock time they remember as being bed time and where the alarm goes off just slightly before the time of day that they wish it would. These are all synced to the Earth's motion and anyway...
  • Powerline frequency stability isn't what it once was, and being allowed to drift more recently, especially outside of Texas (I don't know why Texas...)
  • Wall clocks (and by extension syslog clocks etc.) can generally stand to be gently corrected every now and again so the smooth progression of time is not as important for those purposes (ie. >99% of all purposes I would guess) as it might be to a hyper-accurate physics experiment

What would be the point of UTC, then? (4, Informative)

inglorion_on_the_net (1965514) | about 3 years ago | (#36599646)

If UTC would be redefined to no longer be adjusted to Earth's rotation, then what would be the point of having UTC at all? We already have a time scale that counts seconds without adjusting to Earth's rotation: TAI [wikipedia.org]

More confusion (1)

brazilofmux (905505) | about 3 years ago | (#36599952)

A man with one watch always knows what time it is. A man with two is never sure.

three pictures to explain it, and a solution (2, Informative)

Anonymous Coward | about 3 years ago | (#36599992)

The situation can be explained in three pictures [ucolick.org] .

Using already-deployed code, here is one way to solve the problems [ucolick.org] .

so this what the mayan ment by end of time (2)

Joe_Dragon (2206452) | about 3 years ago | (#36600010)

The old system will end and all new one will start up at the same time with big changes.

what about NIST (1)

FudRucker (866063) | about 3 years ago | (#36600668)

and my clock that syncs to NIST's WWVb transmitter? i seen no mention of it in the PDF

itsabouttime (2)

miruku (642921) | about 3 years ago | (#36600840)

Oh groan, best use of that tag on /. so far.

Seems like a silly thing to do (1)

pablo_max (626328) | about 3 years ago | (#36600842)

I know that we can keep time much more accurate using atomic time.
My questions is, why on earth would we want to? I mean that literally. We live on earth. The earths travel rotation around the sun and the rotation the earth does each day is what is relevant to our lives.
We plant our crops according to the seasons. We wake up because the sun shines. Why should our system of time directly reflect the way we live our lives?

Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Create a Slashdot Account

Loading...