Slashdot Mirror
Earth Travel On Time, Again
burgburgburg writes "The NY Times has an interesting article about a rather puzzling phenomena: for the fifth year in a row, the Earth's travel through space is right on time. The rate that the Earth travels through space has slowed ever so slightly for millenia. To compensate for this, since 1972, scientists have added a "leap second" at the end of each year. The problem: Since 1999, the Earth has been on time. The recognition of a need for a leap second was an unintended consequence of the invention of the atomic clock. Suggested reasons for the unexpected punctuality: the tides, weather and changes in the Earth's core."
The Earth knows that we're watching now, so it's taking extra care to be punctual...
Suggested reasons for the unexpected punctuality: the tides, weather and changes in the Earth's core.
No. God just likes to screw with us.
Scientists: Earth Travel Time on Schedule Scientists Say Earth Is on Schedule in Regards to Rate at Which It Travels Through Space
The Associated Press
BOULDER, Colo. Dec. 30 -- In a phenomenon that has scientists puzzled, the Earth is right on schedule for a fifth straight year. Experts agree that the rate at which the Earth travels through space has slowed ever so slightly for millennia. To make the world's official time agree with where the Earth actually is in space, scientists in 1972 started adding an extra "leap second" on the last day of the year.
For 28 years, scientists repeated the procedure. But in 1999, they discovered the Earth was no longer lagging behind.
At the National Institute for Science and Technology in Boulder, spokesman Fred McGehan said most scientists agree the Earth's orbit around the sun has been gradually slowing for millennia. But he said they don't have a good explanation for why it's suddenly on schedule.
Possible explanations include the tides, weather and changes in the Earth's core, he said.
The leap second was an unexpected consequence of the 1955 invention of the atomic clock, which use the electromagnetic radiation emanated by Cesium atoms to measure time. It is extremely reliable.
Atomic-based Coordinated Universal Time was implemented in 1972, superseding the astronomically determined Greenwich Mean Time.
Leap seconds can be a big deal, affecting everything from communication, navigation and air traffic control systems to the computers that link global financial markets.
Just add {In Space!} to anything.
Hmmm... don't think that'll help my procrastination.
.... we can speed it back up again.
Let's do it!
This may be cyclical like I think Global Warming is. Maybe we are in the mid stage where the Earth is on time and later on we will have to subtract seconds? I don't know but I would not automatically assume it is us humans taht are causing it.
Gorkman
Maybe she got back her driving license after being fined for breaking the speed limit and now it's going faster :)
May the source be with you!
NIST
but who told us about it???
-Is the meaning of life vanity, or is vanity the meaning of life?
We decided that for a change this holiday we'd work on big iron - the earth. Using polar cap cooling and using two atoms instead of one in the atomic clock, we managed to accelerate the earth by 1 second. System is perfectly stable. Except in California. And Iran.
www.voiceofthehive.com - Beekeeping and Honeybees for those who don't.
According to http://tycho.usno.navy.mil/leapsec.html leap seconds compensate for changes in the earths rotational speed not the earths orbital speed.
Don't you guys remember back in 1999 when the moon blasted out of earth's orbit? That would probably explain the change.
I live ze unknown. I love ze unknown. I am ze unknown.
OK so help me out here. Pardon the pun, but how on earth do they figure out that the earth is in the exact same position as it was a 'year' ago? Do they use the background of stars, or some other mechanism? How can they reduce the error in such a measurement so that they can be sure that a second has been 'lost'?
I think the answer to why it's on time is 42...
OR
Earth's friends thought she was sleeping around when she was "late" each year....she's trying to get rid of that image...
--<Mike>--
I really could have used that extra second of sleep after partying late on new years eve.
Squirrel amputees just squirm faster, they'll STILL chase you down and gnaw out your eyes.
Banaaaana!
before the atomic clock the Earth was always on time.
It's good to know that the fudge factor isn't always necessary too, what with a leap second occurring every year at some point the slop has to be soaked up in the system. Were the powers that be planning to save up a leap day? If they had, where would they have put it? Frankly, just letting the extra second add onto the end of the year and letting 43200 years swap noon and midnight would have been an interesting social experiment. Assuming mankind hasn't destroyed itself by then, of course.
for a billion year old rock. but i guess that's why there wansn't any mention of dooms day, which i miss so... WERE ALL GONNA DIE!!
The leap second is added to compensate for the slowing in earth's rotation, not its motion around the sun.
It is somewhat odd that the rotation has stopped slowing down. Some have speculated that as more and larger dams are built, creating large lakes far from the equator, that there's a net movement of mass closer to the axis -- causing the earth's rotation to increase in speed slightly.
On the other hand, global warming and the melting icecaps and warming oceans should move mass away from the axis, slowing down rotation.
It will be very interesting to see what happens over the next few years. I'd be curious if there's any relationship between the non-slowing of the earth's rotation and the decrease in the earth's magnetic field, mentioned in Slashdot a couple of weeks ago.
thad
I love Mondays. On a Monday, anything is possible.
Im presuming that somewhere along the line Feb 29th will have to cease to exist if we are to not end up ahead of time which could happen this year with the event of another leap year. My husband who is always late will love that, great excuse he can be 3 hours late and still be early!
It could be that the purpose of your life is only to serve as a warning to others.
... and not the atomic clocks?
Now there's one less excuse the airlines can claim for why my flight was late.
Kevin Fox
If all the chinese jumped off a chair at once, would it affect the earth? Original answer from StraightDope is here
Now that we've established that the article mistakenly talked about annual rotation instead of daily rotation, it seems plausable that a smaller rotational intertia is to credit.
If the core settled down even a tiny bit, so heavier elements rested slightly closer to the core, the planet's axial rotation would speed up like an ice skater pulling in their arms.
Alternatively, the wearing down of mountains (buildings?) could have the same effect.
If the Earth is speeding up, perhaps the terrorists have already won.
Maybe that's why they're all carrying almanacs!
Kevin Fox
Comment removed based on user account deletion
any takers on what this might mean for date roll-over errors like the *nix epoch in 2038, or even this weird 29-bit thing?
C|N>K
I really should've taken the optimistic view that I'd feel better new year's morning from not spending as much time partying the previous night.
Observe: verb-subject agreement
;-)
The regular mangling of this greek-derived word is a rather puzzling phenomenon.
There are more puzzling phenomena in nature.
I know I'm being pedantic... so sue me!
If the Swiss Army equipment is so good, why don't these people try to take over the world by force instead of making clocks?
There is a very comprehensive reference of currently used time standards over at wolfram research site. It came up yesterday while I was trying to figure out the difference between Universal Time (UT) and Coordinated Universal Time (UTC). In the last link I believe you will find that "Earth's rotation is irregular at the 0.1 second level" along with a diagram of the errors so far.
Must... resist... yo mama... joke....
"Derp de derp."
I miss that extra second of sleep we used to get every New Year's Eve.
We sped up and now the friction is warming up the planet? A whole lot of greenies are going to be very annoyed that we aren't trashing the planet after all! ;)
Agile Artisans
I'm the leader of a Terrorist organization known as FART. Over the past few years Fuck Anal Retentive Timekeepers (FART) has led millions of disenfranchised Timex employees in a quest to change time! Yes, every morning and night (corresponding with sunrise and sunset), we face our asses westward and let our flatulence fly!
It's good to see our efforts to fuck with those atomic timekeeping twits succeeding!
It doesn't matter if there are two or two hundred billion people on this planet. The mass of the Earth as a whole doesn't increase by humans breading or being over weight. You have to keep in perspective that our bodies are formed from the very mass that makes up this planet in the first place. And and when we die, it will return back to the ground.
Which is kind of gross when you think about it. Imagine some of those water molecules in my piss now being recycled back into drinking water....and the cycle continues.
Life is not for the lazy.
The IERS has a plot showing how the length of day has decreased over the past few years. Curiously, the current phase of accelerated rotation of the crust began right around the time we started adding leap seconds to UTC.
It seems to me that physicists assume that their atomic clocks keep perfect time. But what if they don't? What if some key physical constants are changing in our neck of the universe. As an engineer I have found that most physical constants aren't (everything is a function of everything, its just an matter of the coefficient). In the case of the atomic clocks, a change of only 32 parts per billion would change the timebase by one second per year. Perhaps a particularly large, long-wavelength gravity wave has stretched spacetime and changed the clocks? Perhaps the four fundamental forces oscillate in undiscovered ways?
IANAP, so perhaps a professional could explain why the atomic clocks must be right -- why a 32 ppb variation in them is impossible (i.e. would manifest itself in other more obvious ways).
Two wrongs don't make a right, but three lefts do.
Just a thought and I know it's a miniscule mass by comparrison but we have sent some of Earth's mass to the Earth Sun L1 lagrange point which should slightly speed our orbit shouldn't it. The dates may coincide, it was launched in 95 but when it reached it's current orbit is unclear, some time towards the end of 1998 seems to be when some the instruments were first switched on. The on orbit dry mass of SOHO is 1350 kg.
So how about some back of the envelope calculations. How much mass at the Earth Sun L1 Lagrange point would it take to influence our orbit by one second per year?
I fully expect to be out by several orders of magnitude but can anyone answer?
The World of Astronomy site at Wolfram.com is a bit out of date and does not include the most recent changes in time scales. I recommend this page which describes the history of various time scales.
I thought they fixed that core problem a few years back by blowing the shit out of it with a bunch of nukes! I saw a documentary on this recently.
Not only is it running on time, but on mertic time.
You got it backwards. The "leap second" was needed because the Earth *was* taking a little longer. For some reason it has stopped being slow by a second. If anything, its the Democrats trying to get Bush out of office a little sooner.
They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty.
Ben
...beause if Gaia were pregnant, it would mean massively swollen oceans, more earthquakes from the kicking, and a new moon that could severely affect the tides and drown us all. Not to mention the munchies.
Learn all about it at: http://www.democraticunderground.com/discuss/duboa rd.php?az=show_topics&forum=104
----- Indecision is the key to flexibility.
One second per year is about 32 parts per billion. Changing the rotation of the Earth by that amount could be accomplished by moving approximately 8260 cubic miles of "Earth" (i.e., material with the same average density as the planet) from the equator to the poles. Moving the material to the mid-latitudes would require moving more material to create the same rotational speed change. For example, we could move about 28,000 cubic miles of Earth from the equator to the 45 degree latitude belt.
28,000 cubic miles of Earth seems like a lot until you spread it out around the Earth. If it were removed from a 1000 mile wide band around the equator, it would be only 6 feet thick. But this still seems like a lot to me because it would have to include changing the mean sea level by 6 feet too and this would be very detectable from orbiting altimeters such as TOPEX.
Hmmm.... Either I've done these calculations incorrectly, or a great deal of material has been moved, or somebody hasn't published their data on changes in the planet's shape.
Two wrongs don't make a right, but three lefts do.
which is the year that this week falls into, and according to ISO standards the 1st week of the new year is the week that contains the first thursdays in the new year.....
so welcome to week 1 of 2004
All these space ships leaving the Earth taking their damned mass with them. What we need is another asteroid to 'land' and restore the equilibrium ;)
Tidal slowing is also magnitudes more important than anything you'd see from mountain building, earthquakes, or any other surface phenomenon. The earth is BIG. But tides take out a LOT of energy. Tides are the major reason the Earth's rotational period slows over geological time.
So right now, the Earth is not slowing; this must mean a shorter-acting phenomenon is supplying the rotational energy that the tides normally suck out. Again, there is only one thing big enough -- turbulence in the Earth's liquid core. Like the Earth itself the core is BIG so little changes in the fluid flow there can actually affect the Earth noticeably, and that flow is known to be chaotic -- because the magnetic field caused by that flow reverses periodically.
My money would be on a near-term magnetic field polarity reversal. Of course "near term" probably still means it will be ten thousand years before it's a problem. Sucks to be a man-made satellite, though, especially when flying over the South Atlantic, an area where the Earth's magnetic field is already starting to do strange things.
Brackets contain world's first nanosig, highly magnified:[.]
WERE ALL GONNA DIE
The really scary thing with all that is that we are all going to die faster than expected! We now loose 1 second of existence every single year!!!!!!
Talk about a WMD! 5 sec lost * 5 billion people = 792 years of life destroyed in 5 years. It's like if Earth just killed 10 people. We should invade right now, before next year when all that will happen again.
Write boring code, not shiny code!
If the Earth is assumed to be a homogeneous sphere and the rotational axis is assumed to be the straight line passing through the north and south geographic poles, the moment of inertia of the Earth is I = MR^2 where M is the total mass of the Earth and R is its radius. The kinetic energy of a rotating Earth is given by K = 1/2 I w^2, where w is the angular velocity.
The energy associated with a 1-second shorter-than-expected day is equivalent to an extra 1.6e22 Joules of energy or 40 times the annual energy consumption of mankind (DoE 1999). The matlab script is here.
Michael.
Linux : Mac
Well, I suppose Jupiter sacked Atlas for his continual tardiness and the new God is still all gung ho about the promotion to the new job. Eventually he'll get tired too...
Oh well, what the hell...
Global dimming.
To slow down in its orbit, it has to get farther from the sun (otherwise it'd fall in closer to the sun, and it doesn't).
Light can exert pressure. That's the idea behind solar sails.
The sun has put out 3% less light per decade for the last 50 years. It may have been pushing the Earth farther out, and with less light now, it's not.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
I can't believe timekeepers add 1 leap second EVERY year.... just every so often to correct for accumulated discrepancy between calendar time and orbit. Likewise, we don't have Feb 29th every year, but in enough years to make the orbit agree with the calendar over long periods of time. Of course, after many thousands of years even the Gregorian system will have enough error in it to necessitate some other corrections... way down the road... just think of the Y10K problems they'll have....
This sounds like some bizarre cheesy plot from Hollywood gone awry...
"What? Nothing's wrong? But that can't be right! We've got to try and break it again!"
$0.02 (CDN)
It could be, of course, that there's actually some merit to Barry Setterfield's theory that the speed of light is not constant, but rather has been decreasing throughout history.
We here at HaulmarkCards.com think about Dooms Day a lot. An awful lot. We've been trying to come up with some catchy verses and clever phrases for a new line of Dooms Day greeting/sympathy cards. We have three problems:
1. We're not sure exactly when Dooms Day will fall, so getting cards to retailers will be a logistical nightmare,2. We won't have much time afterward to spend the profits, and
3. Well, gosh! We just don't know how to "read" the public on this whole Dooms Day issue. We don't want to come off all tacky with something like, "Life was Swell, See you in Hell!" Then again "Best wishes for a Brighter Tomorrow" just doesn't give us that warm fuzzy glow that your granny has come to expect from Haulmark Cards.So we're asking you, the movers and shakers in the feel-good arena to offer up some suggestions. (In keeping with our policy of not paying for anything, these would be considered free-as-in-"free advice".)
TIAYou were 80% angel, 10% demon. The rest was hard to explain. - Over The Rhine
"Math in a song is good."-Linford
As someone pointed out earlier, the article is incorrect, and a leap second is based on the slowing of earth's rotation.
The dominant force behind the slowing is "tidal braking" from the moon. Basically, just as the moon exerts forces on the ocean, the ocean exerts forces on the moon. As a result, the moon is getting thrown gradually into higher and higher orbits because of force from the earth. The energy has to come from somewhere, and that somewhere is earth's rotational inertia.
Leap seconds were implemented as a result of branch of astronomy known as earth orientation. Basically, Earth Orientation is astronomy backwards. By looking at distant quasars constantly and monitoring atomic clocks, astronomers can see minute changes in earth's rotation. Quasars are observed because they are bright (in the radio part of the spectrum) and are far enough away that any physical motion over time would be negligible in the night sky. Correcting for leap seconds and other rotational issues like precession and nutation allows for the accurate functioning of GPS.
For more information, check out USNO's Earth orientation web site
but they know the error rate and its extremely low. They measure the particle count of cesium or some other radioactive material and the official time is an average of all atomic clocks.
Only the State obtains its revenue by coercion. - Murray Rothbard
It is because the Earth now weighs less due to all the probes we keep crashing into Mars.
Table-ized A.I.
I really could have used that extra second of partying early New Years Day.
:) yes I know ... shameless.
**AA: a bunch of mindless jerks who'll be the first against the wall when the revolution comes
Your SUV will be responsible for the next second that mankind will loose forever.
Think of the children !! Oh, the humanity !!!
This message brought to you by Green Peace and EWUTSOP (Environmental Wackos United To Save Our Planet)
mod parent up please, as this idea is not as far fetched as it seems.
/.-PhD's help me out?
Plants are trapping only a very small amount of weight with each photon they absorb. But there are an awful lot of plants on this planet.
Maybe the produced biomass is not so very small compared to the entire earth weight, especially if you accumulate this over millions of years.
Have I lost the rest of my barely adequate scientific education or could this at least bear some truth?
Could one of our
I recently had to implement code to convert terrestrial time (TT) to martian solar day (MSD). Some interesting tidbits in that research follow.
As you might guess, the extra days in leap years help keep our calendars synchronized with our actual position about the sun (heliocentric longitude). This is called intercalation, and the general rules governing the gregorian calendar cover 400 year periods. Other methods exist which are in a sense more "accurate," but less useful for predicting future dates. Fortunately, the earth is pretty regular in its movement around the sun.
The 0 degree mark for heliocentric longitude occurs at the vernal equinox, an event that can be easily determined from earth, and has been for centuries. In the Iranian calendar, the new year begins on the day of the vernal equinox. Since this event occurs later in the day each year, eventually an extra day must be added. Such calendars are based on observation rather than rule-based model and consequently are implicitly self-calibrating.
Leap seconds, as pointed out, are an entirely different beast, and are meant to shore up the discrepency between our actual rotation and the atomic clocks we use. The current offset is 22 seconds slow officially. Oddly enough, a NASA document from 1997 uses a value of 63 seconds as the offset between TT (terrestial time) and UTC (Greenwich Mean Time). Another from 2000 shows a 32.184 second offset from TT to TIA (atomic). It doesn't exactly correlate or add up, and I'm not precisely sure why that is. Perhaps someone could enlighten me on the matter.
Curiously, our leap years follow the mathematical model while our leap seconds follow the observation method of calibration. Consequently, you can determine the correct date in the future, but not the correct second.
-Hope
What if this is cyclical due to "gravitation friction" of the other planets on earth? Obviously not all of the planets pass by the earth at the same points during it's orbit because orbits are eliptical. Maybe the last few years we have not passed as closely to the other planets and therefore their gravity has not had such an effect on us. Maybe in 2000 years, we'll pass more closely during each orbit and we'll have to shave off 3 or 4 seconds. What we really need is several thousand years of data for this phenomenon, and compare it to how closely other planets passed to the earth during those years. Then we could try to correlate that data and see if this is in fact the reason we witness this.
We could just ask the aliens at Area 51 for their observational data they have on us.
Need Free Juniper/NetScreen Support? JuniperForum
Nope, they are definitely made in Switzerland. Some watches are made in Russia, but the Swiss do very little outsourcing for watch manufacturinng.
Some time ago, I saw a show on the Discovery Channel about the Three Gorges Dam project in China (Google for your own link). Apparently this dam retains so much water at high latitudes, that it was expected to 'speed up the Earth's rotation slightly', much like an ice-skater bringing in their arms so that they rotate faster. Why is this not mentioned as a possibility for not needing a leap second?
Last month, New Scientist had an article about some GPS receivers having a bug related to the fact that 256 weeks have gone by without a leap second. Apparently, there is going to be a 1 second interval at 12 midnight UTC tha will register twice, causing some bizarre readings. Sorry I don't have a link for it.
Something like this was actually tested with a large group of English schoolchildren, I believe; it made a small blip on the Richter scale, but certainly nothing noticable. Fun, but as the StraightDope article says, fairly silly and pointless, as the effects can be estimated fairly easily with some physics.
--- Bwah?
... how come something that travels thousands of kilometers per hour (or maybe even second's I have no idea!) and through what must be the most hostile environment known to man manages to be on time, but my bus manages to be late EVERY FRIGGIN DAY!?!?!?!
Bad mod...
I like to build things and wire stuff together.
I guess for once I can understand how the reporter got confused. The earths rotational speed has nothing to do with how long a year is. It has to do with how long a DAY is.
So why do we gain a second every YEAR? If we were to continue such a trend it would imply that the earth would take twice as long to orbit the sun in approx 3.5 million years. Last I checked that's an alarming rate of change for a planetary object.
You said: "It doesn't radiate everything back
Prime example: fossil fuels.
Vast quantities of energy are stored that way. In addition to the known resources is probably a hundred or a thousand times more fossil biomass all around the planet.
If the above AC is right with his assumption of "1kg mass per second", it would equate about ~31'500 tons of mass per year. Modestly assuming 5% of this is trapped in fossil material NOT radiated back, we would have ~1'500 tons each year. Multiply this with 90 million years since the extinction of the dinosaurs and you have a weight increase of about 150'000'000'000 tons. 150 billion tons. Not THAT much compared to the entire earth, but surely more than the weight of an average mountain.
Take into account the earth and the plants are much older than 90 mio. years and you'll get insane amounts of energy trapped somewhere."
No.
The average temperature of the earth is 800 degrees C but the average temperature of the surface is about 20 degrees C. Since heat doesn't transfer spontaneously from a colder object to a hotter one, the direction of heat transfer is towards the surface of the earth. Now if there was the same or more incident than emitted radiation, the temperature of the surface would increase, but this is not observed. The temperature is constant on the surface so the emitted radiation from the earth must be greater than the incident radiation by exactly the amount of heat transferred from deep in the earth to the surface. The reason that the subsurface remains constantly 800 degrees C is because of spontaneous fission of natural uranium spread out in the earth and decay of the radioactive products.
Since net energy of the earth is decreasing, the mass of the earth would be decreasing, but this is probably easily made up by all the meteors and debris that is absorbed by the atmosphere.
Suddenly, the hairy finger of a familiar monkey tapped me on the shoulder. It was time.--G. T.
And all that energy to matter conversion has increased the mass of the Earth. Which has increased its gravatational field, and the effects of everything elses field on it. Thus the earth is moving faster.
Or possibly space dust.
I guess now I know why I'm always late to meetings ;-)
"Klaatu, verada, necktie!" -Ash
Well this really can't be applied to all that much. In fact, I change out the seismograph drum at our school every few days. *I* can make a mark on the seismograph by jumping up and down (and this is with the gain set to 80 instead of 95). Then again, the seismometer is in the basement of the building, it should be buried about 60 ft. underground.
:P
Regardless of that though, we can still pick up the ground noise of construction equipment completely on the otherside of campus.
Basically, anything hitting/moving along the ground is going to create shock waves. How large depends on the KE involved.
(Hmm, I think the point of this was to say that it doesn't need to be a large group of people, my wussy 165 lb. frame can also create a "small blip on the Richter Scale.")
Which is why soldiers march out of step over bridges, interesting java applet showing why.
...right up to "recently" !
If Google really cared they would fix Android Chrome to reflow text, instead of discriminating
then we have much bigger problems than losing seconds on the atomic clocks. Basic things like our understanding of atomic structure and radioactivity would have to be rewritten.
Clear, Dark Skies
Cool, I ran the NYC marathon this year and the bridge right at the beginning (Verrazano-Narrows)was moving like crazy with everybody on it good thing we were out of step.
some years back the B-52s were told not to play "Rock Lobster" at some arena because organizers were afraid of what could happen with everybody jumping to the beat.
A simpler explanation for those who got lost in the long words.
Each day, the sun rises and sets a little more to the north or little more to the south depending on the season. The days of the year where the sun reaches the most north or most south are solstices. When the sun crosses the middle, they're equinoxes. The official "spring equinox" is when the sun crosses the middle moving north. If you were to call that the first day of the year and beginning counting days, you will total up 365 days between equinoxes. After about four years of that though, you'll be off by one, so you'll need to add an extra day. This is called "intercalation."
One could make a rule to add an extra day every four years, but after 100 years or so, they would be foward one day too many. Skip the 100th year, and after 400 years, they'd be 1 day behind. The rule as it stands is every fourth year, except years ending in '00, plus every 400th year. Easy enough, but still not quite right.
Because the rule is not quite right, it will never be perfectly accurate. But if you follow the rule exactly, you can tell that January 1, 1601 was Monday for instance. You can also tell exactly how many days are between now and January 1, 2400 because you know which years are leap years.
The method of watching the sun and adding leap years as necessary is a great way to stay exactly on time, but really inconvenient if you need to predict exactly how every year will fall for the next 100 years or so.
Some people say so what, just live. Who cares if your birthday in 20 years is on a Tuesday. Tax collectors care... Money lenders care... Hallmark greeting cards cares... Calendar makers care... The Vatican cares... So we use the 400 year rule and call it the Gregorian Calendar. It works well enough.
As for TT, UT, UTC, TIA, ET, and a number of other time standards, well... the important thing is that we're now using very accurate clocks for counting seconds and we've determined that the earth does not spin all the way around in exactly 24 hours no matter how closely we've measured it. In fact, it had slowed down for awhile and now seems to have gotten back up to speed.
We determine the difference between the atomic clock and the earth by watching the stars go by, and after spinning, spinning, spinning, we watch the atomic clock and the sky, and if it doesn't come out just right, we assume the clocks are right and the earth is wrong. To make up the difference, we throw in an extra second once every 6 months as necessary. It hasn't been necessary since 1999 which was the crux of the article.
-Hope
Wonder if biomass could account for the difference. In the past, Earth could be gaining biomass (vegetation, organic life): Sun's energy -> matter. Hence the slowing rotation. But over the past hundred years or so, we've been burning so much fossil fuel, and destroying so much vegetation, the Earth is lightening up again, thus increasing in rotation speed. At the rate we're going, scientists may have to start subtracting seconds...
because Kernel version 2.2.4 was released (http://lwn.net/1999/0325/a/224.html). Linus said some of the new features would be showstoppers:)
Top ten reasons to stop procrastinating: 10.
The Associated Press is
:
(a) making a mountain out of a molehill about this,
(b) reporting the information 6 months late, and
(c) mangling the science in the information beyond all recognition.
This adjustment of leap seconds occurs because the second is based on the rotation of the Earth as it was in 1900. The rotation has slowed down slightly since then, so seconds have to be added once or twice a year to keep the day in sync with the sun.
This is strictly analogous to adding leap days to keep the months in sync with the seasons, because the day does not evenly divide the time of one Earth orbit. Similarly, the second no longer evenly divides one rotation of the earth.
This time difference has nothing to do with traveling through space, and is a routine matter.
Here is the actual announcement:
-----------------
INTERNATIONAL EARTH ROTATION SERVICE (IERS)
Paris, 1 July 2003
NO positive leap second will be introduced at the end of December 2003.
The difference between UTC and the International Atomic Time TAI is
from 1999 January 1, 0h UTC, until further notice : UTC-TAI = -32 s
Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC, or to confirm that there will be no time step at the next possible date.
HCG 50a = 2MASX J11170638+5455016
11h17m06.4s +54d55m02s
For more about this phenomenon, you should read this overview, based on a National Institute of Standards and Technology (NIST) news release. In addition, you'll see pictures of two atomic clocks used to officially measure time since 1971. The first one dates back from 1949, while the second one, based on cesium and built in 1999, is still in use.
+1 LOL after reading that article
.
== WolfriderV6 == I'm willing to admit that *I just might* be wrong... Are you??
A couple of years ago a new pedestrian bridge was opened in London over the Thames but had be shut again almost immediatley after the grand opening because of the alarming way it swinging.
Subsequent investigation discovered that there were a couple of bands playing on the opening day and everyone on the bridge had unconciously fallen into step with the beat.
Fortunately, the earth is pretty regular in its movement around the sun.
Well, according to the article, the Earth has been having trouble with regularity.
Anybody got any bran muffins?
i'd hit it so hard, if you pulled me out you'd be the king of britain [bash.org]
The Earth's Delay has been absorbed by the Dutch Railroad. Since 1999 they have been delayed more and more. It is the law of constant delay.
It has direct relevance with Moore's law. Trains are never delayed when the connecting bus has a delay.
They all launch them in the same direction, thus kicking the earth forward a bit. Maybe Beagle3 could aim for something different than mars?
On first reading, I thought it said 'Time Travel on Earth, Again'...
This will probably be taken as a troll, but it's amazing at how much natural order in the universe happened by chance.
"Power corrupts. PowerPoint corrupts absolutely."
The article mentioned Earth's punctuality may be realted to magnetic phenomenon. The Earth's magentic field has reduced by 10% in the past 150 years according to a study released this month (link below), and they projected that if the tend continues, our magnetic field (and the protection it provides from solar flares) could be gone altogether in 1500 to 2000 years (and it would then take several centuries for a "flip" to occur as happened 780,000 years ago when the field settled into its more recent equilibrium state). Of course, the Geophysical union said this is an "unlikely" scenario, perhaps they're thinking the natural history of earth is calm, peaceful, and gradual -- its NOT! http://www.cnn.com/2003/TECH/science/12/12/magneti c.poles.ap/index.html
Has anyone pondered the idea that we have just entered the Matrix? 1999 could have been the year that the "machines" have resetted us back to that year. Since they are automatrons, for simplicity, they've assumed that if a variable is constant for a given time, it must be a constant [ie earth's rotation]
_______________________________
"I'm not Conceited...I'm just a realist..."
What the hell was I talking about? Forget it.
Dang. Discover is reporting space is smooth, while SciAm features an article on how space is discrete and quantum in nature.
Clear, Dark Skies
This could be just one more "boast" for the Bush campaign - "During my (usurped) presidency, not only did I fight terrorism, Sadam, and free markets, I also kept the world running on time!".
"The large print giveth, and the small print taketh away" -- "Step Right Up", Tom Waits
solid, not just with theory but with lots of observational evidence.
Clear, Dark Skies
We all know that rock is brittle stuff when we see it at room temperature. Here's where I appeal to someone who actually knows if magma can be sticky or rubbery, like a rubber band, at the temperatures found in the core. Maybe a glassblower could speak for the quartz portions, anyway...
If the center of the earth is like a rod, up and down through the middle, and the magma mix is like a collection of rubber bands connected at one end to this rod, with the other end wrapped around a weight or ballbearing or whatever....
Rubber bands only stretch so far, absorbing angular momentum in this case, until they're not elastic anymore. At that point, they stop stretching.
Then perhaps we just witnessed the beginning of the end of the Great Winding Up. This is where the more elastic, stickier, and hottest parts of the core are stretched as far as there going to, in preparation for the Great Snapping Back. So watch for the future need to shave seconds off the day. Or maybe tell your grandkids to tell their grandkids to tell their grandkids.
Sound like fun?
I was disappointed that they only allowed 10 soldiers. It wasn't enough to exceed the stress limits of the bridge and send the company screaming into the drink.
Gamingmuseum.com: Give your 3D accelerator a rest.
Well, everyone keeps saying the world moves faster these days. I guess they are right.
Manipulate the moderator system! Mod someone as "overrated" today.
Someone with mod points didn't like that, -1, Overrated. Haha.
Do not meddle in the affairs of geeks for they are subtle and quick to anger
Since they are going to not add an extra second this year, it made me wonder - are there any systems around that automatically assume a leap second every year and will start to drift off now as a result? Or libraries built to calculate future time that have the same issue...
Just goes to show that any assumptions are dangerous!
"There is more worth loving than we have strength to love." - Brian Jay Stanley
At least they're not calling it a new years tree...
If the only tool you have is a hammer, you'd better start looking for a carpentry job.
The speed of light is a function of the medium it is passing through -- light travels more slowly in materials like optical fiber, water, air, etc. than it does in a "vacuum." The index of refraction defines this differential between the speed of light in the medium vs. in a "vacuum."
I put "vacuum" in quotes because we are assuming that all vacuums (defined by the absense of normal matter) are created equal. Who knows if "vacuum" is really uniform across the universe. Atomic clock makers already know that the Earth's gravitational field distorts space-time and affects the clock rate and they try to compensate for that. But what if other factors (e.g., density of dark matter, zero-point energy, long-wavelength gravtity waves, etc.) affect the local vacuum or the electomagnetic properties of eletron orbits and change the speed of light and/or change the frequency of cesium atoms? (Note that current gravity wave detectors can only detect high-frequency gravity waves -- I doubt they could detect nanohertz waves).
I suspect that clock makers are forced to assume that certain physical properties are constant (speed of light, electromagnetic force constants, etc.) It seems we have a tautology -- we have a definition of the speed of light that assumes the timebase is constant and a timebase that assumes the speed of light is constant. Perhaps we can use pulsars to check the accuracy of our clocks (assuming that we understand the decelleration of pulsars, stretching of space between us and them , etc.)
Two wrongs don't make a right, but three lefts do.
Length-of-day (LOD) data is an important dataset for geology and astronomy. The LOD fluctuates up to a millisecond on a daily basis, well within clock precision for the past several decades. LOD has cycles various months and decades long. These are thought tied to ocean and atmospheric circulation, earthquakes, the motion of the moon, and other unclear causes. LOD is related to similar wobble cycles of the earth's rotation axis.
Of course, one can still speculate as to why the rate of slowing down has slowed down.
A maze of twisty little nanotubes, all alike - nanoDiamond.
baka.
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
gack.
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
Try an experiment for yourself. Put a bunch of ice in a glass. Add water until the ice is floating. Put cellophane over the top to reduce evaporation. Measure the water level. Make the ice melt with a warm water bath, microwave, waiting, or whatever. Measure the water level again.
--- SPOILER ---
The buoyancy of an object is equal to the weight of the fluid it displaces. Any object which floats has weight equal to its buoyancy (otherwise it would move up or down). So, the ice weighs as much as the volume of water that it displaces. When the ice melts, the amount of water from the ice melting is the same as the amount displaced by the ice in the first place. So the water level doesn't change.
This works with water because water expands when it freezes. Most substances contract when frozen, so they will sink. This also doesn't work with Antarctic ice. Antarctic ice is resting on a nice chunk of land (although the land itself is floating -- continents are buoyant, too). Temperature can cause water levels to rise, however, through thermal expansion. Imagine the oceans as one giant thermometer. This is counteracted by increased evaporation, I have no idea which is greater.
And this, folks, is why every ecologist should know how to use differential equations. Seriously. You can make your own models with Stella from http://www.hps-inc.com.