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Is The Earth's Rotation Changing?
Roland Piquepaille writes "We all know about the current controversies associated with the ozone layer or the global warming phenomenon. Now, the NASA's Earth Science Enterprise (ESE) is warning us that atmospheric changes or El Niño events can affect the Earth's rotation. During El Niño years, for example, the rotation of the Earth may slow ever so slightly because of stronger winds, increasing the length of a day by a fraction of a millisecond. David A. Salstein, an atmospheric scientist from Atmospheric and Environmental Research, Inc., led a recent study about this possible effect. Salstein looked at meteorological and astronomical measurements from different sources and found they were in good agreement. Check this column for a synthesis. For technical explanations, images and animations, please read this NASA paper, Changes in the Earth's rotation are in the wind."
This has been known since 1951.
I'll do it for cheesy poofs.
The days are getting longer? Cool, I could use an extra five minutes each day to read Slashdot...
I wish Superman would get off his ass and do that whole 'spin-the-world' backwards so we could go back in time and prevent the term 'El Nino' from being invented - which so many bad stand-up comics have used to no end. Also, I would not buy my Voodoo 3 card.
I hate liberals. If you are a liberal, do not reply.
this is really just a fake news to hype up "The Core", isn't it?
It seems like a reasonable enough argument that the rotation period of the earth would change during an el nino period. But once this the el nino effect had ended the rotation of the earth would have to return to normal, so any effect that might occur would be only short term. Also due to the large difference in the mass of the solid earth and the earths atmosphere, the change in the earths period of rotaion would be so small as to be unmeasurable and therefore unimportant.
Everybody run east as fast as you can, to speed the Earth up again!
/me waits for hundreds of pedantic comments explaining why this wouldn't work
I'm sorry, but isn't this widely known? I learned about this effect in my 9th grade science class. Uneven heating of the surface can cause uneven wind resistance blah blah blah... and several million years from now, the day might be a few seconds longer.
Does simply adding the words "El Nino" makes people think this is a new, important idea? The planet's rotation speed is also affected by the impact of meteors and space dust, but I don't see anyone publishing studies to measure that infinitesimal effect.
It seems to me that whatever changes strong winds make in the earth's rotation must be temporary because of the conservation of angular momentum. When the wind pick up, the earth slows down. Wehn the winds die down, the earth speeds up again.
If you really want to get agitated about the earth's rotation slowing down, consider the moon. Tides act as a brake on the earth/moon system. So the rotation of the earth slows, and the moon (to conserve angular momentum) moves ever so slowly away from the earth.
Try moving towards the screen really fast. It should look green then. Of course, make sure you stop before you run into the screen, because a collision with a monitor at speeds close to the speed of light might hurt.
Still, with a plan, you only get the best you can imagine. I'd always hoped for something better than that. -CP
And what are you talking about with your statement about the change being "unmeasurable"? The point of the article is that it is being measured.
I hate liberals. If you are a liberal, do not reply.
This is clearly a problem with SUVs. A vehicle as heavy as an SUV puts down a trememdous amount of torque when it moves, and this action, combined with the great suburban conspiracy of living to the East of their workplace (you go faster going home, so more torque to slow down the Earth), are creating this problem.
When snow collects on mountains, it increases the earth's radius ever so slightly... so the actual day span increases by a fraction of a second. It's a small fraction though, but it still exists. This happens more during the winter when the earth is farther away from the sun. Anyways, it's nothing to get worried about. We've been dealing with rotational inconsistencies for awhile.
;
What's the average length of a day? Something like 23 hours, 59 minutes and 56 seconds or something like that. Which is why we have a leap year:
If the year is divisible by 4
Unless it's divisible by 100
But always if it's divisible by 400
So hey... leapYear = ((year%400)==0)||(((year%4)==0)&&((year%100)!=0))
Can someone answer this though: Do we manually synchronize our clocks every once and awhile (say every few years anyways) just to make sure? I heard a rumor about it (most people have to reset their clocks after the power goes out anyways, and PC clocks are horribly inaccurate), so is this true?
...due to the Moon and the Sun. On one day the rotation of the Earth will stop and as we only see one side of the Moon, only one side of the Earth will face the Sun. Once I calculated the time when the rotation will stop and I got about 5 billion years (assuming a linear slowdown). It's quite strange because that's about the remaining life of the Sun, too.
Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
In two months.
:-) Don't forget to visit the main page either, complete with pictures of his Survival Tents. This sure is stuff for Something Awful. =)
http://www.poleshiftprepare.com/poleshift.htm
"I myself have outstanding personal knowledge and conviction that the cataclysms will occur in May 2003, which is why I am openly stating this on the Internet, and appealing to similar individuals who wish to take steps in preparing for it."
IT MAY SEEM FUNY NOW BUT U THANK HIM & HIS OUTSTNADING CONVICTION TO TELL US ON TEH INTRANET WHEN TEH POLE SHFITS MAY 2003!!!11 PREPAR URSELF!!!
^-- How my IQ dropped after reading his article... I guess it's the Internet we love and hate.
Beware: In C++, your friends can see your privates!
Well-known branch of astronomy called "LOD" or length of day measurements. Changes up to a millisecond or so each year. Atomic clocks and satellites allowed microsecond precision now. Weather, magnetic storms, earthquakes, ocean currents all tought to affect LOD.
Just like the last one planted by the same folks. Who? its a promo for the movie "the CORE" about what? the slowing rotation of the earth's core (caused by a secret weapon project).
the last one was also in slash dot too. its was on drilling to the earths core with advanced materials. (sorry I cant locate the slashdot article right now, though I did see the last one about the mars core
in that case the movie distibuter's publicity folks were using real science and real information. They were just responible for planting news articles about it strategically. this smells the same, and the timing makes it clear.
Some drink at the fountain of knowledge. Others just gargle.
and other climatic changes certainly make the day seem longer
Get the EULA T-shirt
It seems everyone here is missing the main topic. (And not just the ones modded Offtopic)
The main cause of the earth's rotation slowing _during EL Nino years_ is the change in the angular momentum of the earth. This means, that as some point, the angular momentum will change BACK!! Hence, CONSERVATION of momentum. The net effect in the long run is no change in the earth's rotational period due to this phenomenon.
However, it has been a well known fact that the earth's day will gradually grow longer. One of the causes of this is the earth becoming tidally locked with the moon, the way the moon is now. It's just a function of relative gravitational force.
And offtopic: The geologic record does indicate the magnetic poles reversing every 10k-12k years. You'll have to research the 'why' on your own though. I only remember from my astronomy classes that it does...
The truth is out there, but the server is down or not responding.
Okay ... so the days are getting longer, but what I want to know is: does this mean that I get to sleep a bit longer every night or do I have to work a bit longer every day??
If I recall correctly, earth rotation, in the beginning, was just 12 hours, and it's been slowing down mainly due to the tides.
It appears the link between warming and rotation is pretty good. What is not good is the link between man's action and what appears to be part of the Earth's normal warming and cooling cycles.
Besides, I thought we were to all have died from Global Cooling by now, at least that was what they were saying in the 1970s. How did cooling switch to warming so fast?
First, I'm curious (maybe someone out there has a link?) about how solar wind affects affects day lengths. It's known and been imaged that bursts of solar wind cause the earth's atmosphere to swell, and I'm curious what this redustribution of mass does to the moment of inertia and rotational speed of the planet.
Second, I find it kind of interesting the change in the way we percieve time. Centuries ago, the earth made a great clock. 24 hours was defined as a day, and if all of the sudden the day became longer, that longer period of time was defined as 24 hours. Now, we see that the earth makes a pretty bad clock (by today's standards), and rather than relying on the earth as our ultimate timepiece, we rely on atomic clocks. It seems strange: we have all of these time units like hours, days, months, years, etc., all defined first by astronomical methods, but now because of our (technological) ability to be more regular than the cosmos, the hour, day, month, year, etc. have sort of lost their origins.
The best way to predict the future is to invent it.
But given a random distribution on the direction of movement of all the SUVs, it'd balance itself out.
I mean if 25% are going due north, 25% due south, 25% east, 25% west then the net effect would be 0.
I'm more worried that people in North America are getting fatter, making the earth lopsided. So far it's just USA and Canada putting on the weight. Luckily those earth-conscious Mexicans are starving themselves to counter the effect.
Ok, everyone, all over the planet...
...and ... EAST ... BLOW! ... WEST ... SUCK! ... EAST...
Face east, and...
BLOW...
now face west and...
SUCK
All of these measurements are made under the purview of the International Earth Rotation Service. There are models for all manner of astrophysical and geophysical effects considered in the Conventions that are used when reducing the data.
The way that solar noon is kept at civil time noon is by inserting leap seconds. In most places civil time is offset directly from UTC. When a leap second is inserted the day is 86401 seconds long.
This irregularity upsets some kinds of timekeeping systems, and as a result there has been discussion that leap seconds should be abolished. That would cause noon to drift away from noon. That may not be a good thing.
Another important factor that contributes to the slowing down of Earth's rotation is definitely space dust. Every year, the Earth gains at least 30 million kilograms of space dust. This added mass will indeed reduce the time it takes for the Earth to complete a rotation by fraction of a second.
We need a space vacuum to suck up all of the dust before it gets here...wait a minute, space is already a vacuum!
I've known this for eons. The earth's rotation slows down to a crawl every Monday, and then speeds up really really fast on Saturday/Sunday. Then it slows down again come Monday morning.
Just because you don't want something to be true doesn't mean that it isn't true
And the reverse too. Of course they want global warming to be true, as they've based their whole being on that hypothesis. Disproving global warming to a green would be like disproving God to a Christian; both would result in a crushing blow to the psyche and massive denial.
Panic sells, and simply saying that the Earth has warming and cooling cycles doesn't. A lot of people have a lot to loose if it turns out the latest catastrophe fad is as valid as its predecessors.
The day is slowing down because of tidal drag from the Moon. Tides stretch the Earth along the Earth-Moon line; the Earth's rotation drags the axis of stretch around (about 45 degrees away from the Earth-Moon line, if I remember right). The asymmetrical shape pulls the Moon forward a little in its orbit, and the equal-and-opposite reaction (remember Newton's 3rd law?) slows down the Earth's spin by the same amount.
The Moon was certainly closer at one time -- Robin Canup, who works down the hall from me, has done some fabulous simulations of the formation of the Moon (thought to be from a giant impact of two planetoids; the larger fragment evolved into the Earth, while the smaller one became the Moon). She claims that Moon must have formed right around the Roche limit (the distance at which it would just barely not be pulled apart by tides). If that's so, then it would have had an orbital period of about 6 hours. Meanwhile, the Earth would have been rotating faster yet.
The ongoing tidal drag is evident in the "leap seconds" that some international committee periodically adds to atomic time to get coordinated universal time. The leap seconds are becoming more frequent, because (surprise) the day is slowing down a microscopic but measurable amount compared to its speed in 1951. (One leap second per three years corresponds to a proportional change of only 1 in 10^8 [100,000,000], so no wisecracks about sleeping in late, please!
Sadly, the fact that gasses (identically to liquids) can create drag on any body within them is far from new, startling or amazing.
In fact, here are a few other trivial points:
None of this stuff is outside the scope of an A-level student taking maths and physics. The chances are, though, they won't get 5-figure paychecks for coming up with such trivia.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Have you ever worried about who is responsible for making sure the Earth is rotating? Check the International Earth Rotation Service website.