…but today I got to thinking about perpetual motion. We all know there’s really no such thing, right? At least, I think that’s one of the things we keep trying to create. Even the great pendulum at the Smithsonian is a result of the earth’s rotation, isn’t it?
So I’m thinking about the rotation of the earth on its axis, as well as the way it encircles the sun. Can anyone explain this motion to me ? Are we slowing down? Is this a homework assignment I missed in 7th grade?
thanks – Jim
Replies
The motion of the Earth will go on for a long time because the friction is very, very small, just some cosmic dust, but the Earth is slowing down. Every few years the folks who keep the official time have to add a leap second because the Earth is slowing down. They have to stick an extra second in once in a while, otherwise the clocks would get out ahead of the slowing Earth.
It's because when the second was first precisely defined the Earth ran faster than it does now.
And, it's not all that precise and neat. If my memory of the time times in the naval almanac is right, the leap second is added every eight year. Then, every fortieth leap year wee need an extra leap day. Which is followed by no leapdays at all in years divisible by 400.
It's not the "when," it's the precision of the clocks. The orbit of the Earth is 365.24 (and some bits extra for a good stretch) days long. So, rounding to 1/4 day, every fourth year, we need an extra day. The fiddly bits also accumulate, thus the other "odd" adjustments.
Why is it important? Well, while navigating at sea, a second or time is roughly equivalent to a nautical mile (6020± feet) in longitude--not the sort of error one wants to accumulate.
As to the motion of the planets, it's "simple" gravity. Add in angular momentum, that puts the planet like a ball on the end of a string. In the case of the Earth, the string is about 93 million miles long (8 light-seconds is the number I remember). Part of what hold the system together is the number of pieces-parts. Jupiter & the gas giants actually pull on the inner planets even as the Sun pulls them all in. Give the aforementions lack of an significant drag, the system has only entropy to slow it at all.
"Well, while navigating at sea, a second or time is roughly equivalent to a nautical mile (6020± feet) in longitude--not the sort of error one wants to accumulate."
I may be wrong, but I'm pretty sure the "second" you are refering to here has to do with degrees and not units of time - and it may actually be degree "minutes" that approximate a mile.
I'm pretty sure the "second" you are refering to here has to do with degrees
Ah, yes, this is where it gets tricky. Measurements of latitude are relatively constant around the circumference of the earth. On any given line of longitude, the circle perpendicular to that is divided into 360 equal degrees. Each of those degrees is subtended into 60 minutes of latitude, which closely correspond to nautical miles (subject to how accurately one measures). Each of the minutes is divided into 60 seconds of arc, about 600' or a hundred fathoms.
Now, in measuring longitude, one must know the time difference between a known point (typically GMT or "zulu") and where one is presently. Typically, one takes an angular measurement of the sun, or of celestail bodies. This measurement must be accurate to at least the second of time. The difference, in longititude, between 2235:10 and 2235:11 is about a nautical mile west to east.
To keep it complicated, and to frustrate mapmakers (small children of all ages), the only 'constant' degrees, minutes, and seconds of arc in logititude are measured at the equator. These measurements change as one approaches the poles. To ad a bit more confusion, the Earth is not neatly spherical, but is "oblated," meaning there's a bulge roughly between the two Tropics. (There's those messy tidal forces someone else was pointing out . . . )
In days of old, one sloged through the calculus in Bowditch and/or the Nautical Almanac. Nowadays, Loran & GPS have rendered that chore a bit superfluous. Unless one is navigating without them.
One of the trickiest bits about the 50s era transit of the submarine Nautilus under the north polar ice cap was having to cope with the ever-changing dimensions while navigating. At 89° North, the 360° of longititude are not very far apart at all.
:-)
I'm still a little unclear how a second of time can so closely corespond to a second of arc, but you seem to know your stuff so I'll trust ya. Thanks.
Now is when I remember why I switched into the vocational program after 10th grade.
I do know that when I read the title of this thread, I can't help but think of that old song...
You know, the one that goes...
"Don't know much about gealgebra"
"Don't know much trigonology"
A good heart embiggins even the smallest person.
Quittin' Time
i have invented a perpetual motion machine, i just took a slice of freshly buttered toast and duct taped it to a cat's back, butter side towards the cat. then i picked the cat up, held it upside down, and dropped it. the result was it just spun around in circles, never landing. the toast had to land butter side down, while the cat had to land feet side down. unfortunately i have been unable to harness the power that resulted from this experiment.
I thought you told me you only went to school to eat your lunch!?quittintime
"I thought you told me you only went to school to eat your lunch!?"
I did. That's why I thought "entrophy" was what you got when you shot a big en.
just a thought- sometimes even really, really smart people are wrong.
as an example, i believe some years ago stephen hawking said that the universe must still be expanding because everything was still moving in forward gear, or words to that effect. if and/or when the universe starts contracting, everything, including basic life functions, movements, etc- essentially everything that had ever happened?- would be running in reverse. it didn't take him long to back away from that position, of course. for all i know, he just said in the first place to mess with peoples' heads. who knows? i've also read he has a wicked sense of humor.
also, the speed of the earth's rotation at the equator is approximately 1,000mph. how long is this deceleration supposed to take? and are airbags built to withstand that kind of braking force? not to mention the subsequent re-acceleration? all i know is if i see a gigantic child's hand wrapping a string around the planet we're f***ed.
m
how a second of time can so closely corespond to a second of arc
Ah, that's it, that's precisely how I remember the difference. Minute of Arc of latitude is a mile, second of time is a mile in longitude. By habit & training, I note them differently, too, D/M/S as ° ' "; and time as HHMM:SS. (You want really confusing, the milspec rendering of the present time is 092347EOct2003--echo="E"= GMT+5 hours, or CDT).
Latitude being relatively easy to measure, and being constant all the way around its circumference, the divisions were made early. That's why a nautical mile is one minute of arc of latitude. It started out as 6000 feet long, or 60 cables of 100 fathoms each--the six foot fathom divides neatly into a base 60 system like M/D/S. When accurate chronometers permitted the accurate calculation of longitude, the systems needed 'tweaking' to match the newfound accuracies in measurement. (The orginal French Meter was an even division of the cirfumference of the Earth at the equator, the accuracy of measuring the earth made it 39.37" instead of however many milliradians it started out as.)
I always remembered the physical length of a degree-second (1/360th of a degree) of longitude as equaling about 30 meters. For latitude, around the equator, it's slightly longer, about 31m. Obviously that decreases as you get closer to the poles.
As far as time-measurement errors and how they equate to a ship mis-plotting its position on a chart, at the equator, being off by a second of time would equate to an error of about 1/4th of a nautical mile.
Pre-Harrison, it wasn't uncommon for a ships chronometer to lose 10 minutes a day. That'd give a daily error of 150 nm, or about 175 statute miles.
A very nice book that I read maybe five years ago...Longitude...can't recall the author, but it detailed Harrison's account of inventing an accurate chronometer. A very nice read.
"nice book that I read maybe five years ago...Longitude..."
Not sure if it was based on the book, But I saw a lengthy PBS show on a time piece contest (1600's?) that was for the purpose of accurate navigation. It was a facinating show.
Wouldn't a degree second be 1/3600th of a degree? 60x60?
Yup, omitted a zero. Good catch. 1/3600th.
The PBS show may very well have been based upon Harrison's work. While he worked over several years, I recall around 1670 being somewhere in the timeline.
Longitude by Dava Sobel was an interesting read about an amazingly talented, self-taught mechanic/inventor/scientist. The accounts of the British and other Navies plowing into continents, unawares, due to the "londitude problem" were striking.
I've got some of lithographs of Captian Cook's Alaskan maps on my wall and they are impressively accurate for having been done in 1770's. He, by that time, had one of Harrison's chronometers along.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Thanks for filling gin the details regarding the author. His work was truly impressive, and for a long time, unrecognized, as he worked on his own and wasn't under the umbrella of...what...the Royal Science something-or-other?
While the "official" scientists flailed in their attempts, Harrison delivered...
GOOD GOD ALMIGHTY!
I've been reading this thread and I just honestly can't comprehend all this bull doo-doo about planetary rotation.
THE EARTH IS STATIONARY AND THE UNIVERSE REVOLVES AROUND US!
And you boating people better watch out so you don't fall off the edge of the planet. Don't forget it's flat, not round.
In the middle ages it was commonly believed that the Earth was flat, but many more people knew better than is today commonly supposed. The author of Job, who wrote between about 3000 and 4000 years ago, knew the Earth was spherical and hung in empty space. He wrote: "God stretches out the north over empty space, and hangs the Earth on nothing. . . . He has inscribed a circle on the surface of the waters, at the boundary of light and darkness." (26:7, 10) In 200 BC, Eratosthenes actually measured the circumference of the Earth. Remarkably he used a stick, and was only off by about 10%. And in the Age of Exploration, people knew the Earth was round by watching ships sail away, noting how they rolled over the horizon as they became more distant.
Yeah, the Royal Astronomer was the arbitrator of the large cash prize for finding a solution. But was also a competitor proposing goofy astronomical techniques. (e.g. waiting weeks for the occulation of a star or moon by Jupiter). What if it was cloudy that night?
For all those teen-age fantasies of going back in time and turning the tide of history with a M-16, F-15, or the Enola Gay; maybe the bigger bang would have been to go back with a dozen $10 Timex watches.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
On a remotely related note, there is a web site dedicated to photographing what exists at each of the lattitude and longitude interger intersections in the world. From the photos posted thus far, it appears that these spots may be among the most boring on the planet...
http://www.confluence.org/
The Degree Confluence Project: "The goal of the project is to visit each of the latitude and longitude integer degree intersections in the world, and to take pictures at each location." The pictures are to be posted on the website.
From the photos posted thus far, it appears that these spots may be among the most boring on the planet...
LoL! A few miles SW of Waller, TX, counts in that regard (intersection fo 30N & 96W, closest to my driveway's 30°38.556'N x 96°20.889'W [±5m])
Thanks for the link, I'll have to send that off to some folks I know.
Hmm, might be real hard to see much difference between 30N x 20W and 30N x 30W, now that I think about it . . .
Oh, in case you'd like a lat/long by street address, here's a link: http://www.zipinfo.com/search/zipcode.htmOccupational hazard of my occupation not being around (sorry Bubba)
O.K. people, does the universe have a boundary? I heard it both ways. Just want to see the concensus and insight on the subject.
Edited 10/15/2003 11:41:22 PM ET by TOMCHARK
Define universe.
In a scientific sense, the entire celestial cosmos.
I think the latest speculation was that it was like a soccer ball - if you were to go out one "panel" you would come back in on the other side. Something like a finite universe but that you could keep going in one direction infinitely. Or something like that. A lot of nay sayers on that one however.
Some theories say it is infinite, others say that it is bounded but infinite - i.e. the mobius strip analogy.
Some theories have it expanding infinitely, but if it is expanding, that means that it has a size that is getting bigger and thus must have some type of expanding boundary. The expand-collapse model would seem to also require some type of boundary, at least to the area that matter occupies. I don't understand super symmetry and string theory, but they postulate something like 100 additional dimensions between the 4 dimension (including time) that we occupy, so perhaps different sets of dimensions present boundaries...
So, while I haven't followed it much for a while, I think most theories of the Universe postulate a bounded but infinite Universe...
But most of it is based on pure mathematics, which was never my forte -
So, IMHO - no one really has a clue. Maybe it is all bounded by an infinite amount of ignorance...
I am reaching way back here, but entropy is used in a broader sense than just thermodynamics. My major was chemistry, and some where in the atomic and sub atomic level entropy does indeed mean things are going to energy equalibrium, i.e. lowest energy state.
I remember asking a prof. about where it goes, b/c of the first law...neither created or destroyed.... That is where they really confuse the issue by jumping from sub-atomic to the macro universe. His explanation was that as energy/matter seeks its lowest state (maximum disorder) the universe will be at absolute zeroe, the point of no molecular activity, either atomic or sub-atomic. So true entropy will be really cold.
Dave
The universe is an egg.
In transit from the posterior of a chicken.
A chicken riding on the back of a turtle.
Can't we all just get a log ? - Paul Bunyon
Quittin' Time
The second was not precisely define until the first atomic clock was invented in the late fifties or early sixties.
The twelve month lunar calander was used as early as Stone Hinge, probably earlier. Measurement of solar and lunar movements gave rise to the twenty four hour day. Neither the 24 hour day nor the 12 month lunar year precisely match the actual movement of the earth around the sun or the earths rotation about it's own axis. They are conventions we have define, they just don't fit precisely with what really happens, so every few years we make adjustments to catch up or slow down to where we really are in time.
The whole galaxey is in a contiouse state of entrophy, but the time scale is so long that it is in comprehensable to the non scientist. So, technically you are right. We are slowing down, so is the sun and every thing in the universe. We can even measure the rate of energy decay, but it isn't enough to adjust our clocks a second every few years.
What keeps us where we are is a combination of gravitational attraction and a balancing of centrifical forces in our orbit. Friction in the vacum of space is so negliable that it is not used in any of the calculations I was taught in physics.
In a sense the universe is not even in perpetual motion. Everything has been slowing down since the big bang.
Dave
Back in the days of the real dinosaurs (as opposed to us Cobol programming dinosaurs) the days were shorter and have gotten longer as the Earth’s rotation is slowing by 0.0016 seconds/century. The moon is getting farther away by about 4cm (something less than 2 inches) per year. If I remember correctly, the sun has gotten slightly warmer over the eons and will get warmer still until it eventually bar-b-Q's the earth. So in a few billion years, you guys who complain about the cold will be able to throw away your mittens and long johns - even at the South Pole...
Having gotten a "D" on the test covering Entropy in my Thermodynamics course long ago, I am probably not the one to comment here, but I think the idea of Entropy is not energy decay but just a leveling of temperature throughout the universe. The idea being that at some point in the far distant future, the center of the sun and your wifes feet in bed will all be at the same temperature. Of course, I guess all those super strings could be siphoning off all that energy to another set of dimensions - maybe that's why I have felt so tired lately...
Anyway, I think the slowing of the earth is generally attributed to the tidal forces from the moon and the sun moving the oceans around and distorting the earth and dissipating the energy into the earth as heat from friction.
Of course, I will defer to anyone who actually knows about this stuff...
Yes, Casey. You are right about entropy being an increase in the disorder of the universe. Including an averaging of temperatures.
You are also right about the tides causing the slowing of the earth rotation. The earth's water and rock bulge twice a day due to tidal forces and that converts angluar momentum into heat. So if you have trouble getting everything done in a day, think how tough it was for a T-Rex, who had a shorter day.
This same effect has caused the moon to stop rotating, relative to the earth. The earth is so much bigger that the flexing of the moon used up all its angular momentum so long ago that a majority of the craters are on the far side that we never see.
Those leap second that get added to February every few years aren't the same as the whole day added every fourth year, unless divisible by 100 except when divisible by 400. The seconds are added because the earth is slowing down. The days are added so that our calander doesn't slow creep ahead and we start having summer starting in March. The change from the Julian to the Georgian calender fixed that. There's a conversion for Julian to Georgian dates. Like George W's (the one with the wooden teeth, not the one with the wooden head) birthday got changed during his lifetime. He was born 11 February 1732: when the British empire shifted its calendar, in 1751, the 11th of February "old style" became the 22nd of February "new style," and nowadays Feb 22nd is when Washington's birthday is usually celebrated.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Actually I think the leap second has nothing or next to nothing to do with slowing of the earth's spin. Just like the year is not 365 days but 365 and 1/4 days, a year is not quite exactly 365 and 1/4 days. More like 365 and 1/4 days and some fraction of a second. Hence the leap second.
Not sure however.
I've not seen the great pendulum, but I'd guess that it has to be set in motion by some mechanism or person. However, I do remember being taught years ago that the pattern that a pendulum traces is indeed due to the rotation of the earth.
Jim,
The pendulum at the Smithsonian shows that the earth rotates. It is powered by some magnetic gizmo at the top.
Down foucaults bayou,
KK
" Jim, The pendulum at the Smithsonian shows that the earth rotates."
I've never seen that pendulum, but anything resembling a plumb bob on a very long string WILL rotate on it's own - mimicing the earth's rotation - without any mechanical help.
Nanny,
This pendulum is pretty spectacular with a long swing. It does have a power source at the top. I found a quote for you from http://www.si.edu/resource/faq/nmah/pendulum.htm
Any pendulum consists of a cable or wire or string and a bob. For a pendulum to easily demonstrate the Foucault effect, it should have as long a cable as possible (this one is 52 feet) and a heavy symmetrical bob (this one is hollow brass, weighing about 240 pounds). Like all pendulums this one loses a bit of energy with each swing due to friction from air currents and vibrations in the cable and other factors. Thus, left to itself the pendulum would swing in shorter and shorter arcs until after a few hours it will decrease almost to zero. To keep the Foucault Pendulum going, one must replace the energy lost with each swing. This can be done by giving the pendulum a little "kick" with each swing.
To do this, two iron collars are attached to the cable near the top. There is a doughnut-shaped electromagnet built into the ceiling, and the iron collar swings back and forth inside the hole of the doughnut. When the pendulum cable reaches a particular point in its swing, it is detected by an electronic device and the magnet is turned on at just the right time to give the collar (and thus the cable and the bob) a little "kick" in the exact direction of its natural swing. This restores the energy lost during the swing and keeps the pendulum from stopping. It has no effect on the direction of the swing, and thus does not interfere with the demonstration that the earth is rotating.
Physics is what counteracts universal constipation and a good entropy is the desired result.
>Are we slowing down?
I had a visit the other month from a guy who said he spoke with Einstein in '54, and their 8 min discussion was on pole shifting. The idea is that every 6000 years the earth undergoes cataclysmic change, the earth stops revolving for a day or two, and the poles shift. My eyes glazed over when he talked about his plans for surviving the 1000 mph winds that will wipe out 95% of the population. He was visibly fearful of this as he discussed his hopes to build a survival community.
As evidence of all of this, he noted that the earth is slowing down, which also happened before the past pole shifts. Per Einstein's calculations, which he was working on when he died, it's due to happen right about.....................................now.
Aren't you glad you asked?
Wow, I just rolled my eyes right out of my head. People were screaming while I groped around to find them, and I think I've got them in the wrong sides...
The MAGNETIC poles do reverse, about every 24k years IIRC.
Tell him that the amount of energy required to stop the rotation of the planet would also melt the crust (it's true). His bunker wouldn't help him anymore than a tinfoil hat.
Kooks are so much fun...
didBlah, yada, whatever, Hi how are you today
yeah, but think of the marketing possibilities for folks in the supersturdy, stormproof shelters business!
m
Something to think about. If the earth shifts its poles in a day or two, would there be enough gravitational force to counteract the centrifugal force so that nobody would be thrown into space?
Tom
When the earth shifts poles, I don't think it shifts 180. I think it just shifts off to some other spot.
I wouldn't think it would change instantaneously.
I would think there would be lots of earthquakes and such as the center of spin changes, and the crust gradualy adjusts to the new center of spin.
Makes you wonder what the cause of this is. Is there some great huge glob of a certain kind of matter under the crust... Maybe within the molten mass, that moves about, and causes the change ?
A good heart embiggins even the smallest person.
Quittin' Time
According to Cloud to Jim...
>>I had a visit the other month from a guy who said he spoke with Einstein in '54, and their 8 min discussion was on pole shifting. The idea is that every 6000 years the earth undergoes cataclysmic change, the earth stops revolving for a day or two,
So according to Einstein, the earth stops. So I think the poles have to be switched more or less 180 degrees for that to happen, I just can't think of it any other way.
>>Makes you wonder what the cause of this is. Is there some great huge glob of a certain kind of matter under the crust... Maybe within the molten mass, that moves about, and causes the change ?
I haven't got the vaguest idea, I wasn't there for the conversation. It'll help if we can bring the old man up here in the forum.
At least it doesn't invert and we fall any ways.
Who ever invented work didn't know how to fish....
Oh yes, it does invert. So according to Mongo, we'll be standing on our heads and Mark and his mates will be standing on their feet for a change. I think I'll move south. O.K., so if we all move south which would be north by that time, would the shift in weight just turn the earth right side up again?
What happens when all that blood congeals in our heads...
Who ever invented work didn't know how to fish....
Numb.
Comfortably?
Who ever invented work didn't know how to fish....
Ok, you call miss Celia and ask what the going rate is for seances.
A good heart embiggins even the smallest person.
Quittin' Time
>I haven't got the vaguest idea, I wasn't there for the conversation.
I was there. It was in my living room. And I don't have the vaguest idea! I kept looking around for Alan Funt...he's dead, I know, but either him or Rod Serling.
>It'll help if we can bring the old man up here in the forum.
Oy vey! Once was my limit. Though if you wanna invest, I'll give you his number. He's looking for help to buy land around here for a communal survival shelter thingy. According to him, the last words from Einstein to him were, "Head to the mountains!"
No, I haven't been drinking and I'm not making any of this up. Though if the earth stops revolving, I think I'll start drinking. No sense leaving anything but empties around at the end of the universe.
>>He's looking for help to buy land around here for a communal survival shelter thingy
I have a better idea. I am collecting bets with a pay out of a million to one that the world will end tomorrow.
>>No, I haven't been drinking and I'm not making any of this up.
Cloud, I have absolutely no reason not to believe you. I suspect it was the other guys who had been drinking. Did you read Jeff's post? it's supposed to be 26000 years not 6000 years... you can stop drinking now.
This sounds like one of the grand side effects of owning a Sci-Fi looking home. I bet you do attact some interesting visitors on occasion.
Maybe you need a switch activated, magnetic pole shifting device, rigged to a flip door, on your front stoop so you can send the people thinking they've arrived in another galaxy on their way toward their intended destination.Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
It is an unfortunate side effect. Maybe I need to start a rumor, like a dome creates its own healing force field, or water drains without creating a funnel, or something like that.
A couple of summaries of some recent scientific speculation/findings on the universe:
http://www.sciencedaily.com/releases/2003/10/031015032001.htm
http://www.sciencedaily.com/releases/2003/09/030917072015.htm
http://www.sciencedaily.com/releases/1999/09/990928075411.htm
If you want to argue your case with interested parties other than those of us at Breaktime, you can join a discussion on finite vs infinite universe at:
http://www.physicsforums.com/
Thanks for the leads, will check them out. Can't imagine there is a forum just for that.
I bet those guys know how to party!
I wonder what they talk about at the parties... finite... infinite...finite... infinite...
Sales would skyrocket - I'll provide the "official study data" for a nominal fee? Kevin Halliburton
"I believe that architecture is a pragmatic art. To become art it must be built on a foundation of necessity." - I.M. Pei -
I may be misinterpreting a few of the posts here, but if the Earth were to 'shift poles', I believe we're talking about the shifting of the magnetic poles. None of that should affect the axial orientation or rotation of the earth.
But it would screw up your swing compass.<g>
Gravitational forces are those that relate to two bodies, and those forces are based upon the mass of and distance between those two bodies. So, theoretically, those of us in the northern hemisphere would still be standing firmly on our feet, while Mark and his other Ozzie buds in the southern hemishpere would still be on their heads. If we really want to get picky, I suppose when it comes to gravitational forces, if the Earth were to stop rotating, with no rotational centrifugal/centripetal forces we may all effectively gain a bit of weight.
That said, were the magnetic fields to shift and leave us without a magnetic field surrounding Earth, I suppose we'd all radiologically fry fairly quickly without anything to filter out the offerings from space.
David, you'd probably know, but wouldn't that produce one spectacular aurora borealis? The final party might just be one helluva light show. Have to crank up a little Joplin (Janis, not Scott) to go along with it.
Sorry I have to quote this again, this is from Cloud to Jim.
>>I had a visit the other month from a guy who said he spoke with Einstein in '54, and their 8 min discussion was on pole shifting. The idea is that every 6000 years the earth undergoes cataclysmic change, the earth stops revolving for a day or two, and the poles shift
So according to the old man, the earth comes to a stop. So the earth decelerates from a spinning sphere to a stand still, just imagine the cetrifugal force created. I know what you are going to say. Depending on the rate of deceleration and its characteristics, i.e. linear vs non-linear, you can then use algebra or calculus (remember puzzle #3? Have to get back at you somehow:)) to calculate if the gravitational force is enough to hold you and I down so we don't fly off to the horizon. If we survive then...
>>with no rotational centrifugal/centripetal forces we may all effectively gain a bit of weight.
The weight loss clinics will be swamped.
I took a course in archeoastronomy (hey, you have to get those social science credits out of the way). The shift in earth axis is every 26,000 years (plus or minus a century or two) according to the books. I suggest everyone get back to that Honey-Do list this weekend....that's not a mistake, it's rustic
Entropy: a measure of the degree of disorder in a substance or system: entropy always increases and available energy diminishes in a closed system, as the universe. (2) in information theory, a measure of the information content of a message evaluated as to its uncertainty.
Draw your own conclusions.
dave
>>
Entropy: a measure of the degree of disorder in a substance or system: entropy always increases and available energy diminishes in a closed system...
as here in BT?
>>(2) in information theory, a measure of the information content of a message evaluated as to its uncertainty
Isn't that what we've been referring to as BS? Oh yeah, we're all full of entropy.
yep
On entropy: "available energy diminishes in a closed system" - as I vaguely remember it, energy is only available to do work as the difference in temperature. As entropy is achieved, there is no delta-T and thus no energy is available for work, its all just sorta luke warm. The energy doesn't just evaporate somewhere, it just evens out. The mantra of most introductory physics classes - "energy cannot be created or destroyed" - but it can change form, including to and from matter.
On magnetic pole reversal: Approximaely once every 250,000 years, give or take about three quarters of a million years or so...
http://news.bbc.co.uk/1/hi/sci/tech/2889127.stm
On leap seconds: Civil time is occasionally adjusted by one-second increments to ensure that the difference between a uniform time scale defined by atomic clocks (TAI) does not differ from the Earth's rotational time by more than 0.9 seconds....The Earth is constantly undergoing a deceleration caused by the braking action of the tides....Over the course of one year, the difference accumulates to almost one second, which is compensated by the insertion of a leap second
http://tycho.usno.navy.mil/leapsec.html
The Earth is constantly undergoing a deceleration caused by the braking action of the tides....Over the course of one year, the difference accumulates to almost one second, which is compensated by the insertion of a leap second
There is something illogical about this.
I mean.....
Establishing last year as the standard...
If this year is one second shorter than last year, so they insert a second.... Wouldn't they have to insert like two seconds next year ? And three, the year after that ? Or do they just constantly change the standard ? Or what ?
Seems to me that if every year is exactly the same, and is almost a second off from that standard... then the standard should be set to that time that is almost a second less.
If the earth is slowing, it would seem that every year has to be some bit slower than the year before, and adding one second to this year will bring us to the same time as last year... But adding one second next year, will only catch us up with this year, not with last year....
Either the year is the same, or it isn't the same.
Is it is, or is it ain't ?
Can't we all just get a log ? - Paul Bunyon
Quittin' Time
I talked to a guy once who believed the laws of thermodynamics proved the existence of God.
Obviously, you can't create matter or energy. And thing in a closed system tend to progress to a less ordered state.
His thinking was that if you look backwards in time, things in a closed system (Like the universe) would progress towards a MORE ordered state. Since things can't progress into a more ordered state indefinitely, his theory was that at some point in time a higher being (God) would have had to created the universe as we know it. That being couldn't have been restrained by the same laws of physics that we are, which means he would have had to be God.
Not trying to start a debate - Just thought it was an interesting theory...I could dance with you till the cows come home, on second thought I'll dance with the cows till you come home.
"David, you'd probably know, but wouldn't that produce one spectacular aurora borealis? The final party might just be one helluva light show. Have to crank up a little Joplin (Janis, not Scott) to go along with it.
"
I've never been clear on how quick the transition is other than "geologically brief". But the magnetic field is produced by the movement of molten iron so it can't flip instantly. So, during the transition, I suspect my arouras would get less while Baton Rogue, Panama, and Egypt would get better (and first time) ones.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Gideon account, Velislosky (sp) theories, Electric Universe, etc.
Comments on those?
Yes, the Earth is slowing down.