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Member (Idle past 1655 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: Climate Change Denier comes in from the cold: SCIENCE!!! | |||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10296 Joined: Member Rating: 7.1 |
Percy writes: The melting ice caps are responsible. Somehow they're contributing to a decrease in angular momentum of the Earth's liquid core, and due to conservation of momentum that translates into an increase in angular momentum of Earth's solid portion. I would have liked to understand this better, but the article doesn't go into detail, and at one point I think the article mistakenly says "orbit" where it meant "rotation." It was perhaps written in haste or by someone with insufficient background. I would assume that it is similar to how an ice skater increases their spin rate by pulling their arms in. In this case, it would be pushing the arms out to slow the spin. If you move the ice from the poles and to the equator then that should slow Earth's rotation. By how much, who knows, but at least by some measurable amount even if it is in the nanosecond range.
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Phat Member Posts: 18633 From: Denver,Colorado USA Joined: Member Rating: 4.1 |
Fascist blueprint? This is coming from a proudly evolved animal!
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Rahvin Member Posts: 4061 Joined: Member Rating: 10.0 |
Fascist blueprint? This is coming from a proudly evolved animal! This reply is not even coherent.-->“The human understanding when it has once adopted an opinion (either as being the received opinion or as being agreeable to itself) draws all things else to support and agree with it.” - Francis Bacon "There are two novels that can change a bookish fourteen-year old's life: The Lord of the Rings and Atlas Shrugged. One is a childish fantasy that often engenders a lifelong obsession with its unbelievable heroes, leading to an emotionally stunted, socially crippled adulthood, unable to deal with the real world. The other, of course, involves orcs." - John Rogers “A world that can be explained even with bad reasons is a familiar world. But, on the other hand, in a universe suddenly divested of illusions and lights, man feels an alien, a stranger. His exile is without remedy since he is deprived of the memory of a lost home or the hope of a promised land. This divorce between man and his life, the actor and his setting, is properly the feeling of absurdity.” – Albert Camus "...the pious hope that by combining numerous little turds of variously tainted data, one can obtain a valuable result; but in fact, the outcome is merely a larger than average pile of shit." - Barash, David 1995... "Many that live deserve death. And some die that deserve life. Can you give it to them? Then be not too eager to deal out death in the name of justice, fearing for your own safety. Even the wise cannot see all ends." - Gandalf, J. R. R. Tolkien: The Lord Of the Rings "The last enemy that shall be destroyed is death." -->Nihil supernum --> -->
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Phat Member Posts: 18633 From: Denver,Colorado USA Joined: Member Rating: 4.1 |
I was just poking fun at Omni's proud claim to being an evolved Ape while debunking belief as primitive.
The fascist comment is silly to me...far over the top even for paranoid progressives. We are a long way from being a fascist state.
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Rahvin Member Posts: 4061 Joined: Member Rating: 10.0
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How quickly you've forgotten the discussion we had about fascism in the United States.
Trump (and by extension MAGA) is, and I am not exaggerating, *literally every bit a fascist as Adolf Hitler was.* This is not over the top. This is a careful and deliberate analysis of his own statements and policies, as compared against the actual definitional attributes of fascism. And again repeating from that earlier conversation you and I had, the Democrats are fascist-*lite.* America has and has always had some really ugly authoritarian rot.-->“The human understanding when it has once adopted an opinion (either as being the received opinion or as being agreeable to itself) draws all things else to support and agree with it.” - Francis Bacon "There are two novels that can change a bookish fourteen-year old's life: The Lord of the Rings and Atlas Shrugged. One is a childish fantasy that often engenders a lifelong obsession with its unbelievable heroes, leading to an emotionally stunted, socially crippled adulthood, unable to deal with the real world. The other, of course, involves orcs." - John Rogers “A world that can be explained even with bad reasons is a familiar world. But, on the other hand, in a universe suddenly divested of illusions and lights, man feels an alien, a stranger. His exile is without remedy since he is deprived of the memory of a lost home or the hope of a promised land. This divorce between man and his life, the actor and his setting, is properly the feeling of absurdity.” – Albert Camus "...the pious hope that by combining numerous little turds of variously tainted data, one can obtain a valuable result; but in fact, the outcome is merely a larger than average pile of shit." - Barash, David 1995... "Many that live deserve death. And some die that deserve life. Can you give it to them? Then be not too eager to deal out death in the name of justice, fearing for your own safety. Even the wise cannot see all ends." - Gandalf, J. R. R. Tolkien: The Lord Of the Rings "The last enemy that shall be destroyed is death." -->Nihil supernum --> -->
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Omnivorous Member (Idle past 125 days) Posts: 4001 From: Adirondackia Joined:
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Phat writes: Fascist blueprint? This is coming from a proudly evolved animal! My species evolved from ancestral species. I didn't. Nature made us pretty smart, with some blind spots that Trump and other fascists exploit. But it takes culture to make us dumb enough to follow them."If you can keep your head while those around you are losing theirs, you can collect a lot of heads." Homo sum, humani nihil a me alienum puto.
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dwise1 Member Posts: 6076 Joined: Member Rating: 7.0
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To quote Slartibartfast, "I've always been a big fan of science."
Of course, growing up a lot of my sources were science fiction, starting with comic books. The problem there is that while those writers would start with a valid scientific idea, they would then extend it beyond reason, since all they needed was something that sounded scientific to support their fanciful story; eg, Stan Lee knowing nothing about gamma rays deciding that it sounds good so he used it in his story, the use of mutations to explain the X-Men, Star Trek TNG constantly playing fast and loose with DNA. Despite their many inaccuracies (to greatly understate the matter), such sources still served the purpose of at least making the reader aware of the existence of such ideas and very basically what they were and from there the reader would need to research further. Kind of like Wikipedia should be used, not as a final authority but rather as a starting point in one's research of a subject. Science popularization (eg, Popular Science-type magazines, science TV shows, articles in newspapers and popular magazines) is generally better at conveying the science, but that also often fails. "There is no royal road to mathematics" also applies to science, especially to more advanced scientific ideas (but also, sadly, to more basic ideas), but there's no room nor popular appeal in a general news article for the kind of detailed explanation that would be needed. Add to that publishers' click-bait mentality, such that it's the editors, not the writers, who write the headlines, so even if the author does a conscientiously accurate job of writing, the editor will give it a sensational title that can even contradict the conclusions of the article. Caveat lector! (Let the reader beware!)
According to this article, global warming is affecting Earth's rotation and may cause the addition of the leap second to be delayed from 2026 until 2029: The Earth's rotation is starting to interfere with time and experts are concerned. The melting ice caps are responsible. Somehow they're contributing to a decrease in angular momentum of the Earth's liquid core, and due to conservation of momentum that translates into an increase in angular momentum of Earth's solid portion. I would have liked to understand this better, but the article doesn't go into detail, and at one point I think the article mistakenly says "orbit" where it meant "rotation." It was perhaps written in haste or by someone with insufficient background.
This article seems to fit that pattern. I took a quick look and it looks like her reporting is a bit alarmist. Also, she didn't explain her alarm sufficiently. BTW, I spent the last two decades of my civilian career of Intelligent Designer (AKA, software engineer) working on a precision time and frequency division product that used GPS as a time reference, which involved working with and understanding leap seconds. And since that forms the basis for a popular creationist claim (ie, their gross exaggeration of the rate at which the earth's rotation is slowing down; see my page, Earth's Rotation is Slowing), I have researched the matter further. Our basis for the length of the day is the mean solar day, an average of the time from high noon to high noon, a value which changes day to day because of the effects of the earth's orbit being elliptical. Any form of timekeeping for the general public would need to be synched up with mean solar time. Official time is based on atomic clocks, which provide a straight count of seconds; ie, SI seconds which is 1/86,400 of a mean solar day circa 1900. However, it has been found that the earth's rotation is slowing down at an average rate of two milliseconds per day per century, such that by 2000 the length of the mean solar day has increased by two milliseconds. That means that in about 18 months, that 2 ms per day discrepancy will through our official UTC clock off from mean solar time by about a second, we add a leap second to sync UTC back up with the sun. While the earth is generally slowing down, the factors causing that include factors that slow it down as well as factors that speed it up. For example, the slow rebound of the Northern Hemisphere from the removal of the weight of the ice cap of the previous ice age is slowing the earth's rotation due to conservation of angular momentum. That same conservation of angular momentum causes the earth's spin to speed up when a section of the crust drops lower due to a major earthquake. The rate of earth rotation is constantly monitored by the The International Earth Rotation and Reference Systems Service (IERS -- formerly the International Earth Rotation Service hence the initials) whose findings are used to the International Time Bureau (BIH, Bureau International de l'Heure) to determine when to add or subtract a leap second -- so far, they have only added leap seconds since the earth is slowing down overall. Your article seems to be quoting someone as saying that the earth's rotation is speeding up, from which the article is sounding an alarm. But contrary to that article, there's no need for alarm over the adding of a leap second being delayed, because it has already happened before. After a leap second had been added 31 Dec 1998, the next one had not been added until 31 Dec 2005, a period of seven years without adding a leap second. Similarly, the last time we added a leap second was on 31 Dec 2016, seven years ago (plus 30 Jun 2024 has been announced of having no leap second, and what will happen 31 Dec 2024 has not yet been announced). Nonetheless, having worked close the metal with GPS satellite messages (ICD-GPS-200) and with our own implementation support for leap second changes, preparations have been made to handle the event in which a leap second is subtracted instead of being added. We (ie, the industry) are well aware of the possibilities so no surprise there and no need for any panic.
POST SCRIPT Why are we basing our time on what a second was in 1900? Here is my explanation from my page, Earth's Rotation is Slowing:
quote: BTW, official time is kept by the International Bureau of Time (BIH), the National Institute of Standards and Technology (NIST), and the US Naval Observatory (USNO). One PBS technology series out of Oregon did an episode on time in which they referred to those scientists as "The Time Lords."
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xongsmith Member Posts: 2620 From: massachusetts US Joined: |
i would think tidal friction would be a bigger factor.
"I'm the Grim Reaper now, Mitch. Step aside." Death to #TzarVladimirtheCondemned! Enjoy every sandwich! - xongsmith, 5.7dawkins scale
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dwise1 Member Posts: 6076 Joined: Member Rating: 7.0 |
i would think tidal friction would be a bigger factor. Most definitely, but the discussion was the effects of the melting ice cap on the earth's rotation because of conservation of angular momentum which has nothing to do with tidal friction. My main point was that we are already prepared to account for leap seconds whether they are added, subtracted, or not. More specifically, as I recall (from six years ago, before I retired) from the ICD-GPS-200 document's description of the fields in the appropriate message subframe, the fields are current UTC offset and the future one at the next leap second event (midnight on either 30 June or 31 December). UTC offsets which indicate the adding or subtracting of a leap second, or no change. The GPS system is already set up to support it and so is the application software, assuming that the programmer didn't screw up monumentally (To err is human, but to really foul things up you need a computer). However, since the current day is already more than 2 milliseconds longer than the SI day, we would still need to add leap seconds periodically even if the earth's rotation rate were to suddenly become constant and unchanging for the rest of time. The reason for that is the same as why we must have leap years even when the earth's orbital period does not change, because calendars can only work with whole days and cannot deal with the extra nearly quarter of a day in a year (ie, a 365-day calendar cannot deal directly with 365.2425 day years). Similarly, a clock that deals with a day consisting of whole seconds cannot deal directly with 86400.002 second days. Every day that passes accrues a 2-ms error until it adds up to a second at which point we just add a second to UTC to sync it back up to mean solar time, just as each year that passes accrues a quarter day error until we just add a day ever four years to sync back up with the seasons (though that's an over correction, so we need the extra rules of the Gregorian Calendar). So to end up subtracting leap seconds instead of adding them, the earth's rotation would need to have sped up enough to undo the effects of 1.25 centuries of it having slowed down. Not bloody likely!
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Percy Member Posts: 22934 From: New Hampshire Joined: Member Rating: 6.8 |
dwise1 in Message 954 writes: Most definitely, but the discussion was the effects of the melting ice cap on the earth's rotation because of conservation of angular momentum which has nothing to do with tidal friction. Yeah, this was the part I was wondering about. How do melting ice caps on the surface affect the angular momentum of the ball of liquid surrounding the solid core at the center? A few months ago I came across a piece about plans to abandon the leap second, and while looking for it just now I came across an AP article about the ice cap and liquid core issue that's much more detailed: A faster spinning Earth may cause timekeepers to subtract a second from world clocks Normally at midnight clocks go from 11:59:59 to 12:00:00, but when they add a leap second the clocks go from 11:59:59 to 11:59:60 to 12:00:00. When they subtract a leap second the clocks go from 11:59:58 directly to 12:00:00. The liquid core was described as behaving in "unpredictable ways, with eddies and flows that vary." This can cause transfers of angular momentum between liquid and solid cores and can speed or slow the Earth's rotation. Recently it has worked to increase the rotation, but that has been counteracted by melting ice at the poles, which transfers water toward the equator and slows the rate, just as someone described in an earlier post as like when a spinning skater extends their arms. And there's also the constant presence of tidal friction slowing the rotation. According to the article, what was originally scheduled to happen in 2026 that might be delayed until 2029 was not the adding of a leap second but the subtracting. I found this very surprising. I'd never heard of the subtracting of a leap second. Won't this be the first time a leap second has been subtracted? The article implies this but doesn't explicitly state it. But it at least explains the mystery of how melting ice caps affect the angular momentum of the liquid core. They don't. The melting ice caps slow the rotation, tidal friction slows the rotation, and the behavior of the liquid core can slow or increase the rotation. How much each contributes at any given time controls how much the earth's rotation speeds or slows. One of the scientists doesn't believe a negative leap second will actually be needed. He says the slowing of the earth's rotation from tidal forces is a constant that won't change, and the melting of the ice caps won't change any time soon, while the behavior of the liquid core is capricious and unpredictable. But what about this transition away from the leap second. Apparently, a couple years ago the International Bureau of Weights and Measures, recognizing the problems created by introducing occasional discontinuities in time of one second, proposed a change. UT1 is the time of one Earth rotation, which is inconstant. UTC (Coordinated Universal Time) is synchronous with TAI (International Atomic Time) but is displaced from it by an integral number of seconds. Inconstant UT1 and constant UTC are kept in synchrony by the occasional addition or subtraction of a leap second. The proposed change is that the maximum difference between UT1 and UTC be increased to more than a second so that discontinuities are introduced not more often than every century. They didn't describe how this change would be accomplished, only that methods for accomplishing it be studied and then introduced sometime during the 2030's. See Resolution 4 of the 27th CGPM (2022). This sounds like trouble to me. Leap seconds occur often enough that all our current software is programmed to deal with it, but if leap seconds go away for a century then programmers writing software today are not going take into account a problem that won't occur for a century and whose solution has been left open anyway. It'll be Y2K all over again. But hey, it'll be our children's children's children's children that have to deal with it. It's their problem. For us it's just be happy, don't worry. --Percy
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.5 |
Will the tides themselves be higher because of sea level rise and would that cause more tidal friction (by higher I mean a normal tide of 3 meters changing to 8 meters)? We should be able to answer some questions if we look at the last glacial period and what happened to the rotation as the sea level rose, but probably a few seconds difference wouldn't be recorded in geological processes.
Stop Tzar Vladimir the Condemned! What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that it has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --Percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq Why should anyone debate someone who doesn't know the subject? -- AZPaul3
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Percy Member Posts: 22934 From: New Hampshire Joined: Member Rating: 6.8 |
Tidal friction is planet-wide strain due to the gravity of an orbiting partner. Sea tides are just one small portion of it. Wikipedia's leading paragraph in the Tidal Force article explains it pretty well:
Wikipedia: --Percy
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xongsmith Member Posts: 2620 From: massachusetts US Joined: |
Well, where i used to work at (Millstone Hill Radar Station (across from the linked Haystack Observatory) Len Hanson used to add in the leap second in the little closed sealed room off the hall every few years before he retiredl ( no one could interrupt him! ). i don't know who is doing it there now, but coupled with Colorado and the Annapolis Naval Station time stations, these 3 atomic clocks were the state of the art. They stay in contact 24/7/365.242198 and if one starts to get out of sync the others nudge it back in line. Best 2 out of 3 theory. But the nudge can't do a leap second yet - that is too big a nudge.
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dwise1 Member Posts: 6076 Joined: Member Rating: 7.0 |
I'm curious of the timeframe where the leap second had to be added manually. Now it's done automatically either by the time servers or by devices that communicate with time servers. That had to have waited for the Internet. The Simple Network Time Protocol (SNTP) version 4 document (RFC 2030) dates October 1996, with the first SNTP Request For Comment, RFC 1361, dating August 1992. Before then, guess it had to have been done manually.
And by GPS receivers, and by extension potentially anything that incorporates or communicates with a GPS receiver, like your smartphone (though it also gets time information from the cell towers, which themselves use time-base components which in turn use GPS receivers for a time solution (that was our basic market).
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Tanypteryx Member Posts: 4597 From: Oregon, USA Joined: Member Rating: 9.5 |
Thanks Percy!
Stop Tzar Vladimir the Condemned! What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that it has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --Percy The reason that we have the scientific method is because common sense isn't reliable. -- Taq Why should anyone debate someone who doesn't know the subject? -- AZPaul3
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