Posted on 10/18/2021 8:17:35 AM PDT by LibWhacker
Scaglia Rossa Limestone exposed near Furlo, Italy, in the Northern Apennine Mountains. Limestone at this locality accumulated on the bottom of a shallow sea, in an arm of the ancient Mediterranean ocean nearly 85 million years ago, during what is called Late Cretaceous time. Credit: Ross Mitchell.
Hold on to your hats, because scientists have found more evidence that Earth tips over from time to time. We know that the continents are moving slowly due to plate tectonics, but continental drift only pushes the tectonic plates past each other. It has been debated for the past few decades whether the outer, solid shell of the Earth can wobble about, or even tip over relative to the spin axis. Such a shift of Earth is called "true polar wander," but the evidence for this process has been contentious. New research published in Nature Communications, led by the Earth-Life Science Institute (ELSI) at Tokyo Institute of Technology's Principle Investigator Joe Kirschvink (also a Professor at Caltech) and Prof. Ross Mitchell at the Institute of Geology and Geophysics in Beijing, provides some of the most convincing evidence to date that such planetary tipping has indeed occurred in Earth's past.
True polar wander bears some dissecting. The Earth is a stratified ball, with a solid metal inner core, a liquid metal outer core, and a solid mantle and overriding crust at the surface which we live on. All of this is spinning like a top, once per day. Because the Earth's outer core is liquid, the solid mantle and crust are able to slide around on top of it. Relatively dense structures, such as subducting oceanic plates and massive volcanoes like Hawaii, prefer to be near the Equator, in the same way that your arms like to be out to your side when you are spinning around in an office chair.
Despite this wandering of the crust, Earth' magnetic field is generated by electrical currents in the convecting liquid Ni-Fe metal of the outer core. On long time scales, the overlying wander of the mantle and crust does not affect the core, because those overlying rock layers are transparent to Earth's magnetic field. In contrast, the convection patterns in this outer core are actually forced to dance around Earth's rotation axis, which means that the overall pattern of Earth's magnetic field is predictable, spreading out in the same fashion as iron filings lining up over a small bar magnet. Hence, these data provide excellent information about the direction of the North and South geographic poles, and the tilt gives the distance from the poles (a vertical field means you are at the pole, horizontal tells us it was on the Equator). Many rocks actually record the direction of the local magnetic field as they form, in much the same way that a magnetic tape records your music. For example, tiny crystals of the mineral magnetite produced by some bacteria actually line up like tiny compass needles, and get trapped in the sediments when the rock solidifies. This "fossil" magnetism can be used to track where the spin axis is wandering relative to the crust.
High-resolution sampling on the road cut west of the Apiro Dam lake, in the Central Apennine Mountains of Italy. This particular locality crosses the boundary of a major geomagnetic reversal, known as the Chron 33R / 33N transition, dated close to 80 million years ago. An amazingly high fraction of oriented samples from these localities yields superb records of the ancient magnetic field at the time they formed. Credit: Ross Mitchell.
"Imagine looking at Earth from space," explains Kirschvink "True polar wander would look like the Earth tipping on its side, and what's actually happening is that the whole rocky shell of the planet—the solid mantle and crust—is rotating around the liquid outer core." Although scientists can measure true polar wander occurring today very precisely with satellites, geologists still debate whether large rotations of the mantle and crust have occurred in Earth's past.
One particularly heated debate has been over events during the Late Cretaceous, about 84 million years ago. Over the last three decades, geophysicists have been going back and forth through public arguments in the journal Science, and at numerous meetings, about whether a large true polar wander event occurred in the Cretaceous.
Mitchell and Kirschvink came up with a plan for settling the debate once and for all. Leveraging Mitchell's experience as a student studying the geology of the Apennine Mountains of central Italy, he knew just the right rocks to sample. The international team of researchers then placed their bet that paleomagnetic data from limestones created in the Cretaceous (between ~145.5 and 65.5 million years ago) located in Italy would provide a definitive test. The magnetism of the younger rocks in the same area was studied nearly 50 years ago, and indirectly led to the discovery of the asteroid impact that killed the dinosaurs. Sarah Slotznick, co-author and geobiologist at Dartmouth College explains, "these Italian sedimentary rocks turn out to be special and very reliable because the magnetic minerals are actually fossils of bacteria that formed chains of the mineral magnetite."
Latitude shift recorded in the Scalgia Rossa Limestone of the Italian Apennines. These data show that Italy took a brief excursion towards the Equator between 86 and 80 million years ago, coincident with a rotation observed from magnetic data collected from rocks from the seafloor of the Pacific Ocean. Credit: Ross Mitchell and Christopher Thissen.
To test their hypothesis about true polar wander, paleomagnetic data with lots of redundancy are required to track the wander of the ancient location of Earth's spin axis. Prior studies, especially some claiming that true polar wander does not occur, have failed to explore enough data points according to the team. Says Richard Gordon, a geophysicist at Rice University in Houston who wasn't involved in the study, "that is one reason why it is so refreshing to see this study with its abundant and beautiful paleomagnetic data."
Kirschvink and colleagues found, as the true polar wander hypothesis predicted, the Italian data indicate an ~12˚ tilt of the planet 84 million years ago. The team also found that Earth appears to have corrected itself—after tipping on its side, Earth reversed course and rotated right back, for a total excursion of nearly 25˚ of arc in about five million years. Certainly, this was a cosmic "yo-yo."
The left side, or the right side?
lmao
bookmark
The Outside or the inside
Before politics entered "climate science" in the 1990's, what few people talked about climate cycles at the time described our present as the Current Warming Trend that's been going on since around the early to mid 19th century (1800's). That ended the Little Ice Age that started around 1300 AD, which ended the Medieval Warm Period that started around 900 AD, which ended the Dark Ages (300 AD), which ending the Roman Warming Period (the time of Christ).
Basically, are we experiencing global warming? Yes. Is it a bad thing? Nope, not by a long shot. I'll take a slowly warming climate with higher crop yields, more predictable rains, and less plagues (the plandemic notwithstanding) over any of the cooling periods' lower crop yields, decades and century long droughts, and rampant plagues.
If you think modern wars over oil are bad, imagine living when the wars were over crop land and when there was a high demand for slaves to eek out a little more crop yield from what land you had. Oh wait, you don't have to imagine that. We call those things in history "atrocities" without talking about how desperate so many cultures were for survival during the Little Ice Age. Want to know one of the reason indigenous American tribes warred with each other heavily before whites got here? One reason (by far not the only reason) was they were desperate during the Little Ice Age. Want to know why black kingdoms/tribes in subsaharan Africa began capturing other blacks and selling them as slaves? They had horrible droughts converting their surplus crops into horrible crop shortages -- but they had a surplus of people competing for the same crops for survival. The same with Europe and the northern climate becoming inhospitable, while even central Europe was barely hospitable (you may not have frozen to death but you probably starved with the low crop yields).
Just something to think about the next time the left wants us to fear global warming.
“What is up, should be down and what is down, should be up” so sayeth Algore, Nobel laureate on all things clinate change.
As if I don’t have enough to worry about. 😳
Johnson received his B.A. degree from Clark College (now Clark Atlanta University) in 1976, is a member of Omega Psi Phi Kappa Alpha Alpha Chapter, Decatur, Georgia, and received his J.D. degree from Texas Southern University Thurgood Marshall School of Law in Houston in 1979; he practiced law in Decatur, Georgia, for more than 25 years.
Preaching to the choir. I’ve read “The Chilling Stars” by Svensmark and Calder as well as a number of other papers on the warming and cooling trends across modern history. Perhaps my post wasn’t clear that I don’t believe in anthropomorphic global climate change. The sun and the Earth are more than capable of changing the climate on their own. Humanity’s contributions are about as effective as sneezing at a windmill.
I should have saved Ben's graphic. Having some difficulty finding it to link to my post this morning. What was immediately interesting to me is that my location in SE Idaho would be about 5 degrees south of the equator vs 43 north currently.
“Stuff like this is why I immediately discredit the global climate change crowd. It takes hundreds of thousands if not millions of years for changes to happen globally. The ramping of fossil fuel burning 100 years ago is a fleck of dust on the coffee table of Earth’s time in the solar system.”
You mean to tell me you can’t measure something semi-accurately for 30 years and inevitably determine a man made catastrophic trend on a 4 billion year old planet? Come on, man.
Did the Earth tip on its side 84 million years ago?
I don’t know but everything seems upside down right now.
Did you know your FR account has said “This account has been banned or suspended.” for several days?
But if you keep it to within the past 1,000 years or so, you can disprove the BS by using history that we've all studied.
For instance, it's easy to perceive this: Erik the Red discovered Greenland during the Medieval Warming Period and there were outposts there for centuries, then Greenland became inhospitable during the Little Ice Age, but is now hospitable again during the Current Warming Trend. Military history lovers, look at all the deaths in winter camps during wars in the Little Ice Age like the American Revolution and how that quit being so bad by World War I and World War II (unless you get up into Russia during the winter). Like eating potatoes? They became a staple of the western diet during the Little Ice Age because they're able to grow in colder climates.
One of the Turtles stands up on its hind legs ???
Can’t tip, aren’t any seams on it.
wy69
All the dino’s ran to one side of the planet.
V.A. Firsoff (Valdemar Axel Firsoff, as it turns out) wrote a lot of books (I think he's dead, but perhaps not), including Strange World of the Moon published back in 1959, ten years before the manned landings started, and even before the first robotic landers.
I picked up a used copy for $1.98 at the enormous chain bookstore, which had "Shimon Kaplan, Israel" on the flyleaf or whatever that blank first page is called. Hard to figure, considering this is Grand Rapids Michigan, but it's not exactly like a message in a bottle.
Firsoff's book is interesting in that it shows the prevailing ideas about what would be found on the Moon (it was already believed during the 19th century, and more relevantly, by the 1920s and 1930s in Germany, that humans would visit the Moon). In a chapter "The Earth's Fair Child or a Foundling?" discusses the concept of the birth of the Moon via an overspin (doesn't use that word) condition on the Earth, which appears to be his view.
Firsoff blows off the idea that impact plays any role on the Moon, attributing its surface features to vulcanism, a view that died a quiet death in 1972, when a geologist first set foot on the Moon.
Firsoff attributes lunar craters and other features to the Moon's capture by the Earth (as well as contraction of the lunar sphere), apparently after having been tossed off by the overspin condition very early in the history of the Earth. He appears to envisage three encounters between the formed Moon and the Earth, resulting in temporary capture twice leading to the eventual outright capture....the Moon clearly could not have been the satellite of the Earth then, for a total period of about 2,000 million years... Spurr points out that the face of the Moon shows two systems of great surface fractures, or faults, lying about 30 degrees from the two poles and trending from west-south-west to east-north-east. This is explained by him as a result of the halting of the Moon's rotation... Curiously, the face of the Earth, too, shows a similar structure, with the same general trend -- the Highland Boundary Fault... The poles of the Earth would also seem to have shifted place on at least three occasions, in the Cambrian, Permian, and (lastly) Quaternary Periods, brining ice and cold to previously warm lands... some mighty force made the crust of the Earth slip (the rotational stability of the axis of a mass as large as the Earth is enormous) and the position of the poles wobbled... there exists on the Moon a triple grid of surface fractures... perpendicular to each other within each grid, the grids being of different ages... Cambrian, Perm-Carboniferous, and Tertiary.Fascinating idea, based though it is on outmoded ideas about impact (i.e., Firsoff's view that there was no role for impact). He's basically given us a snapshot of the problems inherent with a fission origin (either by overspin or by impact), not least of which is that the fission origin also requires in orbit formation of the lunar sphere and capture by the Earth, while showing that capture is possible.
One more thing from Firsoff:Unlike any other satellite, the Moon completes her revolution round the Earth outside the sphere of the latter's gravitational predominance. Solar and terrestrial gravity draw level with each other at the distance of 161,800 miles from the center of the Earth, whereas the Moon never comes any nearer it than 221,463 miles.But I dunno if this is true. Objects in prograde orbit around the parent body will accelerate and thus raise altitude, while those in retrograde do the opposite. So, a body in orbit could wind up in escape, particularly if a third body were givin' it a come-hither.
There are several directional references available, obviously. Two obvious and important ones are the plane that contains the earth's orbit, the ecliptic plane, and the other is the one containing the equator, the equatorial plane. The line of intersection of these two planes is called the line of the nodes, or the Vernal Equinox direction. The line from the center of earth to the center of the sun at the equinoxes is (approximately) the VE direction in March, and opposite it in September.
It isn't clear whether the article implies that the rotational axis changes with respect to ecliptic, or whether the rotational axis changes with respect surface of the earth. It has been known since the 19th Century that the axis of rotation of earth "wobbles" with a period of about 14 months and an amplitude of about 20 meters, measured at the surface. In other words, the rotational axis is displaced from the conventional North Pole by that amount near the north pole. Google "Chandler Wobble". It has been known since about the second century BC that the rotational axis of the earth precesses around a line perpendicular to its orbit (though back then they thought it was the sun's orbit) with a period of about 26,000 years. The celestial north pole is now in the direction of Polaris, but it wasn't 2,000 years ago, and will not be in another 2,000 years, but will return in yet another 26,000. Google "precession of the equinoxes"
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