Ebene News – AU – A hitchhiker’s guide to an ancient geomagnetic disturbance

A shift in the Earth’s poles 42,000 years ago may have dramatically altered the planet’s climate, scientists say scientists have found â ???? and they named the period after author Douglas Adams

About 42,000 years ago the Earth was beset by strange ones Its magnetic field collapsed Ice caps surged in North America, Australasia and the Andes Wind belts have shifted in the Pacific and South Oceans Prolonged drought has hit Australia; The largest mammals on this continent are gone Humans went to caves to make ocher-colored art Neanderthals are dead for good

Through it all a giant kauri tree stood tall – ???? until, after nearly two millennia, he died and fell into a swamp, where the chemical records embedded in his flesh were perfectly preserved This tree, unearthed a few years ago near Ngawha Springs, in northern New Zealand, ultimately allowed researchers to adjust a tight schedule for what previously seemed to be a series of intriguing but loosely correlated events

What if, according to the researchers, the crash of the magnetic field caused the climatic changes of that time? And to think that the Ngawha kauri tree had testified to all this

– It must have looked like the end of days, â ???? said Chris SM Turney, a geoscientist at the University of New South Wales in Sydney, Australia, and a member of a large team that described the results in a study published Thursday in Science And this tree has been through it all Which is amazing , reallyâ ????

Comparing ring age data and radioactive carbon concentrations from this and three other kauri trees from the same vintage with recent dating information derived from two stalagmites in the Hulu Caves in China, Dr. Turney and its 32 co-authors were able to determine when the tree lived and died. This gave them what they call a “calibration curve”, “allowing them to convert the radiocarbon from that period into calendar years. / p>

Scientists from all disciplines have said the kauri data is a dazzling addition to the radiocarbon gun and is long overdue

For a radiocarbon person, kauri disks are just amazing, â ???? says Luke C Skinner, a paleoclimatologist at the University of Cambridge, who was not involved in the study He said fossil kauri were the primary means for scientists to get information about the radiocarbon from there so long ago

The tree experienced a long decay of the magnetic field, a period known as the Laschamp excursion, when the magnetic poles tried unsuccessfully to change places.As a result, Dr Turney and his co-authors were able to use the new data to more accurately describe when this excursion happened and trace what else was going on, including the bizarre weather and extinctions

– It was suddenly, my God, these things are actually happening simultaneously all over the world, all at the same time, â ???? Dr Turney said It was just an amazing revelation ????

This discovery unlocked a multi-pronged reflection experiment Earth’s magnetic field, which is constantly generated deep within the planet’s molten outer core, protects against dangerous galactic and solar rays All of these climatic phenomena, Biological and archaeological peculiarities of 42,000 years ago related to the wasted magnetic field? Had its collapse changed the course of life on Earth? And what about other disturbances in the magnetic field, including when the magnetic poles shifted 780,000 years ago?

Scientists have been trying to find answers to these questions since the fact of magnetic pole reversals was established decades ago Therefore, this latest endeavor has attracted close scrutiny

– That’s brave enough, – says Catherine G Constable, a geophysicist at the Scripps Institution of Oceanography in San Diego, who was not involved in the study

Using state-of-the-art global climate model simulations allowing for chemical interactions, Dr Turney and his colleagues used the timeline generated by the kauri tree to try and find out what the climate looked like during the excursion

The data revealed – modest but significant changes in atmospheric chemistry and climate, – according to the paper Among them: a slightly depleted ozone layer; slightly increased ultraviolet radiation, especially near the equator; increased ionizing radiation damaging tissue; and auroras as close to the equator as the 40th parallel of latitude, which would cross the middle of the continental United States in the northern hemisphere and the lower tip of Australia in the south

Adding a period of low solar activity, known as high solar minima, to the mix produced more dramatic effects A particular series of beryllium-10 isotope deposits have been identified in core samples ice from Greenland, dating from the Laschamp excursion 42,000 years ago Such isotopes are created when cosmic rays strike the upper atmosphere; in geological records, they indicate times when the Earth experienced a decrease in the magnetic field and, sometimes, solar changes

In the most extreme computer scenario, with solar effects taken into account, ultraviolet radiation has increased by 10 to 15% compared to the norm and ozone has decreased by approximately the same amount. impacted on the climate system, Dr Turney said:

The simulations suggest that the weakening magnetic field caused some of the climate changes of 42,000 years ago, and that these changes may have had broader impacts: causing the extinction of many large mammals in Australia, hastening the end of the Neanderthals, and possibly giving rise to rock art as humans hid for long periods of time to avoid skin-damaging ultraviolet rays, the authors proposed

In fact, the effects were striking that the researchers gave a new name to the years leading up to the Laschamp excursion midway They call it the Adams transitional geomagnetic event

– The Adams event appears to represent a major climatic, environmental and archaeological frontier that was previously ignored, – The team writes, concluding: “Overall, these findings raise important questions about the evolutionary impacts of inversions and geomagnetic excursions through the deeper geological recordsâ ????

The new name is a tribute to British comedian Douglas Adams, author of “The Hitchhiker’s Guide to the Galaxy” and the book and the radio series – Last Chance to See, – on extinction It’s also a nod to Mr. The famous line of Douglas which is the answer to life, to the universe and to everything is € 42 which Dr Turney said he reminded him of the moment of the magnetic episode 42,000 years ago

Interpretation is meant to create controversy Some scientists who have read the article have expressed admiration for the breathtaking links between the disciplines

– One of the strengths of the article, just from the point of view of its scientific work, not necessarily the analytical science it does, is simply the degree to which it connects all these disparate sources of information to do its business, â ???? said Jason E Smerdon, a climatologist at the Lamont-Doherty Earth Observatory at Columbia University in New York, who was not involved in the study. He called it a tour de force.

Likewise, James ET Channell, professor emeritus of geophysics at the University of Florida, who was not involved in the study but was a peer reviewer, said the researchers had been stuck for a half -th century by whether a decreasing magnetic field affects life Paper opens up new avenues of research

If we knew enough about the tour schedule, maybe we could come back to the problem, â ?? he said

But other scientists said the in-depth analysis made them wonder if there were other explanations for some of the phenomena during the Laschamp excursion.

– It’s about opening a box of worms rather than solving a series of questions, – Dr Skinner said

Like several other interviewees, he questioned whether the Adams event nomenclature would lead to confusion in the scientific literature, and whether it was necessary. But he commended the document for stimulating discussion

Earth, Earth’s magnetic field, geomagnetic inversion, swamp kauri, magnetism

Ebene News – UA – A hitchhiker’s guide to an ancient geomagnetic disturbance

Source: https://www.nytimes.com/2021/02/18/science/laschamp-earth-magnetic-climate.html