science

Earth’s magnetic field flipped 42,000 years ago. The consequences were tragic

Earth's magnetic field flipped 42,000 years ago.  The consequences were tragic

New research has concluded that a period of global turmoil 42,000 years ago was the result of a reversal in Earth’s magnetic field.

According to radiocarbon preserved in ancient tree rings, several centuries of climate collapse, mass extinctions, and even changes in human behavior can be linked to the last time the Earth’s magnetic field changed its polarity.

The research team named the Adams Transitional Geomagnetic Event, or Adams Event, after science fiction writer Douglas Adams, who declared the number 42 the ultimate answer to life, the universe, and everything.

“For the first time ever, we were able to accurately determine the timing and environmental impacts of the last magnetic pole switch.” Earth scientist Chris Tierney said From the University of New South Wales in Australia.

“The results became possible with ancient New Zealand Korean trees, which have been preserved in sediments for more than 40,000 years. By using ancient trees, we can measure and date the rise in radiocarbon levels in the atmosphere caused by the collapse of the Earth’s magnetic field.”

This final period of magnetic reversal is known as the Champagne event, which is what we call the geomagnetic flight. This occurs when the planet’s magnetic poles briefly swap places before returning to their original positions. It is one of the most well-studied events of the Earth’s magnetic field, recorded by magnetic minerals.

This happened about 41,000 years ago, and lasted about 800 years. The impact of this event on life on the planet was not clear, so when scientists discovered an ancient curie tree (Agathis australis) In 2019 That was alive During this time period, they took the opportunity to find out more.

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This is because trees record atmospheric activity in their annual growth rings. In particular, carbon-14 or radiocarbon can reveal a lot of information about celestial activity.

Radiocarbon is only present on Earth in trace amounts compared to other naturally occurring carbon isotopes. It was formed in the upper atmosphere under the bombardment of cosmic rays from space. When these rays enter the atmosphere, they interact with local nitrogen atoms to catalyze a nuclear reaction that produces radiocarbon.

Since cosmic rays are constantly flowing through space, Earth receives a fairly constant supply of radiocarbon. So, a rise in radiocarbonate in tree rings tells us that the Earth was exposed to the most radiocarbon during that year.

When the Earth’s magnetic field weakens, as it did during the Champagne event, more cosmic rays penetrate the atmosphere to produce more radiocarbon. For this reason, scientists have previously been able to confirm that Earth’s magnetic field has weakened to about 28 percent of its natural strength during that 800-year period.

However, the kauri tree allowed the research team to study the years leading up to the Laschamp event. They found that the Adams event occurred about 42,200 years ago, and the magnetic field was at its weakest point Before La Champagne happened.

“The Earth’s magnetic field decreased to a strength of 0-6 percent only during the Adams event,” Tierney explained. “We had no magnetic field at all – the cosmic radiation shield was completely gone.”

During this time, the Sun’s magnetic field had also weakened many times, as it also experienced a magnetic reversal as part of its normal cycle. These periods experience less sunspot activity and glare, but the sun’s magnetic field also provides the Earth with some measure of protection from cosmic rays – so, during these lower boundaries of the sun, cosmic ray bombardment would have increased again.

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This weak magnetic field could have caused fundamental changes in Earth’s atmosphere Ozone, With dire consequences, including electrical storms and astonishing auroras, and Climate change around the world.

“Unfiltered radiation from space has torn apart air molecules in the Earth’s atmosphere, separating electrons and emitting light – a process called ionization.” Tourney said.

“Ionized air” fry “the ozone layer, causing a wave of climate change around the world.”

This corresponds to climate and environmental changes since that time that have been observed in other records from around the world, such as the mysterious extinction of The megafauna of Australia.

Oddly enough, it also coincides with some of our oldest recorded cave art works, leading researchers to assume that the Adams event could have pushed humans inward.

“ This abrupt behavioral shift in very different parts of the world is consistent with the increased or changing use of caves during an Adams event, perhaps as a shelter from increased UV-B rays, which are potentially harmful, during the grandson’s minimum or active solar particles which may also explain the use. Growing sunblock in ocher red, They wrote in their paper.

This is somewhat of a guess, of course, but it indicates that a geomagnetic reversal could be a dangerous, world-changing event. And recent evidence indicates that we are currently on the verge of being on the verge of another.

Researchers say this could be entirely catastrophic in the current climate.

“Our atmosphere is already filled with carbon at levels not seen before by humankind. A magnetic pole reversal or a drastic change in the sun’s activity will be a factor in the unprecedented climate change.” Tourney said.

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“We urgently need to reduce our carbon emissions before such a random event happens again.”

The research has been published in Science.

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