Certain factors about the sustenance of our planet go very far over our heads. Earth’s magnetic field is reportedly in a dramatic state of weakening, and this period of weakness is a portion of a pattern lasting for over a millennia, according to recently published research.
Our magnetic field is important and serves many functions, including protecting us from cosmic radiation and solar winds, in addition to what people usually know about the north and south poles.
Scientists are talking more and more about a coming magnetic pole reversal. They say the last time the poles switched was around 780,000 years ago, but it almost happened again about 40,000 years ago.
It’s not an immediate thing either, it takes thousands of years for the pole reversal to occur. They don’t seem to know whether another pole shift is imminent or not, because little data could possibly exist on an event that occurs so infrequently.
However, a region exists on Earth that scientists say they are concerned about, and it’s called the South Atlantic Anomaly. It is a vast stretch of Earth’s magnetic field stretching from Zimbabwe to Chile. Within this region, the field is so weak apparently satellites have a difficult time entering it because the radiation that comes through could damage them.
University of Rochester, NY physicist Vincent Hare said:
“We’ve known for quite some time that the magnetic field has been changing, but we didn’t really know if this was unusual for this region on a longer timescale, or whether it was normal.”
Archeomagnetic data is the name given to this data that does not commonly exist about the magnetic history of planet Earth.
A very interesting kind of data on the history of Earth’s magnetism was collected via artifacts in Africa, however.
Ancient Africans who lived in the Limpopo River Valley, bordering South Africa, Zimbabwe, and Botswana, lived in the areas that today fall within the borders of the South Atlantic Anomaly.
It is claimed that about 1,000 years ago, the Bantu people in that region performed a ritual in times of hardship. During devastating drought, they would allegedly burn down their grain bins and clay huts, in a sort of cleansing ritual to cause the rain to return. They actually created a perfect scientific record of Earth’s magnetism at that time.
“When you burn clay at very high temperatures, you actually stabilise the magnetic minerals, and when they cool from these very high temperatures, they lock in a record of the earth’s magnetic field,” team member geophysicist John Tarduno said.
“We were looking for recurrent behaviour of anomalies because we think that’s what is happening today and causing the South Atlantic Anomaly,” Tarduno continued.
“We found evidence that these anomalies have happened in the past, and this helps us contextualise the current changes in the magnetic field.”
The researchers continue to explain, that conventionally science says pole reversals sort of begin in the core of our planet, but in contrast to that, the recent studies suggest that the magnetic field above us is linked to what happens at important places in what they call the core-mantle boundary.
“We now know this unusual behaviour has occurred at least a couple of times before the past 160 years, and is part of a bigger long-term pattern,” Hare said.
“However, it’s simply too early to say for certain whether this behaviour will lead to a full pole reversal.”
The research was published in the journal Geophysical Review Letters.