Will we go through the earth's magnetic field?

The following article comes from the WeChat public account: principle, author takeko

The magnetic field of the earth is like an invisible protective shield. It can be said that without geomagnetic fields, it is likely that there will be no vibrant earth today. It can resist many incidents of threatening life from space, and also protect the atmosphere from being stripped by the solar wind.

But the ground magnetic field is not stable because it is generated by the complex process inside the earth. Earth's magnetic pole kept moving. In addition, on average every hundreds of thousands of years, there will be irregular polar reverse, that is, the polarity of the two magnetic poles of the North and South will be exchanged. According to some statistics, in the past 71 million years, about 171 reversions may have occurred.

Some historical data and recent abnormal phenomena in the past century have made people start guess whether our earth is about to go through the next polar reverse incident.

However, a new study published in the "Institute of the American Academy of Sciences" has put together evidence of more than 9,000 years. The team believes that the current changes are not unprecedented, which does not seem to mean that the earth is going to polar reverse.

Unstable geomagnetic

The magnetic field is generated by the charge of sports. In strip magnets, the charge of the movement is an electron that runs in the atom. But for the earth, they are the electrons of the melting iron circulating flow.

In fact, we don't know much about the details of geomagnetic production. However, the mainstream point of view is that the geomagnetic field comes from the process of countermeasures from the abroad. The hot liquid circulates in the nuclear, and the friction between different layers makes them charged, just like the friction between plastic comb and nylon sweater. It is the charging of these movements that generate geomagnetic fields.

These complex internal processes also make the ground magnetic field unstable. Historically, the geomagnetic Arctic moves about 15 kilometers each year. But since the 1990s, this movement has accelerated. Now, it is moving to Siberia at a rate of about 55 kilometers per year. At the same time, in the past 180 years, the intensity of geomagnetic fields has dropped by about 10%.

The geomagnetic field strength drawn in 2020. The significant cold -colored area is the abnormal area of ​​the South Atlantic Ocean. (Figure / Finlay, C. Et Al., Wikimedia Commons)

There are also some phenomena that have attracted people's attention. In the South Atlantic near the South American coast, an area with abnormal magnetic fields is increasingly expanded. This is the weakest area of ​​global geomagnetic, also known as the Southern Atlantic Anomalian Area (SAA). Due to the exposure to the high -charged particles from the sun, satellites have failed several times. NASA has reported that the Hubble Space Telescope does not observe when SAA.

We are not sure about the reasons behind these changes, but the development of these things makes people can't help but start guessing. Maybe we are going to the next polar flip incident?

Global reconstruction that spans 9000 years

However, new studies show that the situation may not be like this.

In this study, the team has drawn a change map of the ground magnetic field for more than 9,000 years. These results are based on the analysis of firing archeological relics, volcanic samples and sediments, such as clay tanks that have been heated to 580 degrees Celsius, a solidly solid volcanic lava, and sediments deposited in lakes or oceans.

All of these have information about the ground magnetic field. They are like time capsule, which records the state of the magnetic field at a certain moment. With the help of sensitive instruments, researchers can measure these magnetization levels and re -create the direction and intensity of specific locations and time.

Subsequently, the team developed a new modeling technology to connect these indirect observation data from different time periods and locations, forming a global magnetic field reconstruction of the past 9000 years.

It is gratifying that this reconstruction model also brings a conclusion about the guess of polar reverse. Researchers believe that the abnormal phenomenon that occurred in the South Atlantic may be a category of repeated phenomenon in history, which is related to the corresponding changes in geomagnetic field strength. According to the similarities with renovation abnormalities, the model predicts that SAA may disappear in the next 300 years. The earth does not seem to go towards polarity in the near future.

Scientists believe that by studying how the magnetic field changes, researchers can understand the basic process of generating magnetic fields in a deeper understanding. At the same time, through the measurement and simulation changes of comparative magnetic fields, the new model can also help determine the age of archeological and geological records.

What is the earth without a magnetic field?

According to speculation, if the polarity is really occurring, the geomagnetic field may fall to zero first, and then continue to grow with the opposite polarity. In other words, it is likely that for a period of time, perhaps for a century, the earth will be in a state of almost no magnetic field. This may be a relatively dangerous period for life. For example, without a protective field, fatal radiation may increase the rate of variation of living cells.

However, in the history of the earth's life, there have been a lot of such events, but life has not been eliminated. What's more noteworthy is that the Earth's magnetic field is relatively stable under 99.9%. It is precisely because of this stability and its reliable protection that the life of the earth has continued hundreds of millions of years.

#Groupe OD creation:

Written article: takeko

Capture: Wenwen

#Reference source:

https://www.lunduniversity.lu.se/article/earths-magnetic-poles-d-liply-flip-studyhtps://www.pnas.org/abs/10.1073/pnas.220074911991199119

https://www.Forbes.com/sites/davidbressan/2022/06/07/earths-magnetic-poles- not-likely-flip-in-the-ful-future

https://www.scienceFocus.com/planet-earth/earth-magnetic-field/

#Image Source:

Cover & First Figure: ESA/ATG MediaLab

This article is authorized to reprint from the WeChat public account "Principles" (ID: Principia1687) Author: takeko

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Reprinted content only represents the author's point of view

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It does not represent the high energy office of the Chinese Academy of Sciences

Edit: Azheng

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