Burnt flint tools from prehistoric sites make it possible to determine the strength of the Earth's magnetic field in ancient times. The information about the magnetic field in ancient times may have implications for the understanding of the magnetic field in our time. The researchers: "About 7,600 years ago the strength of the magnetic field was even lower than today, but within about 600 years the field strengthened and rose again to a high level"
An international study led by Tel Aviv University has revealed rare findings regarding the magnetic field that prevailed in the Jordan region about 10,000 to 8,000 years ago. The researchers examined remains of ceramics and burnt flints from archaeological sites in the past of the eastern Jordan, where the magnetic field of that time was 'recorded'. The information about the magnetic field in the ancient period may have an impact on the understanding of the magnetic field in our time, which is in a weakening trend that causes concern among climate and environmental researchers.
The research was conducted under the leadership of Prof. Erez Ben-Yosef from the Department of Archeology and Ancient Middle Eastern Cultures at Tel Aviv University, and in collaboration with the magnetic laboratory of Prof. L. Taukes at the University of California, San Diego, and other researchers from San Diego and Rome. The article was published in the journal PNAS.
Prof. Ben Yosef explains: "Albert Einstein defined the Earth's magnetic field as one of the five most mysterious phenomena in modern physics. As of today, we know a number of basic facts about it: the magnetic field is created by processes that occur at a depth of about 3,000 km inside the earth (for comparison, the deepest human-made drilling reached a depth of only 20 km), at the point of contact between Earth's mantle and the liquid metal beneath it; It protects the Earth from the constant bombardment of cosmic radiation, thus enabling the existence of life; It is fluctuating, its strength and direction are constantly changing, and it has a connection to various phenomena in the atmosphere and the earth's ecosystem, including probably some influence on the climate. However, the nature and history of the magnetic field remain largely unsolved. In our research, we sought to open a window into the great riddle."
The researchers say that dedicated devices that measure the strength of the Earth's magnetic field were first invented only about 200 years ago. To examine the history of the field in earlier times, science is aided by archaeological and geological materials in which the magnetic field of their time was embedded. These are materials that have been heated to high temperatures, a process that causes the magnetic field to be recorded inside the material: at the moment of cooling. The information remains 'frozen' (forever, or until another heating event) within tiny mineral crystals, and can be extracted through a series of experiments in the magnetic laboratory. Basalt formed from lava in volcanic eruptions, or ceramics produced in a kiln by humans are common materials for experiments of this type. The great advantage of using archaeological findings compared to geological ones is the resolution: while geology speaks in terms of ages - hundreds of thousands and millions of years, archeology is able to date the findings, and the magnetic field recorded by them, with a resolution of hundreds and sometimes even decades (and in specific cases, such as a catastrophic event known, even to give an exact date). The notable disadvantage of archeology is the young age of the findings: the ceramics, which have been used for this purpose until now, were only invented about 8,500 years ago.
Neolithic sites in Jordan
The current study dealt with four archaeological sites in Wadi Paynan in Jordan, about 40 km south of the Dead Sea, which were dated (using carbon 14) to the Neolithic period - about 10,000 to 8,000 years before our time, and some of which predate the invention of ceramics. The researchers examined the magnetic field recorded in 129 items found in the excavations, and this time burnt stones and flint vessels were also added to the ceramic fragments. Prof. Ben Yosef: "This is the first time that burnt flints from a prehistoric site are used to reconstruct the magnetic field of their time. About a year ago, a pioneering study was published at the Hebrew University that showed the feasibility of working with such material, and we took it one step further with measurements from well-dated ancient sites. This fact has a precedential significance for the contribution of archeology to the study of the magnetic field: it extends the research possibilities tens of thousands of years back, since flint tools were used by man for a very long time before the invention of ceramics. In addition, once enough knowledge is accumulated about the changes in the magnetic field over time, it will be possible to reverse the equation, and use the magnetic field recordings to date ancient tools and sites."
Another important finding of the study is the strength of the magnetic field during the examined period. The archaeological remains revealed that at some point in the Neolithic period the field reached a very low intensity, but it recovered and became stronger in a relatively short time. According to Prof. Ben-Yosef, this finding also has significance for us today: "In our time, since the measurements began about 200 years ago, there has been a continuous decrease in the strength of the field. This fact causes fear that we may completely lose the magnetic field, which protects us from cosmic radiation and is therefore essential for the existence of life on Earth. The findings of our research may be reassuring: things have already happened before. About 7,600 years ago the strength of the magnetic field was even lower than today, but within about 600 years the field strengthened and rose to a high level again."
The research was carried out with the support of the Binational Science Foundation, which encourages academic collaborations between universities in Israel and the US. The researchers note that in the present case the collaboration was extremely essential for the success of the research, as it is based on a close integration of methods from the worlds of archeology and geophysics, and the insights obtained are highly relevant to both fields.
More of the topic in Hayadan:
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That's why I don't sleep well and for 3 hours in a row, barely. Probably the problem is the energy movements of the earth.
It's all well and good and still, it's all speculation, because the tools with which we measure are correct for this moment
And that is what nature did or that bang… well professors…….