A Study on 200 million-year cycle of Earth’s Magnetic Field

Agrima Bhatt, Rajasthan University

Geomagnetic field of the earth

The magnetic field of the Earth is roughly a magnetic dipole, with the magnetic field S pole at the geographic north pole and the magnetic field N pole near the geographic south pole. A magnetic field is endlessly long, however, it starts to decrease as it gets further away from its source. The Earth’s magnetosphere is formed by the Earth’s magnetic field, also known as the geomagnetic field, which extends several tens of thousands of kilometers into space. The magnetic field is at least 3.5 billion years old, according to a paleomagnetic analysis of Australian red dacite and pillow basalt.

The overall form of Earth’s magnetosphere is determined and influenced strongly by the solar wind, and any variation in its speed, density, direction, and entrained magnetic field has a powerful impact on Earth’s local space environment. Ionizing radiation and radio interference levels, for example, can fluctuate by hundreds to thousands of times, and the shape and location of the magnetopause and bow shock wave upstream of it can alter by several Earth radii, exposing geosynchronous spacecraft to direct solar wind.

The Earth’s magnetic field is able to protect the world from harmful and lethal solar radiations. Its size and composition are not consistent over time and space, and it has the power to completely turn or reverse itself, with significant consequences. Different living creatures existing on our planet is very much impacted by a weak field. Recent studies explained the fact that the Devonian-Carboniferous mass extinction is connected to heightened levels of harmful UV-B radiation, this result is quite similar to the MPDL’s weakest field observations.

The Earth’s magnetic field was created by the influence of currents in its core that started at least 3,450 million years ago.

The emergence of Earth’s magnetic field

Scholars and different researches from the University of Liverpool add to the growing body of evidence for a 200 million-year cycle in the strengthening of the Earth’s magnetic field. With almost no pre-existing research and accurate data, researchers utilized thermal and microwave paleomagnetic testing on rock samples from ancient lava flows in Eastern Scotland to determine the strength of the geomagnetic field over important periods. The research study also looked over the past findings and the accuracy of all those measurements taken over the last 80 years from samples dating from 200 to 500 million years ago.

The recent discovery suggests that the strength and the intensity of the geomagnetic field present in these rocks was a quarter of what it is today between 332 and 416 million years ago, which is quite similar to a research finding that identified period of low magnetic field strength that started around 120 million years ago. This time has been dubbed “the Mid-Palaeozoic Dipole Low” by experts.

Crucial need to dismantle theories

With the ever-changing climate conditions, there is a high need to decipher past variations in geomagnetic field intensity since it reflects the changes in deep Earth processes over hundreds of millions of years ago and could provide deep insight into how it might change, invert, or flip shortly. When seen in conjunction with other evidence, these data findings suggest the presence of a 200-million-year cycle in the strength of the Earth’s magnetic field linked to deep Earth activities.

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Reference:

1. Hawkins, L. M. A., Grappone, J. M., Sprain, C. J., Saengduean, P., Sage, E. J., Thomas-Cunningham, S., Kugabalan, B., & Biggin, A. J. (2021). Intensity of the Earth’s magnetic field: Evidence for a Mid-Paleozoic dipole low. Proceedings of the National Academy of Sciences, 118(34). https://doi.org/10.1073/pnas.2017342118

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Author info:

Agrima Bhatt is an undergraduate student studying BSc. Biotechnology in Jaipur, Rajasthan. She is a science and research enthusiast who also loves to write articles and short snippets.

Some of her published articles at BioXone are:

1. https://bioxone.in/news/worldnews/molecular-mechanisms-underlying-virescent-mutation-in-cotton/
2. https://bioxone.in/news/worldnews/multi-angle-projection-microscope-a-novel-imaging-technique/
3. https://bioxone.in/news/worldnews/scientists-develop-novel-cholera-vaccine-from-rice-grains/
4. https://bioxone.in/news/worldnews/ai-predicts-the-relation-between-viruses-and-mammals/