The magnetic field of Earth is the natural shield for every creature that reflects harmful space radiation. Over a couple of last centuries, Earth’s magnetic field become 10 percent weaker and the deterioration is accelerating in recent years. Archaeologists have found ancient potteries from Jerusalem that reveal the changing pattern of Earth’s magnetic field.
A group of international scientists from Tel Aviv University, The Hebrew University and the University of California started collecting ancient iron aged vessels from the excavation site near Judah. Those potteries were hidden for more than 600 years beneath the ground. Archaeologists examined total 67 jar handles those are belonging from Iron Age kingdom between the eighth and second centuries B.C. Those handles are holding the record of fluctuating Earth’s magnetic field during those centuries. Their findings were first published in the journal of Proceedings of the National Academy of Sciences(PNAS).
Lead researcher and archaeologist Erez Ben-Yosef from the Tel Aviv University of Israel said in a statement,“We can use it thousands of years later to track the changes with time, and then use the jar samples to reconstruct the magnetic field intensities”. Those jars were filled with olive oil and wines and the handles were engraved with royal stamp markings.
According to The New York Times, during the eruption volcanic lava flows with the direction of magnetic field. The flowing path of lava records the strength and direction of the magnetic field as they become rock solid. Although the methods for dating rocks are not so precise, there could be a mismatch of thousands of years. Those ceramics jars also acted like a lava stone when they were in the liquid state inside the furnace.
Researchers are assuming that Iron Oxide particles of ceramics played the major role to point magnetic field direction. Those 67 jar handles were aged eighth and second centuries BCE. For the oldest jar from late-eighth century BCE, the strength of the magnetic field was stronger than any other jars in the list. By repeating the same process on those jar handles, researchers were able to create a timeline of magnetic field strength.
