In 2008, Erez Ben-Yosef unearthed a piece of Iron Age “trash” and inadvertently revealed the strongest magnetic-field anomaly ever found.
Ben-Yosef, an archaeologist at Tel Aviv University, had been working in southern Jordan with Ron Shaar, who was analyzing archaeological materials around the Levant. Shaar, a geologist at The Hebrew University of Jerusalem, was building a record of the area’s magnetic field.
The hunk of copper slag — a waste byproduct of forging metals — they found recorded an intense spike in Earth’s magnetic field around 3,000 years ago.
When Ben-Yosef’s team first described their discovery, many geophysicists were skeptical because the magnitude of the spike was unprecedented in geologic history. “There was no model that could explain such a spike,” Ben-Yosef told Live Science.
Related: Major ‘magnetic anomaly’ discovered deep below New Zealand’s Lake Rotorua
So Shaar worked hard to give them more evidence. After they had analyzed and described samples from around the region for more than a decade, the anomaly was accepted by the research community and named the Levantine Iron Age Anomaly (LIAA). From about 1100 to 550 B.C., the magnetic field emanating from the Middle East fluctuated in intense surges.
Shaar and Ben-Yosef were using a relatively new technique called archaeomagnetism. With this method, geophysicists can peer into the magnetic particles inside archaeological materials like metal waste, pottery and building stone to recreate Earth’s magnetic past.
This technique has some advantages over traditional methods of reconstructing Earth’s magnetic field, particularly for studying the relatively recent past.
Generally, scientists study Earth’s past magnetic field by looking at snapshots captured in rocks as they cooled into solids. But rock formation doesn’t happen often, so for the most part, it gives scientists a glimpse of Earth’s magnetic field hundreds of thousands to millions of years ago, or after relatively rare events, like volcanic eruptions. Past magnetic-field data helps us understand the “geodynamo” — the engine that…
Click Here to Read the Full Original Article at Latest from Live Science…