CEFR Level: A2 (Elementary)

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Earth’s Magnetic Field Flips Take Longer Than Expected

February 5, 2026

Earth has a magnetic field that protects life on our planet. This invisible force comes from the hot liquid metal deep inside Earth’s core. The magnetic field stops dangerous radiation from the sun and space from reaching us.

The magnetic field has a north pole and a south pole, just like a bar magnet. But these poles don’t stay in the same place forever. Sometimes, the north and south poles switch places. Scientists call this a “geomagnetic reversal” or a “flip.”

New Discovery

Scientists used to think that each flip took about 10,000 years to complete. But a new study by researchers from the United States, France, and Japan has changed this idea.

The team studied rock samples from the ocean floor near Newfoundland, Canada. They drilled 300 meters below the sea floor to find these rocks. The rocks are like a history book—they record what the magnetic field was like millions of years ago.

Surprising Results

The scientists found something surprising. Some magnetic flips 40 million years ago took much longer than expected. One flip lasted 18,000 years. Another flip took 70,000 years!

During a flip, the magnetic field becomes weaker. This means more radiation from space can reach Earth’s surface. Professor Peter Lippert from the University of Utah explains that this extra radiation could affect living things and cause genetic changes.

The researchers were very surprised by their discovery. Lead scientist Yuhji Yamamoto from Japan said the finding was “extraordinary.”

Vocabulary Help

• magnetic field — an invisible force created by magnets or Earth’s core
• reversal — when something changes to the opposite direction
• radiation — harmful energy that comes from the sun and space
• core — the center of something (Earth’s core is very hot)
• sample — a small piece of something used for testing
• genetic — related to genes, which control how living things grow

Grammar Focus

• Past simple vs. present: “Scientists used to think…” (past belief) vs. “The magnetic field protects life” (permanent fact)
• Passive voice introduction: “This invisible force is created by…” / “The study was published…”

Source: Phys.org