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Detailed explanation-1: -NASA watches as weird ‘dent’ in Earth’s magnetic field splits in two. Meet the South Atlantic Anomaly. There’s something very strange happening high above South America and the nearby Atlantic Ocean, and NASA is on the case.

Detailed explanation-2: -They published the idea in 1963 in a Nature paper called ‘Magnetic anomalies over oceanic ridges’. It became known as the Vine-Matthews-Morley hypothesis, recognising the work of Canadian geologist Lawrence Morley who had independently come up with the same idea.

Detailed explanation-3: -The South Atlantic Anomaly is a weak spot in Earth’s magnetic field, which protects the planet from high doses of solar wind and cosmic radiation. This anomaly exists because the Earth’s inner Van Allen radiation belt comes closest to the planet’s surface, causing an increased flux of energetic particles.

Detailed explanation-4: -The researchers’ new theory attributes this dent to two large clumps of dense rock that cup the Earth’s core like a pair of hands 1, 800 miles beneath the Earth’s crust. They say that these rocks likely came from a collision early in Earth’s existence 4.5 billion years ago with a Mars-sized planet named Theia.

Detailed explanation-5: -The Englishman William Gilbert (1540-1603) was the first to investigate the phenomenon of magnetism systematically using scientific methods. He also discovered that the Earth is itself a weak magnet.