‘A force more powerful than gravity’: How magnetism locked itself inside Earth – Times of India


NEW DELHI: Magnetism, one of the most tangible fundamental forces, has been a part of Earth‘s history since its formation. In his new book, “CHARGE: Why Does Gravity Rule?”, theoretical physicist Frank Close explores the origins and impacts of this force, explaining how magnetism became an integral part of our planet.
Five billion years ago, as the newborn Earth existed as a hot plasma with swirling electrical currents, these flows created magnetic fields.As the magma cooled and formed the Earth’s solid outer crust, magnetism was locked into minerals containing iron, such as magnetite. Today, the Earth’s liquid core still generates electric currents, which produce a magnetic field that extends into the atmosphere and beyond, although it remains invisible to our senses.
As Frank Close describes, “Magnetism is a manifestation of electricity, and vice versa. Electricity and magnetism were imprinted into our surroundings from the beginning.” This ancient magnetism left a tangible imprint on the Earth’s crust, where it continues to influence the planet far more powerfully than gravity in certain respects.
Around four billion years ago, as the Earth’s surface cooled, iron and other atomic elements accumulated in the strata. Iron, one of the most stable and abundant elements, became magnetic when influenced by the magnetic field. This property can be demonstrated using a bar magnet and iron filings, which align themselves to reveal the direction of the magnetic force.
The Earth’s magnetic field is analogous to a bar magnet, with north and south magnetic poles extending far into space. Historically, magnetic rocks, known as lodestone or magnetite, were discovered in various parts of the world, such as the Isle of Elba and Mount Ida in Asia Minor. These rocks retain their magnetic properties, revealing the ancient magnetic forces at work.
There are legends about the discovery of magnetism, such as a shepherd named Magnes whose iron-nailed shoes were gripped by magnetite. While the exact origins are uncertain, the power of magnetism has likely been known for thousands of years, inspired by natural magnetization of iron in rocks and further revealed through activities like smelting.
By the sixteenth century, travelers documented significant examples of magnetic rocks from regions like East India and the Chinese coast. The understanding of magnetism evolved through various cultures and languages, becoming an essential part of scientific knowledge.
Frank Close’s exploration in “CHARGE: Why Does Gravity Rule?” highlights how magnetism, though often overshadowed by gravity, plays a crucial role in the Earth’s structure and history. The force of magnetism, imprinted in our planet billions of years ago, continues to be a powerful and fascinating aspect of Earth’s geophysical dynamics.

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