The Lodestone

Magnetism, From the Compass to the Hard Drive

von Miriam Loveridge

446 Seiten, Taschenbuch

Kurzbeschreibung des Verlags

A rock that grabs iron. For two thousand years that was all anyone knew, and it was enough to cross oceans by.

Magnetism is the force you can feel in your hand and cannot see, the one that turned a needle south in China, steered every ship for six centuries, and now stores nearly everything humanity has written on spinning plates the size of a coaster. It is also the reason the planet has an atmosphere, the reason a hospital can see inside you, and the reason a bird knows which way is north.

Thirty-four chapters. No physics background required. From the first lodestone to the fields that unmake atoms.

- Why the Chinese needle pointed south, and how it reached the Mediterranean- The needle at sea, and the terror of a compass that would not sit still- The Earth as a great magnet, proposed in 1600 and proved by a globe of lodestone- Charts of the invisible: mapping a field nobody could see- A twitching needle beside a wire, and the accident that joined electricity to magnetism- The electromagnet, the ring, and turning motion into current- Four equations in plain words, and the light they predicted- Why iron, and why almost nothing else- The temperature at which a magnet forgets- The kingdom of domains inside every piece of steel- The loop that remembers, and why it made recording possible- The engine in the Earth's core, and the stripes it painted on the seafloor- The shield around the planet and the storms that test it- Sound frozen in steel wire, then in tape- A trillion bits per square inch: how a hard drive actually works- The strength of rare earths, and where they come from- The frog that floated in a magnetic field- Trains that touch nothing, and wire without resistance- The machine that listens to water: how an MRI sees inside you- Sunspots, starlight, and the fields that unmake atoms- Bacteria that grow their own magnets, and the bird that sees the field

Ending with the missing half. Every magnet ever found has two poles. The final chapter asks why nobody has ever found one with only one, and what it would mean if they did.

This is the story of the force that pointed the way, told from the rock to the reading head.

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• Reihe: Independently published
• ISBN: 9798175820677
• Sprache: Englisch
• Erscheinungsdatum: 20.09.2026
• Größe: 229 x 152 mm
• Verlag: Independently published