Why a Magnet Doesn't Run Out of Energy by Pulling

A fridge magnet can hold a photograph to the door for twenty years without using any power. A neodymium magnet the size of a coin can hold up hundreds of times its own weight for decades. On Mars, bands of magnetized rock have kept their magnetism for roughly 4 billion years. The answer is calmer than it sounds. Holding something still costs no energy, and every pull is a loan the magnet gets back when the two are pulled apart. The deeper story reaches down to the electron. It explains why solid matter holds together and how the universe keeps its energy books balanced. This long-form science documentary starts with a fridge magnet and the simple physics of why holding something still takes no energy. It follows a paper clip's jump and the failure of every magnet perpetual-motion wheel, then moves to lodestones magnetized by lightning, magnetic domains and the Curie temperature. From there it covers the discovery that electric currents make magnetism and why classical physics says magnets should not exist. Then come electron spin, the Einstein–de Haas experiment and Pauli's exclusion principle, and the exchange effect that makes iron's atoms agree. The final stretch covers why neodymium magnets are so strong, Faraday's lines of force, and Maxwell's discovery that empty space around a magnet stores energy. It ends with the debate over whether magnetic forces do work, copper-pipe braking, motors, superconducting hospital scanners, magnetars, and Earth's weakening field. Sources: Wasilewski, P. and Kletetschka, G. (1999). Lodestone: Nature's only permanent magnet - What it is and how it gets charged. Geophysical Research Letters, 26. https://doi.org/10.1029/1999GL900496 Friedrich, B. and Herschbach, D. (2003). Stern and Gerlach: How a bad cigar helped reorient atomic physics. Physics Today, 56(12). Stern and Gerlach: How a Bad Cigar Helped Reorient Atomic Physics The Nobel Prize in Physics 1945: Wolfgang Pauli, for the discovery of the Exclusion Principle. Nobel Prize Outreach. Nobel Prize in Physics 1945 NASA Jet Propulsion Laboratory (1999). Magnetic stripes preserve record of ancient Mars. Mars Global Surveyor magnetometer results, reported in Science. https://www.jpl.nasa.gov/news/magneti... Center for Astrophysics, Harvard and Smithsonian (2005). Blast affected Earth halfway across Milky Way. The December 27, 2004 giant flare from magnetar SGR 1806-20. Blast Affected Earth From Halfway Across The Milky Way | Center for Astrophysics | Harvard & Smithsonian European Space Agency (2020). Swarm probes weakening of Earth's magnetic field. Swarm probes weakening of Earth’s magnetic field #Magnetism #ElectronSpin #PauliExclusionPrinciple #ConservationOfEnergy #Ferromagnetism #Magnetars #PhysicsDocumentary