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Magnetism in the Universe

Barringer Invitational Lecture. Magnetism in the Universe. A.P. Guimarães Centro Brasileiro de Pesquisas Físicas Rio de Janeiro, Brazil http://www.cbpf.br/~labmag /. Why the Fascination of Magnetism?.

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Magnetism in the Universe

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  1. Barringer Invitational Lecture Magnetism in the Universe A.P. Guimarães Centro Brasileiro de Pesquisas Físicas Rio de Janeiro, Brazil http://www.cbpf.br/~labmag/

  2. Why the Fascination of Magnetism?

  3. “A wonder of such nature I experienced as a child of 4 or 5 years, when my father showed me a compass.” A. Einstein, Autobiographical Notes, in Albert Einstein: Philosopher-Scientist, vol. I, Ed. P.A. Schilpp, Cambridge University Press, London, 1969, p. 9.

  4. The Sources of Magnetism • Electric currents generate magnetic fields • Magnetism of matter arises from atomic currents and the electron spin

  5. 1. History of magnetism

  6. For How Long have Magnetic Phenomena been Known? • ????? • List of commodities in Mesopotamia, including magnetite, described as šadânu sabitu (‘hematite that grasps’) (2000-1500 BC)

  7. Epistola de Magnete (1269) Petrus Peregrinus (?1220) • Peregrinus served in the army of Charles d’Anjou(Charles I)(1226-1285), probably as an engineer • Siege of Lucera, in Italy

  8. Epistola de Magnete (1269) Petrus Peregrinus • Identified and gave names to the poles • Attraction and repulsion • Magnetization of iron by contact • Described ‘wet’ and ‘dry’ compasses • Loadstone connected to the heavens (‘virtuscoeli’)

  9. De Magnete (1600) • Importance of magnetism at the time • Sum of existing knowledge on magnetism • Experimental observations with the loadstone • One of the first scientific treatises

  10. William Gilbert (1544-1603) Elizabeth I (1558-1603) Terrella Gilbert

  11. Magnus magnes ipse est globus terrestris… • The Earth is a great magnet...

  12. Electricity and Magnetism, the Unification: Oersted and Ampère • Ampère:magnetic bodies and electric currents • The experiment of Oersted(1820)

  13. Electricity and Magnetism, the Unification: Michael Faraday(1791-1867) • Discovery of induction • Types of substances (diamagnetic, paramagnetic, ferromagnetic) • Field lines • The concept of field

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