The Spinning Magnet

by Alanna Mitchell

  except when sailing where Halley’s curved lines Ibid.

  for a planetary total of four Sir Alan Cook, “Halley, Edmond (1656–1742),” in Encyclopedia of G and P, eds. David Gubbins and Emilio Herrero-Bervera (Dordrecht, The Netherlands: Springer, 2007), 375.

  uncannily accurate prediction Wakefield, Halley’s Quest, 141.

  one unit of intensity Turner, North Pole, South Pole, 106.

  an elegant formula Ibid., 117, gives a full explanation of the math.

  could be shown to be correct Chris Jones, “Geodynamo,” in Encyclopedia of G and P, 287.

  He enlisted Gauss Turner, North Pole, South Pole, 124.

  fourth and most perfect of his mariner’s clocks Sobel and Andrewes, The Illustrated Longitude, 132.

  Harrison eventually won the reward Ibid., passim.

  near-fanaticism David Gubbins, “Sabine, Edward (1788–1883),” in Encyclopedia of G and P, 891.

  “one of the most turbulent periods” John Cawood, “The Magnetic Crusade: Science and Politics in Early Victorian Britain,” Isis 70, no. 4 (1979): 493, doi:10.1086/352338.

  was newborn Today it is called the British Science Association.

  Sabine already had a passion for magnetism Gubbins, “Sabine, Edward (1788–1883),” 891.

  the scientific mission took on a zeal Cawood, “The Magnetic Crusade,” 517.

  the fervor was about proving British scientific supremacy Ibid., 494.

  masterminded the establishment of observatories Gubbins, “Sabine, Edward (1788–1883),” 891.

  Sabine soldiered on Ibid.

  “the greatest scientific undertaking” William Whewell, quoted by Cawood in “The Magnetic Crusade,” 493.

  more than thirty permanent observatories Cawood, “The Magnetic Crusade,” 512–13.

  complete what Newton had begun Ibid., 493.

  British science historian Ibid., 516.

  CHAPTER 11

  “Magnetism and electricity are not independent things” Feynman, Lectures on Physics, 13–16.

  electrical field lines can end Sean Carroll, in discussion with the author, December 2016.

  but only when they are moving Thanks to Sean Carroll for this explanation, in discussion with the author, December 2016.

  all magnetism is produced from currents of one sort or another Feynman, Lectures, 13–16.

  If you are at rest with respect to an electrical charge Thanks to Andrew D. Jackson for this explanation in a communication with the author in December 2016.

  CHAPTER 12

  It was “cosmologically neutral” John Lewis Heilbron, Electricity in the 17th and 18th Centuries: A Study of Early Modern Physics (Berkeley: University of California Press, 1979), 2.

  The fellows of the society wrote back Ibid., 4.

  As the modern American historian of science J. L. Heilbron explains Ibid., 4–5.

  “Forty years ago, when one knew nothing about electricity” Ibid., 6.

  as absurd as boxing a light beam inside a soap bubble Park Benjamin, The Intellectual Rise in Electricity: A History (London: Longmans, Green & Co., 1895), 502.

  But then in January 1746, the legendary Dutch physicist Pieter van Musschenbroek His experiments followed the similar independent finding of the Prussian Lutheran cleric Ewald von Kleist a few months earlier. Von Kleist, alas, wrote the descriptions of his experiment so poorly that no one could reproduce them. So the credit for the discovery has gone to van Musschenbroek and is named after his city.

  Van Musschenbroek wrote up the experiment in Latin Benjamin, The Intellectual Rise in Electricity, 519.

  “I understand nothing and can explain nothing” Heilbron, Electricity in the 17th and 18th Centuries, 314.

  Future scientific refinements replaced the jar’s water with a lead lining Patricia Fara, An Entertainment for Angels: Electricity in the Enlightenment (Duxford, Cambridge: Icon Books, 2002), 56.

  As the Cambridge University historian of science Patricia Fara explains Ibid., passim.

  It was also dangerous Ibid., 54–55.

  they were living in an “age of wonders” Ibid., 70.

  It smacked of a carnival Ibid., 71.

  At one point, he methodically disassembled Joseph Priestley, The History and Present State of Electricity: With Original Experiments (London: printed for C. Bathurst et al., 1775), 201–203, available online at https://archive.org/details/historyandprese00priegoog.

  So, on a stormy day in Philadelphia in June 1752 Ibid., 216–20.

  The physics of lightning is still being explored today Joseph R. Dwyer and Martin A. Uman, “The Physics of Lightning,” Physics Reports 534, no. 4 (2014): 147–241, doi:10.1016/j.physrep.2013.09.004.

  searching for a positive charge Sometimes a negative or positive spark can come up from the ground to meet its opposite in a cloud.

  At the British court Fara, Entertainment for Angels, 3.

  CHAPTER 13

  Together, the two were always on the move Anja Skaar Jacobsen, “Introduction: Hans Christian Ørsted’s Chemical Philosophy,” in H. C. Ørsted, H. C. Ørsted’s Theory of Force: An Unpublished Textbook in Dynamical Chemistry, ed. and trans. Anja Skaar Jacobsen, Andrew D. Jackson, Karen Jelved, and Helge Kragh (Copenhagen: The Royal Danish Academy of Sciences and Letters, 2003), xii.

  Ørsted referred to his scientific work as his “literary career” Andrew D. Jackson and Karen Jelved, “Translators’ Note,” in Theory of Force, xxxiii.

  form of religious worship Andrew D. Wilson, “Introduction,” in Hans Christian Ørsted, Selected Scientific Works of Hans Christian Ørsted, trans. and ed. Karen Jelved, Andrew D. Jackson, and Ole Knudsen (Princeton: Princeton University Press, 1998), xli.

  Because of this overriding philosophy of nature Robert M. Brain, “Introduction,” in Robert M. Brain, Robert S. Cohen, and Ole Knudsen, eds., Hans Christian Ørsted and the Romantic Legacy in Science: Ideas, Disciplines, Practices (Dordrecht, The Netherlands: Springer, 2007), xvi.

  Galvani experimented on sheep and frogs, alive and dead Fara, An Entertainment for Angels, 150–52.

  who in his 1799 doctoral dissertation Andrew D. Jackson, in a communication with the author in December 2016.

  he would conduct an experiment in class Wilson, “Introduction,” xvii.

  It “threatened to upset the whole structure of Newtonian science” Leslie Pearce Williams, Michael Faraday: A Biography (New York: Simon and Schuster, 1971), 140.

  a Danish first Helge Kragh, “Preface,” in H. C. Ørsted’s Theory of Force, ii.

  And yet, as the science historian Gerald Holton put it Gerald Holton, “The Two Maps: Oersted Medal Response at the Joint American Physical Society, American Association of Physics Teachers Meeting, Chicago, January 22, 1980,” American Journal of Physics 48, no. 12 (1980): 1014–19, doi:10.1119/1.12297.

  He spoke for all Britain Brain, “Introduction,” xiv.

  CHAPTER 14

  Conversations on Chemistry, by Jane Marcet Thanks to Andrew D. Jackson for this note in a communication with the author in December 2016.

  tickets to Davy’s talks by chance These and other details are from Williams, Michael Faraday.

  once described equations as “hieroglyphics” David Bodanis, Electric Universe: How Electricity Switched On the Modern World (New York: Three Rivers Press, 2005), 70.

  Faraday did so and tasted fame Nancy Forbes and Basil Mahon, Faraday, Maxwell, and the Electromagnetic Field: How Two Men Revolutionized Physics (Amherst, NY: Prometheus Books, 2014), 61.

  The wire moved clockwise around the magnet This description of Faraday’s first electric motor is based on ibid., 59.

  “Very satisfactory, but make a more sensible apparatus” David Gooding, “Nature’s School,” in David Gooding and Frank A.J.L. James, ed. and introd., Faraday Rediscovered: Essays on the Life and Work of
Michael Faraday, 1791–1867 (New York: Stockton Press, 1985), 120.

  CHAPTER 15

  “A peculiar aura of good nature” Williams, Michael Faraday, 5.

  glass furnace installed in his laboratory Forbes and Mahon, Faraday, Maxwell, and the Electromagnetic Field, 63.

  fluxes of oxygen in the atmosphere Frank A.J.L. James, Michael Faraday: A Very Short Introduction (Oxford: Oxford University Press, 2010), 83–86.

  Ørsted’s pioneering ideas were an influence Thanks to Andrew D. Jackson for this note in a communication with the author in December 2016.

  At that point in the history of electromagnetism Forbes and Mahon, Faraday, Maxwell, and the Electromagnetic Field, 69.

  On the day he did his experiment This explanation is based on the description in ibid., 70–73.

  CHAPTER 16

  This was a far more difficult task Thanks to Andrew D. Jackson for this note in a communication with the author in December 2016.

  “stretched-out or shrunken-down versions of one another” Turok, The Universe Within, 47.

  The electromagnetic waves we can see Ibid.

  Maxwell’s equations theoretically connected space and time Ibid.

  Neither are time and space separate from each other Brian Greene, “Introduction,” in Albert Einstein, The Meaning of Relativity: Including the Relativistic Theory of the Non-Symmetric Field (Princeton: Princeton University Press, 2014), viii–ix.

  known as his annus mirabilis, or miraculous year Eleven years later, Einstein followed it with his general theory of relativity, which linked space, time, mass, energy, and gravity.

  CHAPTER 17

  Its spin helps to organize the field Thanks to Sabine Stanley for this note in communication with the author in March 2017.

  Then something happened Read Dalrymple, Ancient Earth, Ancient Skies, 20–23, for more detail here. Also, thanks to Sabine Stanley of Johns Hopkins for this and the following explanation in various conversations with the author from 2015 to 2017.

  if only we could get at them Thanks to Sabine Stanley for this in communication with the author in March 2017.

  In the case of the sun Eugene Parker, “Dynamo, Solar,” in Encyclopedia of G and P, eds. David Gubbins and Emilio Herrero-Bervera (Dordrecht, The Netherlands: Springer, 2007), 178.

  including a whole month’s worth drawn by Galileo in 1612 Sobel, Galileo’s Daughter, 58.

  CHAPTER 18

  Known as the Assam earthquake Nicolas Ambrasey and Roger Bilham, “Reevaluated Intensities for the Great Assam Earthquake of 12 June 1897, Shillong, India,” Bulletin of the Seismological Society of America 93, no. 2 (2003): 655–73, doi:10.1785/0120020093.

  six competing theories about the structure of the inner Earth This description is based on Stephen G. Brush, “Chemical History of the Earth’s Core,” Eos, Transactions American Geophysical Union 63, no. 47 (1982): 1185–88, doi:10.1029/EO063i047p01185; Stephen G. Brush, “Nineteenth-Century Debates About the Inside of the Earth: Solid, Liquid or Gas?” Annals of Science 36, no. 3 (1979): 225–54, doi:10.1080/00033797900200231; Stephen G. Brush, “Discovery of the Earth’s Core,” American Journal of Physics 48, no. 9 (1980): 705–24, doi:10.1119/1.12026.

  it really came down to a dispute over how old the Earth was Charles Coulston Gillispie, Genesis and Geology: A Study in the Relations of Scientific Thought, Natural Theology, and Social Opinion in Great Britain, 1790–1850 (New York: Harper, 1959).

  a direct conduit to the seething cauldron below Brush, “Nineteenth-Century Debates,” 228.

  an “ejectum from the solar furnace” Ibid., 229.

  “its figure must yield” Ibid., 239.

  The raw egg wobbled a great deal Ibid., 242.

  She was in her teens Inge Lehmann, “Seismology in the Days of Old,” Eos, Transactions American Geophysical Union 68, no. 3 (1987): 33–35, doi:10.1029/EO068i003p00033-02.

  “the discovery of hell” Erik Hjortenberg, “Inge Lehmann’s Work Materials and Seismological Epistolary Archive,” Annals of Geophysics 52, no. 6 (2009): 691, doi:10.4401/ag-4625.

  gaining entrée into the best society Andrew D. Jackson, in a conversation with the author in March 2016.

  his family only saw him when they ate together Bruce A. Bolt, “Inge Lehmann: 13 May 1888–21 February 1993,” Biographical Memoirs of Fellows of the Royal Society 43 (1997): 287, doi:10.1098/rsbm.19997.0016.

  woodworking, soccer, and needlepoint Hjortenberg, “Inge Lehmann’s Work Materials,” 682.

  teacher gave her tougher problems to solve Bolt, “Inge Lehmann,” 287.

  Lehmann experienced “severe restrictions” Ibid., 288.

  But it was tolerated Ibid., 289.

  “You should know how many incompetent men” Ibid., 297.

  swap his quiet downscale hotel room Hjortenberg, “Inge Lehmann’s Work Materials,” 683.

  “Of course I am in the summerhouse” Ibid., 684.

  “a black art” Bolt, “Inge Lehmann,” 291.

  cardboard oatmeal boxes Ibid., 297.

  He fobbed her off. For four years Hjortenberg, “Inge Lehmann’s Work Materials,” 690–96.

  underpins the development of today’s theory David Gubbins, “Lehmann, Inge (1888–1993),” in Encyclopedia of G and P, eds. David Gubbins and Emilio Herrero-Bervera (Dordrecht, The Netherlands: Springer, 2007), 469.

  chasing keepers in Greenland Bolt, “Inge Lehmann,” 291.

  Jeffreys wrote to Bohr Hjortenberg, “Inge Lehmann’s Work Materials,” 695.

  CHAPTER 19

  Japan is a global volcano hot spot W. Yan, “Japan’s Volcanic History, Hidden Under the Sea,” Eos, Transactions American Geophysical Union 97 (2016), doi:10.1029/2016EO054761.

  Few were aligned anywhere in between This was a miracle, considering the later discovery that the continents had moved.

  the American geophysicist Allan Cox Allan Cox, Richard R. Doell, and G. Brent Dalrymple, “Reversals of the Earth’s Magnetic Field,” Science 144, no. 3626 (1964): 1537–43, doi:10.1126/science.144.3626.1537.

  why a material could hold its magnetic charge Néel also discovered antiferromagnetics, which are substances in whose atoms the spins align in such a way that they fully offset each other. The Néel point, similar to the Curie point, is the temperature at which an antiferromagnetic loses this alignment.

  showed that Brunhes’s findings were absolutely correct Carlo Laj et al., “Brunhes’ Research Revisited: Magnetization of Volcanic Flows and Baked Clays,” Eos, Transactions American Geophysical Union 83, no. 35 (2002): 381–87, doi:10.1029/2002EO000277.

  a truck made into a roving rock-sampling lab Louis Brown, Centennial History of the Carnegie Institution of Washington: Volume 2, The Department of Terrestrial Magnetism (Cambridge: Cambridge University Press, 2004), 121.

  He turned to Néel Turner, North Pole, South Pole, 173.

  “the earth’s magnetization has suffered repeated reversals” J. Hospers, “Summary of Studies on Rock Magnetism,” Journal of Geomagnetism and Geoelectricity 6, no. 4 (1954): 172–75.

  a poll of twenty-eight leading paleomagnetic researchers Turner, North Pole, South Pole, 182–83.

  In 1964, Allan Cox, Richard Doell, and Brent Dalrymple Cox, Doell, and Dalrymple, “Reversals of the Earth’s Magnetic Field,” 1537–43.

  a small tar-paper shack Konrad Krauskopf, “Allan V. Cox, December 17, 1926–January 27, 1987,” in National Academy of Sciences (US), Biographical Memoirs/National Academy of Sciences of the United States of America (Columbia University Press; National Academy of Sciences, vol. 71, 1977), 20, https://www.nap.edu/read/5737/chapter/3.

  CHAPTER 20

  Alfred Wegener gave two public talks David P. Stern, “A Millennium of Geomagnetism,” Reviews of Geophysics 40, no. 3 (2002): 17, doi: 10.1029/2000RG000097; Edward Bullard, “The Emergence of Plate Tectonics: A Persona
l View,” Annual Review of Earth and Planetary Sciences 3, no. 1 (1975): 3–8, doi:10.1146/annurev.ea.03.050175.000245.

  wrote about the backlash Bullard, “Emergence,” 5.

  An article in Time magazine Turner, North Pole, South Pole, 179.

  They re-dubbed the phenomenon “apparent polar wander” There is something known as “true polar wander.” For an explanation, see Vincent Courtillot, “True Polar Wander,” in Encyclopedia of G and P, eds. David Gubbins and Emilio Herrero-Bervera (Dordrecht, The Netherlands: Springer, 2007), 956–67.

  they were underwater volcanoes Bullard, “Emergence,” 10.

  dismissed it as “girl talk” Marie Tharp, “Connect the Dots: Mapping the Seafloor and Discovering the Mid-Ocean Ridge,” in Lamont-Doherty Earth Observatory of Columbia: Twelve Perspectives on the First Fifty Years, 1949–1999, ed. Laurence Lippsett (New York: Lamont-Doherty Earth Observatory of Columbia, 1999).

  amazement, skepticism, and scorn Ibid.

  He became obsessed Lawrence W. Morley, “Early Work Leading to the Explanation of the Banded Geomagnetic Imprinting of the Ocean Floor,” Eos, Transactions American Geophysical Union 67, no. 36 (1986): 665–66, doi:10.1029/EO067i036p00665.

  the evolution of the ocean basins Robert S. Dietz, “Continent and Ocean Basin Evolution by Spreading of the Sea Floor,” Nature 190, no. 4779 (1961): 854–57, doi:10.1038/190854a0.

  Morley swiftly wrote up a paper Morley, “Early Work.”

  “more appropriately discussed at a cocktail party” Ibid.

  “You don’t believe all this rubbish, do you Teddy?” Bullard, “Emergence,” 20.

  “I felt cold chills” Krauskopf, “Allan V. Cox, December 17, 1926–January 27, 1987.”

  CHAPTER 21

  under the supervision of David Gubbins Gubbins studied under the famous Teddy Bullard.

  put together a 380-year record of the field Jeremy Bloxham and David Gubbins, “The Evolution of the Earth’s Magnetic Field,” Scientific American 261, no. 6 (1989), doi:10.1038/scientificamerican1289-68.

  the line ran midway through the Atlantic Ocean For maps over time, see NOAA’s Historical Magnetic Declination map at https://maps.ngdc.noaa.gov/viewers/historical_declination/.