Astronauts are considered radiation workers, just like people who work with nuclear reactors. Their main occupational hazard has been pegged to be the risk of cancer from radiation. Their cumulative exposure over time is carefully tracked, and they wear dosimeters to record radiation during their missions. But radiation is tricky. The damage from a long, slow exposure of a fixed amount would be different from a short, intense exposure of that same amount. Chronic health problems, leading potentially to cancer, are linked to the long, slow exposure. The prime space risk for slow exposure comes from galactic cosmic rays. Those rays, which are high-energy protons and nuclei thought to have been created by explosions of supernovas in the Milky Way, are thrust through space with so much force that some of them are unstoppable by any shield. They carry far more energy than even the most powerful solar particles. They may be even more apt to cause the biological injuries that lead to cancer than other types of radiation, for unknown reasons, NASA has said.
By contrast, the prime risk for catastrophic immediate injury, called acute radiation sickness, is from a large solar particle event. That involves quick, devastating exposure that overwhelms the body’s threshold for radiation. The 200,000 or so people who died in the atomic bombings in Japan in 1945 were killed by acute poisoning, and so was Alexander Litvinenko, a former Russian officer who died in London in 2006 after being slipped the radioactive polonium-210, possibly in a cup of tea. It took him three weeks to die. Images of him, hairless and nearly without eyelashes, lying sick in a hospital bed, flooded the media. Acute radiation sickness begins swiftly. Cells that reproduce quickly in the body, such as hair follicles, those lining the gut, and blood-making cells in bone marrow, are the first to be affected. Nausea comes. Then vomiting. Fatigue, anorexia, and fever follow, and then hemorrhage as bone marrow fails. Death follows if the bone marrow is badly damaged enough. A bone marrow transplant can occasionally save a life if the exposure was relatively low.
But while cancer is the most feared outcome and is perceived as the highest risk, exposure to high levels of radiation has been found to carry many other health effects. Impaired immunity leading to bacterial and viral illness, short-term memory loss, increased risk of heart attack, and blindness can happen soon after exposure. Over time, the risks are for cataracts, fetal malformations, and sterility. Radiation from galactic cosmic rays, particularly the heavy ions, has recently also been linked to damage to the central nervous system, part of the body that had previously been thought to be able to fend off injury. Now it appears that the radiation can prompt the central nervous system to age long before its time, fostering dementia, Alzheimer’s disease, Parkinson’s disease, and other forms of cognitive harm in the relatively young.
Driven not by a possible pole switch but by the push to send long-term missions to the unprotected planet of Mars in the 2030s, scientists are trying to collect more information about exactly how space radiation affects living tissue. At the moment, they don’t know whether it has precisely the same effects as terrestrial sources of radiation, such as X-rays, gamma rays, and radioactive substances. To test this, and see if they can invent effective shields, they have developed materials that resemble human flesh. Known as tissue-equivalent plastic, the most popular formulation has the appearance of a very stiff black crayon. In 2009, they sent some in a telescope to orbit the moon, carefully calibrated to resemble the thickness of muscle that space radiation would have to penetrate before it reached vulnerable bone marrow. Its job is to measure the amount of energy the particles would deposit in tissue and electronics. Results are still being analyzed.
In the meantime, other researchers sent a radiation detector to Mars along with NASA’s Curiosity rover, which was on a mission to determine whether the red planet could support any life. The monitor was shielded with the same material intended to protect astronauts who might travel to Mars. But bad news: During the 253 days it took to travel to Mars from Earth, from November 26, 2011, to August 6, 2012, the monitors, even shielded, absorbed so much radiation that enduring it would be tantamount to cutting twenty years off one’s life. A separate analysis of the radiation that astronauts would likely encounter on an extended trip to Mars found that a single intense solar energetic particle event could simply kill everyone. So far, there are no effective barriers.
Baker and I had talked for hours by this time, trying to imagine the world of the future.
(Might we have to live underground? I asked. Maybe, he said.) He mused about whether space-weather television channels would become a hot item over time. Quoting, he joked, either Niels Bohr or Yogi Berra, he cracked a rare smile and told me that it’s tough to make predictions, especially about the future.
Privately, I took things much further. As the field dwindles, will we become nomads, wandering the Earth with magnetometers to track parts of the planet that have retained remnants of the magnetic field? I wondered if the equinoxes, the two days a year when night and day are the same length, linked to geomagnetic disturbances, will become days of mass terror. Or whether religious sects will emerge to placate an angry sun god, a weird postmodern parallel to the citizens of ancient Egypt and Mexico who worshipped the sun for more benign reasons. Or perhaps necessity will force our magnetic sixth sense to reemerge, allowing us once again, like birds, to see the field in order to survive. I could envision the possibility of cancer communes springing up like the leper colonies of old. Or refuges for the radioactively poisoned or for teenagers whose brains the rays have pushed to early dementia. Will suits of stiff black crayon be all the rage?
And then there were psychological questions. I wondered what it will feel like if the lights, that ultimate symbol of civilization’s progress, go out. Or how we know where we are when we have four or eight poles. Or where we come from, once the current north pole moves to the south. How does a species so used to controlling the conditions of life adapt to the fact that this revolution within the core is happening no matter what we do?
I left Baker’s office overlooking the Rockies, deep in contemplation about the fate of life as we know it. One thing he had said near the beginning of our time together had fastened itself to my imagination. It was not a fact but an image, told with wonder.
He was talking about the solar dynamo and how, for a time, scientists were sure that they understood it fully. The last solar cycle proved them wrong when their predictions about its activity turned out to be wholly incorrect. That’s what he thinks about when he considers the state of knowledge of the Earth’s tortured magnetic field. It is weakening. The north pole is on the run. The South Atlantic Anomaly is shifting, gaining ground fast and becoming a stronger agent for change. All these indicate mysterious goings-on below the surface of this spinning magnet we live on. It’s as if they are pushing up against an opaque glass and, try as we might, we can make out only their shadowed forms.
notes
PART 1
Richard Feynman, Nobel laureate Richard Feynman, interview by Christopher Sykes, Fun to Imagine, BBC, July 15, 1983.
CHAPTER 1
precise mathematical laws so far to describe reality Neil Turok, The Universe Within: From Quantum to Cosmos (Toronto: Anansi Press, 2012), 46 et passim.
CHAPTER 2
holding electrons in place and allowing atoms to link up into molecules Sean Carroll, in discussion with the author, December 2016.
a field for each of the fundamental forces and thirteen other fields governing matter David Tong, “The Real Building Blocks of the Universe,” Royal Institution lecture, November 25, 2016, available online at https://www.youtube.com/watch?v=zNVQfWC_evg. As he explains, the thirteen fields have to do with quarks, the electron, neutrinos, and the Higgs.
have a value everywhere in the world Sean Carroll, in discussion with the author, December 2016.
“to understand invisible angels” Richard Feynman, The Feynman Lectures on Physics: Commemorative Issue, vol. 2 (Pasadena: California Institut
e of Technology, 1989), 20–29.
a little wave tied up into a bundle of energy Tong, “The Real Building Blocks.”
the bits that will eventually form the cores of atoms For more detail, consult G. Brent Dalrymple, Ancient Earth, Ancient Skies: The Age of Earth and Its Cosmic Surroundings (Stanford: Stanford University Press, 2004).
ascending atomic number, from hydrogen on up It goes from hydrogen, with one proton, to the handful of man-made atoms with 118, called Oganesson. So far. New elements with even more protons could be yet created in a lab. The bigger they get, the less stable they are, because the strong nuclear force keeping their protons together is struggling to keep up.
Those variations are called isotopes The nomenclature of an isotope comes from combining its element name and the sum of its protons and neutrons. By far the most common carbon isotope (99 percent) is carbon-12, with six protons and six neutrons. Carbon-13, with six and seven, makes up about 1 percent. Carbon-14, with six and eight, is radioactive and extremely rare and is created when a hot neutron left over from cosmic radiation shows up in the carbon nucleus. This form of carbon is unstable and its mission is to gain greater stability. So, in lockstep with time, one of its neutrons mutates, creating a proton and turning carbon-14 into nitrogen-14. Carbon-14 is the one that scientists use to tell how old a fossil is, a process called radiocarbon dating after the radioactive carbon isotope. They use the transformation of radioactive potassium (K) into argon (Ar) in the same way. That method of dating became a key in proving the theory of pole reversals.
With some exceptions Plasmas, for example.
must spin in opposite directions This is Pauli’s exclusion principle.
Electrons strongly prefer not to be in pairs This is known as Hund’s rule.
made up of two components a vector Technically, the Earth’s magnetic field is an axial vector. Thanks to Andrew D. Jackson for this note in a communication with the author in December 2016.
CHAPTER 4
unusually strong natural magnets Vasilios Melfos et al., “The Ancient Greek Names ‘Magnesia’ and ‘Magnetes’ and Their Origin from the Magnetite Occurrences at the Mavrovouni Mountain of Thessaly, Central Greece. A Mineralogical-Geochemical Approach,” Archaeological and Anthropological Sciences 3, no. 2 (2011): 165–72, doi: 10.1007/s12520-010-0048-6.
“into whose embrace iron leaps” Pliny the Elder, Natural History (Loeb Classical Library, 1938), Book 36, 25, doi:10.4159/DLCL.pliny_elder-natural_history.1938.
as the historian A.R.T. Jonkers chronicles A.R.T. Jonkers, Earth’s Magnetism in the Age of Sail (Baltimore: Johns Hopkins University Press, 2003), 39–41.
correctly predicted the solar eclipse of May 28, 585 BCE Joshua J. Mark, “Thales of Miletus,” Ancient History Encyclopedia, September 2, 2009, http://www.ancient.eu/Thales_of_Miletus/.
wearing bronze slippers Diogenes Laërtius, “Empedocles, 484–424 B.C.,” in Lives of Eminent Philosophers 8: 69, available online at http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0258%3Abook%3D8%3Achapter%3D2.
mysterious circular connection Jonkers, Earth’s Magnetism, 40.
as a Victorian translator put it Titus Lucretius Carus, On the Nature of Things, trans. Hugh Andrew Johnstone Munro (London: Bell, 1908).
Galileo Galilei, Charles Darwin, and Albert Einstein Harvard University scholar Stephen Greenblatt tracked the resurrection of Lucretius’s work in The Swerve: How the World Became Modern (New York: W. W. Norton & Company, 2011).
Gillian Turner, a physicist and historian of magnetism Gillian Turner, North Pole, South Pole: The Epic Quest to Solve the Great Mystery of Earth’s Magnetism (New York: The Experiment, 2011), 9–10.
Lucera in Italy, a geopolitically important site For more about the siege of Lucera, consult Julie Anne Taylor, Muslims in Medieval Italy: The Colony at Lucera (New York: Lexington Books, 2005).
Subsequent archeological excavations John S. Bradford, “The Apulia Expedition: An Interim Report,” Antiquity 24, no. 94 (June 1950): 84–94.
CHAPTER 5
different from the Earth’s geographical pole Gregory A. Good, “Instrumentation, History of,” in Encyclopedia of Geomagnetism and Paleomagnetism, eds. David Gubbins and Emilio Herrero-Bervera (Dordrecht, The Netherlands: Springer, 2007), 435 (referred to subsequently as Encyclopedia of G and P).
By the early fifteenth century Jonkers, Earth’s Magnetism in the Age of Sail, 26.
modern reconstructions See NOAA’s Historical Magnetic Declination map for images: https://maps.ngdc.noaa.gov/viewers/historical_declination/.
Norman measured the dip Allan Chapman, “Norman, Robert (Flourished 1560–1585),” in Encyclopedia of G and P, 707.
A military letter recently uncovered in the Naples state archives Paolo Gasparini et al., “Macedonio Melloni and the Foundation of the Vesuvius Observatory,” in Journal of Volcanology and Geothermal Research 53, no. 1–4 (1992), doi:10.1016/0377-0273(92)90070-T.
CHAPTER 6
not celestial but terrestrial A.R.T. Jonkers, “Geomagnetism, History of,” Encyclopedia of G and P, eds. David Gubbins and Emilio Herrero-Bervera (Dordrecht, The Netherlands: Springer, 2007), 356–57.
The great conundrum was longitude For more, read Dava Sobel and William J. H. Andrewes, The Illustrated Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time (London: Fourth Estate, 1998), and Jonkers, “Geomagnetism.”
68 statute miles or 110 kilometers A.R.T. Jonkers, Andrew Jackson, and Anne Murray, “Four Centuries of Geomagnetic Data from Historical Records,” Review of Geophysics 41, no. 2 (2003): 2–15, doi: 10.1029/2002rg000115. Or, as Sobel puts it, 60 minutes or 1 degree equals 110 kilometers or 68 statute miles in Illustrated Longitude, 7.
spins on an axis at the same rate every day That was beginning to be commonly understood after the 1543 publication of Nicolaus Copernicus’s treatise De Revolutionibus Orbium Coelestium, which described a sun-centered solar system, and the Earth spinning on its axis each day.
you have traveled each day Read Sobel, Illustrated Longitude, for the full story.
with a declination angle of 0 Jonkers, “Geomagnetism,” 356.
At the time Gilbert began his magnetic research Stephen Pumfrey, Latitude and the Magnetic Earth: The True Story of Queen Elizabeth’s Most Distinguished Man of Science (Duxford, Cambridge: Icon Books, 2003), 70.
Back then, it was outrageous Allan Chapman, “Gilbert, William (1544–1603),” in Encyclopedia of G and P, 361.
Gilbert’s main aim Pumfrey, Latitude and the Magnetic Earth, 90.
one scholar who has plowed through the later work Ibid., 91.
To prove his point Dava Sobel, Galileo’s Daughter: A Historical Memoir of Science, Faith, and Love (New York: Penguin Books, 2000), 173.
likely as directed by Inquisitional censors Pumfrey, Latitude and the Magnetic Earth, 222.
under strict house arrest Read Sobel’s Galileo’s Daughter for the full story.
rather than evidence of his fears of official prosecution Chapman, “Gilbert, William (1544–1603),” Encyclopedia of G and P, 361.
Gilbert’s colleague William Harvey unhappily discovered Ibid.
at the heart of the Maker’s creation Jonkers, “Geomagnetism,” 357.
CHAPTER 7
one of about ninety volcanoes L’Équipe Associée de Volcanologie de L’Université de Clermont-Ferrand II, Volcanologie de la Chaîne des Puys, 5th ed. (Clermont-Ferrand: Parc naturel régional des Volcans d’Auvergne, 2009), 20.
two thousand pages of Latin to explain how he came to that date James Barr, “Pre-Scientific Chronology: The Bible and the Origin of the World,” Proceedings of the American Philosophical Society 143, no. 3 (1999): 379–87, http://www.jstor.org/stable/3181950.
still debated into the late twentieth century Ronald L. Numbers, “The Most Important Bibli
cal Discovery of Our Time: William Henry Green and the Demise of Ussher’s Chronology,” Church History 69, no. 2 (2000): 257–76, doi:10.2307/3169579.
Both Neptunists and Plutonists visited the Auvergne Volcanologie, 20.
Modern analysis says Ibid., 144.
the pressure became too great Ibid., 155.
CHAPTER 8
“plodding, industrious mathematician without a spark of genius” S.R.C. Malin and Sir Edward Bullard, “The Direction of the Earth’s Magnetic Field at London, 1570–1975,” Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences 299, no. 1450 (1981): 357–423, doi:10.1098/rsta.1981.0026.
on a fast canter Ibid., 359.
Gunter had taken Ibid., 414.
“A New and Correct CHART” Edmond Halley, The Three Voyages of Edmond Halley in the Paramore 1698–1701, ed. Norman J. W. Thrower (London: Hakluyt Society, 1980), vol. 2.
until the nineteenth century Julie Wakefield, Halley’s Quest: A Selfless Genius and His Troubled Paramore (Washington, DC: Joseph Henry Press, 2005), 141.
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