Roy Kerr successfully solves a decades-old challenge in general relativity; he devises a solution to Einstein’s equations that fully models the gravitational field of a star that is rotating.
The First Texas Symposium on Relativistic Astrophysics is held in Dallas to try to figure out the source of a quasar’s astounding power. This conference was the first notable attempt to link general relativity with astrophysical concerns.
1964
The term black hole is seen in print for the first time in the 18 January 1964 issue of Science News Letter, which was reporting on an astronomy session on degenerate stars at the annual meeting of the American Association for the Advancement of Science (AAAS). Borrowing the term from Robert Dicke, Hong-Yee Chiu, chair of the session, suggested that space was peppered with black holes.
Soviet physicists Yakov Zel’dovich and Igor Novikov, and independently Cornell University physicist Edwin Salpeter, suggest that great energies can be released as matter is drawn to a supermassive collapsed object, forming an accretion disk around it, which could explain a quasar’s long-lasting power.
1965
British physicist Roger Penrose proves theoretically that gravitational collapse always results in the formation of a singularity inside a black hole.
1967
John Wheeler uses the phrase “black hole” to describe his gravitationally collapsed object during a keynote address at the annual meeting of the AAAS. Once his lecture is published in 1968, the scientific community begins to embrace the term as the object’s official name.
British astronomer Jocelyn Bell discovers pulsars, later understood to be spinning neutron stars. The finding convinces many that black holes, too, might exist.
1969
Roger Penrose shows how enormous energies can be extracted from a black hole’s rapid spin.
1971
Based on data from the X-ray satellite Uhuru, an atypical radio source known as Cygnus X-1 is tentatively identified as a black hole, the first to be discovered in space.
1973
Jacob Bekenstein publishes that the area of a black hole’s event horizon is a direct measure of the hole’s entropy.
1974
Attempting to prove Bekenstein wrong, Stephen Hawking instead proves that a black hole can gradually evaporate as it releases radiation (“Hawking radiation”) over time. His finding is a historic link between general relativity and quantum mechanics.
Kip Thorne and Stephen Hawking make a bet on whether Cygnus X-1 is truly a black hole. Thorne is for, Hawking against.
1977
Roger Blandford and Roman Znajek develop their model for extracting energy out of a spinning black hole.
1990
Stephen Hawking concedes to Kip Thorne and agrees that Cygnus X-1 is a black hole.
1999
Construction is completed on the Laser Interferometer Gravitational-Wave Observatory, with one installation in Washington State and another in Louisiana. Operation of the observatory begins in 2001; more advanced detectors are scheduled to be operating in 2015. A gravity-wave signal would provide the first direct proof of a black hole’s existence.
2013
The Texas Symposium, held once again in Dallas, celebrates its fiftieth anniversary. Black holes are now fully accepted. Talks are given on black-hole mergers, their magnetization, energy production, and the gamma-ray bursts they can emit upon their birth.
Notes
Abbreviations
APS, American Philosophical Society Library, Philadelphia
AIP, American Institute of Physics, Niels Bohr Library and Archives, College Park, Maryland
Preface
“Like unicorns and gargoyles”: Thorne, Black Holes and Time Warps, 23.
“Nearly everyone understands”: Wheeler, Cosmic Catastrophes, 176.
“All truth passes through three stages”: The origin of this quotation is often attributed to the nineteenth-century philosopher Arthur Schopenhauer. In the preface to his Die Welt als Wille und Vorstellung (The world as will and representation, 1818), Schopenhauer wrote, “Der Wahrheit ist allerzeit nur ein kurzes Siegesfest beschieden, zwischen den beiden langen Zeiträumen, wo sie als Paradox verdammt und als Trivial gering geschätzt wird,” which translates as, “To truth only a brief celebration of victory is allowed between the two long periods during which it is condemned as paradoxical, or disparaged as trivial.” Many others proceeded to devise variations of this statement. See Shallit, “Science, Pseudoscience,” 2.
“Einstein’s predictions”: Chandrasekhar, “Theory of Relativity,” 249.
“work of art”: Born, “Physics and Relativity,” 253.
energy of a trillion suns: Begelman and Rees, Gravity’s Fatal Attraction, 111.
“Beauty is the splendor of truth”: Wali, “Chandra,” 13. See also “Subramanyan Chandrasekhar—Nobel Lecture: On Stars, Their Evolution and Their Stability” at http://www.nobelprize.org/nobel_prizes/physics/laureates/1983/chandrasekhar-lecture.html.
“We will first understand”: Wheeler and Ford, Geons, Black Holes, 5.
Chapter 1: It Is Therefore Possible That the Largest Luminous Bodies in the Universe May Be Invisible
everything fell toward it: discussed in Aristotle’s De caelo (On the heavens), his cosmological treatise written in the fourth century BCE.
Sun was now at center stage: Copernicus set out his theory in De Evolutionibus Orbium Coelestium (On the revolutions of the heavenly spheres), published in 1543, the year of his death.
Earth was a giant magnet: see William Gilbert, De Magnete (On the magnet, 1600).
threads of magnetic force: discussed in Johannes Kepler’s Epitome Astronomiae Copernicanae (Epitome of Copernican astronomy, 1618–1621).
vortices of aether: described in René Descartes, Le Monde (The world), written between 1629 and 1633 and not published in its entirety until 1677).
“He hesitated and floundered”: Westfall, Never at Rest, 155.
developed an intriguing set of conjectures: Hooke’s paper, titled Attempt to Prove the Motion of the Earth, was published in 1674. He republished it in 1679 in his Lectiones Cutlerianae.
“Circle, Ellipsis”: Westfall, Never at Rest, 382.
“I am … shy”: Brewster, Memoirs of Newton, 193.
“An ellipsis”: Westfall, Never at Rest, 403.
“ecstasy, total surrender”: Westfall, Never at Rest, 103.
Kepler had revealed: Kepler, Astronomia Nova (The new astronomy, 1609).
“For nature is simple”: Newton, Principia, 794.
“I have not as yet”: Newton, Principia, 943.
comet would return: in Halley, Astronomy of Comets.
“the most inventive”: McCormmach, “Michell and Cavendish,” 127.
“father of modern seismology”: Hardin, “Scientific Work,” 30.
Michell was able to compute: Jungnickel and McCormmach, Cavendish, 185.
Cavendish ultimately obtained the torsion balance: Crossley, “Mystery,” 62.
burying original insights: Crossley, “Mystery,” 66.
“short Man”: Montgomery, Orchiston, and Whittingham, “Michell, Laplace,” 90.
“comet of the first magnitude”: Crossley, “Mystery,” 69.
“continued to indulge”: Montgomery, Orchiston, and Whittingham, “Michell, Laplace,” 90.
“odds against the contrary opinion”: Michell, “Inquiry into the Probable Parallax,” 249.
“arguably the most innovative”: Montgomery, Orchiston, and Whittingham, “Michell, Laplace,” 91.
“those fires”: Michell, “Inquiry into the Probable Parallax,” 238.
“a most valuable present”: Michell, “Means of discovering the Distance,” 36.
“On the Means”: Michell, “Means of discovering the Distance,” 36.
over a succession of meetings: Jungnickel and McCormmach, Cavendish, 344–45.
Michell was devoted to the society: Jungnickel and McCormmach, Cavendish, 565, n. 7.
weren’t detecting: McCormmach, “Michell and Cavendish,” 149.
some historians have speculated: Jungnickel and McCormmach, Cavendish, 564.
pull should also affect light: Michell, “Means of discovering the Distance,” 36–37.
“all light”: Michell, “Means of discovering the Distance,” 42.
“A luminous star”: Laplace, System of the World, 367.
appeal from a dogged colleague: Montgomery, Orchiston, and Whittingham, “Michell, Laplace,” 93.
invisible-star speculation: Gillispie, Laplace, 175.
revolved around a luminous star: Michell, “Means of Discovering the Distance,” 50.
Chapter 2: Newton, Forgive Me
“velocity is so nearly that of light”: Maxwell, “Dynamical Theory,” 466.
“the only occupation”: Maxwell, “Introductory Lecture,” 244.
“not correct”: Einstein, Collected Papers, 1:131.
“no such thing”: Einstein, “Autobiographical Notes,” 53.
“introduce another postulate”: as translated in Lorentz et al., Principle of Relativity, 38. The original paper is Einstein, “Elektrodynamik beweger Körper.”
“superfluous”: Lorentz et al., Principle of Relativity, 38.
“an ‘absolutely stationary space’”: Lorentz et al., Principle of Relativity, 38.
“for me”: Born, “Physics and Relativity,” 250.
“space by itself”: Minkowski, “Space and Time,” 75. This was originally presented as an address to the Eightieth Assembly of German Natural Scientists and Physicians, Cologne, Germany, 21 September 1908.
“banal”: Fölsing, Einstein, 245.
“superfluous learnedness”: Pais, “Subtle Is the Lord,” 152.
“child’s play”: Einstein, Collected Papers, 5:324.
happiest times in his life: Stachel, Einstein from “B” to “Z,” 5.
“like a child”: Eisenstaedt, Curious History of Relativity, 67.
“stuck in its diapers”: Fölsing, Einstein, 245. This quotation comes from a book that Einstein wrote for the public in 1917 on special and general relativity titled Über die spezielle und allgemeine Relativitätstheorie, gemeinverständlich (On the special and general theory of relativity, generally comprehensible). Others have translated the quotation into English as general relativity “would perhaps have got no farther than its long clothes.” I chose Fölsing’s translation.
“Grossman, you must help me”: Pais, “Subtle Is the Lord,” 212.
“I was beside myself”: Hoffmann, Einstein, 125.
“boldest dreams”: Einstein, Collected Papers, 8:160.
“Spacetime tells matter”: Wheeler and Ford, Geons, Black Holes, 235.
“Newton, forgive me”: Einstein, “Autobiographical Notes,” 31.
Einstein in 1911 had suggested a specific test: Einstein, “Influence of Gravity.”
“We have no time to snatch a glance at [the Sun]”: Eddington, Stars and Atoms, 115.
unscientifically rooting for Einstein: Eddington, Stars and Atoms, 116.
“LIGHTS ALL ASKEW”: New York Times, 10 November 1919, 17.
“Like the man in the fairy tale”: Einstein, Collected Papers, 10:265.
Chapter 3: One Would Then Find Oneself … in a Geometrical Fairyland
in less than a month: Schwarzschild wrote Einstein from the Russian front with his solution on 22 December 1915. See Einstein, Collected Papers, 8:163–65.
“Mr. Einstein’s result”: Dictionary of Scientific Biography, s.v. “Schwarzschild, Karl.” He wrote those words in his paper “On the Gravitational Field of a Mass Point According to Einstein’s Theory,” first published in Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften zu Berlin, Phys.-Math. Klasse (1916): 189–96. In another English translation (Schwarzschild, “Gravitational Field of a Mass Point,” 952), the phrase is given as “let Mr. Einstein’s result shine with increased clearness.”
“We can wonder”: Schwarzschild, “Ueber das zulässige Krümmungsmaass des Raumes,” 337. Translated from the German, “Man kann die Vorstellungen bis ins Einzelnste ausbilden, wie die Welt in einem sphärischen oder pseudosphärischen [Geometrie]. … Man befindet sich da—wenn man will—in einem geometrischen Märchenland, aber das Schöne an diesem Märchen ist, dass man nicht weiss, ob es nicht am Ende doch Wirklichkeit ist.” The translation used is from Chandrasekhar, Truth and Beauty, 146.
avidly followed Einstein’s progress: AIP, Spencer Weart interview with Martin Schwarzschild, 10 March 1977.
wanted to remove all doubt: Schemmel, “Astronomical Road,” 465.
“The consequences”: Sampson, “Principles of Relativity and Equivalence,” 155.
“they got stuck”: Eisenstaedt, Curious History of Relativity, 266.
“The mass would produce”: Eddington, Internal Constitution of the Stars, 6.
“They realized”: Eisenstaedt, Curious History of Relativity, 264.
best way to describe this unusual place: Eisenstaedt, Curious History of Relativity, 307–8.
the magic sphere would stretch: Wheeler, Cosmic Catastrophes, 179.
He figured that Schwarzschild’s novel entity: Earman and Eisenstaedt, “Einstein and Singularities,” 186. Einstein mentioned this specifically in Meaning of Relativity, 3rd ed., 124, and in earlier editions of the book.
Many viewed Schwarzschild’s sphere: see Piaggio and Critchlow, “Supposed Relativity Method.”
worked out a little calculation: Eisenstaedt, Curious History of Relativity, 261.
densities could ever be greater: see Jeffreys, “Compressibility of Dwarf Stars.”
“clearly not physically meaningful”: Schwarzschild, “Gravitational Field of a Sphere,” 434. See http://cds.cern.ch/record/412373/files/9912033.pdf.
had been in the audience: Schemmel, “Astronomical Road,” 464.
completed two papers: Schwarzschild, “Gravitational Field of a Mass Point,” and “Gravitational Field of a Sphere.”
“As you see, the war”: Einstein, Collected Papers, 8:164.
always ready for a good beer: Weart interview with Schwarzschild.
“I would not have expected”: Einstein, Collected Papers, 8:175.
“there will come a time”: Anderson, “Advance of the Perihelion,” 627.
“concentration to that extent”: Lodge, “Supposed Weight and Ultimate Fate of Radiation,” 551.
“A stellar system”: Lodge, “Supposed Weight and Ultimate Fate of Radiation,” 551.
Chapter 4: There Should Be a Law of Nature to Prevent a Star from Behaving in This Absurd Way!
slight but distinct wobble: Bessel, “Variations of Proper Motions.”
completed one orbit: Bessel, “Variations of Proper Motions,” 139.
“The subject”: Bessel, “Variations of Proper Motions,” 136.
closest to gleaming Sirius: Holberg and Wesemael, “Discovery of the Companion of Sirius,” 167.
testing the optics: Holberg and Wesemael, “Discovery of the Companion of Sirius,” 162.
“there might have been a [prearranged] connection”: Welther, “Discovery of Sirius B,” 34.
“It remains”: Bond, “Companion of Sirius,” 286–87. See also Holberg and Wesemael, “Discovery of the Companion of Sirius,” 165.
Lalande Prize: Holberg and Wesemael, “Discovery of the Companion of Sirius,” 170–71.
sunlike star cooling off: DeVorkin, “Hertzsprung-Russell Diagram,” 32.
companion known since 1783: It was discovered by William Herschel, during his double-star searches, on 31 January 1783. See Herschel, “Catalogue of Double Stars,” 73.
confirmed the spectrum: Adams, “A-Type Star.”
“I was flabbergasted”: Philip and DeVorkin, “In Memory of Henry Norris Russell,” 90.
Adams determined: Adams, “Spectrum of the Companion of Sirius.”
Soon theorists: see Öpik, “Densities of Visual Binary Stars,” and Eddington, “Relation B
etween the Masses.”
“an impossible result”: Öpik, “Densities of Visual Binary Stars,” 302.
“The message”: Eddington, Stars and Atoms, 50.
Ralph Fowler: Fowler, “On Dense Matter.”
“It is something”: AIP, Spencer Weart interview with Subrahmanyan Chandrasekhar, 17 May 1977. See http://www.aip.org/history/ohilist/4551_1.html.
result published as a brief 1931 paper: Chandrasekhar, “Maximum Mass of Ideal White Dwarfs.”
“I am sorry”: Weart interview with Chandrasekhar.
a stronger (and stranger) conclusion: Wali, “Chandra’s Work in Historical Context.”
“inconceivable”: Chandrasekhar, “Highly Collapsed Configurations,” 463.
“there exists in the whole quantum theory”: Landau, “Theory of Stars,” 287.
“ridiculous” result: Landau, “Theory of Stars,” 287.
a thought that the Danish atomic physicist Niels Bohr: Hufbauer, “Landau’s Youthful Sallies,” 340.
The stellar core was a “pathological” region … “one gigantic nucleus”: Landau, “Theory of Stars,” 287–88.
“We may conclude”: Chandrasekhar, “Remarks on the State of Matter,” 327.
The top Britishers in stellar physics—Eddington, James Jeans, and Edward Milne—were too busy arguing: Miller, Empire of the Stars, 81–82.
“It is necessary”: Chandrasekhar, “Stellar Configurations,” 377.
“but I kept away from it”: Weart interview with Chandrasekhar.
“It seemed to me”: Weart interview with Chandrasekhar.
He decided to take on the challenge: Thorne, Black Holes and Time Warps, 153.
This time he had an exact solution: Wali, Chandra, 124.
“Involved in the puzzles”: Miller, Empire of the Stars, 103.
“when the central density”: Chandrasekhar, “Highly Collapsed Configurations (Second Paper),” 207.
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