Subject Index

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Page numbers listed correspond to the print edition of this book. You can use your device’s search function to locate particular terms in the text.

COVERAGE AND ABBREVIATIONS

This index covers the Prologue, Chapters, Epilogue, and Notes.

Additional information about subjects will be found in the Glossary (pages 54760) and Chronology (pages 53746).

Letters appended to page numbers have the following meanings:

b—box

f—figure or photograph

n—footnote

N—in the Notes, the page to which the note refers; for example, 561N26 means “the note to page 26, which will be found on page 561

Absolute interval in spacetime, 90, 92, 91b–92b, 414

Absoluteness of space and time:

Newton’s concepts of, 62–63

Einstein’s rejection of, 72

implies speed of light is relative, 63, 79

experimental evidence against, 65–66

theoretical arguments against, 66–68

see also Relativity of space and time

Absoluteness of speed of light:

not true in Newtonian physics, 63, 79, 133

Einstein’s conception of, 72–73, 79

consequences of, 73–76, 77b, 82

tested by Michelson-Morley experiment, 64, 78–79

tested in modern particle accelerators, 83–84

Acceleration radiation and accelerated viewpoint, 443–46, 444b

Accelerators, particle, 83–84, 86, 237, 339, 340

Accretion disk around black hole:

concept of, 46, 47f, 346

anchoring by black hole’s spin, 346–47

possible roles in quasars and jet production, 346–54

Accretion of gas onto black hole:

in science fiction scenario, 24–25, 24f

as source of X-rays and other radiation, 307–9, 307f, 308f, 318

see also Accretion disk

Accretion of gas onto neutron star, 241–43, 242f

Active galactic nuclei (AGN), 351–53

Adiabatic index, 149, 200b; see also Resistance to compression

Aether:

Newtonian concept of, 63, 564N63

and Michelson–Morley experiment, 64–65, 565N64, 565N65

Einstein’s rejection of, 72, 82, 85

Angular momentum, 27

Antimatter, 173, 173n, 340, 359, 439n, 445

Ants:

T. H. White’s Society of, 137, 285

parable of the, 246–49, 247f

Astronomers contrasted with other scientists, 319–21, 328, 341–42

Astrophysicists contrasted with other scientists, 319–21, 341–42

Atom, structure of, 170b; see also Nucleus, atomic

Atomic bomb, see Nuclear weapons research

Bekenstein’s conjecture about black-hole entropy, 425–26, 442, 445–46

Bets by Thorne:

with Chandrasekhar, about black-hole stability, 296, 298, 298n

with Hawking, about Cyg X-1, 314–15, 315f

with Hawking and Preskill, about cosmic censorship, 481–82, 481f

with Zel’dovich, about black-hole evaporation, 433, 435, 438–39

no bet about time machines, 521

Big bang:

like time reversed stellar implosion, 268–69, 450

singularity at beginning of, 465, 478, 487f, 525

gravitational waves from, 380

tiny black holes created in, 50–51, 447–48

wormholes created in, 497

nonlinearity in, 363b

failure of general relativity in, 86

quantum gravity as key to, 525

speculations on what preceded, 456, 525

topology as a tool for studying, 464f–65f, 471

Big crunch, 450, 454–55, 464f, 465f, 465, 468, 487f, 525, 581N465

Black-hole binary:

and observational search for black holes, 304–9, 305f, 308f, 315–19, 315f

inspiral and coalescence, 48–49, 358–59, 359f, 394–95, 413

as source of gravitational waves, 48–49, 357–61, 379, 393–96, 413

embedding diagrams for, 358f, 359f

Black hole, eighteenth-century version of, 122–24, 123f, 132, 133, 138, 251–53, 252f, 568N122, 568N123

Black-hole evaporation:

overview of, 50–51

presaged by Wheeler’s speculations, 210–11, 21 1f, 244–45, 253–54

presaged by Zel’dovich, 429–35

predicted by Hawking, 435–36; see also

Hawking radiation

details of, 446–48

endpoint of, 482

observational search for, 447–48

Black-hole evolution:

Hawking’s area-increase theorem, 413, 413n, 416–17, 422–23, 427, 462

laws of black-hole mechanics and thermodynamics, 427, 436, 442, 445–46

Black hole, fall of objects into, 33, 291–92, 292f;

see also Accretion disk around black hole;

Accretion of gas onto black hole

Black-hole formation by stellar implosion, see

Implosion of star to form black hole

Black hole, gigantic:

formation of, 354–55, 396

serendipitous discovery of, 322, 326, 355

as power source for quasars and radio galaxies, 346–54; see also Quasars; Radio galaxies; Radio jets; Radio waves, cosmic

number of in Universe, 354

in center of our Milky Way galaxy, 354

rate of swallowing Universe’s matter, 355–56

Black-hole interior:

summary of current understanding, 29–32, 36, 472–73

details of current understanding, 473–80

Oppenheimer–Snyder description of, 450–53, 452f, 473

Khalatnikov–Lifshitz claim of no singularity, and their retraction, 453–56, 455f, 459, 466–69, 473–74

singularity at center, overview of, 29–32

Penrose’s theorem that hole contains singularity, 462–63

BKL (mixmaster) singularity, 468–69, 474–76, 475f

foam-like structure of singularity, 476–79, 478f, 525

aging of tidal gravity in, 479–80

speculations on travel to another universe, 456–58, 457f, 473–74, 484

see also Singularity

Black hole, names for:

Schwarzschild singularity, 121, 136–37, 244, 250, 255

frozen star, 255–56, 291

collapsed star, 256

black hole, coined by Wheeler, 256–57

Black hole, observational searches for:

by blot-out of starlight, 303

by gravitational focusing of light, 303–4, 303f

in binary star systems, 304–9, 305f, 308f, 315–19, 315f

by X-rays from gas accreting onto hole, 307–9, 307f, 308f, 309–14

using gravitational waves, 360–61, 393–96

serendipitous discovery by radio telescopes, 322, 326

no definitive signature as yet, 317–19, 360–61

signature in gravitational waves, 360–61

Black hole, predictions of and resistance to predictions:

Schwarzschild’s prediction of, 131–34

Chandrasekhar’s prediction of, 160

Oppenheimer-Snyder prediction of, 211–19

Einstein’s rejection of, 121, 134–37, 523

Eddington’s rejection of, 134–35, 161–63, 523

Wheeler’s temporary rejection of, 209–11, 21 1f, 238, 523

Wheeler’s acceptance and advocacy of, 239–40, 244–45, 253

widespread resistance to, 138–39, 196–97, 219

astronomers’ resistance, 196–97

Black hole, primordial, 50–51, 447–48

Black-hole properties:

overview of properties, 23–56, 258–59

circumference, 28–29, 28n

radius, 30–33

shape, 28, 51–52, 293, 293f

blots out light from stars behind it, 26, 41, 303

warpage of space, 43; see also Embedding diagrams

tidal gravity, 34–37

spin and swirl of space, 27–28, 50–52, 289–94, 291f, 292f, 346–48, 408f; see also Kerr solution

gyroscopic action, 346–48

orbits, 38–40, 52, 291–92, 292f

gravitational acceleration, 40, 43

gravitational focusing of light, 41–44, 42f, 303–4, 303f

gravitational blueshift of light, 44

electric charge and field, 286, 288–89

rotational energy, 53, 294

entropy, 423–26, 442, 445–46

atmosphere, 443–46, 444b

superradiance, 433

pulsations, 295–99

stability, 296–98

Hawking’s area-increase theorem, 413, 413n, 416–17, 422–23, 427, 462

laws of black-hole mechanics and thermodynamics, 427, 436, 442, 445–46

uniqueness of, see “Hair” on black holes as described by membrane paradigm, 405–11, 443, 445; see also Membrane paradigm

see also Critical circumference; Embedding diagrams; ”Hair“; Hawking radiation; Horizon; Schwarzschild geometry; Schwarzschild singularity; Singularity

Blandford-Znajek process, 53–54, 54f, 349f, 350–53, 407–9, 408f, 577N350

Chain reactions, nuclear:

concept of, 220, 222, 222b

Zel’dovich–Khariton theory of, 223

Chandrasekhar–Eddington confrontation, 158–63

Chandrasekhar limit, 151–52, 154f, 156b–57b, 161f, 175

Chaos, 362b

Chemical reactions, 183b, 339–40

Chronology protection conjecture, 521

Clocks, perfect and rubbery, 397–403, 398b, 399f

Cold, dead matter, 197–98, 200b–202b, 203n

Cold fusion, 64

Conservation laws, 284

Cosmic censorship conjecture, 36, 481, 524

Cosmic rays, 165, 173–74, 173n, 174f, 189, 192, 231, 574N239

Critical circumference:

for eighteenth-century black hole, 122, 123f, 252f

predicted by Schwarzschild geometry, 132–38, 132f, 214–15

role in stellar implosion, 214, 217–19, 244, 248–55, 266, 274, 279–81, 329, 415b

role in accretion onto black hole, 139, 418b

and frequencies of gravitational waves, 367

and hoop conjecture, 266, 267f

see also Horizon

Cygnus A:

discovery of, 325f

identification of galaxy, 330–33, 332f–33f

discovery of double lobes, 333, 332f–33f

discovery of jets, 343–45

radio pictures of, 332f–33f, 344f

Cygnus X-1, 314–21, 316f

Dark star (eighteenth-century version of black hole), 122–24, 123f, 132, 133, 138, 251–53, 252f, 568N122, 568N123

Degeneracy of electrons:

concept of, 145n, 145–46, 148

relativistic vs. nonrelativistic, 150–51

in an atom, 170b

Eddington’s views on, 158–60

prevents small black holes from forming, 447

see also Pressure, nonthermal, degeneracy

Degeneracy of neutrons and protons:

in an atomic nucleus, 169

in a neutron star, 170

Differential equation, 153n–54n

Differential geometry, 113–14, 471

Doppler shift, 32, 100, 101b, 103b, 304, 305f, 506–7

Einstein field equation, formulation of:

Einstein’s struggle to discover, 113–17

Hilbert’s discovery of, 117, 119

details of, 118b–19b, 567Nl18–19

see also General relativity

Einstein’s legacy, overview of, 523–25

Einstein X-ray telescope, 314

Electric field lines:

around a charged black hole, 284, 286, 288–89, 289f, 294, 405–7, 406f

see also Magnetic field lines

Electromagnetic laws, see Maxwell’s laws of electromagnetism

Electromagnetic radiation, spectrum of, 25f

Embedding diagrams:

introduced and explained, 126–31, 129f, 127f

as part of a “paradigm,” 401

for star near critical circumference, 129f, 132f, 135

for imploding star, 213–14, 214f, 246–50, 247f

for black hole, 31f, 397, 399f

for electrically charged black hole, 288–89, 289f

for spinning black hole, 291, 291f

for binary black hole emitting gravitational waves, 357, 358f

for binary black hole merging, 359f

for travel to another universe, 456, 457f

for quantum foam, 487f, 495f

for a wormhole, 484–85, 485f, 501f

for creation of a wormhole, 496f

Entropy:

definition of, 423, 424b

increase of, 422–26, 424b

of black hole, 423–26, 442, 445–46

Equation of state:

concept of, 153, 193b

of white-dwarf matter, 150–53, 154f, 156b–57b, 200b–201b

of nuclear matter, 193b–95b, 200b–202b

of cold, dead matter, 200b–202b

Equivalence principle, 44–45, 97–98, 99f, 100, 103b, 109, 371

ETH (Zurich Politechnikum), 60, 62, 68, 69, 71, 93, 113, 115

Exotic material:

nature of, 488–90, 508

vacuum fluctuations as, 491–92, 498, 583N491, 583N492

required to hold a wormhole open, 488, 489b, 490–91, 493–94, 498, 504

required when creating a time machine, 499n

Experimental physicists contrasted with other scientists, 319–21, 328

Fifth force, 64

Fission, nuclear:

concept of, 221b–22b

discovery of, 220

Bohr–Wheeler theory of, 220–23

see also Chain reactions

Free will, 509

Fusion, nuclear:

concept of, 183b, 221b–22b

keeps stars hot, 182, 184, 191

as possible power source for quasars, 340

cold fusion, 64

Gamma rays:

as part of electromagnetic spectrum, 25f

emitted by gas accreting into black hole, 26

emitted in black-hole evaporation, 447–48

General covariance, 114n

General relativity:

Einstein’s struggle to formulate, 96–117

domain of validity, 84–85

experimental tests of, 57–58, 116–17, 393, 563N57–58, 568N131

marriage with quantum mechanics, see Quantum gravity

see also specific concepts: Einstein field equation; Equivalence principle; Gravitational time dilation; Gravity, tidal; Relativity, principle of; Space warpage; Spacetime curvature; Time warpage

Geodesic, 108–12, 108f, 118b, 126–27, 401

Global methods, 465, 490, 490n, 491

Golden age, 258–61, 260f, 299, 341, 346, 370, 426

Grandfather paradox, 508n

Gravitational collapse, see Implosion of star

Gravitational lens and focusing, 41–43, 42f 303–4m 303f, 489b, 507

Gravitational redshift of light:

description of, 32, 131–33, 132f, 142–43, 213f, 214–15, 445, 562N44

deduced from gravitational time dilation, 131, 214

astronomical observations of, 131, 143, 148

Gravitational time dilation:

Einstein’s inference of, 100, 102b–3b

near surface of a star or Sun, 130–31, 214

Gravitational waves:

nature of, 48–49, 358, 362–65, 364f

contrasted with electromagnetic waves, 379–81

strength of, 365

frequencies of, 367, 386, 393

sources of, 379–80

emission of, 379–80

polarizations of, 393–94

from black-hole binaries, 48–49, 357–61, 393–96, 413

waveforms of, 393–96, 394f

information carried by, 49, 360–61, 394–96, 524

extraction of information from, 393–96, 394f

may revolutionize our understanding of Universe, 378–81, 524

observational proof they exist, 392–93

1940s and 1950s skepticism about, 523

Gravitational-wave detectors:

Weber’s invention of, 366–69

bar detectors, 367–69, 368f, 372, 374–78, 385–87

interferometric detectors, 382–96, 383f, 384b–85b, 388f, 392f; see also LIGO; VIRGO

bars and interferometers compared, 385–87

Braginsky’s standard quantum limit, 372, 374–76, 386

quantum nondemolition, 375–76, 377f, 386–87 see also LIGO; VIRGO

Gravitational-wave recoil (kick-back), 48, 358–59, 393

Gravity, Einstein’s laws of, see General relativity

Gravity, Newton’s law of:

description of, 61, 93–94, 403, 405

Einstein’s objections to, 96

Gravity, tidal:

Newtonian explanation of, 34–35, 104–6, 104f, 106b

Einstein’s explanation—spacetime curvature, 110–12, 110f, 112f

due to Moon, 105, 106b, 111–12f, 362–65, 362b, 364f, 451

in a gravitational wave, 362–65, 364f near singularity inside black hole, see Singularity, tidal gravity near

Great Terror, 181, 185–86, 233b, 268

“Hair” on black holes:

no-hair conjecture, 274f, 275, 277

first evidence of hairlessness, 273–75

Israel’s theorem (proof of hairlessness for nonspinning holes), 279–80

proof for spinning, charged holes, 285

Price’s theorem (how the hair gets lost), 280–85, 282f, 283f, 350

implications of hairlessness: “black-hole uniqueness,” 27, 286, 425

quantum hair, 284

Hawking radiation from a black hole:

Zel’dovich’s discovery of, for a rotating hole, 429–35

Hawking’s discovery of, in general, 435–36

Zel’dovich’s acceptance of, 439

based on quantum field theory in curved

spacetime, 436–39

properties of, 435–36

relationship to superradiance, 433n

as evaporation of black-hole atmosphere, 443–45, 443f

see also Black-hole evaporation

H-bomb: see Nuclear weapons research

Hoop conjecture:

formulation of, 266–67, 267f

evidence for, 264–67

Horizon of black hole:

overview of, 26, 28–30

name coined, 255

circumference of, 28–29, 28n

spin of, 291–94

maximum spin rate, 51–52, 293–94

shape of, 28, 51, 293, 293f

entropy of, 423–26, 442, 445–46

surface gravity of, 436

temperature of, 427, 436, 442, 445, 446

freezing of things near, 217–18, 239, 244–49, 255–56, 291–92

makes quantum fields exotic, 491–92

membrane-paradigm description of, 405–11, 406f, 41 0f, 443, 445

Hawking’s area-increase theorem for, 413, 413n, 416–17, 422–23, 427, 462

laws of evolution of, 427, 436, 442, 446

apparent horizon vs. absolute horizon, 414–17, 415b

teleological evolution of absolute horizon, 417, 418b

apparent horizon as harbinger of singularity, 462–63

see also Critical circumference

Hyperspace, 55, 55f, 128–30, 214, 214f, 289, 291, 456–58, 457f, 458f, 484–86, 487f, 496f, 500–501, 501f

Implosion of star to form black hole:

overview, 27

limited by white-dwarf and neutron-star

masses, 159–61, 161f, 175–78, 177f

prevented by mass ejection, 196–97, 205–6, 210–11, 211f, 238

masses of parent stars, 205–6

Oppenheimer-Snyder predictions of, 211–19

Finkelstein’s reference frame for, 245–46, 249, 255

simulations on a computer, 238–39, 240–41

parable of the ants describing, 246–49, 247f

freezing of implosion as seen from outside, 217–18, 239, 244–49, 255–56

non-freezing as seen in the star, 218, 239, 244–49

creation of singularity, 250, 251, 253–56; see also Singularity

like time-reversed big bang, 268–69, 268n

as proposed power source for quasars, 341

see also Hoop conjecture

Implosion of star to form neutron star, 171, 172f, 173–75; see also Supernovae

Inertial reference frame, 80, 96–98, 99f, 106, 109, 249

Infrared radiation, 25f

Interferometry:

principles of, 384b–85b

and Michelson–Morley experiment, 64

and radio telescopes, 329f, 330

and gravitational-wave detection, 382–84, 383f, 384b–85b; see also Gravitational-wave detectors; LI GO

Interval in spacetime, 90, 92, 91b–92b

Kerr solution for spinning black hole, 289–90, 294, 341–42, 359–61, 359f, 575N289

Laser, invention of, 366, 366n

Laws of physics:

nature of, 57–58, 84–86

logical meshing of, 236–37, 437–38

force the universe to behave as it does, 27, 27n, 57, 86

permitted versus compulsory predictions, 137–38, 285–86; see also Stability and instability

metaprinciples obeyed by, 82–83, 94

should be beautiful, 66, 79, 82, 85

domains of validity of, 38–39, 57–58, 84–86, 193, 405, 514–15, 525

see also Newtonian laws of physics; Paradigm

Length contraction due to relative motion, 65–66, 68, 71, 76, 78, 84, 130, 565N66, 565N68

Les Houches, France, physics summer school, 369–70, 426–28, 433, 434f, 580N426

Light:

as part of electromagnetic spectrum, 25f

Newton’s corpuscular description of, 122–23

Huygens’ wave description of, 123, 147b

Einstein’s wave/particle duality of, 147b

see also Absoluteness of speed of light; Maxwell’s laws of electromagnetism

LIGO:

genesis of, 381–83, 394–91

description of, 391–93

organization of, 391, 391n

Linearity, 373b, 384b–85b; see also Nonlinearity

Magnetic field lines:

depicted, 67f, 262, 263f

“no ends” law, 66, 67f, 79, 81–82, 85, 565N66

magnetic repulsion between, 262

gravitational attraction between, 262–65 around

an imploding star, 273–74

around a black hole, 295, 348, 349f, 350–51, 408–9

in radio sources, 338–39, 342, 348, 349f, 350–51, 408–9

see also Electric field lines

Manhattan project, 223

Mass-energy equivalence and conversion (“E = Mc2”):

details of, 172b, 441n

as consequence of principle of relativity, 82

as implying that energy curves spacetime, 488

as power source for supernovae, 173

Matricide paradox, 56, 508–9, 508n

Matterhorn project, 229

Maxwell’s laws of electromagnetism, 62, 66, 67f, 71, 79, 81–82, 85, 147b, 433, 525, 565N66, 565N68

Membrane paradigm for black holes, 405–11, 443, 445

Mercury, perihelion shift of, 94, 95b, 103, 107, 116–17, 119b

Metaprinciple, 82–83, 94

Michaelson–Morley experiment, 64–66, 72–73, 78, 85, 383f, 565N64, 565N65

Microwave radiation, 25f

Mledina and Serona, tale of, 88–90

Moon:

apparent anomaly in orbital motion, 94, 567N94

as source of tides on Earth’s oceans, 105, 106b, 111–12f, 362–65, 362b, 364f, 451

search for X-rays from, 311, 312f

Naked singularity, 480–82

NASA, 321, 354, 390,

National Science Foundation (NSF), 389–90

Neptune, 94

Neutron, discovery of, 169, 171

Neutron stars:

Zwicky’s prediction of, 165–66

Zwicky’s computations of, 207

Landau’s neutron cores, 182, 182f, 184–86, 191

Oppenheimer–Volkoff–Tolman computations of, 193b–96b

Harrison–Wakano–Wheeler computations of, 198–206

formation in supernovae, 171, 172f, 173–75, 174f

minimum mass, 190–91

maximum mass, 192, 195b

maximum mass determines fates of dying stars, 176–78

observations of, see Pulsar

in binary system, 58, 313, 379, 393, 571N191

as source of gravitational waves, 380, 393–94, 403

see also Pulsar

Newtonian laws of physics:

nature of and applications of, 61–63

foundations of, 61–63

crumbling of foundations of, 63–72

domain of validity of, 84–85

Newton’s laws of motion, 61, 81, 93, 563N61

see also Gravity, Newton’s law of; Maxwell’s laws of electromagnetism

Nobel prize awarded to:

Einstein, 69, 83, 103, 147b

Chandrasekhar, 149

Landau, 187

Townes, Basov, and Prokharov, 366

Hulse and Taylor, 393

Nonlinearity:

concept of, 361, 362b–63b

of black holes’ spacetime warpage, 361

see also Linearity

Novae, 166–68

Nuclear burning (fusion), see Fusion

Nuclear force:

concept of, 169

compared to gravitational force, 184

compared to electromagnetic force, 221b

in atomic nuclei, 170b, 183b

at high densities, 205, pressure due to, 177, 190–92, 194b–95b, 203f, 202b, 571N196

Nuclear weapons research:

American A-bomb project, 223–24

Soviet A-bomb project, 224–26

American H-bomb (super bomb) project, 226–29, 231–32

Soviet H-bomb (super bomb) project, 229–32, 233b–34b

Teller–Ulam/Sakarov–Zel’dovich secret, 241–43, 243f

relation to astrophysics research, 238–43

Nucleus, atomic, 169, 170f, 171, 183b, 221b

Oppenheimer security clearance hearings, 232, 234–35

Oppenheimer–Wheeler confrontation:

background of, 220, 223–24, 226–27, 234–35

confrontation, 209–11, 223–24, 238, 240

Orbit around gravitating body:

in science fiction scenario, 24

used to compute body’s mass, 26, 561N26, 563N61

explained by Newton’s laws, 61

Paradigm, 402–11, 416

concept of, 401

flat-spacetime paradigm for gravity, 401–5

curved-spacetime paradigm for gravity, 401–3

Newtonian paradigm for gravity, 403–5

membrane paradigm for black holes, 405–11, 443, 445

Pauli exclusion principle, 170b

Perturbation methods, 275, 276b, 296–98

Photoelectric effect, 147b

Photon:

and wave-particle duality, 146, 147b, 322

virtual, 439–41, 440f

spontaneous emission of, 431b

see also Gamma rays; Light; X-rays

Physical laws, see Laws of physics

Piezoelectric effect, 368f, 369, 372

Planck-Wheeler length, time, and area, 426, 426n, 442, 446, 476n, 494, 494n, 518, 520, 563N55, 582N476

Plasma, 349f, 350, 353, 408–9, 408f

Plutonium, 199, 222–25, 222b, 573N220, 221

Polarization:

of light, 406n

of a gravitational wave, 393–94, 406n

of metal or a black-hole horizon, by electric charge, 405–7, 406f

Polchinski’s paradox, 509–15, 510f, 512f, 513b–14b

Power notation for large numbers, 29b

Pressure:

physical cause of, 143–45

in rocks, 145, 201b

thermal, 144–45, 159–60

nonthermal, degeneracy 145–46, 148–52, 159–60, 169, 170b, 175–78, 193b, 200b–203b

nuclear, 177, 190–92, 194b-95b, 203f, 202b, 571N196

creates spacetime curvature, 118b–19b, 567N118–19

balances gravity in star, 135f, 137, 143–45, 144f, 151, 154f, 156b–57b, 160, 161f, 175–77, 190, 199, 202, 253

see also Equation of state

Probability, quantum mechanical, 147b, 477, 478f, 495f,496, 515

Pulsar:

nature of, 317–18

discovery of, 174, 468

as proof that neutron stars exist, 317

and tests of general relativity, 58, 393

radio waves from, 379

see also Neutron star

Quanta, 141

Quantum electrodynamics, 433

Quantum fields, 284

Quantum fields in curved spacetime, 436–39, 444b, 447–48, 482, 492, 517, 524

Quantum foam, 55–56, 477–78, 478f, 494–97, 495f

Quantum gravity:

Wheeler’s motivation for, 210, 236–37, 244, 253–56, 262, 301, 449

Wheeler–DeWitt and Hartle–Hawking approach to, 479n

realm of validity, 85–86

nonexistence of time in, 476–77, 518–19

quantum foam of space (wormholes) in, 55–56, 477–78, 478f, 494–97, 495f

at endpoint of stellar implosion, 210, 476–79

in singularity inside black hole, 453, 476–79

and time-machine destruction, 518–20

what we may learn from in future, 52–25

Quantum limits on measurement accuracies, 372–75, 386

Quantum mechanics:

discovery of the laws of, 141, 147b, 162, 180–81

nature of and domain of, 50, 141, 372, 510–11, 514–15

as primary, with classical physics secondary, 514–15

and matter at high densities, 145–46, 147b, 150–52

and atoms, molecules, crystals, 166, 169, 372

and atomic nuclei, 169, 184, 199; see also

Fusion; Nuclear force; Nucleus, atomic

and superconductivity, 231, 339

and superfluidity, 186–87, 186n, 208

and spectral lines of light, 335

and entropy, 423, 445–46

and quantum hair on black holes, 284

and time machines, 515, 517–23

on macroscopic scales, 372–76,

marriage with special relativity, 150–52, 160

marriage with general relativity, see Quantum gravity

speculations about failure of, 184, 207

see also other Quantum entries: Degeneracy;

Hawking radiation; Probability; Uncertainty

principle; Vacuum fluctuations;

Wave-particle duality

Quantum nondemolition, 375–76, 377f, 386–87

Quarks, search for, 370–71

Quasars:

overview of, 45–48, 47f

discovery of, 335–37

variability of, 337–38

energy of, 339

speculations about power source, 273, 339–41

gigantic black holes as power source, 346–54, 407–10, 408f

role of accretion disks in, 346–54

detailed model of, 351–53, 352f

Radio galaxies:

discovery of, 330–31

discovery of double radio lobes, 333

further observations of, 334

energy requirements of, 339

speculations about power source, 273, 339–41

gigantic black holes as power source, 346–54, 407–10, 408f

role of accretion disks in, 346–54

detailed model of, 351–53, 352f

see also Cygnus A; Quasars; Radio jets

Radio jets:

discovery of, 343–45

gyroscopic stability of source, 345

gigantic black hole as source, 345–54, 407–10, 408f

Radio telescopes:

Jansky’s and Reber’s, 323–24, 234f–25f

relation to radar, 327

interferometers, principle of, 328–30, 329f

Jodrell Bank, 331–33, 332f–33f

Greenbank and Owens Valley, 334

Very Large Array (VLA), 343, 344f, 345

VLBI, 345

improvements in angular resolution, 328, 330, 335, 342, 345

as key to revolution in understanding the Universe, 378–79

Radio waves, as part of electromagnetic spectrum, 25f, 322–23, 379

Radio waves, cosmic:

discovery of by Jansky, 323, 324f–25f

observations by Reber, 324–26, 324f–25f, 327–28

difficulty explaining, 323–24

explained as synchrotron radiation, 338–39, 338f

see also Cygnus A; Radio galaxies; Radio jets; Radio telescopes

Rayleigh–Taylor instability, 241–42, 242f

Reference frame:

concept of, 80

inertial (freely moving or freely falling), 80, 96–98, 99f, 106, 109, 249

non-inertial, 114

Finkelstein’s, for stellar implosion, 245–46, 249, 255

accelerated, near black hole, 443–46, 444b

Reissner–Nordström solution af Einstein field equation, 286, 458, 473, 581N458, 582N473, 582N473–74

Relativity of space and time:

Einstein’s conception of, 72–78

deduced from principle of relativity, 73, 77b

explained in terms of spacetime, 88–92, 91b–92b

see also Absoluteness of space and time; Length contraction; Time dilation

Relativity, principle of:

formulated in absence of gravity, 73, 81

as a metaprinciple, 82

consequences of, 76–78, 82

generalized to include gravity, 98, 100, 99f, 114

Relativity theory, see General Relativity; Special Relativity

Relativists contrasted with other scientists, 319–21, 341–42

Research methods and styles:

relation between experimental and theoretical, 64–65

interaction of theorists and experimenters/observers, 207–8, 315–17, 319–21, 326, 372, 376

interactions between various communities of researchers, 319–21, 326, 328, 341–43

interaction between individual researchers, 70–71, 187–89, 193b–96b, 240, 429, 499–500, 505

“small science” style vs. “big science” style, 388–91

massive, worldwide research efforts, 315–17, 319–21

solitude and introspection, 370, 499–500, 505 competition, 369–70

mathematical manipulations of laws, 61, 119–20, 563N61

attitudes toward mathematics, 469–72

different mathematical representations of same physics, 402

order-of-magnitude calculations, 193b

mind flips, 403, 404f, 405, 410–11

mental blocks, 71, 82, 244, 255, 295, 335, 338–39, 417

physical intuition, 79, 96, 119–20, 269, 279, 429

role of subconscious mind, 462

curiosity, 207, 236–37

self-confidence, 207–8

role of a first quick survey, 193b, 212

choice of physical laws, 193b

level of rigor, 441–42, 469

idealizations, 215–17, 217f

approximations, 194b–95b, 276b

perturbation methods, 275, 276b, 296–98

arguments by analogy, 429–30

thought experiments, 110–11, 122, 128, 445–46, 492–93, 496, 500–503, 503n

Sagan-type questions, 493, 496, 497, 508

pedagogy as tool in research, 96

examples of deductive reasoning, 102b–3b, 77b

influence of names, definitions, and viewpoints, 254–56, 295–96, 401–11, 416–17

paradigms, 401–11, 416; see also Paradigm

mentors and their styles, 261–62, 269–72

Resistance to compression:

concept of, 149–50

of white-dwarf matter, 149–53, 154f, 156b–57b, of nuclear matter, 193b–95b, 200b–202b

of cold, dead matter, 200b–202b

see also Equation of state

Rockefeller Foundation fellowships, 179, 220

Rulers, perfect and rubbery, 397–400, 398b, 399f

Sagan-type questions, 493, 496, 497, 508

Schwarzschild geometry for black hole or star:

Schwarzschild’s discovery of, 124

space warpage of, 128–30, 129f, 132–34, 132f

time warpage of, 130–31, 132–34, 132f

Schwarzschild singularity (black hole), 121, 136–37, 244, 250, 255; see also Black hole

Scientific revolution, 401, 403, 405

Sensor, for gravitational-wave detector, 368–69, 372, 374–76, 377f, 386

Shock waves, 173, 215–16, 217f, 238–40, 301, 307, 307f, 453

Singularity, naked, 36, 470–72, 524

Singularity, quantum gravity description of, 476–79, 478f

Singularity theorems:

black holes contain singularities (Penrose), 462–63, 468, 472

Universe began in singularity (Hawking–Penrose), 465

physicists’ reactions to, 524

Singularity, tidal gravity near:

perfectly spherical (Oppenheimer–Snyder), 451–53, 452f

mixmaster, 474–76, 475f

BKL, 30–31, 468–69, 474–76, 475f

aging of, 479–80

see also Black-hole interior

Sirius, 142, 159–60, 161f, 176–77, 177f, 205, 302

Sirius B, 142–43, 143f, 145, 148, 150, 152, 155, 160, 568N143

Soviet Union:

science under Lenin, 179–81

control on travel abroad, 181, 277–78, 466

organization of science in, 287b-88b, 382

influence of Landau on science in, 181, 470–71

attitudes toward topology, 469–72

see also Great Terror: Nuclear weapons research

Space:

foamlike structure in quantum gravity, 477–78, 478f, 494–97, 495f

contraction of: see Length contraction

see also Absoluteness of space and time; Relativity of space and time; Space warpage

Space warpage (curvature):

concept deduced by Einstein, 107

concept explained, 108–9, 108f

as due to rubbery rulers, 397–400, 399f

see also Black-hole properties; Embedding diagrams; Gravitational waves; Wormholes

Spacetime:

concept formulated by Minkowski, 87–88, 92–93, 414

absoluteness of, 90, 92, 91b-92b, 414

space and time derived from, 90, 92

Spacetime curvature (warpage):

concept deduced by Einstein, 107–8

equivalent to tidal gravity, 110–12, 110f, 112f

produced by mass, energy, and pressure, 113–19, 118b-19b

as due to rubbery clocks and rulers, 397–400

objects made from, overview of, 523–24

Spacetime diagrams:

in flat spacetime, 74–76, 75f, 77b, 91b

in curved spacetime, 249–51, 251f

for a star that implodes to form a black hole, 249–51, 251f, 281, 282f, 415b

for the growth of a black hole when matter falls in, 418b

for the fall of an astronaut into a black hole, 452f

for the expanding universe, 460–61

Special relativity:

Einstein’s formulation of, 80–83

experimental tests of, 78, 83–84, 566N78

Spectrum of electromagnetic waves, 25f, 379

Speed of light:

as maximum speed anything can travel, 82

see also Absoluteness of speed of light

Stability and instability:

of cold, dead stars, 203–5, 204b

of black holes, 296–98

of formation of singularity by imploding star, 453–56, 455f, 459, 466, 473–74

of travel through black hole to another universe, 473–74

Star:

laws governing structure of, 143–44, 144f

squeeze/pressure balance in, 135f, 137, 143–45, 144f, 151, 154f, 156b-57b, 160, 161f, 175–77, 190, 199, 202, 253

origin of heat, 182, 184, 191; see also Fusion, nuclear

cold, dead stars, 198, 203f, 202–6, 203n, 204b

unstable stars, 203–5, 204b

supermassive stars, 341

see also Black holes; Neutron stars; Sun; White dwarf stars

Stroboscopic sensor, 376

Strong force, see Nuclear force Sun:

compared with Earth and white dwarf, 143

origin of its heat, 182, 184, 191

fate when it dies, 159, 161f, 175, 177f

Super bomb, see Nuclear weapons research

Superconductivity, 231, 339

Superfluidity, 186–87, 186n, 208

Supernovae:

Baade–Zwicky discovery of, 166–68

photograph of, 167

energy of, 168, 171, 174f

powered by stellar implosion to form neutron star, 171, 172f, 173–75

as sources of gravitational waves, 380

Superradiance, 433n

Synchrotron radiation, 338–38, 338f

Tensor analysis, see Differential geometry

Texas Symposium on Relativistic Astrophysics, 240, 341–42, 498, 577N341, 577N342

Theoretical Minimum, Landau’s, 470–71

Theory:

misleading concept, so not used in this book, 86

see instead Laws of physics

Thermodynamics:

concept of, 422

laws of, 422–23, 436

second law of, 422–26, 424b

of black holes, 427, 436, 442, 445–46; see also Entropy; Horizon; Hawking radiation

Thermonuclear burning and evolution, 197–98, 228–29, 573N229; see also Fusion

Thought experiments, 110–11, 122, 128, 445–46, 492–93, 496, 500–503, 503n

Tidal gravity, see Gravity, tidal

Tides on ocean, 35, 57, 61, 93, 105, 106b, 111–13, 112f, 362–65, 364f, 451

Time, besides the following entries, see

Absoluteness of space and time; Quantum gravity, nonexistence of time in; Relativity of space and time

Time dilation:

due to relative motion, 37, 66, 68, 71, 76, 78, 84, 565N66, 565N68

gravitational, see Gravitational time dilation

Time machines (for backward time travel):

creation of requires exotic material, 499n

as solutions to the Einstein field equation, 499n

based on rapidly spinning matter, 499n, 521

based on cosmic strings, 521, 521n

based on wormholes, 55–56, 502–4, 503f

must accompany non-quantum creation of a wormhole (Geroch theorem), 497

possible if one can travel faster than light, 498–99

paradoxes due to, 508’-15

publicity about, 516

Time machines, destruction of when first activated:

by radiation? No, 505–7, 506f

by vacuum fluctuations? Probably yes, 56, 516–21, 518f

quantum gravity controls the answer, 521, 524

Time warpage:

due to high-speed motion or gravitational

acceleration, see Time dilation

concept deduced by Einstein, 107

as due to rubbery clocks, 397, 400–401, 403

see also Time machines

Topology:

concepts of 463–65, 464b–65b

as foundation for global methods, 465

use of to prove that singularities must occur, 462–63, 465

why introduced into physics by British, 469–77

abortive introduction in Russia, 471–72

Uhuru X-ray telescope, 311f, 312f, 314, 316

Ultraviolet radiation, 25f

Uncertainty principle, 372, 373b-74b, 375

Unification of all physical laws, 525

Universe:

origin of, see Big bang

expansion of, 337

structure of, 301, 302f

ultimate fate of, 355–56; see also Big crunch

speculations on travel to another, 456–58, 457f, 473–74, 484

steady-state theory of, 460

Uranium, 199, 220–23, 221b-22b, 225, 230

Uranus, 94

Vacuum fluctuations:

concept of, 430–31, 430b-31b, 491–92

as cause of spontaneous emission of radiation, 431b, 432–33

and virtual particles, 439–45, 440f, 441n, 444b

as form of exotic material, 491–92

as destroyers of time machines, 516–21

VIRGO, 392–93

Virtual particles, 439–45, 440f, 441n, 444b

Wave-particle duality:

concept of, 146

history of ideas on, 147b

illustrated by X-rays and radio waves, 322

and the uncertainty principle, 373b

and electron degeneracy, 146

and vacuum fluctuations, 439

Weak energy condition, 508

White dwarf stars:

mystery of, 142–45

observations of, 142

Chandrasekhar’s computations of, 153–55

properties of, 142, 143f, 150, 154f, 167f

maximum mass determines fates of dying stars, 159–60, 161f, 176–78, 177f

maximum mass, 151–52, 154f, 156b-57b, 161f

see also Sirius B

World War I, 124

World War II, 166, 197, 219, 222–24, 300, 309, 324, 327, 366, 469

Wormholes, classical:

overview of, 54–56, 55f

concept of, 484–85

brief summary of present status, 524

embedding diagrams of, 485f, 501f

as solutions of Einstein field equation, 486, 488, 490

probably do not occur naturally in Universe, 486

pinch-off if not threaded by exotic material, 486–88, 487f, 491

creation of, by extraction from quantum foam, 56, 494–96, 497–98

creation of, by non-quantum means, 496–97, 497–98

travel through, 500–501, 500f, relative motion of mouths, 501–4, 501f

the hookup of time through, 500–502

time machine based on, 502–4, 503f

Wormholes, quantum (in quantum foam), 55–56, 494–96, 495f

X-ray astronomy and telescopes, 309–14, 311f, 312f, 378–79; see also Cygnus X-1

X-rays:

as part of electromagnetic spectrum, 25f, 322, 379

as high-energy photons, 146 emitted by gas accreting into black hole, 25, 307–9, 307f, 308f, 318, 379

as key to revolution in our understanding of Universe, 378–79

role in hydrogen bomb, 243, 243f