Alpher, Ralph, 100

Andromeda galaxy (nebula), 82, 161, 167–68, 205–206

Cepheid stars in, 78–79

as galaxy, 79–80

anthropic principle, 242

antimatter, 117

balance with matter, 63–64

and charge symmetry, 65, 67

discovery of, 60–62, 112

domination of matter over, 63, 67, 91

energy released by, 61

location of, 62–63

production of excess, 65–66

antiparticles, 114. See also particles

astrologers and astrology, 14, 17, 19, 57

astronomers, 14, 168

astronomy, 14, 57

radio, 190

X-ray, 190

astrophotography, 53

atmosphere

of Earth, 27, 74, 197, 204–205, 232, 234

life's requirement for, 234–35, 240

of planets, 51, 128

of a star, 194–95

of the sun, 205

atomic nuclei, 31, 113. See also fusion

atoms

absorption of radiation by, 109, 130

behavior of, 241, 244

collapse of, 131, 219

helium, 128, 133

hydrogen, 128, 129, 133, 134, 139, 192, 244

nature of, 69, 108, 113, 115

neutral, 110–11

primordial, 95, 98

repulsion of, 30

simple, 139

and spectral lines, 106, 109

See also recombination

baryogenesis, 63, 67

baryon acoustic oscillations, 164, 187

baryons, 71, 113, 117, 197

Bessel, Friedrich, 56–57, 74, 82

big bang model, 91, 94, 97, 101, 118, 120, 128

biosphere, 225

blackbody radiation, 98–99, 101–102, 106

black dwarf stars, 212

black holes

at the end of the universe, 215, 216, 217–18

formation of, 125, 137, 154, 256–57n5

mass of, 148, 253n9, 257n2

in the Milky Way, 137

nature of, 137–38, 141, 212–13, 237

relativity and, 172, 211

supermassive, 137, 200

blazars, 199

Boltzmann constant, 32

Bose, Satyendra Nath, 112

bosons, 35, 112, 117, 221

Brahe, Tycho, 16, 18, 25, 55–56, 57, 79, 82, 178

Bremsstrahlung (“braking radiation”), 150

brown dwarf stars, 148, 211, 212, 213

Bullet Cluster, 153–54, 162

Bunsen, Robert, 51

candles, standard, 177–79, 180, 197

Casimir effect, 131

Cepheid stars, 75–77, 176

chain reactions, 71, 193, 197

charge-parity-time (CPT), 64

clusters

Bullet Cluster, 153–54, 162

collision of, 153

Coma Cluster, 144–46, 161

and the cosmic web, 161–62, 165

dark matter surrounding, 159

demise of, 219

formation of, 170

of galaxies, 144, 146, 148–50

Great Attractor, 167–69, 207

local, 166

Lockyer's sketches of, 46

measurement of, 146, 150–52, 163, 171, 175, 187, 200

Norma Cluster, 169, 170

survival of, 184, 194, 207

Virgo Cluster, 168, 169, 170

Zwicky's study of, 144–46, 148

See also superclusters

COBE (Cosmic Background Explorer), 133

Coma Berenices, 143

Coma Cluster, 144–46, 161

comets, orbit of, 264

Comte, Auguste, 53

Copernicus, Nicolaus, 16, 17, 94, 96

cosmic dawn, 134, 135, 137, 139–41, 165, 202

cosmic distance ladder, 176–77, 180

cosmic evolution. See universe: evolution of

cosmic microwave background (CMB)

detection of, 100–102, 132

exhaustion of, 207–208

formation of, 127

observation of, 122–23, 166, 167, 219, 250n3

cosmic strings, 130

cosmic web, 159, 161–63

finite nature of, 169–70

movement of, 165–66

patterns in, 162–64

cosmological constant, 186, 187, 219

cosmological models

big bang model, 91, 94, 97, 101, 118, 120, 128

Brahe's, 18

braneworld, 223

concordance, 188

epicycle geocentric, 16–17

geocentric, 13, 15–16, 18, 166–67

and gravity, 31

heliocentric, 17, 19, 27, 56, 84

messy, 27

Ptolemaic system, 15, 16

steady-state model, 97, 99–100, 101

cosmological principle, perfect, 97, 101

cosmologists, 30, 62, 129–30, 161, 167, 168, 178, 180, 181, 189–90, 199, 206

cosmology/cosmologies

defined, 171

factors governing, 240–41

modern age of, 177

pre-scientific, 15

Coulomb constant, 32, 33

C-symmetry, 64–65

Curtis, Heber, 77–78, 79

curvature, 172–73

dark energy

and accelerated expansion, 182–83, 188, 207

density of, 184, 241

detection of, 186–87, 256n3 (ch. 13)

nature of, 219, 244

phantom, 219

as vacuum energy, 185–86

dark matter

discovery of, 146

evidence for, 149–50

and inflation, 151

nature of, 151–57, 188, 220, 244

deceleration, 181

degeneracy pressure, 211

degenerates, 210

density, 183–84

constant, 97, 184

of dark energy, 184, 241

decrease in, 93

in the early universe, 129–30, 131, 132, 135

energy, 127

high density, 151, 162, 164

infinite, 29

of matter, 128, 183–84

patterns of, 201

of radiation, 94, 183, 235

deuterons, 71

dew point, 68

diamonds, 210

Dicke, Robert, 100, 101

Dirac, Paul Adrien Maurice, 60, 110, 111–12, 114

Dirac field, 116

distance measures

Cepheid variables, 176

light-years, 74, 81, 166, 250n1 (ch. 5)

parallax, 55–57, 74, 82, 176

parsecs, 81–82, 160–61

standard candles, 177–79, 180, 197

standard rulers, 187

Doppler effect, 52, 80–81

Drake, Frank, 239

Drake equation, 239–40

dunkle Materie. See dark matter

dynamics, 80, 86, 91, 93

Modified Newtonian, 152

See also thermodynamics

Dyson, Freeman, 237

Dyson sphere, 237

Earth

atmosphere of, 27, 74, 197, 204–205, 232, 234

as center of universe, 13, 15–16, 18, 166–67

future of, 204–205

orbit of, 18, 82, 85, 167, 204, 217

photo, 226

rotation and revolution of, 191

eclipses, 45–47, 204, 249n4

as omens, 14–15

Eddington, Arthur, 192

Einstein, Albert

cosmological constant, 186

energy-mass equivalency, 116

on gravity, 85–86, 93

photoelectric effect, 108

simplification of equations, 97

subatomic particles, 110

theory of relativity, 30, 84, 87, 186

view of the universe, 85

electric fields, 115

electricity, 50

electromagnetic fields, 115

electromagnetic radiation, 29, 115, 138

electromagnetism, 32, 34–35, 39, 50, 66, 93, 105, 113, 114, 115, 117

electrons, 60–61, 98, 108–109

energy of, 108–109, 117

mass of, 118

electronuclear force, 35–36

electroweak force, 35

electroweak unification, 67

elliptical orbits, 20, 22, 23, 24, 27, 43, 44, 148. See also orbits

energy

changing states of, 131

conservation of, 183

distortion of space-time by, 30, 86

of electrons, 108–109, 117

and gravity, 31, 114, 145, 200, 237

kinetic, 40, 144–45

as light, 98, 106

loss of, 83, 93, 94, 218

and mass, 85, 86, 111, 116, 132, 193

negative states of, 61

nuclear, 137

of photons, 107, 115, 136

positive states of, 61

potential, 40, 145

quantized, 108

of quantum fields, 130

radiation, 106, 107, 140

released by antimatter, 61

scales of, 32, 35

subatomic quantum nature of, 109

from sunlight, 193, 231, 234

from supernova explosions, 106, 196

vacuum, 117, 130–31, 185–87, 221

vibrational, 106, 117

in wavelengths of light, 33

See also dark energy

entropy, 222, 223

Epoch of Reionization, 141

equilibrium, 40, 66, 99, 145, 148, 150

hydrostatic, 162, 194, 197

Eris, 148

expansion

accelerating rate of, 219

vs. contraction, 125

differing rates of, 175

Hoyle's skepticism about, 94

slowing rate of, 127–28

superluminal, 123

of the universe, 83, 88, 92, 99, 119, 122, 186

Zwicky's skepticism about, 95

extragalactic objects, 143

Fermi, Enrico, 112, 236

fermions, 112

Fermi paradox, 236

Feynman, Richard, 118

fields, 114–15

electric, 115

electromagnetic, 115

gravity, 115

Higgs, 35, 38, 221

magnetic, 37, 115, 200, 234

nuclear, 216

quantum, 115, 117, 130, 185

flatness problem, 40

formalism, 60, 111

Fraunhofer, Joseph von, 51

Friedmann, Alexander, 87, 93

fusion, 193–95

helium, 194, 195–96

hydrogen, 134, 192–93, 206

nuclear, 210, 216

galaxies

distances to, 80

dwarf, 162, 168, 199

elliptical, 201

future of, 256n3 (ch. 13)

irregular, 201

locations of, 161

mass of, 144–45, 153–54

motion of, 82–83

nebulae as, 79–80

orbits in, 165, 167, 199

protogalaxies, 136

speed of, 80–81

spiral, 143

study of, 190

See also Andromeda galaxy (nebula); clusters; Milky Way galaxy; superclusters

galaxy rotation curves, 147, 152, 154

Galileo Galilei, 16, 25–26, 49, 189

and the rings of Saturn, 50

Sidereus Nuncius, 21

Gamov, George, 100

Gerlach, Walther, 110–11

GeV (giga-electron volt), 34, 248n5

Gliese 445, 160

gluons, 69

Grand Unification epoch (GUT epoch), 36, 67, 69

Grand Unified Theories (GUT), 36, 38, 216

gravitational attraction, 44

gravitational constant, 32

gravitational fields, 115

gravitational lensing, 151–52, 153

gravity

and baryons, 151

and the big bang, 118

and the cosmic web, 165–66

Einstein's view of, 85–86, 93

and energy, 31, 114, 145, 200, 237

and the expansion of the universe, 93–94, 124

as natural force, 30–31, 34–35, 39, 44, 103, 113–14

positrons’ use of, 218

quantum, 33, 118

universal, 44–45, 84

and universe formation, 133

Great Attractor, 167–69, 207

great voids, 254n1

Great Wall (CfA2 Great Wall), 162

Guth, Alan, 38, 129

Halley, Edmund, 43, 45–47

Hawking Radiation, 217

heat death, 218

Heisenberg, Werner, 110

helium, 71, 72, 76, 92, 150, 193, 203, 211

helium fusion, 194, 195–96

Herman, Robert, 100

Herschel, William, 47–49

Hertzsprung, Ejnar, 191–92

Higgs, Peter, 35

Higgs boson, 117, 221

Higgs field, 35, 38, 221

Hooke, Robert, 43

Hooke's law, 30

horizon problem, 39

Hoyle, Fred, 94, 95–97, 101

Hubble, Edwin

discovery of Cepheids in the Andromeda Nebula, 78–79, 83, 84, 176, 186

discovery of “island universes,” 137

on the expansion of the universe, 161

on extra-galactic nebulae, 200

use of telescope by, 189

Hubble's constant, 219

Hubble Space Telescope, 83, 143, 175

hydrogen, 72, 150, 192–93, 203

hydrogen fusion, 134, 192–93, 206

neutral, 139–40

plasma soup, 192

hydrostatic equilibrium, 162, 194, 197. See also equilibrium

inertia, 85

infinity, 29, 30, 54–55, 185, 223

inflation

and dark matter, 151

discovery of, 67

eternal, 242

and the expansion of the universe, 38, 40–41, 62, 116, 129–32, 174

explanation for, 38–39

unknown aspects of, 223

intergalactic motion, 167–68

interstellar neighborhood, 228

interstellar travel, 238, 258n6

island universes, 58, 78, 137, 199, 207

James Webb Space Telescope, 139

Janssen, Jules, 52

Jeans, James, 106

Jupiter, 191, 204, 234–35

moons of, 26

orbit of, 23, 234

kaons, 64

Karman Line, 257n1 (epilogue)

Kepler, Johannes

use of Brahe's tables, 18

on our connection to the cosmos, 34, 244

Harmonices Mundi, 21

ideas of, 16

laws of, 44, 20, 22, 23–24

on the order of the universe, 19–20, 22–23, 25

Rudolphine Tables, 24

on the rule of geometry, 19, 23, 171

Kirchhoff, Gustav, 51

Laniakea Supercluster, 169, 225

Large Hadron Collider, 35, 155–56

Leavitt, Henrietta Swan, 74–75

Lemaître, George, 87, 93

leptons, 70–71, 113, 117

life

alien, 238

conditions necessary for, 231–36

planets suitable for, 229, 235

reasons for, 242

search for, 230–31, 237–39

uniqueness of, 227–28, 239–40

light

in the dark ages, 138–39

energy as, 98, 106

infra-red, 49

speed of, 32, 33, 166

tired, 94–95, 251n2

See also redshift

light-years, 74, 81, 166, 250n1 (ch. 5). See also parsecs

LINERs (low ionization nuclear emission-line regions), 199

LIRGs (luminous infra-red galaxies), 199

lithium, 71, 72, 92, 150

Local Bubble, 225

Local Group, 168–70, 207, 225, 230

local superclusters, 232

Lockyer, Joseph, 52

Lockyer, Norman, 46

logarithms, 19

luminosity, 76

MACHOs (MAssive Compact Halo Objects), 154

Magellanic Clouds, 74–75, 199

magnetic fields, 37, 115, 234

self-reinforcing, 200

magnetism, 50, 52, 58

Mars, 23, 204

mass

of black holes, 148, 253n9, 257n2

electron, 118

energy and, 85, 86, 111, 116, 132, 193

of galaxies, 144–45, 153–54

of stars, 196

of the universe, 151

matter

and antimatter, 62–64, 92, 117

density of, 128, 183–84

excess of, 65

in the Milky Way, 61

Maxwell, James Clerk, 50, 110

Mercury, 23, 148–49, 204

orbit of, 23, 204, 248–49

mesons, 113

Messier, Charles, 49–50

microwave antenna, 100–101

Milky Way galaxy

appearance of, 129

black holes in, 137

collision with Andromeda, 205–207

evolution of, 137, 203, 212

formation of, 151

as galaxy, 225, 228–29

images of, 166–69, 190

intelligent species in, 240

and the laws of physics, 244

location of a Cepheid star in, 77

matter in, 61

observation of, 190

as one galaxy among many, 225

orbits within, 190

photo, 229

planets in, 228

size of, 78–79, 81–82, 160, 199, 200, 226

stars in, 95, 160

Minkowski, Hermann, 84. See also space-time

MOND (Modified Newtonian Dynamics), 152–53

monopole, 37–38, 39

moon (Earth's), 15, 26, 43, 54, 166, 204, 234

orbit of, 44, 47

recession of, 47

sketches of, 21

moons

of Jupiter, 26

of the outer worlds, 43, 53, 204, 230, 234, 239

of Saturn, 26

Mount Wilson Observatory, 78, 143

nanozoology, 112

nebulae, 49, 53, 74, 190, 197–98

disappearance of, 209

planetary, 195

spiral, 58, 78–79, 143, 161

velocity of, 81

See also Andromeda galaxy (nebula)

Neptune, 15, 149

neutral atoms, 110–11

neutrinos, 70, 113, 193

neutrons, 69, 71, 92, 113, 196, 216

neutron stars, 213

Newton, Isaac, 43–44, 51, 54, 55, 84, 118

laws of, 47

Newton's constant, 33

Norma Cluster, 169, 170

novae, 196. See also supernovae

nuclear forces, 34–35

strong, 35, 64, 69, 117

weak, 35, 63–66, 113, 117, 155–56

nuclear fusion, 210, 216. See also fusion

nuclear reactors, 70, 71

nucleation points, 37

nucleosynthesis, 72

Olbers, Heinrich, 54

Olbers’ paradox, 54–55, 102

Oort cloud, 160

orbits

of asteroids, 204

atomic, 92, 218

circular, 17, 27

of comets, 234

of Earth, 18, 82, 85, 167, 204, 217

elliptical, 20, 22, 23, 24, 27, 43, 44, 148

in galaxies, 165, 167, 199

of Jupiter, 23, 234

of Jupiter's moons, 26

of Mars, 23

of Mercury, 23, 248–49, 204

in the Milky Way, 190

of the moon, 44, 47

planetary, 16–17, 20, 22, 27, 118, 172, 212–13

of Saturn, 79

speed of, 44, 147

of the sun, 18, 167

of Uranus, 149

of Vulcan, 149

oscillations, 41

baryon acoustic, 164, 187

parallax, 55–57, 74, 82, 176

parsecs, 81–82, 160–61. See also light-years

particle-antiparticle pair, 257n2

particle colliders, 34–35, 70

particles

antiparticles, 114 (see also antimatter)

baryons, 71, 113, 117, 197

bosons, 35, 112, 117

electrons, 60–61, 98, 108–109

fermions, 112

gluons, 69

kaons, 64

leptons, 70–71, 113, 117

mesons, 113

neutrinos, 70, 113, 193

neutrons, 69, 71, 92, 113, 196, 216

photons, 35, 60–61, 92, 93, 94, 107, 113–14, 116–17, 193

pions, 64

positrons, 60–61, 193

protons, 69, 71, 92, 113, 193, 216, 217

subatomic, 110–11, 115, 139, 155, 185, 192, 215, 217

transformation of, 117

virtual, 117

Pauli, Wolfgang, 110

peculiar velocity, 82. See also velocity

Penzias, Arno, 100, 101, 132

phantom dark energy, 219. See also dark energy

phase transitions, 36–37, 67, 68, 220

philosophy, 242–43

photoelectric effect, 108

photography, 53, 57

visible light, 201

photons, 35, 60–61, 92, 93, 94, 113–14, 116–17, 193

decoupling of, 98

energy of, 107, 115, 136

physics

factors governing, 240–41

high-energy, 62

particle, 64

plasma, 100, 105

subatomic, 221

theoretical, 87

pions, 64

Planck, Max, 33, 99, 106–107, 110

Planck collaboration, 133, 252n1 (interlude), 253n5

Planck constant, 33, 107–108

Planck era/epoch, 32, 67, 208

Planck length, 33

Planck scale, 186

Planck units, 33

planetary nebulae, 195. See also nebulae

planetary systems, 198

planets

atmosphere of, 51, 128

elliptical orbits of, 20, 22

end of, 211–12

Eris, 148

Jupiter, 23, 26, 191, 204, 234–35

laws of motion, 20

Mars, 23, 204

mass of, 191

Mercury, 23, 148–49, 204

in the Milky Way, 228

Neptune, 15, 149

orbits of, 16–17, 20, 22, 27, 118, 172, 212–13

Pluto, 148

rogue, 213

Saturn, 26, 50, 79, 249n9

suitable for life, 229

Uranus, 15, 48, 149

Venus, 234

See also Earth

plasma, 66, 92, 94, 98, 134, 136, 140, 141, 150, 162, 164, 191–92, 200

physics, 100, 105

quark-gluon, 69, 98

Pluto, 148

positronium, 218

positrons, 60–61, 193

probabilities, 243

protogalaxies, 136. See also galaxies

protons, 69, 71, 92, 113, 193, 216, 217

Proxima Centauri, 160, 209, 226

P-symmetry, 64, 67

Ptolemaic system, 15, 16

quanta, 107

quantization, 107–108

quantum fields, 115, 117, 185

energy of, 130

quantum field theory, 115–16, 118, 186–87

quantum fluctuations, 131–32, 221

quantum foam, 117

quantum gravity, 33, 118

quantum gravity theory, 118

quantum mechanics, 33, 34, 99, 111, 115, 139, 185, 221, 223, 244

quantum physics, 60

quantum theory, 252–53n3

quark-gluon plasma, 69, 98

quarks, 63, 68, 113, 252n4

quark soup, 67, 68–69

quasars, 199

radiation, 93–94, 98, 106, 108

21-cm, 140

blackbody, 98–99, 101–102, 106

density of, 94, 183, 235

electromagnetic, 29, 115, 138

Hawking Radiation, 217

high-energy, 62, 67, 71

high-frequency, 106

high-intensity, 71

infrared, 99

low-frequency, 106, 107

microwave, 129

thermal, 98–99

ultraviolet, 140

X-ray, 140, 150, 195

Rayleigh, John, 106

recession, 47, 81, 83

recombination, 98, 151, 164

redshift, 81, 83, 88, 93–95, 99, 123, 136, 143, 145, 147, 167, 175, 180, 207–208

relativity

Einstein's theory of, 30, 84, 87, 186

general, 29, 30–31, 84, 85, 86, 87, 118, 171–72, 211, 244

special, 32, 60, 86, 115, 123, 152–53, 185

repulsiveness, 39

Riemann, Bernard, 85

Robertson, Bob, 87

Rubin, Vera, 146–47

Russell, Henry, 191–92

Sagittarius A, 137, 211

Saturn

moons of, 26

orbit of, 79

rings of, 50, 249n9

Schrödinger, Erwin, 60, 110

Schwinger, Julian, 118

scientific revolution, 15–16

Seyferts, 199

Shapley, Harlow, 77–78, 79

singularities, 30, 31–32

Sitter, Willem de, 87, 93

solar system, 171, 191, 198, 204–205, 211–12, 227, 235–36, 239

sound waves, 164

space-time, 30, 84–86, 88

curved, 186

distortion of, 30, 86

spectral lines, 106, 109. See also atoms

spectroscopy, 52, 56, 57

spin, 110–12, 139

stars

61 Cygni, 56–57

atmosphere of, 194–95

black dwarf, 212

brightness of, 192

brown dwarf, 148, 211, 212, 213

Cepheid, 75–77, 176

death of, 140, 195–96

end of, 210–11

evolution of, 193–94

formation of, 134–36, 197–98, 201–203

future of, 208–209, 256n3 (ch. 13)

luminosity of, 76

mass of, 196

in the Milky Way, 95, 160

nature of, 190–91

neutron, 213

new, 178

novae, 196

Population I, 134

Population II, 134

Population III (Pop-3), 134

red giant, 194, 196

variable, 75–76

white dwarf, 195, 197, 210, 212, 216–17

steady-state model, 97, 99–100, 101

Stern, Otto, 110–11

string theories, 223, 242

strong nuclear force, 35, 64, 69, 117

subatomic particles, 110–11, 115, 139, 155, 185, 192, 215, 217. See also particles

sun

atmosphere of, 205

as center of universe, 17, 19, 27, 56, 84

density of, 192–93

life cycle of, 203–204

orbit of, 18, 167

as white dwarf, 212

superclusters, 168–69, 254n1

Laniakea, 169, 225

local, 232

Virgo, 169, 225

See also clusters

supernovae

discovery of, 177–78

energy released by, 106, 196

explosions of, 140, 196

measurement of, 255n5

type Ia, 178–80, 181, 197

type II (core-collapse), 196

symmetry, 35, 60, 61, 63, 112, 213, 215, 224

charge (C), 64–65, 67

parity (P), 64, 67

spherical, 162

of the universe, 35

violations of, 64–65

telescopes, 49, 56, 57, 189

Galileo's invention of, 26

used by Hubble, 78–79

See also Hubble Space Telescope

TeVeS (Tensor-Vector-Scalar), 153

theory of everything (TOE), 36, 118

thermal radiation, 98–99

thermodynamics, 105, 222, 237

time, as fourth dimension, 84–85. See also space-time

tired light, 94–95, 251n2

Tombaugh, Clyde, 48

Tomonaga, Sin-Itiro, 118

tritium, 71

ultraviolet radiation, 140

universe

age of, 102–103, 123, 124

center of, 120

components of, 69, 72

cooling of, 68, 71, 92, 94, 100

edge of, 120–21

end of, 218–20, 245

evolution of, 200, 227, 245

expansion of, 83–86, 88, 92, 94, 95, 99, 119, 122, 123, 125, 127–28, 175, 186, 219

future of, 206, 206–13

heat death of, 218–19

hierarchical nature of, 165–66

history of, 66–67, 68

as homogenous, 96–97

as isotropic, 96–97

mass of, 151

observable, 233

origins of, 31, 34

regeneration of, 222–23

scale of, 77–78

shape of, 121–23, 174–75, 182

size of, 73–74, 103, 122, 189, 226

standard model, 117, 118

See also island universes

Uranus, 15, 48, 149

vacuum decay, 221

vacuum energy, 117, 130–31, 185–86, 221

variable stars, 75–76

velocity, 44, 81, 82, 88, 176, 180

peculiar, 82

Venus, 234

Virgo Cluster, 169

Virgo Supercluster, 169, 225

virial theorem, 144

Voyager 1, 159–60

Vulcan, 149

Walker, Arthur, 87

water vapor, 68

weak nuclear force, 35, 63–66, 113, 117, 155–56

white dwarf stars, 195, 197, 210, 212, 216–17

Wilson, Robert, 100, 101, 132

WIMPs (Weakly Interacting Massive Particles), 154–56

WMAP (Wilkinson Microwave Anisotropy Probe), 133

X-ray radiation, 140, 150, 195

yottawatts, 193

Zone of Avoidance, 168, 169

Zwicky, Fritz, 83, 95, 143–44, 146, 178