19 Roy H. Williams, ‘String Theology’, 31 July 2006 (http://www. mondaymorningmemo.com/newsletters/string-theology/).
20 ‘The mind-blowing concepts of one of the world’s most brilliant theoretical physicists’, Australian Broadcasting Corporation, 25 February 2016.
21 Arthur C. Clarke, ‘The Wall of Darkness’, The Other Side of the Sky, Gollancz, London, 2003.
22 Lisa Randall and Raman Sundrum, ‘Large mass hierarchy from a small extra dimension’, Physical Review Letters, vol. 83 (17), 1999, p. 3,370 (http://arxiv.org/pdf/hep-ph/9905221vl.pdf); Lisa Randall, Warped Passages: Unravelling the Mysteries of the Universe’s Hidden Dimensions, HarperCollins, New York, 2006.
23 The radius of the horizon of black holes goes up in step with their mass. So a black hole with twice the mass of another has a horizon of twice the radius. But, because the force of gravity weakens according to the square of distance, this means a black hole with twice the mass of another actually has a gravity only half as strong. Not only this but the rate at which the gravity of such a hole changes – the ‘tidal force’ – is only one-quarter as strong. Since it is the tidal force that ultimately tears apart particle—antiparticle pairs, creating Hawking radiation, Hawking radiation is comparatively weak for big black holes and strong for small black holes.
24 Steve Connor, ‘Stephen Hawking admits the biggest blunder of his scientific career — early belief that everything swallowed up by a black hole must be lost for ever’, Independent, 11 April 2013 (http://www. independent.co.uk/news/science/stephen-hawking-admits-the-biggest-blunder-of-his-scientific-career-early-belief-that-everything-8568418. html).
25 A black body absorbs all the heat that falls on it. The heat is distributed between all the atoms by countless collisions in which fast-moving atoms transfer energy to slower-moving atoms. The result is that the black body emits heat that depends in no way on the kind of atoms the body is made of. Instead, ‘black body radiation’ has a universal spectrum that depends only on one number: the body’s temperature.
26 Jacob Bekenstein, ‘Black holes and the second law’, Nuovo Cimento Letters, vol. 4, 1972, p. 737; Jacob Bekenstein, ‘Black holes and entropy’, Physical Review D, vol. 7, 1973, p. 2,333.
27 Andrew Strominger and Cumrun Vafa, ‘Microscopic origin of the Bekenstein-Hawking entropy’, 1996 (http://arxiv.org/pdf/hepth/ 9601029v2.pdf).
28 Although the Universe is 13.82 billion years old, the distance to the cosmic light horizon — the edge of the observable Universe – is about 42 billion light years. This is because the Universe, during its first split-second of existence, ‘inflated’ far faster than the speed of light. This does not violate relativity because space – the backdrop to cosmic events — can expand at any rate whatsoever.
29 Juan Maldacena, ‘The Large N Limit of Superconformai field theories and supergravity’, Advances in Theoretical and Mathematical Physics, vol. 2, 1998, p. 231 (http://arxiv.org/pdf/hep-th/9711200.pdf).
30 See Chapter 8.
31 Van Raamsdonk, quoted in Ron Cowen, ‘The quantum source of space-time’, Nature, vol. 527, 19 November 2015, p. 290.
32 Albert Einstein, Boris Podolsky and Nathan Rosen, ‘Can quantum-mechanical description of physical reality be considered complete?’, Physical Review, vol. 47 (10), May 1935, p. 777 (http://journals.aps.org/ pr/pdf/10.1103/PhysRev.47.777).
33 Albert Einstein and Nathan Rosen, ‘The particle problem in the general theory of relativity’, Physical Review, vol. 48 (1), July 1935, p. 73.
34 Light is given out when an electron in an atom drops from a high-energy to a low-energy orbit. No light is given out by atoms such as hydrogen – which each possess a single electron – if either the atoms are so cold that every electron is in its lowest-energy orbit or the atoms are so hot that they have been stripped of their lone electrons.
35 Repulsive gravity can come about because in the general theory of relativity the ‘source’ of gravity is in fact energy density (u) + 3 x pressure (P). The pressure exerted by the atoms of normal matter is negligible compared with the energy density of matter. But there is the possibility of novel ‘stuff’ where this is not true. The dark energy is such stuff. In fact, for the dark energy, the pressure is not only negative — it sucks rather than blows – but less than -1/3u. This reverses the ‘sign’ of the source of gravity, turning it from attractive to repulsive. It is this repulsive gravity that is speeding up the expansion of the Universe. The irony is that the dark energy is everywhere trying to shrink. Only through general relativity does this manifest itself as repulsive gravity.
36 In the general theory of relativity, empty space can have intrinsic curvature, or energy. This is known as the ‘cosmological constant’. Zero is a very special number and cosmologists have not been surprised to find that the cosmological constant is non-zero. The surprise is its smallness. Quantum theory predicts that, because of ‘quantum fluctuations’, the vacuum should contain energy. But quantum theory predicts an energy-density for the vacuum – that is, a value for the dark energy — which is 10120 (1 followed by 120 zeroes) bigger than what is observed. This is the biggest discrepancy between a prediction and an observation in the history of science! This number could be brought down to the energy density actually observed if there is another contribution to the vacuum energy which is negative and differs only in the 119th decimal place. This is a tall order. But it is conceivable that supersymmetry could do this since the energy of the fluctuations in the boson fields is positive while the energy in the fermion fields is negative.
37 Mordehai Milgrom of the Weizmann Institute in Rehovot, Israel, believes that, below an acceleration of about one-billionth of a g, gravity changes to a stronger form that does not weaken as quickly with distance as an inverse-square-law force. This Modified Newtonian Dynamics, or MOND, can describe the motions of stars orbiting in all spiral galaxies with a single formula. By comparison, a different amount of dark matter with a different distribution is required to explain the motion of stars in each spiral galaxy. A form of MOND which is compatible with Einstein’s theory of relativity was found by Jacob Bekenstein of the Hebrew University of Jerusalem in 2000. See Jacob Bekenstein, ‘Relativistic gravitation theory for the MOND paradigm’ (http://arxiv.org/pdf/astro-ph/0403694v6.pdf).
38 Rory Carroll, ‘Kip Thorne: physicist studying time travel tapped for Hollywood film’, Guardian, 21 June 2013 (https://www.theguardian. com/science/2013/jun/21/kip-thorne-time-travel-scientist-film).
39 B. Oberg (ed.), The Papers of Benjamin Franklin, vol. 31, Yale University Press, New Haven, 1995, p. 455.
40 ‘Clarke’s Third Law’, Profiles of the Future, Gateway, London, 2013.
Acknowledgements
My thanks to the following people who helped me directly, inspired me or simply encouraged me during the writing of this book: Karen, Bea Hemming, Felicity Bryan, Paul Murphy, Michele Topham, Manjit Kumar, Thomas Levenson, David Tong, Andy Hamilton, Lee Smolin, Nima Arkani-Hamed, John English, Tash Aw, Brian Clegg, Graham Farmelo, David Berman, Gennady Gorelik, Neil Turok, Neil Belton, Brian May, Julia Bateson, Nick Booth, Jonathon Tullett, Daniel Tullett, Jose Tate, Barbara Brighton-Pell, Patrick O’Halloran, Sue Noyce, Graham Noyce, Brian Chilver, Pat Chilver, Jean Dyke, Amanda Capewell, Sam Capewell, Grace Capewell, Rob Capewell.
Index
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.
Aare, river 94
Aargau Cantonal School 94
acceleration 14
Ackroyd, Peter 26, 35, 228–9
Adam’s apple 4
Adams, Douglas 17, 101, 193, 227, 238, 246, 251
Adams, John Couch 73–4, 79, 234
AEG 118, 241
al-Qazwini, Zakanya 40
alchemy 34
Alexandria 228
Library of 227
Alice in Wonderland 173
Alpha Centauri 81
Alpher, Ralph 1
65
Alvin, submersible 63
ammonia 242
Andromeda, Great Nebula in 163
angular momentum 54, 184–5, 226, 232–3
Conservation of 55, 184, 226
antiparticle 47, 187, 198, 210, 231, 253
antimatter 231, 252
Apollo 11 50, 55
Apollo 15 49, 120
Apollo 16 49
Apollo 18 50
Aquarius
Age of 65
constellation of 65, 69
Arago, Françoise 74
Aries, constellation of 65
Aristarchus crater 49–50
Aristotle 6, 97
Arkam-Hamed, Nima, 188–9, 192, 194, 198–9, 204–5, 207, 215, 218–24
Arnaudon, L. 231
arrow of time 166–8
asteroid 57, 61, 85, 225, 232, 236
asteroid belt 61
asteroid impact 49
Atlantic ocean 39–40, 43, 45, 58, 232
Aswan 228
AT&T 165
atom 159
impossibility of 244
atomic clock 102, 126
atomic nucleus 159, 183, 187, 190, 196, 199, 202, 229, 244–5, 248, 251
Aurau 93
autumn 38, 40, 44, 59, 65
Babylon 52–3
Babylonians 52–3, 65–6
Babylonian clay tablets 52
bacterium xvi, 7, 131
Bailey, Nathan 230
Ballard, Bob 63
Baruch, Bernard 20
baryon 252–3
Bath 72
Baton Rouge, Louisiana 133
Batygin, Konstantin 75, 235
Beatles, the 149
Beck, Anna 241
Bede 40
Beethoven, Ludwig van 31
Bekenstein, Jacob 211–13, 236, 254–5
Bell, Jocelyn 159, 245
Bellos, Alex 242
Benford, Gregory 244
Berlin 68–9, 74, 117, 135–8, 144, 147, 150, 152, 154, 170, 243, 247, 251
Berkeley, California 189
Berman, David xiii, 204–6, 215, 218, 220, 222, 241
Bern 98–9, 108, 115, 117–18, 135, 238, 240, 243
bear pits of 118
Berry, Dave 103
Bertault, Simone 243
Besso, Michele 100, 105, 108, 110
Bible, the 34
BICEP2 192, 251
big bang XV, xvii, 80–1, 109, 150, 160–9, 192, 199, 208, 236, 246–8, 253
forging of elements in 164, 246–7
hot 164
origin of term 246
big bang universes 162
big crunch 168
Big Splash, theory 57
binomial theorem 7
black body 165, 211, 247, 254
black body radiation 247, 254
black hole
binary xvi-xvii, 131–2
entropy of a 212–13, 254
evaporation of 211
event horizon of 132, 154
fridge-sized 81
information paradox 211
merger 132
origin of term 244
primordial 81
spinning (Kerr) 244
supermassive 160, 210, 236
stellar-mass 160, 210–11, 236
Black Hole Blues 133, 150, 242
Boeing 747 102
Bohr, Niels 10, 173, 179, 185, 222, 248
Bondi, Hermann 117
bore
meaning of 230
Severn 37–8, 44, 67, 231
Born, Max 181
boson 156, 197, 255
vector 190, 198
Boughn, Stephen 251
Boyle, Robert 248
Bragg, William 173, 248
Brahe, Tycho 10–11
Brewster, David 229
British Museum 52
Bronstein, Matvei 195, 251
Brown, Mike 75–6, 235
Brown, Robert 100
Brownian motion 100
Brumfiel, Geoff 250
brute force, method 234
Cadiz 45
Cairngorm mountains 234
calcium 247
calcium carbonate 52
calculus 7, 24, 31, 41, 228
Callisto 16
Cambridge
University of 6, 26, 145, 156, 159, 191, 204, 229, 239, 252
village of 4, 29
Cancer, constellation of 87
Canterbury Cathedral 48
Capricorn
constellation of 69
Caprotti, Selina 100
Carroll, Rory 256
Castelvecchi, Davide 242
CERN 46, 231
carbon 246
cataract 228–9
Cepheid variable 163, 246
Ceres 236–7
Chadwick, James 158–9
Chaplin, Charlie 149, 243
Challis, George 73
charge (see electric charge)
Chaucer, Geoffrey 230
Chandrasekhar, Subrahmanyan 154, 156–60
Chandrasekhar limit 156, 159–60
Charon 54, 61–2
Chen, L. 232
Ch’ient’ang’kian River 37
Chou, James Chin-Wen 241
Christchurch earthquake 50
Churchill, Winston xvii
Clarke, Arthur C. 204, 224, 253, 256
Clarke’s third law 256
comet 72, 225, 234
Halley’s 33
comet impact 49
Commissariat, Tushna 251
Constantine I 26
Copernicus, Nicolaus 8
corner-cube reflector 55, 233
cosmic background radiation 166, 192
cosmic ray 102–3
Creator, the 7, 34
Crimea 147
Crotts, Arlin 49–50, 232
Cygnus X-l 160
day, length of in past 51–4
d’Arrest, Heinrich 68–70
dark energy 81, 221, 255
discovery of 81
dark matter 79–82, 197, 220–2, 236, 252, 255
Darwin, Charles 21, 96, 237
Davisson, Clinton 181
Dawn, space probe 236
de Broglie, Louis 181
decoherence 249
DeMoivre, Abraham 229
de Sitter, Willem 145, 162
Descartes, René 15
Defoe, Daniel 4, 225
density fluctuations, cosmic 80
Dickey, J. O. 233
diffraction grating 235
dimension
familiar 109
compact 202
Dirac, Paul 68, 234
Dix, Justin 230
Doctor Who 143
Doppler shift 77, 235, 246
double-slit experiment 237
Draco
constellation of 66
Drever, Ronald 132–3, 242
duality
between quantum and gravitational description 214–15
string theory 217
wave-particle 155–6, 180–1, 184, 218
DVD 212
dwarf planet 61–2, 75–6, 237
dynamics 14
dynamo, AC 94, 99
Dyson, Freeman 248
Earth
distance from Moon 38
distance from Sun 83
gravitational acceleration of 241
estimate of diameter of 227–8
age of 76, 225
mantle of 57
mass of 19
radioactive heating of 62
radius of 19
speed of equator 13, 66
tidal bulges of 43, 53, 55, 58, 230
tilt of spin axis 64–5
Echo 1, satellite 165
ecliptic 65, 225
Eddington, Arthur Stanley 145, 147–9, 161, 246
Edgeworth, Kenneth 62
Edison, Thomas 87
Egyptians, ancient 66
Ehrenfest, Paul 243
Ekman, Martin 67
element 7
7, 87, 133, 159, 163–4, 233, 235, 245–7
according to Greeks 9, 21
Enceladus, moon 64
energy, law of conservation of 206, 231
entanglement (see also non-locality) 185–6, 215–17
Eocene 233
equator, speed of 13, 66
ET civilisation 192
ellipse 10
focus of 10
shape of 10–11
Einstein, Albert xvi-xvii, 6, 21, 33, 89, 91–170, 174, 176–80, 184–5, 189–93, 199, 201–2, 205–6, 209, 212–17, 219, 222–4, 228–29, 231, 236–44, 247–8, 251–2, 254–5
Einstein, Hans Albert 98
Einstein, Lieserl 98–9
electric charge (see also charge) 110, 159, 161, 175, 177, 198, 202, 231
quantisation of 202
electrical era xvii
electromagnetic force 22, 81, 159, 196, 198, 205
range of 161, 190
strength compared with force of gravity 19, 190, 207–8
electron 19, 47, 110, 155–9, 165–7, 169, 175, 178–9, 181, 183, 188, 190, 193, 196–9, 201, 205, 207, 231, 234, 244–5, 248, 252, 255
degeneracy pressure 156–9 interference of 181, 248
shell 245
electronvolt 251
Elektrotechnische Fabrik J. Einstein & Cie 118
Encke, Joseph Franz 69
entropy 166
of a black hole 212–13, 254
epicycle 8
equinoxes, precession of 64–7
Equivalence, Principle of 123, 146
Eratosthenes, 227–8
Euclid 135
Elements 135
5th postulate 135
Europa 16, 61
ocean of 63–4
event horizon 132, 154, 191, 209–10, 212–13
Everett, Hugh, III 12
exoplanet 77, 88, 235–6
falling
and not feeling gravity 117–20
In a circle 17
Faraday, Michael 114, 224
Ferdinand, Archduke Franz 147
fermion 156, 159, 197, 255
fertiliser 24
Feynman ’s Lost Lecture 26, 229
Feynman, Richard 23, 26, 96, 139, 196, 228–9, 238, 244, 252
field 114, 241, 252
First Council of Nicaea 26
FitzGerald, George 142, 239
First World War 147, 242
Flamsteed, John 73
Florian 233, 242
Fluckiger, Max 240
Folsing, Albrecht 116, 150, 170, 238
Ford, Kent 78, 80
Friedmann-Lemaître universes (see big bang universes)
fluxions 24
force
centripetal 15–16, 66, 226, 231, 233
fundamental 22, 161, 189–91, 196, 201, 203–5, 207, 209, 220