Preface 1
1 Introduction
1.1 The cosmological standard model . . . . . . . . . . . . . . . . . . . . 4
2 How does Science work? 13
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2 Scientific Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3 Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.3.1 Colour dependent gravity . . . . . . . . . . . . . . . . . . . . 17
2.3.2 The Perihelion Shift in the Orbit of Mercury . . . . . . . . . . 19
2.4 Changing Theory in Physics . . . . . . . . . . . . . . . . . . . . . . . 20
2.5 Cosmological Simulations . . . . . . . . . . . . . . . . . . . . . . . . . 22
3 What observations do we use? 27 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2 What reaches us . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2.1 Different forms of light - electromagnetic radiation . . . . . . 28
3.2.2 Non-standard messengers - neutrinos and gravitational waves 31
3.3 How Observations are Made . . . . . . . . . . . . . . . . . . . . . . . 34
3.3.1 Optical Telescopes . . . . . . . . . . . . . . . . . . . . . . . . 35
3.3.2 Radio Telescopes . . . . . . . 1 . . . . . . . . . . . . . . . . . . 38
3.3.3 Microwave Telescopes . . . . . . . . . . . . . . . . . . . . . . . 40
3.3.4 Examples for non-standard messenger observatories . . . . . . 43
3.4 Future experiments and telescopes . . . . . . . . . . . . . . . . . . . . 47
3.5 Closing Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
4 What can we actually observe and measure? 51
4.1 Things we can observe directly . . . . . . . . . . . . . . . . . . . . . . 51
4.2 Distance units in cosmology . . . . . . . . . . . . . . . . . . . . . . . 55
4.3 How to measure distances in cosmology . . . . . . . . . . . . . . . . . 56
4.4 Putting things into perspective . . . . . . . . . . . . . . . . . . . . . 62 4.5 A very large map: the distribution of galaxies . . . . . . . . . . . . . 63
4.6 An even larger map: the Cosmic Microwave Background . . . . . . . 66
5 What is the universe made of? 69
5.1 Familiar types of matter, what is normal stuff made off? . . . . . . . 69
5.1.1 Matter on the smallest scales - up to atoms . . . . . . . . . . 69
5.1.2 Larger scales - particles interacting . . . . . . . . . . . . . . . 71
5.1.3 Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
5.2 Where does normal matter come from . . . . . . . . . . . . . . . . . 76
5.3 Exotic Stuff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.3.1 Dark Matter - Cold and Hot . . . . . . . . . . . . . . . . . . . 79
5.3.2 Dark matter candidates - WIMPS, MACHOS, and Black Holes 82
5.4 Weird stuff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
5.4.1 The cosmological constant - _ . . . . . . . . . . . . . . . . . . 83
5.4.2 Quintessence . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.5 Cutouts and leftovers . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 6 What underlying Forces shape the Universe? 87
6.1 The four forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
6.2 What are forces and fields . . . . . . . . . . . . . . . . . . . . . . . . 88
6.3 Forces in Newtonian mechanics . . . 1 . . . . . . . . . . . . . . . . . . 88
6.4 Electromagnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.5 The other forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.6 Gravity . .
About the Author: David R. Matravers is Professor Emeritus at the Institute of Cosmology and Gravitation at the University of Portsmouth.
Karim A. Malik is Director of the Astronomy Unit at Queen Mary University of London and Reader in Theoretical Cosmology.
Their research interests include all aspects of theoretical cosmology, such as the physics of the early universe, the formation of the Cosmic Microwave Background and the large scale structure of the universe.
