## Description

A few decades ago, astronomy and particle physics started to merge in the common field of cosmology. The general public had always been more interested in the visible objects of astronomy than in invisible atoms, and probably met cosmology first in Steven Weinberg’s famous book The First Three Minutes. More recently Stephen Hawking’s A Brief History of Time has caused an avalanche of interest in this subject.

Although there are now many popular monographs on cosmology, there are so far no introductory textbooks at university undergraduate level. Chapters on cosmology can be found in introductory books on relativity or astronomy, but they cover only part of the subject. One reason may be that cosmology is explicitly cross-disciplinary, and therefore it does not occupy a prominent position in either physics or astronomy curricula.

At the University of Helsinki I decided to try to take advantage of the great interest in cosmology among the younger students, offering them a one-semester course about one year before their specialization started. Hence I could not count on much familiarity with quantum mechanics, general relativity, particle physics, astrophysics or statistical mechanics. At this level, there are courses with the generic name of Structure of Matter dealing with Lorentz transformations and the basic concepts of quantum mechanics. My course aimed at the same level. Its main constraint was that it had to be taught as a one-semester course, so that it would be accepted in physics and astronomy curricula. The present book is based on that course, given three times to physics and astronomy students in Helsinki.

Of course there already exist good books on cosmology. The reader will in fact find many references to such books, which have been an invaluable source of information to me. The problem is only that they address a postgraduate audience that intends to specialize in cosmology research. My readers will have to turn to these books later when they have mastered all the professional skills of physics and mathematics.

In this book I am not attempting to teach basic physics to astronomers. They will need much more. I am trying to teach just enough physics to be able to explain the main ideas in cosmology without too much hand-waving. I have tried to avoid the other extreme, practised by some of my particle physics colleagues, of writing books on cosmology with the obvious intent of making particle physicists out of every theoretical

astronomer

Contents

1 From Newton to Hubble

2 Special Relativity

3 General Relativity

4 Tests of General Relativity

5 Cosmological Models

6 Thermal History of the Universe

7 Cosmic Inflation

8 Cosmic Microwave Background

9 Dark Matter

10 Cosmic Structures

11 Dark Energy

12 Epilogue