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The Restless universe
Introduction to The restless Universe

intro 1/2

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1 The lawful Universe

2 The clockwork Universe

3 The irreversible Universe

4 The intangible Universe

5 The uncertain Universe

6 Closing items

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Other titles in the Physical World series

Describing motion

Predicting motion

Classical physics of matter

Static fields and potentials

Dynamic fields and waves

Quantum physics: an introduction

Quantum physics of matter

Introduction to The restless Universe

(Title 1 in the Physical World series)

Part 1 of 2 | Part 2 of 2

Do not expect to understand everything you read in this site. On the surface, we hope that it provides a coherent and interesting survey. But the more you think about some of the issues raised, the more puzzling they may seem. If, at the end of the book, you are left with questions as well as answers, that will be an excellent starting point for the rest of the course.

As the course progresses, we will introduce the units in which physical quantities are generally measured. For example, time is measured in seconds, length in metres, energy in joules and electric current in amperes.

A detailed understanding of these units is not needed yet, and would make a rather dull start to the course. In the few places where units appear in this book, please skip past them if the meaning is unclear.

A note on powers of ten and significant figures

Many physical quantities span vast ranges of magnitude. Figures 0.1 and 0.2 use images to indicate the range of lengths and times that are of importance in physics.
figure 0.1, Snapshots of the Universe at a selection of length scales
Figure 0.1 Snapshots of the Universe at a selection of length scales from the smallest to the largest scale.
Click here for larger image (38.26kb)
figure 0.2, A range of time scales of relevance to the UniverseFigure 0.2 A range of time scales of relevance to the Universe. Time is measured in billions ofyears since the Big Bang. The evolution of the Universe is marked by the onset of various ages: from the appearance of particles and galaxies to the emergence of life and intelligence.
Click here for larger image (27.36kb)

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A note on powers of ten and significant figures

Some highlights of physics

Featured Physicists

Suggestions for further reading

Questions, answers and comments

Acknowledgements

Index

S207 The Physical World
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