I Space-Time, Light and the aether 1
1 What is (Special) Relativity? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.1 Principle of Relativity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 Time, a 4th coordinate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.3 Path toward Lorentz coordinate transformations . . . . . . . . . . . . . . 101.4 Highlights: How did relativity happen? . . . . . . . . . . . . . . . . . . . 13
2 Light and the aether . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152.1 Measuring space and time: SI unit system . . . . . . . . . . . . . . . . . . 152.2 Speed of light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172.3 Essay: aether and Special Relativity . . . . . . . . . . . . . . . . . . . . . 25
3 Material Bodies in SR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333.1 The Michelson-Morley Experiment . . . . . . . . . . . . . . . . . . . . . . 333.2 Body contraction and time dilation . . . . . . . . . . . . . . . . . . . . . . 363.3 Is the Lorentz-FitzGerald body contraction measurable? . . . . . . . . . . 383.4 Experiments require understanding of body contraction . . . . . . . . . . 403.5 Resolving misunderstandings of SR . . . . . . . . . . . . . . . . . . . . . . 42
II Time Dilation, and Lorentz-Fitzgerald Body Contraction 47

4 Time Dilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494.1 Proper time of a traveler . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494.2 Relativistic light-clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524.3 Talking about time (dilation) . . . . . . . . . . . . . . . . . . . . . . . . . 56
5 The Lorentz-FitzGerald Body Contraction . . . . . . . . . . . . . . . . . . . . . . 615.1 Light-clock moving parallel to light path . . . . . . . . . . . . . . . . . . . 615.2 Body contraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 635.3 Arbitrary orientation of the light clock . . . . . . . . . . . . . . . . . . . . 66
III The Lorentz Transformation 73
6 Relativistic Coordinate Transformation . . . . . . . . . . . . . . . . . . . . . . . 756.1 Derivation of the Lorentz coordinate transformation . . . . . . . . . . . . 756.2 Explicit form of the Lorentz transformation . . . . . . . . . . . . . . . . . 796.3 The nonrelativistic Galilean limit . . . . . . . . . . . . . . . . . . . . . . . 846.4 The inverse Lorentz coordinate transformation . . . . . . . . . . . . . . . 85
7 Some Consequences of Lorentz Transformation . . . . . . . . . . . . . . . . . . . 887.1 Invariance of proper time . . . . . . . . . . . . . . . . . . . . . . . . . . . 887.2 Relativistic addition of velocities . . . . . . . . . . . . . . . . . . . . . . . 927.3 Two Lorentz coordinate transformations in sequence . . . . . . . . . . . . 997.4 Rapidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
IV Measurement 111
8 Time Measurement and Lorentz Transformation . . . . . . . . . . . . . . . . . . 1138.1 Graphic representation of Lorentz Transformation . . . . . . . . . . . . . 1138.2 Time dilation and simultaneity . . . . . . . . . . . . . . . . . . . . . . . . 114
9 Methods of Measuring Spatial Separation . . . . . . . . . . . . . . . . . . . . . . 1199.1 Introductory remarks . . . . . . . . . . . . . . . . . . .
About the Author:

Johann Rafelski is a theoretical physicist working at The University of Arizona in Tucson, USA. Born in Kraków, Poland in 1950, he received his Ph.D. with Walter Greiner at Johann Wolfgang Goethe University, Frankfurt, Germany in 1973. In 1977 Rafelski arrived at CERN-Geneva, where with Rolf Hagedorn he developed the search for quark-gluon plasma in relativistic heavy ion collision as a novel research domain. He invented and developed the strangeness quark flavor as the signature of quark-gluon plasma, advancing the discovery of this new phase of primordial matter. Professor Rafelski teaches Relativity, Quantum, Particle and Nuclear Physics; in addition to CERN and Arizona, he also has held professional appointments at the University of Pennsylvania in Philadelphia, Argonne National Laboratory in Chicago, the University of Frankfurt, the University of Cape Town, the University of Paris-Jussieu, and the Ecole Polytechnique. He has been a DFG Excellence Initiative Professor at Ludwig-Maximillian University Munich. In collaboration with researchers from the Ecole Polytechnique in Paris and ELI-Beamlines in Prague he is using ultra-intense lasers in nuclear and fundamental physics.