cmsj@ihuxm.UUCP (11/04/83)
In an effort to shed some facts on the continuing debate over whether the speed of light has changed through time, I offer the following information (gleaned from my 1st year college Physics text - Resnick and Halliday). Date Experimenter Method Speed Uncertainty (* 10**8 m/sec) (* 10**5 m/sec) 1600(?) Galileo Lanterns "If not instantaneous, it is extraordinarily rapid" 1675 Roemer Astronomical 2 unknown 1729 Bradley Astronomical 3.04 unknown 1849 Fizeau Toothed wheel 3.133 unknown 1862 Foucault Rotating mirror 2.98 5 1876 Cornu Toothed wheel 2.9999 2 1880 Michelson Rotating mirror 2.9991 .5 1883 Newcomb " " 2.9986 .3 1883 Michelson " " 2.99853 .6 1906 Rosa & Dorsey E&M Theory 2.99781 .1 1923 Mercier Standing waves 2.99782 .15 1926 Michelson Rotating mirror 2.99796 .04 1928 Karolus et al Kerr Cell 2.99778 .10 1932 Michelson et al Rotating mirror 2.99774 .11 1940 Huettel Kerr Cell 2.99768 .10 1941 Anderson Kerr Cell 2.99776 .14 1950 Essen Microwaves 2.997925 .03 1950 Bergstrand Geodimeter 2.997927 .0025 1950 Houston Vibrating Crystal 2.99775 .09 1950 Bol et al Microwaves 2.997893 .004 1951 Aslakson Shoran radar 2.998942 .019 1952 Rank et al Molecular Spectra 2.99776 .07 1952 Froome Microwave Interferometer 2.997926 .007 1954 Florman Radio Interferometer 2.997951 .031 1954 Rank et al Molecular Spectra 2.997898 .030 1956 Edge Geodimeter 2.997929 .002 ---------------------------------------------------------------- I assume full responsibility for any typographical errors introduced during my transcription from the aforementioned text. I would appreciate hearing from anyone who finds any errors in the table. And now, one editorial remark, if I may: Is it the speed of light that changes with time or is it our capability of measuring the speed of light that changes with time. I personally suspect that the latter is true. Chris Jachcinski *!ihnp4!ihuxm!cmsj