The Meaning of the Lightspeed on the Basis of Its Determinations
Numerical values of the speed of light in a vacuum pretty near to the recommended SI value for c0, have historically been determined by R(φ)mer, Bradley, Fizeau, and Foucault. c0 is so higher than any other speed usually encountered, that it could be taken as a limit without bothering classical mechanics. This value gains a fundamental role in the special relativity the-ory, whose foremost purpose is to harmonize electrodynamics and mechanics. Today, however, the observations of slow and fast light effects put the question whether to restrict the use of the term signal to those propagating at speeds less or equal than c0 only, and interpret the new observations as new phenomena, or relinquish the idea of a fixed numerical value of c0 at least as far as transmission and reception of signals and data are concerned. In this work, we briefly recall four classical determinations of the speed of light, and emphasize the details of the relevant experimental settings that might be amenable to alternative interpretations. The resulting analysis remarks that astronomical measurements carried out at the time shared none of current concerns of telecommunications. For the so-called Earth-bound measurements, c0 looks instead like a linear conversion factor, resembling e.g., parallel-to-serial conversions. We conclude that providing c0 with metric units is tantamount to conferring a structure to empty space, and that telecommunications could drop them without hindering further developments.
S.L.Vesely A.A.Vesely
I.T.B.-C.N.R.,Italy Via L.Anelli 13,Milano 20122,Italy
国际会议
Progress in Electromagnetics Research Symposium 2009(2009年电磁学研究新进展学术研讨会)(PIERS 2009)
北京
英文
219-225
2009-03-23（万方平台首次上网日期，不代表论文的发表时间）