1. ** ^  ** See   "Google Scholar 'luminiferous ether'  "  .
2. ** ^  ** The 19th century science book _ A Guide to the Scientific Knowledge of Things Familiar  _ provides a brief summary of scientific thinking in this field at the time.
3. ** ^  ** Robert Boyle, _The Works of the Honourable Robert Boyle_ , ed. Thomas Birch, 2nd edn., 6 vols. (London, 1772), III, 316; quoted in E. A. Burtt, _The Metaphysical Foundations of Modern Science_ (Garden City, New York: Doubleday & Company, 1954), 191–192.
4. ** ^  ** Edwin Arthur Burtt (2003).  _The Metaphysical Foundations of Modern Science_  (illustrated, unabridged, reprinted ed.). Courier Corporation. p. 270.  ISBN  "ISBN \(identifier\)")  978-0-486-42551-1   .   Extract of page 270 
5. ** ^  ** Cesar A. Sciammarella; Federico M. Sciammarella (2012).  _Experimental Mechanics of Solids_  . John Wiley & Sons. p. 146.  ISBN  "ISBN \(identifier\)")  978-1-119-97009-5   .   Extract of page 146 
6. ** ^  **  Gillispie, Charles Coulston  (1960).  _The Edge of Objectivity: An Essay in the History of Scientific Ideas_  . Princeton University Press. p.  408  .  ISBN  "ISBN \(identifier\)")  0-691-02350-6   .
7. ** ^  ** Schwartz, Melvin (1987). _Principles of Electrodynamics_ (Revised ed.). Dover Publications, Inc. pp. 106–107.  ISBN  "ISBN \(identifier\)")  978-0-486-65493-5   .
8. ** ^  ** Nichols, Edward L. (November 1904).  "The Fundamental Concepts of Physical Science"  . _Popular Science Monthly_ . **66** .
9. ** ^  ** Yousef, Mohamed Haj (2018-01-01).  _Duality of Time: Complex-Time Geometry and Perpetual Creation of Space_  . Mohamed Haj Yousef.  ISBN  "ISBN \(identifier\)")  978-1-5395-7920-5   .
10. ** ^  **  "Selected Papers of Great American Physicists"  (PDF)  . _www.aip.org_ .  Archived  (PDF)  from the original on 15 July 2015  . Retrieved  30 April  2018  .
11. ** ^  ** They commented in a footnote: "From [the Michelson–Morley] experiment it is not inferred that the velocity of the earth is but a few kilometers per second, but rather that the dimensions of the apparatus vary very nearly as required by relativity. From the present experiment we similarly infer that the frequency of light varies conformably to the theory."
12. ** ^  ** The confusion over this point can be seen in Sagnac's conclusion that "in the ambient space, light is propagated with a velocity V0, independent of the movement as a whole of the luminous source O and the optical system. That is a property of space which experimentally characterizes the luminiferous aether." The invariance of light speed, independent of the movement of the source, is also one of the two fundamental principles of special relativity.
13. ** ^  ** Roberts, Schleif (2006); Physics FAQ:  Experiments that Apparently are NOT Consistent with SR/GR   Archived  2009-10-15 at the  Wayback Machine 
14. ** ^  ** Lorentz wrote: "One cannot deny to the bearer of these properties a certain substantiality, and if so, then one may, in all modesty, call true time the time measured by clocks which are fixed in this medium, and consider simultaneity as a primary concept." However, he went on to say that this was based on his conception of "infinite velocity", which according to his own theory is not physically realizable. Lorentz also admitted that the postulate of an absolute but undetectable rest frame was purely metaphysical, and had no empirical consequences.
15. ** ^  **  "Einstein: Ether and Relativity"  . _Maths History_ . Retrieved  7 August  2023  .
16. ** ^  ** Dirac wrote about his theory: "We have now the velocity at all points of space-time, playing a fundamental part in electrodynamics. It is natural to regard it as the velocity of some real physical thing. Thus with the new theory of electrodynamics we are rather forced to have an aether."
17. ** ^  **  "Dr Charles Kenneth Thornhill"  . _etherphysics.net_ . Retrieved  7 August  2023  .
18. ** ^  ** Isaacson, Walter (2007).   _Einstein: His life and Universe_  . New York: Simon & Schuster. pp.  47  –48.
19. ** ^  ** Albert Einstein's 'First' Paper (1894 or 1895),  http://www.straco.ch/papers/Einstein%20First%20Paper.pdf   Archived  2020-07-27 at the  Wayback Machine 
20. ** ^  ** Einstein 1920: _We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an aether. According to the general theory of relativity space without aether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this aether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it._